John M. Giurini, DPM, FACFAS

• Associate Professor of Surgery
• Harvard Medical School
• Chief of Podiatric Surgery
• Department of Surgery
• Beth Israel Deaconess Medical Center
• Boston, Massachusetts

The drug competitively inhibits aldosterone at the distal tubule and thus reduces potassium loss m the unne hair loss cure 4 hunger purchase 1 mg finpecia free shipping. The diuretic effect of spironolactone is relatively weak compared with the loop or thiazide diuretics zinc cure hair loss best finpecia 1mg. In most cases hair loss icd-9 quality 1mg finpecia, it is used in combination with either furosemide or hydrochlorothiazide predominantly for its potassium-sparing effects hair loss on arms discount 1mg finpecia overnight delivery. The major adverse effect of spironolactone is hyperkalemia hair loss cure news 2015 buy finpecia 1 mg line, which hair loss in men young order finpecia 1mg overnight delivery, in most patients, is not a significant problem in the absence of excessive potassium intake. Similarly, if coadministration of a potassium supplement is necessary, serum potassium levels should be monitored carefully. The selection of a specific drug depends upon the primary goal of therapy, underlying or associated conditions, and whether or not the treatment is acute or chronic in nature. One approach to classifying vasodilators groups the drug classes according to their major mechanism of action (Table 79. Another method is to group drugs according to their predominant site of action (predominately venous, arteriolar, or balanced; Table 79. Depending on the therapeutic goals, one may select an agent that has predominant effects on venous capacitance, arteriolar resistance, or both. Thiazide Diuretics Thiazides inhibit sodium and chloride transport in the distal convoluted tubule of the nephron. Thiazide diuretics have been available for many years and there is broad experience with these agents. Hydrochlorothiazide and chlorothiazide are the primary drugs in this class used in children with cardiovascular disease. In this situation, they may be used in combination with a loop diuretic and/or a potassiumsparing agent. Adverse effects of thiazides include hypokalemia, hyperuricemia, and hypercalcemia. Nonrenal effects of thiazide diuretics that have been described in older patients and adults include carbohydrate intolerance and adverse effects on plasma cholesterol and triglycerides. The extent and implications of potential disturbances in cholesterol, lipoproteins, and triglycerides have not been determined in young children. Nitric Oxide-Modifying Drugs Relaxation of vascular smooth muscle by drugs in this class is mediated by nitric oxide. It exhibits several thiazide properties although it does not have a classic thiazide structure. Nitroglycerin Nitroglycerin relaxes smooth muscle in the cardiovascular, respiratory, and gastrointestinal systems. At the usual therapeutic concentrations, the predominant site of action is the venous vascular bed. Nitroglycerin has been largely replaced by other agents, but is sometimes administered after cardiac surgery. At low doses, there is little effect on systemic vascular resistance, systemic arterial pressure, or heart rate. However, higher doses can produce arteriolar dilation with hypotension and reflex tachycardia. Patients with decreased intravascular volume (low preload) may respond adversely to nitroglycerin because a further decline in filling pressure may significantly reduce cardiac output. Overdose causes hypotension and tachycardia, which respond quickly to a reduction in dose or cessation of the infusion. Inhibition of this phosphodiesterase results in pulmonary vasodilation and will also increase the efficacy of inhaled nitric oxide (48,68,69). Orally administered sildenafil has been shown to be effective in treating persistent pulmonary hypertension in newborns and is well tolerated. The primary use of sildenafil in children with cardiac disease is for patients with acute or chronic pulmonary hypertension following cardiac surgery. Nitroprusside is occasionally administered to pediatric cardiac surgical patients in the immediate postoperative period. In addition, it may be effective acutely in children with left ventricular dysfunction and low cardiac output. The major adverse effects of nitroprusside are a direct extension of its powerful vasodilator activity. Due to limited stability and photodegradation, nitroprusside solutions must be freshly prepared before use and protected from light. Phentolamine is a competitive nonselective antagonist of a-adrenergic receptors that blocks a1- and az-receptors. Blockade of presynaptic az-adrenergic receptors may contribute to the tachycardia and arrhythmias that occur at high doses of phentolamine. Administration of phentolamine to patients with low cardiac output produces a decrease in systemic vascular resistance with a resultant increase in cardiac output. Although phentolamine is classified as a mixed vasodilator, the effects on venous capacitance are minimal compared with other mixed vasodilators. Newborns are more sensitive to the negative inotropic effects of calcium channel blockers than are older children, and intravenous administration of calcium channel blockers in infants has been associated with cardiovascular collapse. Calcium channel antagonists are categorized into three major chemical classes: phenylalkylamines. Drugs of the dihydropyridine class exhibit the most pronounced vasodilation and should be selected if that is the primary goal of therapy. In young infants, nifedipine is used primarily to treat pulmonary hypertension associated Pulmonary Vasodilators Nitric Oxide Nitric oxide is a gas that is administered via inhalation. Nitric oxide plays a central role in the management of infants with persistent pulmonary hypertension of the newborn (66,67). This agent is also beneficial in the perioperative period for infants and children with pulmonary arterial hypertension associated with congenital heart disease (48). Enalapril and Lisinopril the mechanism of action, hemodynamics, and clinical indications for enalapril and lisinopril are similar to those described above for captopril. Enalapril and lisinopril can be administered once daily, which may improve compliance compared to captopril. However, based on theoretical considerations and results obtained from clinical trials in adults, these agents may prove to be useful in the pediatric population. This effect has been shown experimentally to be beneficial in animal models of muscular dystrophy and connective tissue disorders (73,74). Use of these agents in pediatric patients with connective tissue disease such as Marfan and Loeys-Dietz syndromes and Duchenne muscular dystrophy is a subject of current investigation. Mild-to-moderate diuresis may occur because of increased renal blood flow and reduced aldosterone formation. Captopril is administered orally and peak plasma concentrations generally occur 1 to 2 hours after a single oral dose. Approximately 50% is excreted in the urine unchanged, and thus, captopril plasma clearance is reduced in patients with impaired renal function. Captopril is used for the treatment of systemic hypertension and congestive heart failure in infants, children, and adolescents. Less serious reactions include rash, taste impairment, and minor gastrointestinal disturbances. In general, potassium supplements and potassium-sparing diuretics should not be administered concomitantly to patients receiving captopril because of the risk of hyperkalemia. Aldosterone plays an important role in promoting the abnormal collagen production and interstitial fibrosis that occurs in chronic heart failure. Administration of aldosterone antagonists, such as spironolactone or eplerenone, to adult patients with heart failure treated with conventional therapy results in increased diuresis and symptomatic improvement (72,75). It is administered intravenously and produces vasodilation, increases glomerular filtration rate, inhibits renal sodium reabsorption, and promotes diuresis. Despite considerable investigation in the adult population, the role and efficacy of nesiritide is controversial. Several studies in children suggest nesiritide may increase urine output and reduce levels of neurohormonal markers of heart failure. Some centers use nesiritide acutely for infants with low cardiac output following cardiac surgery and for infants with severely depressed cardiac function due to cardiomyopathy (48,76,77). Furthermore, individual drugs differ with regard to the degree of important ancillary properties such as a-adrenergic receptor blockade, antioxidant activity, and intrinsic sympathomimetic activity (81,82). Because of these important differences, the various j3-blockers are not interchangeable. These changes in thyroid hormone levels are referred to as "non-thyroidal illness syndrome" and generally have not been thought to represent true hypothyroidism. Some centers administer either thyroxine or triiodothyronine in the postoperative period if thyroid-stimulating hormone is elevated, circulating thyroid hormone levels are reduced, and the child has evidence of low cardiac output (78). However, relatively little published information exists regarding the safety, efficacy, and longterm effects of thyroid hormone administration to children in the early postcardiac surgery period. Propranolol Propranolol was the first commercially available f3-adrenergic blocker in the United States, and consequently, this is the drug in this class with the most widely published experience in pediatrics. Propranolol is available for oral or intravenous administration, but if intravenous f3-blockertherapy is necessary, the short-acting f3-adrenergic blocker, esmolol (see below) should be used because of the risk of hypotension and bradycardia from the intravenous administration of propranolol. In the past, it was sometimes used in an attempt to reduce the frequency and severity of hypercyanotic episodes in infants with tetralogy of Failor. Presently, most patients undergo surgical correction or palliation if hypercyanotic episodes occur. Propranolol is well absorbed after an oral dose, although it undergoes extensive first-past hepatic metabolism that reduces the bioavailability to approximately 30% to 40%. Classdependent effects of f3-adrenergic blockers include depression of contractility, atrioventricular block, bronchospasm, and sleep disturbances. Blood glucose should be monitored in infants receiving propranolol (or other f3-adrenergic receptor blockers) who are unable to feed normally. The first line of therapy in this setting is infusion of catecholamines such as dopamine or norepinephrine. However, shock persists in some infants and children despite maximal supportive therapy. In contrast to catecholamines, the responses to vasopressin are preserved in the presence of acidosis or hypoxia. Based on results from studies demonstrating a beneficial effect of vasopressin infusion in patients with vasodilatory septic shock, several investigators have administered vasopressin to infants with vasodilatory shock following cardiopulmonary bypass (79,80). However, additional Esmolol Esmolol is a f31-selective adrenergic blocker with a short plasma half-life (-5 to 10 minutes). The major difference is that because of its rapid plasma clearance (and short elimination half-life), esmolol is administered by continuous intravenous infusion that can be easily titrated. Thus, the use of a central venous (umbilical venous) catheter is recommended whenever possible. Although the intravenous route is preferred, it can be given vra an umbilical arterial catheter. Additional side effects include fever, irritability, edema, and cutaneous flushing. Metoprolol is more lipid soluble than atenolol and has greater passage across the blood-brain barrier as compared to atenolol. Metoprolol is metabolized more rapidly than atenolol and has a shorter plasma elimmatron half-life, Extended release preparations of metoprolol are available but are difficult to use in infants and small children consequent to inflexibility in the dosage form to permit weightbased. Atenolol has the advantage of requirmg only once or twice daily administration because of a longer elimination half-life (8 to 10 hours). Flexibility in oral dosing of atenolol for young mfants and children can be achieved via the extemporaneous formulation of a liquid preparation. In addition it exhibits antioxidant, anti-inflammatory, and antiapoptotic activrnes, Results from a randomized controlled trial of carvedilol therapy in children with heart failure failed to show a beneficial effect of the drug on a composite measure of heart failure outcomes (83). However, event rates were lower than expected, the study population was heterogeneous, and the trial may have been underpowered. Furthermore, the improvement rate among placebo-treated patients was higher than predicted, and trough carvedilol concentrations in the blood were lower than expected (based on adult studies). Additional studies are necessary to define the potential role of carvedilol (and other. Early treatment can be lifesaving and conversely, withholding therapy can be disastrous if the ductus arteriosus closes in a patient with a ductus-dependent defect. Pharmacokinetics differ in infants compared to older children, and developmental changes in ion channels and the autonomic nervous system affect the responses to these agents. Despite these considerations, there is a paucity of information in young children from prospective trials and therapeutic approaches are extrapolated from studies in adults. Several antiarrhythmic agents are available, but only the most commonly used drugs in the pediatric population are presented in this chapter. Children receiving antiarrhythmic agents must be monitored carefully because many of these agents have variable potential to produce arrhythmias. For those agents with defined serum concentration-effect profiles, therapeutic drug monitoring is recommended during their use to facilitate safe and effective treatment. It should be noted that while pro arrhythmic effects are likely to occur soon after initiation of treatment, late effects for most drugs have been reported. The Vaughan Williams classification of antiarrhythmic medications describes antiarrhythmic actions and is used traditionally (84). However, the therapeutic utility of this classification scheme is somewhat limited from a clinical standpoint because several drugs have more than one effect, antiarrhythmic actions do not always correlate with efficacy, and some useful agents such as adenosine do not fit into this classification (85). Class I Agents A common feature of Class I antiarrhythmic agents is blockade of sodium channels. While oral administration is common for chronic use of procainamide in adults, the drug is usually administered by the intravenous route in pediatric patients with careful monitoring of infusion-related hypotension. The risk of proarrhythmia, especially torsade de pointes, is moderate and not related to serum drug concentrations.

Diseases

• Radio-ulnar synostosis type 2
• Epidermolysis bullosa, pretibial
• Chondrodysplasia punctata, Sheffield type
• Epidermodysplasia verruciformis
• Ruvalcaba Myhre syndrome
• Chromosome 20 Chromosome 22

With the sample volume positioned in the transverse arch hair loss cure timeline cheap finpecia 1mg mastercard, retrograde systolic flow (arrows) from the patent ductus arteriosus into the aorta is identified hair loss 46 year old female cheap finpecia american express, consistent with ductaldependent systemic circulation hair loss meme order cheap finpecia on-line. The organs in the splanchnic circulation are the first to suffer ischemic injury because sympathetic outflow and innervation is rich in these regions (135 hair loss testosterone discount 1mg finpecia fast delivery,149-152) and because of the selective effects of angiotensin (153 hair loss icd-9 buy finpecia amex,154) curezone hair loss buy cheap finpecia on line. Ischemic organ damage may occur even in the presence of normal global oxygen economy if regional vascular resistance is sufficiently elevated (133,134,155-157). There now exists compelling evidence that splanchnic/mesenteric ischemia is a frequent common pathway for multisystem organ dysfunction and death (158-161), and regional cellular oxygen deficit is underrecognized, underdiagnosed, and undertreated (162). Strategies targeting earlier detection and treatment of shock could improve outcome, with greater impact in populations with higher baseline mortality risk (163). Oxygen Flux in Single-Ventricle Parallel Circulation With univentricular parallel anatomy, both the pulmonary circulation and the systemic circulation are fed by arterial blood that is only partially saturated with oxygen. If Sa02 is >75%, a higher Qp is necessary to maintain the same pulmonary O2 uptake; conversely if Qp falls, Sa02 will also fall. If the Sa02 is low, then a higher Qs is necessary to maintain systemic O2 uptake; if Qs falls, then Sa02 also falls. Changes in Sa02 result in opposite effects on pulmonary and systemic oxygen economy. Conversely, since a tradeoff of Qs and Qp will exist for any Qt, increases in Sa02 that are not a result of increased Qt will be offset by a reduction in Qs. As a result, moderate alterations in Qp/Qs balance will have minimal effect on D02; more effectively, alterable determinants of D02 include hemoglobin and Qt. Oxygen economy at higher or lower Qp/Qs and varying Qt is illustrated in Table 48. Thus matching ofD02 to changes in V02 are more effectivevia interventions in total cardiac output or hemoglobin concentration than by precise manipulation of Qp/Qs balance. An important limitation in circulatory reserve resulting from this complex relationship is that increases in systemic oxygen consumption cannot be buffered by increased extraction (166). In a patient with normal in-series circulation, at constant cardiac output, increased V02 will reduce Sv02, but pulmonary oxygen uptake will increase to match. In the critically ill patient, tissue oxygen utilization will usually continue until the Sv02 falls to <50%; thus, a doubling of V02 can be met without an increase in cardiac output. Since normal lungs can fully oxygenate fully de saturated systemic venous blood, the resulting. Sa02 is unchanged, D02 is maintained, and the increased V02 can be met by increased extraction alone. Similarly, cellular oxygen utilization can be maintained during a reduction in cardiac output and D02 by increased extraction. In a patient with univentricular parallel circulation, increased oxygen extraction (either because of increased V02 or decreased D02) will reduce Sv02 and Sa02. The result is that conditions that increase oxygen extraction will also decrease oxygen delivery through a reduction in Sa02. For any given fall in cardiac output, D02 and Sv02 will be disproportionately reduced, because Sa02 will also fall. Thus, changes in oxygen supply and demand are interdependent and destabilizing in the patient with parallel univentricular physiology. Generalization of this approach was based on circulatory models that assumed either a constant arteriovenous oxygen difference (of typically 25%) or a constant mixed Sv02 (of typically 50%). In either model, an Sa02 of 75% would then result from mixing equal parts of systemic venous and (fully saturated) pulmonary venous blood; deviations of Sa02 from 75% in these models would result from, and be diagnostic of, deviations of Qp/Qs from 1. Under these conditions, systemic oxygen delivery generally increases as Sa02 approaches 75% to 80% and falls at higher saturation owing to increasing Qp/Qs imbalance, However, in the perioperative period, total cardiac output and metabolic demand may frequently be mismatched as a result of the inherent instability of parallel circulation as described above, and variability of Qp/Qs, Qt, and V02 (168-170). The range of s-o, at any given Sa O, is shown in a model with variable total cardiac output and bounded by Qp/Qs as low as 0. The slope of the Sa02-Sv02 relationship, as total cardiac output changes, is determined by the Qp/Qs ratio. As part of this approach, the SaO, was used as a key indicator to detect pulmonary overcirculation, which would result in a higher Sa O, as Qp/Qs rose. However, this would be true only if the systemic arteriovenous difference did not increase, which would occur only if the increase in Qp resulted from increased Qt at constant Qs. Preoperatively, these approaches may be partially effective in limiting pulmonary overcirculation, but only hypercapnia increases systemic oxygen delivery (175). Reduction of fiOz may cause the resulting alveolar oxygen tension to be inadequate to fully oxygenate the pulmonary capillary blood, an effect that may be common at fiOz < 0. Thus, reduction in Sa02 by intentionally limiting fiOz may result solely from pulmonary capillary desaturation rather than reductions in Qp. Unless SpvOz is measured or fiOz is high enough to make pulmonary capillary desaturation unlikely, the calculated Qp/Qs at low fi02 may be falsely low because of Spv02 < 95%. Because of variability in both SpvOz and the arteriovenous saturation difference, the Sa02 does not reliably characterize the parallel circulation. In these studies, the Qp/Qs range could be restricted by placement of a resistive shunt, and the importance of shunt size was emphasized. These models also demonstrated that the combination of low total cardiac output and high Qp/Qs severely impaired systemic oxygen delivery. Not surprisingly, peri operative management based primarily on optimization of Sa02 is associated with an early mortality of >20%. With this approach, cardiovascular collapse and mortality typically result from an acute hemodynamic event that occurs unexpectedly in an apparently stable postoperative hemodynamic setting (73,179,180). This above analysis provides an explanation for the profound circulatory derangements that are possible despite having Sa02 in the typical target range. These theoretical and actual limitations have led to the development of management strategies aided by SvOz measurement to more closely assess Qp/Qs, adequacy of oxygen delivery, and whole-body oxygen economy. The use of continuous SvO, has greatly reduced the perioperative occurrence of sudden unexpected circulatory collapse (73,179,182). A life-threatening hemodynamic deterioration is clearly shown with Sv02 monitoring despite Sa02 in the 75% to 80% range. An initial deterioration in Sv02 (arrow a) was partially corrected with additional analgesia (arrow b) but did not prevent a subsequent critical deterioration in systemic oxygen delivery (arrow e), which was effectively treated with a combination of additional analgesia/anesthesia and increased inotropic and vasodilator infusions. Conventional parameters (arterial blood pressure and Sa02) show only subtle changes that provide neither an early warning of the critical situation nor feedback about the effectivenessof corrective measures. Given the instability of oxygen supply/demand relationships, and the inadequacy of assessment based on arterial blood pressure and Sa02 monitoring, improved outcome requires early detection and treatment of deficiencies in oxygen economy. Direct or surrogate measurement of Sv02 permits continuous assessment of adequacy of systemic oxygen delivery in the most vulnerable postoperative period. Although ductal closure is rarely immediate, nearly all infants will have physiologic closure of the ductus arteriosus by the fourth day of life; 20% of infants will demonstrate functional ductal closure during the first day of life, and >80% of infants demonstrate ductal closure during the second day of life. For patients who present in shock with suspected ductal closure or a restrictive duct, initial dosing will range from 0. Once ductal patency is ensured, the infusion rate can be decreased to an effective dose as low as 0. Two-site nearinfrared transcutaneous oximetry as a non-invasive indicator of mixed venous oxygen saturation in cardiac neonates. Anesthesiology 2003;97:A1393) 5 to 10 mg/kg/day has been effective in reducing the need for mechanical ventilation preoperatively. Patients who received aminophylline had a decreased incidence of apnea and did not require intubation when compared with the placebo group of whom 35% required intubation (198). Furthermore, whereas hypercarbia improved cerebral oxygenation, hypoxia provided no benefit to cerebral saturation (201). Patients with restrictive atrial communication also necessitate supplemental oxygen administration. In patients who have severely restrictive or absent atrial septal defect, supplemental oxygen and other medical therapies are ineffective in treating the severe arterial desaturation, prompting emergency intervention with balloon atrial septostomy, atrial septal balloon dilation and/or stent, surgical septectomy, or immediate stage 1 palliation. Vasoactive Medications the need for preoperative inotropic support is variable and directed by clinical presentation and echocardiographic features. Patients who present in cardiogenic shock most commonly benefit from inotropic support as do patients with significantly reduced right ventricular function. For those patients in whom Qp/Qs is elevated and systemic perfusion is compromised, inodilator therapy with milrinone, a phosphodiesterase inhibitor, might be warranted. Furthermore, milrinone could result in significant hypotension in patients already at risk for decreased perfusion secondary to aortopulmonary runoff. Strategic monitoring and thoughtful assessment of these patients will be directed at these concerns. Respiratory Support and Inspired Gases In the preoperative patient without anatomic limitation to pulmonary blood flow, mechanical ventilation and medical gas manipulation of pulmonary arteriolar resistance are sometimes necessary and beneficial. Controlled positive-pressure ventilation with care taken to avoid hyperventilation can limit pulmonary blood flow. Clinical experience supports the use of hypoxia as a means to attenuate an elevated Qp/Qs (173,200). Hypoxic gas mixtures are achieved through blending nitrogen and oxygen to achieve inspired subatmospheric fi02 of 0. The use of inspired gases in humans has been best studied in an acute model by Tabbutt et al. Although both strategies were successful in acutely Other Adjunctive Therapies the hypoxic patient with inefficient single-ventricle physiology benefits from increased oxygen carrying capacity. Other means to improve systemic perfusion include therapies that attenuate sympathetic vascular tone. For the term infant who is >2,500 g, our recommendations for fluid requirements during the first day of life are 70 to 80 mLlkg/day with escalation to 100 mLlkg/day on day of life three and then, 120 to 140 mLlkg/day for infants 4 days of age and older. The preterm infant requires more fluid due to higher transdermal insensible losses at a lower weight. Recognition of such physiologic necessities drove the development of numerous surgical approaches (202,203). Permutations of a staged surgical pathway that was successfully championed by Norwood et al. The staged approach ultimately leads the patient on a pathway to a single-ventricle in-series circulation, usually culminating in a Fontan operation with the final result similar to patients with tricuspid atresia and hypoplastic right heart syndrome (206). Stage 2 palliation unloads the single ventricle by replacing the systemic-to-pulmonary shunt with a superior cavopulmonary anastomosis (208). Stage 1 Palliation Surgical Approaches the goals of stage 1 palliation include relief of ductaldependent systemic flow, provision of unrestricted coronary artery flow, creation of a nonrestrictive atrial septal defect to prevent pulmonary venous hypertension, and provision of a reliable but restricted source of pulmonary blood flow. A connection is created between the smaller ascending aorta and the pulmonary root for provision of coronary blood flow. Variations in surgical techniques include resection of ductal tissue or co arc tecto my as opposed to patching of the region of ductal insertion. The aim of stage 1 palliation is to create a stable anatomy that permits growth and maturation of the pulmonary vasculature so that it can accommodate subsequent single-ventricle palliation. It is important that successful surgical strategies have a low incidence of recurrent or residual lesions because these are a source of interstage mortality and can limit suitability for single-ventricle palliation. Development of a restrictive atrial septal defect rarely complicates the inter stage course (215). The observation that smaller ascending aortic size and presence of aortic atresia are risk factors for mortality is an indication that coronary insufficiency is a cause of death following stage 1 palliation, and strategies that target creation of a large ascending aorta-to-pulmonary root anastomosis are likely to result in improved outcome (216-219). Arch reconstruction strategies that include coarctecto my appear to have a lower incidence of late arch obstruction (70,216). A modification of the systemic-to-pulmonary artery shunt developed by Blalock, Thomas, and Taussig has historically been the source of pulmonary blood flow following stage 1 palliation (220). Both the diameter and length of this shunt are relevant to determining its flow-resistive characteristics (176). Physiologic limitations result from the inherent Qp/Qs mismatch of the parallel circulation and diastolic aortic runoff to the pulmonary circulation with risk of aortocoronary flow impairment (221,222). Additionally, competition between cerebral and pulmonary circulations for blood flow is possible if the shunt originates from the innominate artery (183). Furthermore, the systemic-to-pulmonary artery shunt is susceptible to occlusion from thrombosis or thromboembolism (215,223). Use of this approach has also been reported in the rare neonate who cannot be stabilized by medical interventions because of excessive pulmonary blood flow (243). Intervention to provide a reliable atrial septal communication is also necessary and may include a balloon septostomy and/or stent placement within the atrial septum (245). The second-stage procedure combines aortic arch reconstruction and a superior cavopulmonary connection (191,212,213). Important shortcomings of hybrid palliation include the potential for retrograde arch obstruction that can result in cerebral and coronary ischemia (246,247). Anesthetic Management Trauma and surgical stress induce a neurohumoral and cytokine response, the magnitude of which is associated with organ dysfunction and death (249). Anesthetic techniques that reduce the magnitude of biologic markers of stress are associated with decreased mortality (250). Because of the extent of surgical trauma and the use of profound hypothermia with or without circulatory arrest, anesthetic techniques that use high doses of synthetic opioids to reduce the stress response and preserve the limited neonatal cardiac reserve are rational and associated with improved outcome (146,251). Kaplan-Meier curves for transplantation-free survival among all infants who underwent the Norwood procedure, according to the intention-to-treat analysis. Some patients may require dopamine at 2 to 5,ug/kg/min, or epinephrine or norepinephrine at 0. Afterload Reduction Anesthetic drugs alone cannot completely eliminate the stress response to profound hypothermia (146). As an alternative approach to obtain Qp/Qs balance, pharmacologic interruption of systemic vasoconstrictor responses using a-adrenergic blockade was popularized by Poirier et a1. Such an approach has been shown to increase systemic oxygen delivery (179) and is associated with improved survival (179,180). The importance of shunt size in limiting Qp/Qs extremes has been modeled, and smaller shunts make pulmonary overcirculation less likely (176). Treatment with phenoxybenzamine, a long-acting irreversible a-adrenergic receptor blocker, improved systemic oxygen delivery as signaled by SvOz (178,255).

In these cases hair loss in men quotes finpecia 1 mg sale, the defect incorporates a remnant of the membranous septum and is perimembranous (74) hair loss with menopause trusted 1mg finpecia. Its superior margin is usually formed by the deviated muscular outlet (or infundibular) septum hair loss cure for man 1mg finpecia with amex. Since deviation of the outlet septum is often easily appreciated by echo cardiography hair loss network cheap finpecia 1 mg fast delivery, identification of this anatomy is key to diagnosis hair loss icd-9 purchase finpecia us. By contrast hair loss cure november 2015 buy finpecia 1mg low price, the intracardiac anatomy is highly variable (78) and surgical planning for individual patients is facilitated by establishing the precise configuration of each of the cardinal anatomical components. The arrow points to point of fibrous connnuity between the leaflets of the aortic valve and the hypoplastic pulmonary valve. In each case, effort should be made to exclude additional muscular defects by imaging the ventricular septum with reduced Doppler color scale. The degree of aortic override varies significantly between 15% and 95% (83), a feature which has created some confusion. However, most authorities agree that, compared to normal, there is rightwards malposition and clockwise rotation of the aortic root (76,77,84-86). The degree of narrowing of the subpulmonary infundibulum is variable in extent and timing. A right-sided aortic arch may be diagnosed on plain chest x-ray by the absence of the expected left-sided aortic knuckle. By echocardiogram, a right aortic arch is best diagnosed from the suprasternal notch. To obtain a full arch image, the transducer must be rotated clockwise from the standard position, so that the marker faces away from the patient and the plane of ultrasound extends from the left border of the sternum to an area just right of the spine (l01). From this position, the first branch of a right aortic arch can be traced coursing leftward (in contrast to a left aortic arch where this vessel would course rightwards before bifurcating). A right-sided aortic arch may also be diagnosed by fetal echocardiography, when, in a transverse view, the "sausage-shaped" arch is located to the right of the trachea, rather than its usual left-sided position (102). A single coronary artery (more often from the left coronary sinus) is the second most frequent variant and occurs in ",1 % of patients (90). When a single coronary arises from the left sinus, it is the right branch that lies in a vulnerable position, whereas when the single coronary arises from the right sinus, it is the left branch that is vulnerable (94). Preoperative coronary angiography became routine and, if anomalies were suspected, corrective surgery was delayed until midchildhood by use of a palliative shunt procedure (93). For the majority of patients who have a reasonably sized pulmonary valve annulus, the now standard transatrial-transpulmonary approach (see below) can be used successfully, even in the presence of coronary artery anomalies (95). It is not always possible to directly identify anomalous coronaries at the time of surgery, so it is important that the coronary anatomy be delineated by careful preoperative echocardiography. Regardless of the formal classification, this variant has such marked variability in pulmonary blood supply, clinical presentation, and surgical management strategies that it warrants special consideration. In this textbook, this entity is described in detail in the Chapter 42 titled "Pulmonary Atresia and Ventricular Septal Defect," and is not discussed further here. Although use of the term is generally discouraged (because it is teleologically incorrect), this anatomy is sometimes known as a "hemitruncus. This variant is associated with significantly aneurysmal main and branch pulmonary arteries that may compromise the airways and respiratory function. The first description of this anomaly is attributed to Chevers (111) in 1847 and the first detailed case report was published in 1927 by Kurtz et al. This is almost always caused predominantly by a ring of tissue present at the level where the pulmonary valve leaflets would be expected, rather than by infundibular stenosis (113,114). The authors suggested that their findings might explain why some patients continue to experience respiratory problems, despite relief of compression of the main stem bronchus by surgical repair (114). Most are initially cyanotic, but this usually becomes less apparent during the first week of life (114). Although there is probably a spectrum of disease, general consensus divides patients into two groups: those who exhibit severe respiratory problems in early in life and those who do not. For severely affected infants, some clinical improvement may be gained by prone positioning, which allows the pulmonary arteries to fall forward and away from the bronchi. It is clear from early surgical series that infants who present with severe respiratory distress and require preoperative ventilation have the highest surgical mortality (119). The pulmonary arteries can be reduced by removal of tissue from either their anterior or posterior walls. Even after complete surgical repair with apparent relief of airway obstruction, patients may suffer long-term problems such as recurrent respiratory tract infection, wheezing, and reactive airways disease; some require reintervention for such symptoms (119). The median gestational age at diagnosis was 24 weeks, with 45% of cases diagnosed before 24 weeks. The authors reported that the presence of associated chromosomal abnormalities or severe extracardiac abnormalities were factors that determined parental choice (128). Cyanosis may be recognized at the time of delivery, during routine measurement of newborn oxygen saturation or perhaps only during episodes of crying. During hypercyanotic spells, which are often provoked by crying but then associated with a quite different frantic cry during the episode that is probably due to the pain of skeletal muscle and myocardial ischemia, the patient develops abruptly worsening cyanosis and breathlessness that may ultimately lead to loss of consciousness and, in severe untreated cases, death. The mechanism for cyanotic spells remains unknown but the previous assumption that they were related to "infundibular spasm" is difficult to reconcile with the lack of a "sphincter" function of the subpulmonary infundibulum and the frequent recognition of identical clinical features in those lacking a subpulmonary infundibulum. It is usually possible to diagnose a right-sided aortic arch from the chest x-ray by absence of the usual left-sided aortic knuckle, a bulge to the right of the upper mediastinum, and an impression to the right of the trachea (139). In unremitting cases, intravenous systemic vasoconstrictors, for example, phenylephrine (boluses of 0. Very occasionally, severe life-threatening spells may require emergent surgical intervention or mechanical circulatory support. In many centers, a move towards earlier corrective surgery has obviated the need for medical management in this condition. Those who develop heart failure usually derive some benefit from pharmacotherapy (141-143), and caloric supplementation with nasogastric tube feeds allows continued weight gain (144). In contrast, infants who develop episodic cyanosis during hypercyanotic spells usually do respond to medical therapy, both as prophylaxis and for acute treatment. Since most hypercyanotic spells are provoked, or worsened, by crying, the infant should be picked up and comforted as soon as an episode begins, ideally while being held in a position of flexed knees and hips that kinks or compresses the femoral arteries and increases peripheral systemic vascular resistance. Many groups consider their onset as an indication for surgical correction, but interval prophylaxis with beta-receptor antagonists (oral propranolol in a dose of 0. However, the procedure destroys the native pulmonary valve and so this technique should be reserved for the limited number of, usually very young, premature or small, infants in whom a transannular patch will almost certainly be necessary in any case, or in whom the pulmonary arteries are diminutive and would increase surgical mortality or morbidity (150). Taussig to the realization that infants with severe pulmonary stenosis and right heart hypoplasia died not, as was widely believed, from heart failure but because of the sudden cessation of pulmonary blood flow that occurred with closure of their arterial duct (151). Robert Gross and John Hubbard successfully ligated a persistently patent arterial duct (152), Taussig made the leap of imagination to think it "ought also to be possible to build one" (151). Subsequently (after she failed to interest Gross in the idea) she worked together with her surgical colleague in Baltimore, Dr. Denton Cooley, who at the time was a surgical intern present in the operating room, has provided a detailed description of this first procedure and an explanation of its significance in his 2010 "Reflections of the Pioneers" essay (154). Although these procedures proved useful in specific anatomical circumstances, their use never overtook that of the B-T-T shunt due to complications related to technical issues and pulmonary hypertension. Shaw survived to adulthood and had a successful career as a professional musician (168). Nevertheless, cross-circulation carried considerable risk to both the donor and the patient and work continued on the development of a completely artificial means of supporting the circulation during surgery; a task that had occupied John H. Kirklin (171,173) published a series of detailed papers explaining the developments that had contributed to these improved outcomes. He particularly commented on the need for "vigorous pursuit" of normalized postoperative blood gases and volume status, reduced use of outflow tract patches, myocardial protection strategies, and close attention to hemostasis (171,172). These "transannular" patches provided complete relief of outflow tract obstruction but at the cost of destroying competency of the pulmonary valve leaflets. Since attempts at full repair in infants had accrued a high mortality (174,175), cardiologists and surgeons favored a staged approach, with initial palliation by B-T-T-shunt, for those who developed severe and early cyanosis (174,176). Comparison of mortality rates before and after the introduction of complete repair during infancy lent strength to his argument (185). After changing to a strategy of complete primary repair rather than palliative shunting, mortality in the first 25 children aged under 2 years at the time of repair was only 4% (185). When follow-up studies suggested that early repair might carry hemodynamic and anatomical advantages, Dr. Coincidental to the move towards earlier complete repair, but occurring over a similar time course, surgeons also changed their operating techniques. Furthermore, of the surviving infants, >90% are expected to be alive 30 years after repair (202). During childhood, approximately 5% of patients require reoperation and a further 6% require catheter intervention (134). Those repaired at older ages have the most fibrosis, suggesting that pre- and perioperative factors are the most important insults (233). Right Ventricular Diastolic Dysfunction While disruption of the pulmonary valve during surgical repair usually initiates the pathophysiology described above, not all patients are affected in this way. In the mid-term (2 years postrepair) postoperative restriction predicts later restrictive physiology (241) but long-term prospective studies with serial follow-up are lacking. As well as anatomical considerations, there are physiologic factors linking the ventricles. Even in health, the filling of one ventricle influences the compliance and filling of the other (diastolic ventricular-ventricular interaction). In the subsequent systole, initial movement of the septum is back towards the neutral position (to the right) and this creates paradoxical septal motion. However, the clinical meaning and the mechanisms underlying this relationship remain uncertain. Does it imply that intrinsic contractile function of the myocardium in each ventricle is interdependent Regular visits also provide an opportunity for patient education and advice on maintaining a healthy lifestyle. Routine Holter monitoring has not proven useful for predicting clinically important arrhythmias but patients should be asked about symptoms of palpitations and syncope. Echocardiography should be performed at each visit and regular cardiopulmonary exercise testing is useful to formally document changes in exercise capacity. In patients for whom further interventions are planned, cardiac catheterization is sometimes necessary to assess hemodynamics and anatomy and, in middle-aged patients, to exclude atherosclerotic coronary artery disease. However, there are also aortic root histologic (274) and elastic (275) abnormalities in these patients, and it seems likely that these, too, playa role. All aortic root measurements were enlarged at the time of repair, but within 7 years, the annulus and sinotubular Z-scores had returned to normal and the aortic sinus measurements showed significant regression (280). However, as discussed earlier, at present there is no consensus as to the indications and optimal timing of this procedure. If they become significantly stenosed or regurgitant, surgically placed valves can often be re-replaced nonsurgically with the previous percutaneously implanted valve providing support for the new valve. Current guidelines should be consulted but, in general, antibiotic prophylaxis is only recommended for those patients with conduits and prosthetic valves. Caution with combined hormonal preparations is required in women with significant ventricular dysfunction or atrial arrhythmias because of the associated thromboembolic risks of estrogen (281,282). Congenital cardiac disease and inbreeding: specific defects escape higher risk due to parental consanguinity. Low-copy repeats mediate the common 3-Mb deletion in patients with velo-cardio-facial syndrome. Comprehensive genotype-phenotype analysis in 230 patients with tetralogy of Failor. Multifactorial inheritance hypothesis for the etiology of congenital heart diseases. The nature and significance of anomalous coronary arteries in tetralogy of Fallot. Transatrial-transpulmonary tetralogy of Fallot repair is effective in the presence of anomalous coronary arteries. Tetralogy of Failor with anomalous origin of left anterior descending coronary artery. Repair of tetralogy of Failor with anomalous coronary arteries coursing across the obstructed right ventricular outflow tract. Repair of tetralogy of Fallot with anomalous origin of left anterior descending coronary artery. Left hemitruncus associated with tetralogy of Fallot: fetal diagnosis and postnatal echocardiographic and cardiac computed tomographic confirmation. Anomalous origin of a pulmonary artery from the ascending aorta: associated anomalies and pathogenesis. Absent left pulmonary artery and double aortic arch in tetralogy of Fallot: reconstruction using homograft saphenous vein or iliac artery. Tetralogy of Failor with absent pulmonary valve: echocardiographic morphometric features of the right-sided structures and their relationship to presentation and outcome. Compression of intrapulmonary bronchi by abnormally branching pulmonary arteries associated with absent pulmonary valves. Sakamoto T, et al, One-stage intracardiac repair in combination with external stenting of the trachea and right bronchus for tetralogy of Fallot with an absent pulmonary valve and tracheobronchomalacia. Primary repair is superior to initial palliation in children with atrioventricular septal defect and tetralogy of Fallot. Trends in prenatal diagnosis, pregnancy termination, and perinatal mortality of newborns with congenital heart disease in France, 1983-2000: a population-based evaluation. Spectrum of clinical features associated with interstitial chromosome 22q 11 deletions: a European collaborative study. Guidelines on the use of irradiated blood components prepared by the British Committee for Standards in Haematology blood transfusion task force. Pathological Researches: Essay on the Malformations of the Heart, or of its Arteries.

However hair loss cure 4 lupus discount finpecia, over time hair loss in men kissing finpecia 1mg mastercard, hypoxemia and cyanosis increase as the patient outgrows the relatively fixed sources of pulmonary blood flow hair loss in men 4 men buy finpecia with mastercard. This occurs most commonly at 4 to 6 weeks of age after the pulmonary arteriolar resistance has decreased hair loss in men memes finpecia 1mg fast delivery. Absence or severe hypoplasia of the central pulmonary arteries and the presence of multiple major collateral arteries reduces the likelihood of successful biventricular repair in these patients (22) hair loss chemotherapy quality 1 mg finpecia. As patients outgrow shunts performed early in life hair loss cure female purchase finpecia, they become increasingly cyanotic. These shunts usually improve oxygenation, but complications of shunts include distortion and stenosis of pulmonary arteries and occasionally lead to pulmonary vascular obstructive disease. The classic or modified Blalock-ThomasTaussig shunt is the preferred palliative shunt. These procedures produce more rapid enlargement of the central pulmoriary arteries than systemic-to-peripheral pulmonary artery shunts and also produce less distortion of the peripheral pulmonary arterial architecture. However, in patients with inadequate distal distribution from the central confluence or those with significant peripheral stenosis, these large central connections may produce segmental pulmonary hypertension. Due to the fact that all palliative approaches are associated with potential complications, a substantial number of older patients will have arterial beds damaged by these procedures. The frequency of late arterial distortion also emphasizes the need to obtain a detailed understanding of the pulmonary vascular architecture prior to planning an interventional strategy. The heart size is normal for patients with normal or decreased pulmonary blood flow. A systolic murmur may be audible along the lower left sternal border but usually is not more than grade 3/6 in intensity. If systemicto-pulmonary collateral vessels are present, continuous murmurs can be heard. These may be multiple and often are most prominent over the back because these vessels usually originate from the descending aorta. Electrocardiographic Features Right ventricular hypertrophy and right-axis deviation are the rule. In patients with increased pulmonary blood flow (a small subgroup), combined ventricular hypertrophy and left atrial enlargement may occur. Radiographic Features Physical Examination Profound cyanosis usually is present in the early neonatal period. It is common for the degree of cyanosis and the arterial oxygen tension to fluctuate considerably during the first several days as the ductus arteriosus constricts and relaxes. Growth and development can be delayed, but if pulmonary flow is adequate and systemic hypoxemia is only mild, this may not be the case. Heart failure caused by excessive pulmonary blood flow is uncommon in these patients; therefore, growth failure on this basis is infrequent. The heart frequently has a characteristic appearance likened to the shape of a boot (coeur en sabot). This is due to levorotation of the heart, which produces a prominent, upturned cardiac apex, secondary to right ventricular hypertrophy. There is also a concavity in the region of the main pulmonary artery produced by underdevelopment of the subpulmonary infundibulum. The pulmonary vascular markings usually have a heterogeneous reticular appearance that does not conform to the usual arborization pattern of pulmonary vessels. This appearance is caused by collateral arteries from the systemic circulation that frequently are quite large and supply blood to the pulmonary artery. In patients with small systemic collaterals, the lung fields may have diminished vascular markings. Echocardiographic Features Echocardiography usually provides the initial diagnosis, can determine the presence (and size) of a central pulmonary arterial confluence, can detect large collateral vessels, and can define many associated cardiovascular malformations. Echocardiographic techniques cannot completely delineate the distal pulmonary arterial tree or the sources of pulmonary arterial supply. The distinguishing feature between these two anomalies is that in truncus arteriosus, the pulmonary arteries arise directly from the posterolateral aspect of the truncal root prior to the arch. Echocardiographic scans from the suprasternal notch and high parasternal windows (both right and left) frequently provide important information about the size and status of the proximal pulmonary arteries. When the pulmonary arteries are confluent and clearly identified by echocardiography, newborns with ductal-dependent pulmonary blood flow can undergo a palliative systemic-to-pulmonary artery shunt procedure without cardiac catheterization (34,35). The 2-D echo cardiographic evaluation of these features can be difficult when the pulmonary arteries are nonconfluent, the pulmonary arteries are extremely hypoplastic, or multiple collateral arteries are present in the area of the confluence. In these situations, color flow imaging markedly enhances evaluation of the pulmonary and collateral arteries (35). This technique has been especially helpful in neonates with hypoplastic but confluent pulmonary arteries (35,36). Although all collateral arteries cannot be defined using echocardiography, their presence should be noted and their origins delineated as precisely as possible. Knowledge of an unusual origin of a collateral vessel (such as from the abdominal aorta, a brachiocephalic artery, or a coronary artery). This modified parasternal short-axis scan demonstrates an unusual origin of a collateral artery. The right coronary artery gave rise to a large coronary-to-pulmonary artery fistula (" Fistula). Echocardiographic examinations can define many of the other abnormalities associated with conotruncal malformations. Short-axis parasternal and subcostal scans have been helpful in detecting coronary artery abnormalities, especially in neonates. Color flow imaging and continuous wave Doppler techniques allow serial noninvasive assessments of surgically created shunts and right ventricular-to-pulmonary artery conduits (37,38). Suprasternal notch scans define the sidedness and branching pattern of the aortic arch. Cardiac Catheterization and Angiocardiography Patients with small central pulmonary arteries or multiple sources of pulmonary flow should have cardiac catheterization for pulmonary angiographic mapping before definitive repair. For the neonate undergoing palliation, it is our policy to refer patients with small, but echocardiographically detectable, centrally confluent pulmonary arteries for a shunt to establish a reliable source of pulmonary blood flow without catheterization. These patients, who often have hypoxemia and cyanosis in the first few days of life, are treated with prostaglandin E1 to maintain ductal patency until they can have an operation. In infants who require more pulmonary blood flow and in whom no proximal pulmonary arteries can be visualized echocardiographically, catheterization and angiography ate performed to determine the source of pulmonary blood flow and to define the possible surgical options to increase pulmonary blood flow. Systemic arterial blood oxygen desaturation is present, and the degree depends on the volume of pulmonary blood flow. In such cases, usually it is easy to enter the true pulmonary arteries through the large communication, measure the pressure, and estimate pulmonary flow by the Fick principle. Ventricular and aortic root angiography should be done if this information is unavailable from noninvasive imaging studies. Ventriculography should be performed with an injection into the left ventricular cavity while the cameras are positioned to record a 70-degree left anterior oblique view with 20 degrees of cranial angulation. This projection displays the middle portion and most of the upper interventricular septum tangentially. Although the coronary artery anatomy can be visualized during a ventricular injection, it is better defined by an aortic root angiocardiogram and a 70-degree left anterior oblique view (with or without 20 degrees of cranial angulation). Of surgical importance is the origin of the left anterior descending coronary artery from the right coronary artery, which occurs in approximately 5% of patients (39). It is particularly important to define the coronary artery preoperatively if there have been previous surgical procedures resulting in pericardial adhesions that obscure the coronary anatomy. We found it necessary to do selective injection of individual coronary arteries only in patients with large aortic roots and high rates of flow (particularly in patients with Waterston shunts). Angiographic delineation of the anatomy of pulmonary blood supply is of critical importance. A large-field radiographic format using biplane angiocardiography is advantageous in this situation. The image should provide a large field of view, ideally visualizing both lung fields simultaneously. Subtraction techniques have also proved useful in demonstrating the anatomy of interest. Determining the presence or absence of a central pulmonary arterial confluence is of paramount importance. If a pulmonary artery confluence is present, the systemic-to-pulmonary collateral vessels may communicate directly with it or connect to it indirectly by a connection to a peripheral branch of the pulmonary artery. In addition, systemic collaterals may not communicate with central pulmonary arteries at all, instead terminating by connections to peripheral pulmonary artery branches that are separate from the confluence (noncommunicating) (29). Angiographic evaluation should be tailored to the type of systemic-to-pulmonary collateral artery anatomy found in each patient. Historically, an initial aortogram was necessary to demonstrate the number and location of the systemicto-pulmonary collateral arteries. However, prior delineation of at least the origins of collateral vessels by echocardiography or other imaging studies allows one to proceed directly to selective injections in some cases. This avoids the larger-volume contrast injection used during nonselective aortography. The purpose of selective injections in the systemic-to-pulmonary collateral arteries usually is to delineate the extent of the pulmonary arterial tree supplied by each collateral vessel and to determine which type of pulmonary artery connection is present. Such collateral injections can be enhanced by selective balloon occlusion techniques (40). This allows detection of discrete stenoses or tubular hypoplasia involving the pulmonary arteries as well as the degree to which the central and peripheral pulmonary arteries communicate (41). Both the size and the peripheral distribution of the pulmonary arteries are important in planning the surgical treatment of these patients. Pulmonary vein wedge angiogram demonstrating a hypoplastic demonstrates relatively large pulmonary confluence (arrow) but fails to define connections of individual, systemically derived collateral arteries. Identifying communications between adjacent areas of the peripheral pulmonary arterial tree is particularly important and requires close attention to the sequential flow of contrast medium. Occasionally, an evanescent negative washout pattern can be appreciated that is due to a stream of unopacified blood from a connecting pulmonary artery flowing into an area of opacified pulmonary arterial tree. If the initial echocardiogram or aortogram does not allow identification of a pulmonary artery confluence and selective injection of systemic-to-pulmonary collateral arteries fails to identify such a confluence, a retrograde pulmonary vein wedge injection may be helpful to identify hypoplastic central pulmonary arteries. Aortogram Some patients with complex patterns of pulmonary blood supply may require multiple injections of contrast material before the pulmonary vascular supply is documented. Because these patients often are hypoxemic and polycythemic, our policy is to inject a total dose of not more than 5 to 6 mL of contrast material per kilogram of body weight during any single procedure. Adequate hydration of these patients before, during, and after the study is mandatory to prevent thromboembolic complication or a potential complication secondary to hyperosmolality caused by the contrast material. Magnetic resonance imaging of sources of pulmonary blood can reduce the amount of contrast material needed at the time of angiographic examination (42). When the physical examination is complemented by an electrocardiogram and chest radiograph, an accurate clinical diagnosis often can be established. Selective injection into a collateral artery arising from middle portion of descending thoracic aorta (same patient as in. Note stream of unopacified blood (arrow) washing out contrast medium in right pulmonary artery, an indication of competitive blood flow from a connecting vessel (see text). Most patients would have had an operation to increase pulmonary blood flow; however, some patients can reach adulthood without having undergone palliative surgery. Phlebotomy may occasionally offer relief from the side effects of extreme polycythemia in extremely hypoxemic patients. It is critical to map the pulmonary artery architecture and sources of pulmonary blood supply. The goals of operation can be palliative for those patients whose pulmonary artery anatomy precludes complete repair. In contrast, for patients whose pulmonary artery anatomy appears amenable to reconstruction, procedures leading to complete repair are indicated. Such procedures have included right ventricular outflow reconstruction for inducement of central pulmonary artery growth. Such a connection can promote growth of the hypoplastic central pulmonary arteries so that they are adequate for complete repair (43). These unifocalizations are designed to incorporate the maximum number of pulmonary artery segments into the eventual right ventricular outflow reconstruction. Historically, a staged reconstructive surgical approach was applied in patients who did not meet the criteria for complete repair at presentation (46). This involved lateral thoracotomies for "unifocalization" procedures to deal with significant arborization abnormalities of the pulmonary arteries and to create a single, central arterial source for each lung. If these operations were successful, the two reconstructed central pulmonary arteries were connected. One hundred and sixty patients had preliminary surgical staging, including systemic-to-pulmonary artery shunts, right ventricular outflow reconstruction, and/or unifocalization procedures. Note two large systemic-to-pulmonary collateral arteries, absence of a pulmonary artery confluence, and abnormal branching pattern of right pulmonary artery. Other investigators have reported similar results with the staged approach (48,49). Actuarial survival of patients who underwent palliative or reconstructive procedures, but had not yet undergone or were turned down for complete intracardiac repair. Malhorta and Hanley (53) have reported that a "complete" unifocalization could be accomplished in 76% of 464 patients managed in this way. The earlier interventions inherent in this more aggressive approach may reduce the occurrence of segmental pulmonary vascular disease and progressive "loss" 100 80 60 86% 75% of segmental pulmonary arteries. Our current approach at Mayo Clinic is similar favoring complete unifocalization via median sternotomy at 4 to 8 months of age in newly diagnosed patients. Women who have had correction and who have pulmonary artery pressures that are normal or only slightly increased should tolerate pregnancy well. For women in whom significant pulmonary artery hypertension persists after correction, pregnancy probably is not advisable.

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