Septal Ablation Versus Surgical Myomectomy for Hypertrophic Obstructive Cardiomyopathy.

PURPOSE OF REVIEW: Patients with hypertrophic cardiomyopathy (HCM) who have left ventricular outflow tract obstruction (LVOTO) often experience severe symptoms and functional limitation. Relief of LVOTO can be achieved by two invasive interventions, i.e., surgery myectomy and alcohol septal ablation (ASA), leading in experienced hands to a dramatic improvement in clinical status. Despite extensive research, however, the choice of the best option in individual patients remains challenging and poses numerous clinical dilemmas. RECENT FINDINGS: Invasive strategies have been recently incorporated in recommendations for the diagnosis and treatment of HCM on both sides of the Atlantic. These guidelines are based on a bulk of well-designed but retrospective studies as well as on expert opinions. Evidence now exists that adequate evaluation and management of HCM requires a multidisciplinary team capable of choosing the best available options. Management of LVOTO still varies largely based on local expertise and patient preference. Following the trend that has emerged for other cardiac diseases amenable to invasive interventions, the concept of a "HCM heart team" is coming of age.

Interventional vs. surgical mitral valve therapy. Which technique for which patient?

Mitral regurgitation (MR) is the most frequent valvular heart disease in developed countries. Surgical repair represents the optimal treatment for severe degenerative MR; however, surgical correction of functional MR is controversial. The Euro Heart Survey showed that up to 50 % of patients with severe MR are today denied surgical treatment. Therefore, new transcatheter techniques have been developed to treat MR with less invasive approaches. Currently, the device with the widest clinical use is the MitraClip System. In this scenario, a multidisciplinary team approach is key in providing optimal individually tailored treatment for patients with MR.

The pivotal role of echocardiography in the assessment of multivalvular heart disease.

Multivalvular heart disease (MHD) accounts for approximately 15% of the patients undergoing valve surgery in the EuroHeart Survey and for 8.6% of all valvular surgical interventions. Most clinical studies on valvular heart disease are focused on single-valve disease and very few data stress the difficulties encountered in the diagnostic assessment and clinical decision making of multiple defects, also concerning the reciprocal hemodynamic influence or the overlap of surgical indications. Many fields related to multiple valve disease are not encountered in the European Guidelines on Valvular Heart Disease (ESC) or the American College of Cardiology/American Heart Association (ACC/AHA). Increasing age and new trends of mixed population have newly aroused interest in multivalvular heart disease in the developed countries, still in need of new clinical insights. According to the high comorbidities of candidates, the appropriate diagnostic framework necessary for the correct diagnosis and best clinical outcome may still be challenging. The paper reviews multivalvular heart disease (except congenital heart disease) from aetiology and background definition to surgical outcome, with special emphasis on echocardiographic assessment and clinical interpretation.

Effects of chronic elevation of atrial natriuretic peptide and free fatty acid levels in the induction of type 2 diabetes mellitus and insulin resistance in patients with mitral valve disease.

BACKGROUND AND AIMS: The relationship between atrial natriuretic peptide (ANP), increased free fatty acid (FFA) and insulin resistance in patients with mitral valve disease (MVD), a group characterised by elevated atrial pressure and increased ANP levels, is not defined. The present study was performed to evaluate, in MVD patients, the relationship between increased ANP and FFA levels and insulin resistance and the role of mitral valve replacement/repair in ameliorating these metabolic alterations. Conversely, coronary heart disease (CHD) patients were evaluated before and after coronary artery bypass grafting (CABG), since they are known to be insulin resistant in the presence of chronic FFA increase. METHODS AND RESULTS: Fifty MVD patients and 55 CHD patients were studied before and 2 months after surgery and compared with 166 normal subjects. Before surgery, 56% of MVD patients had impaired glucose tolerance or newly diagnosed type 2 diabetes after a standard oral glucose load and this percentage decreased to 46% after surgery. In CHD, impaired glucose tolerance (IGT) or newly diagnosed type 2 diabetic patients were 67% of patients before and after CABG. In MVD, left atrial (LA) volume, ANP, FFA incremental area and insulin levels were higher and Insulin Sensitivity (IS) index significantly reduced while after surgery, LA volume, ANP and FFA significantly decreased and IS index significantly improved. In CHD, insulin resistance and hyperinsulinaemia were present both before and after surgery with increased tumour necrosis factor (TNF)-α and interleukin (IL)-6 levels. CONCLUSION: In MVD, a higher degree of abnormal glucose tolerance and insulin resistance are associated to increased levels of ANP and FFA, while these metabolic alterations are improved by mitral valve replacement/repair surgery. Clinical Trial.gov registration number NCT 00520962.

Review of the MitraClip clinical evidence.

MitraClip system is the only catheter-based device for percutaneous mitral valve repair available for clinical use, after receipt of the CE Mark in 2008, while it is currently under review for FDA approval in the US. To date, over 3500 MitraClip implants have been performed worldwide, mainly in high risk surgical patients. The aim of this review is to review all the current evidences of the MitraClip therapy in an aim to define its clinical role in the treatment of mitral regurgitation (MR).

Mortality reduction in cardiac anesthesia and intensive care: results of the first International Consensus Conference.

There is no consensus on which drugs/techniques/strategies can affect mortality in the perioperative period of cardiac surgery. With the aim of identifying these measures, and suggesting measures for prioritized future investigation we performed the first International Consensus Conference on this topic. The consensus was a continuous international internet-based process with a final meeting on 28 June 2010 in Milan at the Vita-Salute University. Participants included 340 cardiac anesthesiologists, cardiac surgeons, and cardiologists from 65 countries all over the world. A comprehensive literature review was performed to identify topics that subsequently generated position statements for discussion, voting, and ranking. Of the 17 major topics with a documented mortality effect, seven were subsequently excluded after further evaluation due to concerns about clinical applicability and/or study methodology. The following topics are documented as reducing mortality: administration of insulin, levosimendan, volatile anesthetics, statins, chronic ß-blockade, early aspirin therapy, the use of pre-operative intra-aortic balloon counterpulsation, and referral to high-volume centers. The following are documented as increasing mortality: administration of aprotinin and aged red blood cell transfusion. These interventions were classified according to the level of evidence and effect on mortality and a position statement was generated. This International Consensus Conference has identified the non-surgical interventions that merit urgent study to achieve further reductions in mortality after cardiac surgery: insulin, intra-aortic balloon counterpulsation, levosimendan, volatile anesthetics, statins, chronic ß-blockade, early aspirin therapy, and referral to high-volume centers. The use of aprotinin and aged red blood cells may result in increased mortality.

Patient selection for MitraClip therapy impaired left ventricular systolic function.

Mitral regurgitation (MR) is a disabling disease associated with poor prognosis and high incidence of clinical events if left untreated. To reduce the invasiveness of the surgical approach, different types of transcatheter procedures are becoming available. The MitraClip procedure (Abbott Vascular Inc. Menlo Park, CA, USA) is yet the only catheter-based procedure available in clinical practice at the moment. The device has been evaluated in a number of preclinical studies, registries and in FDA approved clinical trials. (EVEREST trial, ACCESS-EU trial). Indication and timing of intervention is a crucial step in the diagnostic-therapeutic pathway of patients with mitral regurgitation. The aim of this review is to clarify the potential of MitraClip in clinical practice, particularly focusing on patient selection for this novel therapy. Patient selection and overall decision making is strongly influenced by anatomical and clinical factors. Decision-making in degenerative MR (DMR) vs. functional (FMR) can be quite different. Generally, MitraClip is effective in treating either type II or IIIb dysfunction (at the moment FMR is the main indication for MitraClip in Europe, according to the ACCESS registry data). The relative role of MitraClip and surgery in the management of patients with MR is still unclear. From the global initial experience, MitraClip therapy could be complementary to surgery in those patients at high risk for surgery who have ideal anatomical characteristics for implantation. The procedure is quite predictable in patients with favorable anatomy. In patients with suboptimal anatomy, if the risk of surgery is too high, MitraClip could be still indicated sometimes. Our preliminary experience suggests that in patients with DMR, the EVEREST anatomical criteria are strong predictors of early and mid-term success. According to it, MitraClip therapy is appropriate in those DMR patients with high surgical risk and ideal anatomy for clip implantation according to the EVEREST criteria. In FMR refractory to medical therapy and resynchronization therapy, MitraClip could be considered as first option therapy, particularly in those patients with comorbidities, or advanced age, being the operative risk of surgery above 5% in this population. In the future, novel devices, improved knowledge, more efficient imaging and transcatheter mitral prosthetic valve implantation may expand the indications to those patients currently not treated by MitraClip for anatomical unsuitability, and may improve the results both in term of early efficacy and long term durability.

Intra-procedural monitoring protocol using routine transthoracic echocardiography with backup trans-oesophageal probe in transcatheter aortic valve replacement: a single centre experience.

AIM: The aim of this study is to describe our 9-year experience in transcatheter aortic valve replacement (TAVR) using transthoracic echocardiography (TTE) as a routine intra-procedural imaging modality with trans-oesophageal echocardiography (TEE) as a backup. METHODS AND RESULTS: From January 2008 to December 2017, 1218 patients underwent transfemoral TAVR at our Institution. Except the first 20 cases, all procedures have been performed under conscious sedation, with fluoroscopic guidance and TTE imaging monitoring. Once the TTE resulted suboptimal for final result assessment or a complication was either suspected or identified on TTE, TEE evaluation was promptly performed under general anaesthesia. Only 24 (1.9%) cases required a switch to TEE: 6 cases for suboptimal TTE prosthetic valve leak (PVL) quantification; 12 cases for haemodynamic instability; 2 cases for pericardial effusion without haemodynamic instability; 4 cases for urgent TAVR. The 30-days and 1-year all-cause mortality were 2.1% and 10.2%, respectively. Cardiac mortality at 30-days and 1-year follow-up were 0.6% and 4.1%, respectively. Intra-procedural and pre-discharge TT evaluation showed good agreement for PVL quantification (k agreement: 0.827, P = 0.005). CONCLUSION: TTE monitoring seems a reasonable imaging tool for TAVR intra-procedural monitoring without delay in diagnosis of complications and a reliable paravalvular leak assessment. However, TEE is undoubtedly essential in identifying the exact mechanism in most of the complications.

Influence of concomitant mitral valve dysfunction on survival after aortic valve replacement.

Aortic valve pathology is the most common acquired valvular heart disease in the adults of western countries, and mitral regurgitation (MR) is often clinically present in patients with degenerative aortic stenosis or insufficiency. Many studies report an incidence of MR between 65-75% in patients evaluated for aortic valve replacement. Severe aortic valve disease may be associated with functional mitral regurgitation (FMR) defined as the failure of mitral valve to prevent systolic backward flow in the absence of any significant structural or intrinsic valvular disease. Increased afterload and left ventricular remodeling have been implicated to explain FMR in patients with aortic valve disease. Moreover, organic mitral valve disease can be associated with aortic stenosis and can be rheumatic or degenerative. We have examined the data of the literature to understand the evolution of MR, the impact of mitral regurgitation on the outcome of patients undergoing aortic valve replacement, and to determine clinical predictors of prognosis in patients with concomitant MR at the time of aortic valve replacement.

Basal insulin therapy is associated with beneficial effects on postoperative infective complications, independently from circulating glucose levels in patients admitted for cardiac surgery.

BACKGROUND: Although hyperglycemia is a strong predictor of postoperative infective complications (PIC), little is known about the effect of basal insulin therapy (BIT) per se on PIC. AIM: To evaluate if there is an association between BIT, independent of glucose levels, and a possible improvement of PIC during the perioperative cardiosurgery period (PCP). METHODS: In 812 patients admitted for cardiac intervention and treated with a continuous intravenous insulin infusion (CIII) for hyperglycemic levels (>130 mg/dl), a retrospective analysis was performed during the PCP (January 2009-December 2011). Upon transfer to the cardiac surgery division, if fasting glucose was ≥130 mg/dl, a basal + premeal insulin therapy was initiated (121 patients, group 1); for <130 mg/dl, a premeal insulin alone was initiated (691 patients, group 2). FINDINGS: Compared with group 2, group 1 showed reductions in PIC (2.48% vs 7.96%, p < 0.049; odds ratio: 0.294; 95% CI: 0.110-0.780), C-Reactive Protein (p < 0.05) and white blood cell (p < 0.05) levels despite glucose levels and CIII that were higher during the first two days after surgery (179.8 ± 25.3 vs 169.5 ± 10.6 mg/dl, p < 0.01; 0.046 ± 0.008 vs 0.037 ± 0.015 U/kg/h, p < 0.05, respectively). Normal glucose levels were achieved in both groups from day 3 before the discharge. The mean length of hospital duration was 18% lower in group 1 than in group 2 (7.21 ± 05.08 vs 8.76 ± 9.08 days, p < 0.007), providing a significant impact on public health costs. CONCLUSIONS: Basal + preprandial insulin therapy was associated with a lower frequency of PIC than preprandial insulin therapy alone, suggesting a beneficial effect of basal insulin therapy on post-surgery outcome.

Atrial electroanatomic remodeling after circumferential radiofrequency pulmonary vein ablation: efficacy of an anatomic approach in a large cohort of patients with atrial fibrillation.

BACKGROUND: Circumferential radiofrequency ablation around pulmonary vein (PV) ostia has recently been described as a new anatomic approach for atrial fibrillation (AF). METHODS AND RESULTS: We treated 251 consecutive patients with paroxysmal (n=179) or permanent (n=72) AF. Circular PV lesions were deployed transseptally during sinus rhythm (n=124) or AF (n=127) using 3D electroanatomic guidance. Procedures lasted 148+/-26 minutes. Among 980 lesions surrounding individual PVs (n=956) or 2 ipsilateral veins with close openings or common ostium (n=24), 75% were defined as complete by a bipolar electrogram amplitude <0.1 mV inside the lesion and a delay >30 ms across the line. The amount of low-voltage encircled area was 3594+/-449 mm(2), which accounted for 23+/-9% of the total left atrial (LA) map surface. Major complications (cardiac tamponade) occurred in 2 patients (0.8%). No PV stenoses were detected by transesophageal echocardiography. After 10.4+/-4.5 months, 152 patients with paroxysmal AF (85%) and 49 with permanent AF (68%) were AF-free. Patients with and without AF recurrence did not differ in age, AF duration, prevalence of heart disease, or ejection fraction, but the LA diameter was significantly higher (P<0.001) in permanent AF patients with recurrence. The proportion of PVs with complete lesions was similar between patients with and without recurrence, but the latter had larger low-voltage encircled areas after radiofrequency (expressed as percent of LA surface area; P<0.001). CONCLUSIONS: Circumferential PV ablation is a safe and effective treatment for AF. Its success is likely due to both PV trigger isolation and electroanatomic remodeling of the area encompassing the PV ostia.

Echocardiography during infusion of dobutamine for identification of reversibly dysfunction in patients with chronic coronary artery disease.

OBJECTIVES: The aim of this study was to test whether the contractile response of akinetic myocardium to low dose dobutamine is useful for detecting myocardial viability in patients with coronary artery disease and persistent left ventricular dysfunction. BACKGROUND: In some patients with chronic coronary artery disease, persistent abnormalities of left ventricular wall motion can be reversed by successful coronary artery bypass surgery. Thus, identification of potentially reversible dysfunction has important therapeutic and prognostic implications. Echocardiography during infusion of low dose dobutamine can detect viable myocardium in patients after thrombolytic therapy. However, there is no detailed information on the use of this method in patients with chronic left ventricular dysfunction without reperfusion. METHODS: We studied 33 selected patients with angiographically proved coronary artery disease and persistent left ventricular dysfunction. The effect of dobutamine infusion (5 micrograms/kg body weight per min, followed by 10 micrograms/kg per min) on left ventricular wall motion was evaluated by transthoracic echocardiography before coronary artery bypass grafting and compared with that obtained immediately after the operation (evaluated by intraoperative epicardial echocardiography) and both 2 weeks and 3 months later. Left ventricular wall motion was analyzed qualitatively by dividing the left ventricle into 16 segments, and a score was assigned to each region. RESULTS: Before coronary artery bypass surgery, 314 segments were akinetic. Of these, 183 became normokinetic immediately after revascularization, and 15 became hypokinetic. Dobutamine infusion was able to predict improvement in 178 of the 205 segments that recovered function after revascularization (sensitivity 86.8%) and to identify 89 of the 109 segments that did not recover postoperatively (specificity 81.6%). Mean (+/- SD) segment scores were 2.24 +/- 0.35 at baseline, 1.49 +/- 0.34 (p < 0.001) after dobutamine infusion, 1.51 +/- 0.38 (p < 0.001) immediately after and 1.51 +/- 0.38 (p < 0.001) 2 weeks after coronary artery bypass and 1.55 +/- 0.37 (p < 0.001) at 3-month follow-up. CONCLUSIONS: Echocardiography during infusion of low dose dobutamine is a safe and accurate method for identifying reversible dysfunctioning myocardium and predicts early reversibility of wall motion after surgical revascularization in selected patients with coronary artery disease with chronic left ventricular dysfunction.

Acute and short-term effects of partial left ventriculectomy in dilated cardiomyopathy: assessment by pressure-volume loops.

OBJECTIVES: The aim of this study was to evaluate the short-term effects of partial left ventriculectomy (PLV) on left ventricular (LV) pressure-volume (P-V) loops, wall stress, and the synchrony of LV segmental volume motions in patients with dilated cardiomyopathy. BACKGROUND: Surgical LV volume reduction is under investigation as an alternative for, or bridge to, heart transplantation for patients with end-stage dilated cardiomyopathy. METHODS: We measured P-V loops in eight patients with dilated cardiomyopathy before, during and two to five days after PLV. The conductance catheter technique was used to measure LV volume instantaneously. RESULTS: The PLV reduced end-diastolic volume (EDV) acutely from 141+/-27 to 68+/-16 ml/m2 (p < 0.001) and to 65+/-6 ml/m2 (p < 0.001) at two to five days postoperation (post-op). Cardiac index (CI) increased from 1.5+/-0.5 to 2.6+/-0.6 l/min/m2 (p < 0.002) and was 1.8+/-0.3 l/min/m2 (NS) at two to five days post-op. The LV ejection fraction (EF) increased from 15+/-8% to 35+/-6% (p < 0.001) and to 26+/-3% (p < 0.003) at two to five days post-op. Tau decreased from 54+/-8 to 38+/-6 ms (p < 0.05) and was 38+/-5 ms (NS) at two to five days post-op. Peak wall stress decreased from 254+/-85 to 157+/-49 mm Hg (p < 0.001) and to 184+/-40 mm Hg (p < 0.003) two to five days post-op. The synchrony of LV segmental volume changes increased from 68+/-6% before PLV to 80+/-7% after surgery (p < 0.01) and was 73+/-4% (NS) at two to five days post-op. The LV synchrony index and CI showed a significant (p < 0.0001) correlation. CONCLUSIONS: The acute decrease in LV volume in heart-failure patients following PLV resulted at short-term in unchanged SV, increases in LVEF, and decreases in peak wall stress. The increase in LV synchrony with PLV suggests that the transition to a more uniform LV contraction and relaxation pattern might be a rationale of the working mechanism of PLV.

Oxidative stress during reperfusion of human hearts: potential sources of oxygen free radicals.

OBJECTIVE: The aim was to examine the role of neutrophil activation in the genesis of oxidative stress during the early phases of reperfusion after ischaemia in patients subjected to aortocoronary bypass grafting. METHODS: Ten selected patients were studied. All had normal ejection fraction and normal left ventricular end diastolic pressures before operation. Each patient required at least three grafts, so that the duration of aortic crossclamping exceeded 30 min, the minimum ischaemic period required to detect oxidative stress upon reperfusion. Oxidative stress was assessed by measuring the formation and release of oxidised glutathione (GSSG) in the coronary sinus 1 min before and 3 min after the start of the cardiopulmonary bypass, and then 1, 5, 10, and 20 min after removal of the aortic clamp, and again 5 and 10 min after the end of the cardiopulmonary bypass. The arterial-coronary sinus difference for neutrophils, elastase-alpha 1 protease complex (elastase), and creatine phosphokinase was also monitored at the same intervals. RESULTS: Before clamping GSSG was undetectable in arterial and coronary sinus blood. There was no significant arterial-coronary sinus difference for neutrophils or elastase [53(SEM 66) cell.ml-1 and 1.10(2.49) micrograms.litre-1, respectively[. Five minutes after re-establishment of coronary blood flow, there was both a release of GSSG into the coronary sinus [arterial-coronary sinus difference: 11(2.6) nmol.dl-1] and an accumulation of neutrophils in the heart [arterial-coronary sinus difference: 262(33), P < 0.01 cell.ml-1], whereas no elastase release from the heart was measured [arterial-coronary sinus difference 7.6(4.46) microgram.litre-1, NS]. The arterial levels of elastase increased progressively during the operation from 48(5) microgram.litre-1 (preclamping) to 405(62) microgram.litre-1, P < 0.01 (end of the cardiopulmonary bypass). CONCLUSIONS: These data indicate that, in man, neutrophils do accumulate in the myocardium during early reperfusion. However, they are not activated when oxidative stress occurs. It is unlikely that the neutrophil localisation in the heart has pathological significance in the production of oxygen free radicals during early reperfusion. Free radical accumulation in the coronary vessels may contribute to disorders of coronary flow associated with reperfusion.

What Does The Blanking Period Blank?

In the management of paroxysmal, drug-refractory atrial fibrillation, pulmonary vein isolation has become a widely accepted treatment option. Currently, the arrhythmias following any form of myocardial ablation are not considered within a period of three months, known as "the blanking period". Although this period is authority- rather than evidence-based, it has become universally recognized. Indeed, several mechanisms play a role to determine the transient increased risk of post-procedural atrial tachyarrhythmias, occurring early after the procedure. Acute inflammatory changes may be responsible for immediate recurrence, since application of ablative energy on atrial tissue has a pro-inflammatory- and potentially arrhythmogenic effect. Atrial arrhythmias within the first 3 months after ablation are very common (35% to 65% of cases) and their significance as predictor of late recurrences is more significant during the first month. Furthermore, the current biological evidences indicate that the edema of the surrounding and ablated tissue is no longer present after 1 month. In our letter we advocate the reasons why a blanking period of four weeks should appear more reasonable, fostering its clinical importance and utility.

Oxygen free radicals and myocardial damage: protective role of thiol-containing agents.

It has been suggested that the sudden presence of oxygen during reperfusion after a period of ischemia may be toxic for the myocardial cell. The oxygen molecule is capable of producing reactions in the cell, forming highly reactive free radicals, and inducing lipid peroxidation of membranes, altering their integrity and increasing their fluidity and permeability. The ischemic and reperfused cardiac cell is the prime candidate for this reaction sequence and may explain the molecular mechanism underlying the pathologic events related to membrane dysfunction and calcium homeostasis. However, the myocardium has a series of defense mechanisms including the enzymes superoxide dismutase (SOD), catalase, and glutathione peroxidase plus other endogenous antioxidants such as vitamin E, ascorbic acid, and cysteine to protect the cell against the cytotoxic oxygen metabolites. The prerequisite for oxygen free radical involvement in ischemia and reperfusion damage is that ischemia alters the defense mechanisms against oxygen toxicity. It is known that ischemia may impair mitochondrial SOD and, with reperfusion, oxidative stress may occur as shown by tissue accumulation and release of oxidized glutathione. This tripeptide molecule in the cofactor of glutathione peroxidase, the enzyme that removes hydrogen and lipid peroxides. Its formation and subsequent release is a reliable index of oxidative damage. In our study, we investigated the effects of N-acetylcysteine on oxidative damage in the isolated rabbit heart. N-acetylcysteine increases, in a dose-dependent manner (from 10(-7) to 10(-5) M), the myocardial glutathione content and provides an important degree of protection against ischemia and reperfusion. Oxidative stress does not occur, mitochondrial function is maintained, enzyme release is reduced, and contractile recovery is increased. Similarly, we administered N-acetylcysteine in the pulmonary artery of coronary artery disease patients undergoing coronary bypass grafting (150 mg/kg in 1 hour followed by 150 mg/kg in 4 hours). The degree of oxidative stress on reperfusion was reduced and recovery of cardiac function improved. In this article, we review the cardioprotective role of thiol-containing agents.

Repair of common atrioventricular canal associated with transposition of the great arteries and left ventricular outflow obstruction.

A 9-year-old girl was successfully operated upon for transposition of the great arteries (TGA), complete atrioventricular (AV) canal, severe left ventricular outflow obstruction, absence of the coronary sinus, and a large left superior vena cava draining into the left upper corner of a common atrium. The interventricular communication was closed and the common AV orifice was partitioned, a Mustard operation was performed, and a valved conduit was inserted between the left ventricle and the pulmonary artery. This operation, which leads to a four-chamber heart, may be preferable for this condition to the previously reported Fontan type of repair. The same approach may be also used to correct those cases of double-outlet right ventricle with complete AV canal in which the interventricular communication does not extend into the perimembranous area.

Growth of the pulmonary anulus and pulmonary arteries after the Waterston anastomosis.

Twenty-six patients with tetralogy of Fallot underwent angiocardiography before a Waterston shunt and again several years later, prior to complete repair (mean interval 40 +/- 15.6 [SD] months). The ratio between the diameter of the pulmonary valve anulus (PVA) and that of the descending thoracic aorta (Ao) increased by 0.32 +/- 0.233, significantly more than is reported to occur after a Blalock-Taussig anastomosis (p = 0.0001). This increase had some relation to the interval between the two angiographic studies (r = 0.34, p = 0.08) and to the mean pressure in the main pulmonary artery (MPA) at the time of the second study (r = 0.35, p = 0.08). The ratio of diameter of the right (RPA) and left pulmonary arteries (LPA) and that of the Ao also increased by 0.24 +/- 0.226 and 0.20 +/- 0.201, respectively. These data suggest that an initial large aortopulmonary shunt may result in less need for transannular patching at complete repair.

Repair of tetralogy of Fallot after Waterston anastomosis.

Sixty-three corrective operations have been performed in patients with Tetralogy of Fallot and a previously constructed Waterston shunt. The patients were from 1.4 to 8 years of age (median 4.3 years), and the mean interval between the Waterston shunt and the repair was 39.3 +/- 16.05 months. Three patients developed pulmonary atresia and six required a second anastomosis prior to intracardiac repair. Kinking and stenosis of the right pulmonary artery at the site of the Waterston anastomosis occurred in 12 (19 percent; 70 percent confidence limits 14 to 26 percent) patients who required patch enlargement of the right pulmonary artery at repair. Seven (11 percent; 70 percent confidence limits 7 to 17 percent) patients died in the hospital and three (5 percent; 70 percent confidence limits 2 to 11 percent) during the period of late follow-up. None of the early or late deaths was specifically related to the presence of the previously performed Waterston anastomosis.