Sam Suleman

Selective Right Ventricular Unloading and Novel Technical Concepts in Ebstein's Anomaly

BACKGROUND Favorable outcomes in Ebsteins anomaly are predicated on tricuspid valve competence and right ventricular function. Successful valve repair should be aggressively pursued to avoid the morbidity of prosthetic tricuspid valve replacement. We report our experience with valve-sparing intracardiac repair, emphasizing novel concepts and techniques of valve repair supplemented by selective bidirectional Glenn (BDG). METHODS Between June 1993 and December 2008, 57 nonneonatal patients underwent Ebsteins anomaly repairs. The median age at operation was 8.1 years. All were symptomatic in New York Heart Association (NYHA) functional class II (n = 38), III (n = 17), or IV (n = 1). Preoperatively, 26 had mild or moderate cyanosis at rest. We used a number of valve reconstructive techniques that differed substantially from those currently described. BDG was performed in 31 patients (55%) who met specific criteria. RESULTS No early or late deaths occurred. At the initial repair, 3 patients received a prosthetic valve. Four patients required reoperation for severe tricuspid regurgitation. Repeat repairs were successful in 2 patients. At follow-up (range, 3 months to 6 years), all patients were acyanotic and in NYHA class I. Tricuspid regurgitation was mild or less in 49 (86%) and moderate in 6 (11%). Freedom from a prosthesis was 91% (52 of 57). CONCLUSIONS Following a protocol using BDG for ventricular unloading in selected patients with Ebsteins anomaly can achieve a durable valve-sparing repair using the techniques described. Excellent functional midterm outcomes can be obtained with a selective one and a half ventricle approach to Ebsteins anomaly.

Homograft Valved Right Ventricle to Pulmonary Artery Conduit as a Modification of the Norwood Procedure

Background— The use of a right ventricle to pulmonary artery (RV-PA) conduit in the Norwood procedure has been proposed to increase postoperative hemodynamic stability. A valve within the conduit should further decrease RV volume load. We report our clinical experience with this modification. Methods and Results— From February 2002 through August 2005, we performed 88 consecutive Norwood procedures using RV-PA conduits. We used composite valved conduits made from cryopreserved homograft and polytetrafluoroethylene (PTFE) in 66 cases (54 pulmonary, 12 aortic homografts), other valved conduits in 14, and unvalved PTFE in 8 cases. Hospital survival was 88.6% overall and increased to 93.1% after the initial year. Early interventions were required in 18 patients (16 for cyanosis). Prestage II cardiac catheterization was performed at a mean age of 126 days. Mean Qp/Qs was 1, with mean aortic saturation 71%, mean O2 extraction 24%, and mean right ventricular end-diastolic pressure 9 mm Hg. Patient weight, use of an aortic homograft valve in the conduit, stage I palliation within the first year of our experience, and low O2 extraction and high transpulmonary gradient prestage II were risk factors for overall death. Early interventions were more frequent in aortic valve conduits compared with all other conduits. Conclusions— The valved RV-PA conduit was associated with low early mortality after the Norwood procedure. The majority of these patients had normal cardiac output and well-maintained RV function. There may be a higher risk for early conduit interventions and death when aortic valve homografts are used in the RV-PA conduit.

Midterm Results of the Modified Ross/Konno Procedure in Neonates and Infants

BACKGROUND The management of congenital aortic stenosis in neonates and infants continues to be a surgical challenge. We have performed the modified Ross-Konno procedure for patients who have severe aortic insufficiency or significant residual stenosis after balloon aortic dilation. The midterm results of this procedure were evaluated in this subset of patients. METHODS Between 1994 and 2010, a total of 24 patients younger than 1 year of age underwent the modified Ross-Konno procedure. The diagnoses were aortic stenosis with or without subaortic stenosis (n = 16), Shones complex (n = 7), and interrupted aortic arch with subaortic stenosis (n = 1). The aortic root was replaced with a pulmonary autograft, and the left ventricular outflow tract (LVOT) was enlarged with a right ventricular infundibular free wall muscular extension harvested with the autograft. RESULTS Age at operation ranged from 1 to 236 days (median 28 days). The median follow-up period was 81 months (range 1-173 months). There was 1 early death and no late mortality. Overall the 1-, 2-, and 5-year survival rate was 95% ± 4.5%. Freedom from aortic stenosis was 94.7% ± 5.1% at 1, 2, and 5 years. Less than mild aortic insufficiency was 93.3% ± 6.4% at 2 years, and 74.7% ± 12.9% at 5 years. In total, 23 reoperations and reinterventions were performed; 14 were allograft conduit replacements. Two patients required aortic valve plasty. None required valve replacement. The reintervention-free rate was 64.6% ± 10.8% at 2 years and 36.9% ± 11.3% at 5 years. CONCLUSIONS Pulmonary autografts demonstrated good durability with low mortality and morbidity. This study shows that the modified Ross-Konno procedure can be a practical choice in selective cases for complex LVOT stenosis in neonates and infants.

Fetal myocardial protection is markedly improved by reduced cardioplegic calcium content

BACKGROUND Fetal cardiac surgery holds a clear therapeutic benefit in the treatment of lesions that increase in complexity due to pathologic blood flow patterns during development. Fetal and neonatal myocardial physiology differ substantially, particularly in the regulation of myocardial calcium concentration. To examine issues of calcium homeostasis and fetal myocardial protection, a novel isolated biventricular working fetal heart preparation was developed. METHODS Hearts from 20 fetal lambs, 115 to 125 days gestation, were harvested and perfused with standard Krebs-Henseleit (K-H) solution. The descending aorta was ligated distal to the ductal insertion and the branch pulmonary arteries were ligated to mimic fetal cardiovascular physiology. Hearts were arrested for 30 minutes with normocalcemic (n = 8), hypocalcemic (n = 6), or hypercalcemic (n = 6) cold crystalloid cardioplegia before reperfusion with K-H solution. RESULTS Compared with normocalcemic cardioplegia, hypocalcemic cardioplegia improved preservation of left ventricular (LV) systolic function (88% +/- 2.2% vs 64% +/- 15% recovery of end-systolic elastance, p = 0.02), diastolic function (12% +/- 21% vs 38% +/- 11% increase in end-diastolic stiffness, p = 0.04), and myocardial contractility (97% +/- 9.6% vs 75.2% +/- 13% recovery of preload recruitable stroke work [PRSW], p = 0.04). In contrast, the fetal myocardium was sensitive to hypercalcemic arrest with poor preservation of LV systolic function (37.5% +/- 8.4% recovery of elastance), diastolic function (86% +/- 21% increased stiffness), and overall contractility (32% +/- 13% recovery of PRSW). Myocardial water content was reduced in hearts arrested with hypocalcemic cardioplegia (79% +/- 1.8% vs 83.7% +/- 0.9%, p = 0.0006). CONCLUSIONS This study demonstrates the sensitivity of the fetal myocardium to cardioplegic calcium concentration. Hypocalcemic cardioplegia provides superior preservation of systolic, diastolic, and contractile function of the fetal myocardium.