Effect of shunt type on echocardiographic indices after initial palliations for hypoplastic left heart syndrome: Blalock-Taussig shunt versus right ventricle-pulmonary artery conduit.

OBJECTIVES: The study objective was to compare echocardiographic indices in infants with hypoplastic left heart syndrome (HLHS) randomized to different surgical pathways. BACKGROUND: Initial surgical palliation for HLHS has evolved to two strategies that vary by source of pulmonary blood flow: a modified Blalock-Taussig (BT) shunt or a right ventricle to pulmonary artery (RV-PA) conduit. METHODS: Seventeen patients were randomized to either a BT shunt or RV-PA as their first-stage palliation, and 15 survived through bidirectional Glenn (BDG) (seven BT shunts/eight RV-PAs). Echocardiography was performed pre-stage 1 palliation (S1P), early post-S1P, pre-BDG, and post-BDG. Echocardiographic measurements included indices of right ventricle function and shape, right ventricle myocardial performance index, neoaortic Doppler flow patterns and cardiac output, Doppler inflow and tissue imaging, and conduit/neoaortic regurgitant fraction. RESULTS: There were no significant differences in right ventricle size, shape, or estimates of systolic and diastolic function between groups. Patterns of changes in neoaortic Doppler flow in the RV-PA conduit group showed a decrease in all indices of systemic flow early after initial palliation, but these measures consistently increase later post-S1P and post-BDG. In contrast, the BT shunt group increases these same indices post-S1P and pre-BDG with a decrease after shunt removal. CONCLUSIONS: Right ventricle size and function do not appear significantly affected by surgical type of initial palliation for HLHS, and this correlates with early outcome. Echocardiographic Doppler findings correlate well with the expected physiologies of the different shunts as these infants progress through initial palliative strategies.

Early cavopulmonary anastomosis after Norwood procedure results in excellent Fontan outcome.

BACKGROUND: Children with univentricular hearts and aortic arch obstruction are treated sequentially with Norwood procedure, superior cavopulmonary anastomosis (SCPA), and Fontan operation. Early SCPA results in lower initial O2 saturation and longer hospitalization, but not increased mortality. We sought to determine the impact of early SCPA on Fontan candidacy and outcomes. METHODS: Eighty-five consecutive patients undergoing Norwood operation between January 1998 and February 2003 were divided into group 1 (SCPA at less than 4 months, n = 33) and group 2 (SCPA at more than 4 months, n = 52). Of the original cohort, 69 have undergone Fontan operation, 7 await Fontan, 1 was transplanted, 3 are not Fontan candidates, and 5 died late after SCPA. Group 1 (n = 25) and group 2 (n = 44) patients who have completed Fontan operation were compared for preoperative and perioperative variables: age, size, O2 saturation, pulmonary artery pressure and size, prevalence of tricuspid regurgitation and ventricular dysfunction, extubation rate in operating room, duration of pleural drainage, hospital stay, and discharge O2 saturation. Late functional status and ventricular function were also compared. Survival was compared for original groups 1 and 2. RESULTS: There were no differences for any preoperative or perioperative variable, or late functional assessment. Actuarial survival at 6 years was also not different (88% +/- 5% for group 1 and 94% +/- 4% for group 2, p = 0.72). CONCLUSIONS: Although initially more cyanotic and hospitalized longer than older peers, younger SCPA patients achieve clinical equivalence by the time of Fontan operation and afterward. We conclude that both short- and long-term outcomes support performance of early SCPA.

Long-term and developmental outcomes of children with complex congenital heart disease.

As short-term survival of complex congenital heart disease continues to improve dramatically with advances in medical and surgical treatment, further efforts must be made to understand the long-term outcomes of our efforts. As survival continues to improve, cardiovascular morbidity and, equally importantly, neurodevelopmental and social outcomes must be a continual focus in our treatment of these complex patients. Further study of these effects is underway, and more is certainly warranted. Understanding should lead to modification of current techniques and management strategies, all with the ultimate goal of improving our patients' quality of life.

Alteration of the critical arteriovenous oxygen saturation relationship by sustained afterload reduction after the Norwood procedure.

OBJECTIVES: Hemodynamic vulnerability after the Norwood procedure for hypoplastic left heart syndrome results from impaired myocardial function, and critical inefficiency of parallel circulation. Traditional management strategies have attempted to optimize circulatory efficiency by using arterial oxygen saturation (SaO(2)) as an index of pulmonary/systemic flow balance, attempting to maintain SaO(2) within a theoretically optimal critical range of 75% to 80%. This optimal range of SaO(2) has not been verified clinically, and strategies targeting SaO(2) may be limited by the fact that SaO(2) is a poor predictor of systemic oxygen delivery. We have previously reported higher venous saturation (SvO(2)), lower arteriovenous oxygen content difference, lower systemic vascular resistance, lower pulmonary/systemic flow ratio, and improved survival with the perioperative use of phenoxybenzamine and continuous monitoring of SvO(2). In this investigation, we tested the hypothesis that intense afterload reduction with phenoxybenzamine would modify the SvO(2)-SaO(2) relationship by preventing deterioration of systemic oxygen delivery at high SaO(2). METHODS: Seventy-one consecutive neonates undergoing the Norwood procedure with and without phenoxybenzamine were studied. Perioperative hemodynamic management targeted SvO(2) greater than 50%. Hemodynamic data were prospectively acquired for 48 hours postoperatively and analyzed to assess the effect of phenoxybenzamine on the relationship between SaO(2) and SvO(2) and other hemodynamic indices. Sixty-two patients received phenoxybenzamine 0.25 mg/kg on cardiopulmonary bypass; 9 who did not served as controls. RESULTS: In control patients, SvO(2) peaked at an SaO(2) of 77%, with reduced SvO(2) at SaO(2) > 85% and SaO(2) < 70% (P <.01), while arteriovenous oxygen content difference increased with SaO(2) greater than 80% (P <.001). In patients receiving phenoxybenzamine, the SvO(2) increased linearly with SaO(2) greater than 65% (P <.001), and arteriovenous oxygen content difference was constant at all SaO(2) (P = ns). The SvO(2) was higher, and the arteriovenous oxygen content difference lower, across the whole SaO(2) range with phenoxybenzamine (P <.0001). CONCLUSIONS: A critical range of SaO(2) for optimizing systemic oxygen delivery was confirmed in control patients, and was effectively eliminated by phenoxybenzamine, specifically by eliminating the systemic hypoperfusion associated with high SaO(2). This effect allows higher SaO(2) to be included in a rational hemodynamic strategy to improve systemic oxygen delivery in the early postoperative management of patients receiving intense afterload reduction with phenoxybenzamine. The predictability of SvO(2) from SaO(2) is low in both groups, emphasizing the importance of SvO(2) measurement in these patients.