E Belli

Effects of lack of pulsatility on pulmonary endothelial function in the Fontan circulation

OBJECTIVES Continuous flow in the Fontan circulation results in impairment of pulmonary artery endothelial function, increased pulmonary arterial resistance, and, potentially, late failure of Fontan circulation. We investigated the mechanisms of vascular remodeling and altered vascular reactivity associated with chronic privation of pulsatility on pulmonary vasculature. METHODS A total of 30 pigs were evenly distributed in 3 groups: 10 underwent a sham procedure (group I) and 20 underwent a cavopulmonary shunt between the superior vena cava and right pulmonary artery--10 with complete ligation of the proximal right pulmonary artery (group II, nonpulsatile) and 10 with partial ligation (group III, micropulsatile). At 3 months postoperatively, the in vivo hemodynamics, in vitro vasomotricity (concentration response curves on pulmonary artery isolated rings), and endothelial nitric oxide synthase protein level were assessed. A comparison between group and between the right and left lung in each group was performed. RESULTS Group II developed right pulmonary hypertension and increased right pulmonary resistance. Endothelial function was altered in group II, as reflected by a decrease in the vasodilation response to acetylcholine and ionophoric calcium but preservation of the nonendothelial-dependent response to sodium nitroprusside. Group III micropulsatility attenuated pulmonary hypertension but did not prevent impairment of the endothelial-dependant relaxation response. Right lung Western blotting revealed decreased endothelial nitric oxide synthase in group II (0.941 ± 0.149 vs sham 1.536 ± 0.222, P = .045) that was preserved in group III (1.275 ± 0.236, P = .39). CONCLUSIONS In a chronic model of unilateral cavopulmonary shunt, pulsatility loss resulted in an altered endothelial-dependant vasorelaxation response of the pulmonary arteries. Micropulsatility limited the effects of pulsatility loss. These results are of importance for potential therapies against pulmonary hypertension in the nonpulsatile Fontan circulation, by retaining accessory pulmonary flow or pharmaceutical modulation of nonendothelial-dependant pulmonary vasorelaxation.

Late outcomes after arterial switch operation for Taussig-Bing anomaly

OBJECTIVE To assess the long-term results of the arterial switch operation (ASO) for Taussig-Bing Anomaly (TBA) and identify risk factors affecting outcomes. METHODS Retrospective review and late follow-up was performed for all TBA patients from 1997 to 2010 (follow-up >3 years). Selection criteria included the absence of mitro-pulmonary continuity. RESULTS Sixty-nine children underwent ASO at a median age of 24 days (interquartile range [IR] 11-125), with concomitant repair of aortic arch obstruction in 26 (37.7%). Complex coronary anatomy (n = 38; 55.0%) was common. Nine (13.0%) patients had staged repair. Hospital mortality was 5.8% (95% confidence interval [CI], 1.6%-14.2%; n = 4). Median follow-up was 11.2 years (IR 7.2-13.8). Subsequent mortality was confined to the first postoperative year (n = 5, 86% [95% CI, 78%-95%]), 1-, and 10-year survival). Overall mortality was related to coronary pattern (Yacoub types C and E vs A and D, multivariate, hazard ratio [HR] 12.2 [95% CI, 1.2-122.1], P = .03). At latest follow-up, 96% of the survivors are asymptomatic, with normal ventricular function. Cumulative incidence of reintervention at 10 years was 53% (95% CI, 28%-77%). Concomitant aortic arch obstruction was a predictor of reintervention (multivariate, HR 2.9 [95% CI, 1.1-7.4], P = .03). No mortality occurred upon reinterventions. CONCLUSIONS In the largest series to date of ASO for TBA, mortality is confined to the first postoperative year, and related to coronary artery pattern. Beyond the first year, needed reinterventions are frequent, but with sustained functional status and no mortality over >10 years follow-up. Aortic arch obstruction is the main predictor for reintervention. Despite a significant rate of early events, favorable long-term outcomes argue for use of the ASO in TBA patients.

Hypoplasies trachéales complexes du nourrisson : extension des limites de la « Slide Tracheoplasty »

Objectifs La tracheoplastie de glissement ou « slide tracheoplasty » est progressivement devenue la technique de choix pour le traitement des hypoplasies etendues de la trachee chez l’enfant et le nourrisson. Cependant, certaines situations rendent difficile cette technique et l’hypoplasie est alors le plus souvent corrigee par mise en place de materiel etranger. Materiel et methodes Cinq patients âges de 1 a 6 mois presentant des hypoplasies complexes de trachees ont ete operes entre 2001 et 2005 par notre equipe. L’hypoplasie etait dite complexe car associee a une stenose critique, une stenose du cricoide, une hypoplasie des bronches, une bronche tracheale ou encore une atresie de l’oesophage avec tracheomalacie severe. Tous ont ete traites par des variantes de « slide tracheoplasty ». Resultats En postoperatoire, la duree moyenne de ventilation a ete de 8 jours et la duree moyenne de reanimation de 15 jours avec une mortalite nulle. Le principal facteur de morbidite a ete une paralysie recurentielle unilaterale chez 2 patients. A long terme (suivi moyen de 27 mois), aucun enfant n’a du subir de reintervention, tous presentent une croissance et une activite normales. Conclusions La slide tracheoplasty represente une bonne alternative therapeutique en cas d’hypoplasie severe et complexe de la trachee chez le nourrisson.