Impact of pulmonary artery coarctation on pulmonary artery growth and definitive repair following modified Blalock-Taussig shunt.

Abstract

Pulmonary artery coarctation may pose a risk for pulmonary stenosis and subsequent failure to achieve definitive repair. We sought to assess the impact of pulmonary artery coarctation on pulmonary artery growth. A retrospective chart review was performed in 130 patients, including 37 single ventricles with a modified Blalock-Taussig shunt as first palliation. Pulmonary artery coarctation was defined as discrete stenosis of the pulmonary artery, with a diameter of less than 3 mm and with the ductus arteriosus connected. Preoperative echocardiography showed pulmonary artery coarctation in 29 patients (22%). Concomitant pulmonary artery plasty was performed in 14 patients with discrete stenosis having a diameter of less than 2 mm. Pre-modified Blalock-Taussig shunt left pulmonary artery z-scores were lower in patients with pulmonary artery coarctation than in those without (-4.0 [-5.8, -2.1] vs -1.7 [-2.6, -0.8], P < .001), and this remained the same even after modified Blalock-Taussig shunt (-2.5 [-5.1, -0.5] vs -0.5 [-2.4, 0.8], P = .010). Concomitant pulmonary artery plasty did not result in catch-up growth of the left pulmonary artery (post-modified Blalock-Taussig shunt left pulmonary artery z-score in patients with pulmonary artery plasty: -3.0 (-6.5, -2.0) versus those without: -1.8 (-3.3, -0.3), P = .279). Definitive repair/Fontan completion was achieved in 111 patients (85%), and this was not affected by the presence of pulmonary artery coarctation. Pulmonary artery coarctation affected disproportionate pulmonary artery growth throughout the staged repair, but did not result in failure of definitive repair/Fontan completion. Pulmonary artery plasty during the neonatal period did not contribute to catch-up growth of the left pulmonary artery; therefore, surgical indications and timing should be carefully considered.