OBJECTIVETo compare the effect of different antegrade pulmonary blood flow on the further development of pulmonary artery after Glenn procedure in cyanotic congenital heart defects (CHD) patients.

METHODSBetween October 2000 and December 2006, 132 CHD patients with decreased pulmonary artery blood flow underwent bidirectional Glenn shunt, among them 18 patients received intraoperative lung biopsy. Patients were divided into two groups according to their different sources of antegrade pulmonary blood flow: antegrade arterial blood flow group (n = 33) and antegrade venous blood flow group (n = 99). The percutaneous oxygen saturation (SpO2), hemoglobin (Hb) concentration, and hemotocrit (Hct) value were examined and recorded before and after operation. The diameters of left pulmonary artery (LPA) and right pulmonary artery (RPA) were measured with two-dimensional echocardiography and the results were used to calculate the pulmonary artery index (PAI). The method of half-quantitative morphometric technique and an image analyzer were used to measure the following indicators of pulmonary microvessels: the percentage of media thickness (MT%), the percentage of media section area (MS%), vascular numbers of per square centimeter (VPSC), and mean alveolar number (MAN).

RESULTSBefore the operation, obvious cyanosis was found in both groups, while SpO2, Hct, and Hb were not significantly different (P > 0.05). LPA, RPA, and PAI were not significantly different between two groups (P > 0.05). The MT% and MS% in antegrade venous blood flow group were significantly less than those in antegrade arterial blood flow group (P < 0.05), but VPSC and MAN were not significantly different (P > 0.05). After Glenn procedure, hypoxia and cyanosis were remarkably improved in both two groups. There was a significantly negative correlation between SpO2 and Hct (r = -0.49, P < 0.01) or Hb (r = -0.196, P < 0.01 ). The PAI increased by 22% in antegrade arterial blood flow group and 44% in antegrade venous blood flow group (P < 0.05). The diameters of LPA and RPA in antegrade venous blood flow group were significantly larger than those in antegrade arterial blood flow group (P < 0.05) and the growth of RPA in antegrade arterial blood flow group was not significant.

CONCLUSIONA better pulmonary artery growth occurs in the patients of pulmonary stenosis after Glenn shunt than in those of pulmonary atresia, and it contributes to an earlier completion of Fontan procedure.