[Growth of the pulmonary arteries and morphological assessment after Blalock-Taussig shunts]

Clinical and angiographic results were studied after 121 classic Blalock-Taussig shunts (CBT) and 74 modified Blalock-Taussig shunts (MBT) with polytetrafluoroethylene grafts. 1. The actuarial shunt patency rate in all 195 patients showed a significant difference in patency between CBT and MBT at six months after operation. (CBT = 91.6%, MBT = 98.6%, p0.05). The patency rate of 4-mm MBT grafts was lower than that of CBT of grafts. 2. The 109 patients who underwent postoperative angiography were evaluated for morphological features of anastomosis. The incidence of pulmonary arterial stenosis caused by anastomosis was 15.3% with CBT and 18.9% with MBT; these values were not significantly different. The primary characteristic of CBT anastomosis was a funnel-shaped stenosis at the side of shunt vessel, but this feature did not disturb pulmonary artery growth. In contrast, MBT grafts sometimes narrowed along their entire length, causing deterioration of pulmonary artery growth. 3. The 60 patients in whom pre- and post-operative pulmonary artery sizes were able to be evaluated were studied for pulmonary artery growth. The development ratio (DR) was calculated as the ratio of postoperative to preoperative pulmonary artery index (post-PAI/pre-PAI). a) DR in patients with lower preoperative PAI was greater than that in patients with higher preoperative PAI. b) DR in patients under the age of 6 months was greater than that in older patients. c) There were no significant differences in DR between CBT and MBT or between pulmonary stenosis and pulmonary atresia. d) Relative to the BT shunt, the ipsilateral pulmonary artery grew to the same degree as the contralateral artery.(ABSTRACT TRUNCATED AT 250 WORDS)