AbstractConstruction of a modified Blalock-Taussig shunt using polytetrafluroethylene is frequently used for palliation in infants with complex cyanotic heart disease. This study was performed to assess angiographically the late patency rate of such prosthetic shunts. A modified Blalock-Taussig shunt had been constructed in 82 children and, of these, 63 (77%) patients had post-operative angiography and were included in this study. There were 29 males and 34 females, ranging in age from 1 day to 164 months. A second shunt was needed in 7 patients. Thus, 70 shunts were studied. Of the shunts, 16 were 4 mm in diameter, 28 shunts 5 mm in diameter, and 26 shunts 6 mm in diameter. Postoperative angiography was performed on 1 day to 132 months (median 39 months) after construction of the shunts. Acute post operative occlusion occurred in 2(3%) patients, who had 5 and 6 mm shunts, respectively. At the latest follow-up (median 39 ± 26 months), 6(9%) late occlusions were noticed. Overall patency was 89% for all the shunts, with 94% of the 4 mm shunts, 85% of the 5 mm and 88% of the 6 mm shunts being patent. Regression analysis showed a progressive reduction in diameter of the graft with time. This narrowing of the graft may have been related to the formation of a ‘neointima’ due to fibrous hyperplasia.