Asymptomatic strictures in femoro-popliteal vein grafts.

Strictures in saphenous vein grafts represent a preventable cause of graft failure, but these lesions may remain undetected by standard clinical methods until occlusion occurs. A study has been undertaken using intravenous digital subtraction angiography (I.V. DSA) to determine the incidence of asymptomatic strictures in a series of femoro-popliteal vein grafts and all lesions detected have been followed-up without treatment to assess their effect on patency rates. Eighty grafts in 69 asymptomatic patients were examined by I.V. DSA at a variable time postoperatively and again after a mean interval of 13 months. At the first examination a total of 30 strictures were found in 22 grafts (27.5%). At the second examination 5 the 22 strictured grafts (22.7%) had occluded. In contrast, only 4 of the 58 non-strictured grafts (6.9%) had occluded and this difference was statistically significant (chi 2 = 4.0 P less than 0.05). Six new strictures were detected, 2 in previously normal grafts and 4 in already strictured grafts, giving a total of 36 lesions altogether. The finding of a 27.5% stricture rate in asymptomatic patients, carrying a 3-fold increase in occlusion risk leads to the conclusion that screening of these grafts is essential. Sixty-five percent of strictures remained stable and asymptomatic, and this indicates that secondary intervention should be on a selective basis.