The closure index: prediction of long-term patency of femoropopliteal vein grafts.

Of 227 reversed saphenous vein femoropopliteal graft procedures performed between January 1, 1974, and December 31, 1978 limbs (72 patients) and postoperative angiograms (37% of total) were reviewed to assess the influence of graft diameter, length, and runoff on patency rates. Patient characteristics were as follows: mean age was 64 years; 73% were men; 22% were diabetics; and 68% had ischemia as the indication. Patients were followed from 26 to 86 months (mean 52 months). Patency of grafts was assessed by physical examination or arteriography and evaluated by the life-table method. Postoperative angiograms were reviewed, and the diameter and length of the vein graft, as well as the diameter and number of runoff vessels, were noted. These variables were then related by the closure index (CI). Limbs were stratified into three groups: group I--CI less than equal to 50, 51 limbs; group II--50 less than CI less than 100, 22 limbs; and group III--CI greater than equal to 100, 12 limbs. Cumulative patency rates at 3 and 5 years, respectively, were as follows; total group, 60.6% and 52.3%; group I, 71.1% and 59.6%; group II, 47.7% and 47.7%; and group III, 15.6% at 3 years. Many factors cause graft failure. Between 30 days and 5 years, thrombosis of the graft is promoted by stasis. Low-flow velocity is most often associated with a "mismatch" of graft diameter and length to runoff. Patients with a CI of 50 or lower have a 72% chance of prolonged graft patency, but in those with a CI of 100 or higher, graft failure within 1 year is to be expected. The CI enables the surgeon to predict the likelihood of long-term patency of femoropopliteal grafts.