Platelet aggregation index and femoropopliteal graft patency

Platelet aggregation index [PAI], based on the aggregation pattern and platelet count, was determined in the 40 patients available for platelet analysis who underwent 53 femoropopliteal bypasses with 6-mm, externally-supported, knitted Dacron grafts from 1982 to1992 mean follow up 50 months]. This index was found to be stable both pre-and postoperatively. The PAI value, the patient's age, history of hypertension atherosclerotic heart disease, diabetes, and/or smoking, the site of the distal anastomosis, previous ipsilateral bypass and state of runoff determined by preoperative angiography were analyzed for predicting closure, using the Cox proportional hazards regression model. Of the studied risk factors, the PAI was the most highly predictive variable for graft closure [P < 0.0001]. An increase of 10 units was associated with an increased relative risk of 2.02. Throughout the follow up period, 15 of l6 grafts remained patent in patients with an PAI < 15, whereas only 2 grafts out of 17 remained patent in patients with a PAI > 30. These data suggest that the PAI is an accurate predictor of the Outcome of femoropopliteal bypass using externally-supported, knitted Dacron grafts