A scoring system to predict the outcome of long femorodistal arterial bypass grafts to single calf or pedal vessels

Objectives: The aim of tills study was to develop a scoring system to predict the outcome of long femorocrural and femoropedal bypass grafts performed for critical limb ischaemia. Setting: Teaching hospital. Methods: An analysis of 109 consecutive femorodistal bypass grafts performed for critical lower limb ischaemia between June 1991 to December 1994. Factors shown to affect the outcome were: inflow, number of patent calf vessels, graft material, straight pow to the foot and patent pedal vessels. These variables were weighted according to their relative significance (multivariate Cox regression) and a scoring system (ranging from 0 to 10) was developed. Results: Patients with a preoperative score of 0-4 (n=35) showed a secondary patency of 36% at 1 month, 12% at 3 months and 0% at 10 months (Cum SE = 6.90/0.0). Secondary patency rates for the 46 patients with score 5-7 were 88.7% at 3 months, 56.3% at 12, and 45.1% at 2 and 3 years (Cum SE = 9.82), while the respective values for the 28 patients with score 8-10 were 92.7%, 88.5% and 81.7% (Cum SE = 8.08). The difference was highly significant (p = 0.000) in all tests of equality. In addition, the median total hospital cost was pound 12600 for the group 0-4 compared with pound 8100 (group 5-7) and pound 4400 (group 8-10) (p=0.0085). Conclusions: This preoperative scoring system appears to correlate well with the outcome of distal revascularisation io single calf or pedal vessels. If applied to patient selection, it could significantly reduce the total hospital cost per leg saved. A prospective testing of its predictive ability is needed and is in progress.