To compare late patency after direct and crossover bypass in good-risk patients with unilateral iliac occlusive disease not amenable to angioplasty.
Between May 1986 and March 1991, 143 patients with unilateral iliac artery occlusive disease and disabling claudication were randomized into two surgical treatment groups, ie, crossover bypass (n = 74) or direct bypass (n = 69). The size of the patient population was calculated to allow detection of a possible 20% difference in patency in favor of direct bypass with a one-sided alpha risk of 0.05 and a beta risk of 0.10. Patients underwent yearly follow-up examinations using color flow duplex scanning with ankle-brachial systolic pressure index measurement. Digital angiography was performed if hemodynamic abnormalities were noted. Median follow-up was 7.4 years. Primary endpoints were primary patency and assisted primary patency estimated by the Kaplan-Meier method with 95% confidence interval. Secondary endpoints were secondary patency and postoperative mortality and morbidity.
Cardiovascular risk factors, preoperative symptoms, iliac lesions TASC class (C in 87 [61%] patients and D in 56 [39%] patients), and superficial femoral artery (SFA) run-off were comparable in the two treatment groups. One patient in the direct bypass group died postoperatively. Primary patency at 5 years was higher in the direct bypass group than in the crossover bypass group (92.7 +/- 6.1% vs 73.2 +/- 10%, P = .001). Assisted primary patency and secondary patency at 5 years were also higher after direct bypass than crossover bypass (92.7 +/- 6.1% vs 84.3 +/- 8.5%, P = .04 and 97.0 +/- 3.0% vs 89.8 +/- 7.1%, P = .03, respectively). Patency at 5 years after crossover bypass was significantly higher in patients presenting no or low-grade SFA stenosis than in patients presenting high-grade (> or =50%) stenosis or occlusion of the SFA (74.0 +/- 12% vs 62.5 +/- 19%, P = .04). In both treatment groups, patency was comparable using polytetrafluoroethylene (PTFE) and polyester grafts. Overall survival was 59.5 +/- 12% at 10 years.
This study showed that late patency was higher after direct bypass than crossover bypass in good-risk patients with unilateral iliac occlusive disease not amenable to angioplasty. Crossover bypass should be reserved for high-risk patients with unilateral iliac occlusion not amenable to percutaneous recanalization.