External beam radiation for prevention of intimal hyperplasia in peripheral arterial bypasses

Neointimal hyperplasia is one of the limiting factors in infrainguinal prosthetic vascular grafting. We conducted a pilot study to assess the possible role of radiotherapy for the prevention of this proliferating cellular process.

Ten patients (7 men, 3 women; median age: 73 years) suffering from critical leg ischemia were treated by infrainguinal revascularization using 6-mm polytetrafluoroethylene. Postoperative radiation therapy of the anastomotic sites started within 24 h. A dose of 20.4 Gy was delivered in 12 fractions in 2.5 weeks by external beam radiation with electrons. The target volume was defined as the clip-marked anastomotic region plus a 1.5-cm safety margin in each direction.

Radiation therapy was technically feasible in all cases without radiation-related side effects. In one patient, radiotherapy had to be terminated prematurely, because of a hematoma at the distal anastomotic site with consequent skin necrosis. One patient developed an occlusion of a suprainguinal graft without anastomotic stenosis after 9 months; 2 other grafts occluded at 12-month intervals. At a median follow-up of 16 months, the remaining 6 patients had no signs of restenosis.

The restenosis rate of peripheral vascular grafts after external beam radiation was lower than expected without additional treatment. The value of this approach will now be determined in a randomized prospective trial.