Rupture of excluded popliteal artery aneurysm: implications for type II endoleaks--a case report

The fate of popliteal artery aneurysms after ligation and bypass is believed to be relatively innocuous. The patient presented in this report, however, experienced spontaneous rupture of a popliteal aneurysm 11 years after ligation and bypass. Magnetic resonance angiography was used to establish the diagnosis of rupture, which was subsequently confirmed at surgery. Intraoperative arteriography demonstrated persistent collateral arterial perfusion of the excluded popliteal aneurysm sac. The collateral arterial flow originated from the superior and inferior lateral genicular arteries. The persistent arterial perfusion resulted in growth of the aneurysm from 4.2 to 7.0 cm over the 11-year period. The ruptured aneurysm was successfully treated by direct arterial exposure and suture ligation of the collateral vessels performed from within the aneurysm sac. The development of popliteal aneurysm expansion and rupture as a result of collateral arterial perfusion suggests that persistent collateral perfusion of abdominal aortic aneurysms after endovascular repair (type II endoleak) may lead to aneurysm rupture. Therefore, close observation and intervention for aneurysm expansion to prevent rupture of the excluded aneurysm are warranted.