Surgical management of popliteal artery aneurysms: which factors affect outcomes?

OBJECTIVE

Popliteal artery aneurysm (PAA) is uncommon. The clinical presentation of PAA includes rupture, embolism, and thrombosis. In this article, we evaluate the results of our 20-year experience with surgical management of PAAs, analyzing the role of anatomic, clinical, and surgical factors that potentially affect early and long-term results.

METHODS

From January 1984 to December 2004, 159 PAAs in 137 patients were operated on at our department. Data from all the patients were retrospectively collected in a database. PAAs were asymptomatic in 67 cases (42%); 5 (3%) PAAs were ruptured. In 51 cases (32%), PAA caused intermittent claudication. The remaining 36 limbs (23%) had threatening ischemia due in 30 cases to acute PAA thrombosis, in 4 cases to chronic PAA thrombosis, and in 2 cases to distal embolization. In selected patients with acute ischemia, preoperative intra-arterial thrombolysis with urokinase was performed. Early results in terms of mortality, graft thrombosis, and limb salvage were assessed. Follow-up consisted of clinical and ultrasonographic examinations at 1, 6, and 12 months and yearly thereafter. Long-term survival, patency, and limb salvage rates were analyzed.

RESULTS

Forty cases were treated with aneurysmectomy and prosthetic graft interposition; in 39 cases, the aneurysm was opened, and a graft was placed inside the aneurysm. Four patients had aneurysmectomy with end-to-end anastomosis. In 73 cases, ligation of the aneurysm with bypass grafting (39 with a prosthetic graft and 34 with an autologous vein) was performed. The remaining three patients underwent endovascular exclusion of their PAAs. A medial approach was used in 97 patients (61%), and a posterior approach was used in 59 patients (37.1%). The outflow vessel was in most cases (93.7%) the below-knee popliteal artery. Thirty-day amputation and death rates were 4.4% (7/159 limbs) and 2.1% (3/137 patients), respectively. The amputation rate was significantly higher in symptomatic limbs than in asymptomatic ones (6.5% and 1.4%, respectively; P = .05). Eight limbs (5%) had an early graft thrombosis that required a reintervention. Follow-up was available in 116 patients (84.7%) and 138 limbs (86%) with a mean follow-up time of 40 months (range, 1-205 months). The cumulative estimated 60-month survival, limb salvage, and primary and secondary patency rates were 84.2%, 86.7%, 66.3%, and 83.6%, respectively. Asymptomatic limbs had significantly better results than symptomatic ones in terms of limb salvage (93.4% and 80.4%, respectively; P = .03; log-rank, 4.2) and primary patency (86.5% and 51.6%, respectively; P = .001; log-rank, 10.3). Among symptomatic patients, results were better in claudicant limbs than in acutely ischemic ones in terms of limb salvage (90.5% and 58.7%, respectively; P = .001; log-rank, 17.5). Univariate analysis showed the absence of symptoms, the presence of two or three tibial vessels, the use of a posterior approach, the kind of intervention, and the site of distal anastomosis to significantly affect long-term patency. Cox regression for factors affecting 60-month primary patency showed that clinical presentation, runoff status, and the site of distal anastomosis significantly influenced long-term results.

CONCLUSIONS

Results of surgery on asymptomatic PAAs are good-significantly better than those for symptomatic ones. Elective surgical intervention should be performed in patients with a low surgical risk and a long life expectancy when the correct indication exists. In thrombosed aneurysms, intra-arterial thrombolysis may represent an alternative to emergent surgical management. Our data demonstrated that results are similarly good in claudicants, and this fact confirms that only acute ischemia due to PAA thrombosis represents a real surgical challenge. In selected patients with focal lesions, a posterior approach seems to offer better long-term results. The runoff status and the site of distal anastomosis affect long-term patency as well.