Graft patency is not the only clinical predictor of success after exclusion and bypass of popliteal artery aneurysms

Abstract

Purpose: The traditional measure of success after exclusion and bypass of popliteal artery aneurysm (PAA) is graft patency. In addition to fate of the bypass, we hypothesize that late outcome after surgical treatment of PAA is influenced by completeness of exclusion. Methods: Thirty patients who underwent 41 reconstructions for PAA over a 10-year period were reviewed. Results: Excluded PAAs were examined with duplex ultrasound scan for size, patency, and patent feeding branches; bypass grafts and native inflow and outflow arteries were examined for patency and size. Thirty-six limbs were available for follow-up (mean follow-up period, 46 ± 42 months). Only two aneurysms (5.6%) appeared patent on duplex ultrasound scan, but five limbs had patent arterial branches communicating with thrombosed excluded PAAs. PAA diameter decreased from 2.5 ± 0.8 cm to 1.7 ± 0.5 cm (P < .0001) in most. However, 12 excluded PAAs (33%) showed significant enlargement from 2.2 ± 0.9 cm to 2.8 ± 1.0 cm (P = .002). A quarter of enlarging excluded PAA were associated with new compressive symptoms. Three methods of PAA exclusion were used: proximal and distal ligation with short segment isolation (type 1), proximal and distal ligation with long segment isolation (type 2), and single ligature (type 3). In univariate analysis, type of exclusion significantly influenced late size of excluded PAA (P = .004). Type 1 exclusion was superior to both type 2 and 3 exclusions in producing aneurysm diameter reduction. Type 3 exclusion resulted in aneurysm growth. In addition, excluded aneurysms with visualized feeding branches were associated with significant growth compared with PAAs without feeding branches (P = .006). Graft primary and assisted primary patency rates at 5 years were 86% ± 9.4% and 92% ± 7.4%, respectively. Although graft diameter and native donor artery diameter significantly increased, this did not adversely affect graft patency. Conclusion: Enlargement of excluded PAA after surgical treatment can cause compressive symptoms. Exclusion requires adequate vascular isolation to prevent late PAA enlargement, with proximal and distal arterial ligation best performed adjacent to the aneurysm. Vein graft enlargement occurs, but this enlargement does not adversely influence patency.