Long-Term Results and Risk Analysis of Redo Distal Bypass for Critical Limb Ischemia.

BACKGROUND: Distal bypass is the optimal treatment for patients with critical limb ischemia (CLI). However, effectiveness of redo distal bypass (rDB) after failed initial distal bypass (iDB) remains uncertain. This study aimed to analyze long-term results of rDB for CLI.

METHODS: Patients undergoing rDB for CLI from 2009 to 2018 at a single institute were retrospectively reviewed. Operative details, primary and secondary patency, survival rate, major amputation-free rate, and risk factors affecting patency were analyzed. The distal runoff was evaluated using the infrapopliteal Global Limb Anatomic Staging System (GLASS) grade (0 to 4: 0 represents good runoff and 4 represents the poorest runoff).

RESULTS: Of 310 iDB (251 patients), 46 rDB were performed in 44 patients: 27 men, mean age 75 ± 10 years, diabetes mellitus 77%, chronic renal failure with hemodialysis 45%. Only the autologous veins were used in distal bypasses: a great saphenous vein (GSV) in 28 (57%), a small saphenous vein in 13 (27%), an arm vein in 6 (12%), and a superficial femoral vein in 2 (4%). The GSV was used less frequently for rDB than for iDB (57% vs. 90%, P < 0.0001). The infrapopliteal GLASS grade 4 was recognized more in rDB than iDB (76% vs. 60%, P = 0.04). Primary and secondary patency of rDB was 25% and 44% at 1 year and 14% and 29% at 3 years, respectively, which were significantly lower than those of iDB (P < 0.0001). The survival rate after rDB was 68% at 1 year and 53% at 3 years. Freedom from major amputation rate in rDB was 83% at 1 year and 66% at 3 years. Multivariate analysis showed the risk factor influencing on secondary patency was patent duration of the iDB graft (P = 0.012). Secondary patency of rDB was higher in the group of late graft occlusion ≥6 months after iDB (late group) than in the group of early graft occlusion < 6 months after iDB (early group) (94% vs. 9% at 1 year and 75% vs. 5% at 3 years, P < 0.0001). However, freedom from major amputation rate at 3 years was comparable between both groups (71% in the late group vs. 61% in the early group).

CONCLUSIONS: Patency of rDB was significantly lower than that of iDB partly because of less use of the GSV and poorer runoff. Because survival and graft patency after rDB was low, rDB should be a suboptimal treatment especially in patients with early graft occlusion within 6 months after iDB.