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Lower extremity bypass in the Medicare population: Type, technique and outcomes
Objective: The purpose of this study was to compare rates of secondary interventions and amputation-free survival after femoral-popliteal (FPB) and femoral-tibial bypass (FTB) with In Situ or reversed vein technique in the Medicare population with claudication and critical limb ischemia (CLI).
Methods: Secondary analysis of the MedPAR file from 2005 to 2008. Rates of secondary procedures (patch angioplasty, segmental vein interposition and vein graft thrombectomy) during 30, 60 and 90 days after the initial bypass were compared with Chi-square and multivariable logistic regression analysis. Kaplan-Meier method with estimating and comparing survival curves and Cox proportional hazard method with adjustment for possible confounders and computing hazard ratio (HR) with 95% confidence interval (CI) were utilized for comparison of one year amputation-free survival.
Results: Patients with CLI and FTB were more likely than those with FPB to have segmental vein interposition and vein graft thrombectomy in all observed periods. The latter was also found in patients with claudication. These patients, in addition, were more likely to have patch angioplasty during 60 and 90 days after FTB compared to FPB. There were no significant differences in the rates of the secondary interventions between the two bypass techniques in all patients. For patients in both clinical groups (claudication and CLI) one year amputation-free survival after FTB was significantly worse than after FPB (claudication: HR=2.8, 95%CI=1.69-2.81, P<0.0001; CLI: HR=1.4, 95%CI=1.33-1.46, P<0.0001). Among patients who underwent FPB we found differences in the amputation-free survival associated with the bypass technique (In Situ or reversed). Those with claudication and reverse vein bypass had worse amputation free survival than patients with the In Situ technique (HR=1.56, 95%CI=1.04-2.33, P=0.03). In the CLI group with FPB, patients with reversed vein technique also tended to worse outcome (HR=1.08, 95%CI=1.0-1.16, P=0.06). However, among patients who underwent FTB, we did not find a significant difference in one-year amputation-free survival between patients with In Situ and reverse vein technique in both clinical groups.
Conclusion: Femoral-popliteal bypass has significantly lower rates of secondary interventions and better amputation-free survival compared to femoral-tibial bypass regardless of indication for the bypass. In patients who undergo femoral-popliteal bypass, the In Situ technique may be advantageous.