The Effect of Immunosuppression on Lower Extremity Arterial Bypass Outcomes

Abstract

Myointimal hyperplasia is a pathologic result of the body's natural inflammatory response to injury of the blood vessels and a leading cause of peripheral arterial bypass failure. Because immunosuppressive agents are known to abate inflammation, we hypothesized the superior outcome of lower extremity bypass in renal transplant recipients compared with the hemodialysis population. The vascular surgery registry at a single tertiary care center was retrospectively reviewed to identify patients who underwent lower extremity bypass procedures. All patients with a history of renal transplantation were selected for analysis. A consecutive group of bypass patients with dialysis-dependent renal failure was selected as a control cohort. The primary endpoint was amputation-free survival. Vascular reconstruction for chronic peripheral vascular disease yielded an amputation-free survival rate of 82% at 1 year for the those in the control group as compared with only 22% in the those with a history of renal transplantation (p = 0.02), which corresponded exactly with primary patency at 1 year. Patients were operated on for severe claudication (n = 1), rest pain (n = 1), and tissue loss (n = 17). There was no difference between the groups with regard to indication for operation or comorbid conditions. These data suggest a deleterious effect of immunosuppression on outcome of lower extremity bypass procedures at the doses required to prevent allograft rejection. This finding, which has been scarcely reported, underscores the importance of peripheral vascular disease screening in the transplant population and early intervention when clinically indicated.