Systemic Immunosuppression Does Not Affect Revascularization Outcomes in Patients with Chronic Limb Threatening Ischemia.

Overview

abstract

OBJECTIVE: Many patients with chronic limb threating ischemia (CLTI) have additional comorbidities requiring systemic immunosuppression. Few studies have analyzed whether these medications may inhibit graft integration and effectiveness, or conversely, whether they may prevent inflammation and/or restenosis. Therefore, our study aim was to examine the effect of systemic immunosuppression versus no immunosuppression on outcomes following any first-time lower extremity revascularization for CLTI. METHODS: We identified all patients undergoing first-time infrainguinal bypass graft (BPG) or percutaneous transluminal angioplasty with or without stenting (PTA/S) for CLTI at our institution between 2005-2014. Patients were stratified by procedure type and immunosuppression status, defined as ≥6 weeks of any systemic immunosuppression therapy ongoing at the time of intervention. Immunosuppression versus non-immunosuppression were the primary comparison groups in our analyses. Primary outcomes included perioperative complications, re-intervention, primary patency, and limb salvage, with Kaplan Meier and Cox proportional hazard models used for univariate and multivariate analyses, respectively. RESULTS: Among 1,312 patients, 667 (51%) patients underwent BPG and 651 (49%) underwent PTA/S, of whom 65 (10%) and 95 (15%) were on systemic immunosuppression therapy, respectively. Whether assessing BPG or PTA/S patients, there were no differences noted in perioperative outcomes, including perioperative mortality, myocardial infarction (MI), stroke, hematoma, and surgical site infection (p>0.05). For BPG patients, Kaplan-Meier analysis and Log-rank testing demonstrated no significant difference in three-year reintervention (37% vs. 33% [control], p=0.75), major amputation (27% vs. 15%, p=0.64), or primary patency (72% vs. 66%, p=0.35) rates. Multivariate analysis via Cox regression confirmed these findings (Immunosuppression HR for reintervention: 0.95, 95% CI [0.56-1.60], p=0.85; for major amputation: HR 1.44, 95% CI [0.70-2.96], p=0.32; for primary patency: HR 0.97, 95% CI [0.69-1.38], p=0.88). For PTA/S patients, univariate analysis revealed similar rates of reintervention (37% vs. 39% [control], p=0.57) and primary patency (59% vs. 63%, p=0.21); however, immunosuppressed patients had higher rates of major amputation (23% vs. 12%, p=0.01). After using Cox regression to adjust for baseline demographics, as well as operative and anatomic characteristics, immunosuppression was not associated with any differences in reintervention (HR 0.75, 95% CI [0.49-1.16], p=0.20), major amputation (HR 1.46, 95% CI [0.81-2.62], p=0.20), or primary patency (HR 0.84; 95% CI [0.59-1.19]; p=0.32). Sensitivity analyses for the differences in makeup of immunosuppression regimens (steroids vs. other classes) did not alter the interpretation of any findings in either BPG or PTA/S cohorts. CONCLUSIONS: Our findings demonstrate that patients with chronic systemic immunosuppression, as compared to those who are not immunosuppressed, does not have a significant effect on late outcomes following lower extremity revascularization, as measured by primary patency, reintervention, or major amputation.