Dissertations & Theses (Open Access)

Date of Award

Summer 5-2019

Degree Name

Master of Public Health (MPH)

Advisor(s)

Alanna C. Morrison, Phd

Second Advisor

Houssam K. Younes, Md

Abstract

Objective: Endovascular intervention is commonly pursued as first-line management of symptomatic, long-segment superficial femoral artery (SFA) disease. The relative effectiveness and comparative long-term outcomes among bare metal stents (BMSs), covered stents (CSs), and drug-eluting stents (DESs) for long-segment SFA lesions remain uncertain.

Methods: A retrospective cohort study identified patients with symptomatic SFA lesions measuring at least 15cm who successfully received an endovascular stent (BMS, CS, or DES). The outcomes were patency, patient presentation upon stent occlusion, amputation free survival (AFS), and all-cause mortality. Proportional hazards regressions and a multinomial logistic regression model were used to control for significant confounders.

Results: A total of 226 procedures were analyzed (BMS: 95 [42%]; CS: 74 [33%]; DES: 57 [25%]). There were no significant differences among the three stent types with respect to age, prevalence of either diabetes or end-stage renal disease, or smoking history. The median length of the SFA lesion varied across the cohorts (BMS: 28cm (interquartile range [IQR] 20-30cm); CS: 26cm [IQR 20-30cm]; DES: 20cm [IQR 16-25cm]; P = .002). The unadjusted primary patency of BMSs at 12-, 24-, and 48-months following index stent placement was 57%, 47%, and 44%, respectively. This is compared to 62%, 49%, and 42% for CSs, and 81%, 66%, and 53% for DESs, respectively (log-rank P = .044). In adjusted models, however, there were no significant differences in primary patency among the stent types. Compared to CSs however, DESs were associated with improved primary-assisted patency (hazard ratio [HR] for patency loss: 0.35, P = .008) and secondary patency (HR: 0.32, P = .011). Across the entire follow-up period, stent occlusions occurred in 38 (40%) BMS cases, 42 (57%) CSs, and 11 (19%) DESs (P < .001). Of these, acute limb ischemia (ALI) occurred in 2 (5%) BMS cases, 14 (33%) CSs, and 1 (9%) DES (P = .010). After adjustment, the relative risk of presenting with ALI as opposed to claudication was 27 times greater among occluded covered stents compared to bare metal stents (P = .020). There were no significant differences in AFS or all-cause mortality across the three cohorts.

Conclusions: For long-segment SFA lesions, DESs are associated with improved primary assisted and secondary patency over long-term follow-up. In the event of stent occlusion, covered stents confer an increased risk of acute ischemia.

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