Cost-Effectiveness of Solitaire Stent Retriever Evaluated in the SWIFT PRIME Trial

February 7, 2017—Findings on the cost-effectiveness of thrombectomy using the Solitaire stent retriever (Medtronic) for acute ischemic stroke in the SWIFT PRIME trial (Solitaire With the Intention for Thrombectomy as Primary Endovascular Treatment for Acute Ischemic Stroke) were published by Theresa I. Shireman, PhD, et al in Stroke (2017;48:379–387).

According to the investigators, clinical trials have demonstrated improved 90-day outcomes for patients with acute ischemic stroke treated with stent retriever thrombectomy plus tissue-type plasminogen activator (SST+tPA) compared with tPA alone. Previous studies suggested that this strategy may be cost-effective, but models were derived from pooled data and older assumptions.

As summarized in Stroke, in this prospective economic substudy conducted alongside the SWIFT PRIME trial, in-trial costs were measured for patients using detailed medical resource utilization and hospital billing data. Utility weights were assessed at 30 and 90 days using the EuroQol-5 dimension questionnaire. Post-trial costs and life expectancies were estimated for each surviving patient using a model based on trial data and inputs derived from a contemporary cohort of ischemic stroke survivors.

The investigators found that index hospitalization costs were $17,183 higher per patient for SST+tPA than for tPA ($45,761 vs $28,578; P < .001), driven by initial procedural costs. Between discharge and 90 days, costs were $4,904 lower per patient for SST+tPA than for tPA ($11,270 vs $16,174; P = .014); total 90-day costs remained higher with SST+tPA ($57,031 vs $44,752; P < .001). Higher utility values for SST+tPA led to higher in-trial quality-adjusted life-years (0.131 vs 0.105; P = .005). In lifetime projections, SST+tPA was associated with substantial gains in quality-adjusted life-years (6.79 vs 5.05), cost savings of $23,203 per patient, and was economically dominant when compared with tPA alone in 90% of bootstrap replicates.

Among patients with acute ischemic stroke enrolled in the SWIFT PRIME trial, SST increased initial treatment costs but was projected to improve quality-adjusted life-expectancy and reduce health care costs over a lifetime horizon compared with tPA alone, concluded the investigators in Stroke.