Neal S. Parikh, MD
Ganesalingam J, Pizzo E, Morris S, Sunderland T, Ames D, and Lobotesis K. Cost-Utility Analysis of Mechanical Thrombectomy Using Stent Retrievers in Acute Ischemic Stroke. Stroke. 2015
Five large, randomized clinical trials recently demonstrated that mechanical thrombectomy (MT) significantly reduces disability and mortality in patients presenting with proximal large vessel occlusions. MT is performed after IV-tPA administration or, when IV-tPA is contraindicated, as the sole intervention. In this issue of Stroke, Ganesalingam and colleagues seek to determine whether adjunctive MT for stroke is cost-effective, as compared to IV-tPA alone.
Data from the MT trials were used to determine the proportion of patients expected to achieve three functional categories (independent, dependent and deceased). These data were then run through a long-run Markov state-transition model to estimate the costs and outcomes over 20 years. The Markov model was transformed every 3 months over 20 years, which means patients in the independent (mRS 0,1,2) category were given the ability to have a recurrent stroke and change to any of the three states. The model utilizes cost data from the United Kingdom’s National Health Services (NHS): the cost of TPA was $2,953, the cost of MT was $13,803. The model makes a reasonable, evidence-based assumption that functional outcome correlates with quality adjusted life years (QALYs). Cost effectiveness was determined by assessing the incremental cost per gained QALY and the Net Monetary Benefits (NMB) of adjunctive MT over IV-tPA alone. NHS thresholds for willingness to pay per QALY were utilized: $33,000-$49,500.
The incremental cost of MT over IV-tPA alone was $11,651 per QALY gained. The NMB was below even the lower willingness to pay thresholds. Varying the cost of MT up to $33,000 and the utility of functional independence did not negate the results.
Given the meaningful clinical impact of MT on disability and death and the cost-effectiveness of the therapy, it is imperative that the treatment be made available to more patients. The therapy will become more cost-effective with improvements in stroke referral networks, technology and futile inter-hospital transfer rates (1). However, propagation of MT will face costly infrastructure challenges, as, even under optimal modeling, access to comprehensive stroke centers is limited in the United States (2). It would be worthwhile to assess the comparative and cost effectiveness of directed stroke prevention as compared to stroke treatment infrastructure development.
(1) Fuentes, et al. Futile interhospital transfer for endovascular treatment in acute ischemic stroke. Stroke. 2015;46:2156-2161.
(2) Mullen, et al. Optimization modeling to maximize population access to comprehensive stroke centers. Neurology. 2015;84:1196-1205.