Introduction: The Vertebrobasilar Flow Evaluation and Risk of Transient Ischemic Attack and Stroke (VERiTAS) study demonstrated posterior circulation distal flow status, as determined by quantitative magnetic resonance angiography (qMRA), is a robust predictor of vertebrobasilar (VB) stroke risk in patients with symptomatic atherosclerotic VB disease. In this study we examine the cost-effectiveness of qMRA screening in identifying patients who may benefit from submaximal angioplasty to restore VB flow.
Methods: A Markov model was created comparing a “no screening” strategy with standard medical management alone and a “screening” strategy involving qMRA imaging and submaximal angioplasty for treatable patients with low VB flow. A 30 year time horizon was modeled. Outcomes included the average number of quality-adjusted life years (QALY) and lifetime costs. Rates of stroke and death were obtained from VERiTAS data, and disability rates and costs were derived from VERiTAS and the literature.
Results: At a 6% periprocedural stroke risk, the “screening” strategy saved an average of 0.364 QALYs per patient, and a lifetime cost savings of $8,346 versus the “no screening” strategy. Amongst patients with low flow suitable for intervention, the benefit was substantially higher, averaging 1.485 QALYs saved and lifetime cost savings of $28,017. The benefit of screening declined at higher periprocedural risk.
Conclusions: qMRA screening and submaximal angioplasty in suitable patients is cost-effective both in terms of QALY and lifetime costs for patients with symptomatic VB occlusive disease. With potential health and economic savings, a clinical trial examining the peri-procedural risk of submaximal angioplasty is warranted.
Patient Care: Vertebrobasilar (VB) disease is common and associated with a high rate of morbidity and mortality. The Vertebrobasilar Flow Evaluation and Risk of Transient Ischemic Attack and Stroke (VERiTAS) study identified that posterior circulation distal flow status, as determined on qMRA, is a robust predictor of VB stroke risk. Whether or not qMRA screening in patients with VB disease leads to better clinical outcomes and cost savings is unknown, however.
This research applies a quantitative Markov model to data from VERiTAS and the literature to identify that screening and submaximal angioplasty leads to an increase in quality adjusted life years (QALY) and lifetime medical costs in patients with symptomatic VB disease. This may improve patient care by justifying screening and intervention in patients with posterior circulation ischemia secondary to atherosclerotic disease.
In this study, a sensitivity analysis further quantifies QALY and cost savings for prospective patients based on their life expectancy and peri-procedural stroke risk to aid decision making. Taken together, the results of this study provide evidence that qMRA screening yields both health and economic savings, and justifies a clinical trial examining peri-procedural risk of submaximal angioplasty in this challenging population.
Learning Objectives: By the conclusion of this session, participants should be able to:
1) Describe the QALY and lifetime cost benefits of qMRA screening and submaximal angioplasty in patients with symptomatic VB occlusive disease.
2) Identify if a specific patient with symptomatic VB occlusive disease may benefit from qMRA screening given their life expectancy and institutional peri-procedural angioplasty stroke risk.
3) Recognize the utility of Markov computational models to evaluate the effectiveness of different treatment strategies.