Cost-Effectiveness of Screening for Asymptomatic Carotid Artery Stenosis Based on Atherosclerotic Cardiovascular Disease Risk Thresholds

Abstract

AbstractBackgroundCarotid artery stenosis (50-99% extracranial internal carotid artery narrowing) is a risk factor for ischemic stroke. Yet, no population-based studies have directly assessed the benefits and harms of screening for asymptomatic carotid artery stenosis (ACAS). Given the variability in ACAS prevalence and stroke risk according to clinical factors, we sought to evaluate the cost-effectiveness of ACAS screening by cardiovascular risk-stratified subgroups.MethodsWe developed a microsimulation model of ACAS and stroke to project the lifetime costs and quality-adjusted life-years (QALYs) associated with ACAS screening, stratified by individuals’ 10-year atherosclerotic cardiovascular disease (ASCVD) risk predicted from the pooled cohort equations. The model cohort was representative of US adults aged 50–80 years without history of stroke, constructed using sampling with replacement from the National Health and Nutrition Examination Survey. We used the Cardiovascular Health Study to estimate the severity of ACAS based on individual characteristics (e.g., age, sex, smoking status, blood pressure, and cholesterol). Stroke risks were functions of these characteristics and ACAS severity. In the model, individuals testing positive with Duplex ultrasound (>70% stenosis) and a confirmatory diagnostic test undergo revascularization, which reduces the risk of stroke but also introduces complication risks. Diagnostic performance parameters, revascularization benefits and risks, event rates associated with stroke, utility weights, and costs were estimated from published sources. Cost-effectiveness was assessed from the health care sector perspective using a $100,000/QALY threshold.ResultsWe found that screening individuals with a 10-year ASCVD risk greater than 25% was the most cost-effective strategy, with an incremental cost-effectiveness ratio of $78,000/QALY. This strategy would make approximately 23% of the US adult population aged 50–80 years eligible for screening, averting an estimated 53,709 strokes. Results were sensitive to variations in key parameters, including the efficacy and complication risk of revascularization.ConclusionsAlthough the US Preventive Services Task Force recommends against ACAS screening in the general population, a one-time screening may be cost-effective for adults with ASCVD risk >25%. Nonetheless, the cost-effectiveness of such screening is contingent on updated findings from ongoing research like the CREST-2 trial, which could reshape the understanding of revascularization’s efficacy in contemporary medical practice.