Growth of Carotid Artery Duplex Ultrasound Among Medicare Beneficiaries (2000-2007)

OBJECTIVE. Although intervention in asymptomatic carotid artery stenosis remains controversial, most carotid interventions are performed in asymptomatic individuals. Carotid duplex ultrasound is the diagnostic test that precedes more than 90% of carotid interventions. In terms of economic incentives, providers who perform carotid artery revascularization may experience synergy if they also provide carotid duplex ultrasound, because the diagnostic service is reimbursed and also can lead to referrals for revascularization procedures. To test the hypothesis that providers of revascularization services are incentivized to increase utilization of carotid duplex ultrasound, we compared the utilization of carotid duplex ultrasound among Medicare beneficiaries by three specialties that perform revascularization for carotid stenosis (interventional radiology, vascular surgery, and cardiology) with one that usually does not (diagnostic radiology). MATERIALS AND METHODS. We analyzed 100% of procedure-specific claims submitted to Medicare by the four specialties during 2000, 2002, 2004, 2005, 2006, and 2007. Only professional and global components of services approved by Medicare were included. Compounded annual growth rates were used to compare utilization by different specialties. RESULTS. Utilization by diagnostic radiology increased at a compound annual growth rate of 1% during 2000-2007. Interventional radiology and vascular surgery experienced higher compound annual growth rates of 3% and 6%, respectively. Utilization by cardiology increased at a rate 11 times that of diagnostic radiology, translating into an additional 960 procedures per 100,000 Medicare beneficiaries by cardiology in 2007 than in 2000. CONCLUSION. Medicare beneficiaries are increasingly being tested for carotid artery stenosis, especially by specialties that perform revascularization for carotid stenosis. The health benefits of this practice are uncertain.