Specialists Performing Carotid Stenting Procedures

Carotid endarterectomy is performed on approximately 100,000 Americans every year to reduce their risk for stroke, a procedure performed by surgeons, followed by diagnostic carotid and cerebral angiography by radiologists. According to researchers, carotid stenting has emerged as a “promising and innovative alternative to carotid endarterectomy.” Carotid stenting is minimally invasive and may be of particular benefit in patients at high risk. Initially approved in 2004, carotid stenting has been adopted by physicians in a range of specialties including surgery, radiology, and cardiology. How physician specialty related to utilization rates or outcomes has not been well documented. The researchers recently conducted an observational analysis to examine the current specialty composition of physicians performing carotid stenting and the extent to which specialty accounts for variation in use and outcomes across varying healthcare markets. They reported study results online in Archives of Internal Medicine [doi:10.1001/archinternmed.2011.354]. The researchers analyzed data from the Centers for Medicare & Medicaid Services Physician Carrier (Part B), Medicare Provider Analysis and Review (MEDPAR), and Denominator files from January 1, 2005, to December 31, 2007. Physician Carrier files include claims from noninstitutional healthcare providers, MEDPAR files provide data on acute care hospitalizations, and Denominator files contain information on eligibility and enrollment. The analysis included data on Medicare beneficiaries ≥65 years of age who underwent carotid stenting during the study period in 306 hospital referral regions (HRRs). The researchers assessed how frequently carotid stenting was performed by physicians with various specialties in each HRR and then utilized multivariable regression models to compare population-based utilization rates and 30-day outcomes for the procedure across HRRs, based on the proportion performed by cardiologists, surgeons, radiologists, or a combination of specialists. There were 26,889 patients who were continuously enrolled in fee-for-service programs at least 1 year prior to their procedure. The researchers reviewed all claims in the Physician Carrier and MEDPAR files to gather data on the presence of comorbidities in this subset population. International Classification of Diseases, Ninth Revision, Clinical Modifications diagnostic codes were used to calculate an Elixhauser comorbidity score. The analysis found 272 HRRs where a minimum of 15 carotid stenting procedures were performed. The researchers identified 28,700 procedures in 26,938 patients during the study period. Of those, 52.0% (n=14,919) were performed by cardiologists, 27.3% (n=7840) by surgeons, and 17.8% (n=5112) by radiologists; the remaining 3.2% (n=829) were performed by other specialties (primarily neurologists and internal medicine physicians). Of the operators performing carotid stenting, 34.9% (n=904) were cardiologists, 33.4% (n=864) were surgeons, 27.8% (n=719) were radiologists, and 3.9% (n=101) were other specialists. In the group of surgeons, 62.4% (n=539) were vascular surgeons, 20.8% (n=180) were general surgeons, 7.9% (n=68) were neurosurgeons, and 7.9% (n=68) were cardiothoracic surgeons. Among patients treated by cardiologists, there were significantly higher rates of invasive cardiac procedures and lower rates of acute stroke or transient ischemic attacks in the 180 days before the procedure compared with patients treated by other specialists. In addition, in HRRs where cardiologists performed most of the procedures, population-based utilization rates were significantly higher than in HRRs where most carotid stenting procedures were done by other specialists or a combination of specialists (P<.001). HRRs where cardiologists performed most carotid stenting procedures were more likely to be located in the South and the Midwest and to have a greater number of operators performing the procedure per 100,000 enrollees, compared with HRRs where other specialists performed most of the carotid stenting procedures. There was no difference in 30-day risk-standardized mortality (1.9% vs 1.9%; P=.26) or 30-day risk-standardized mortality or stroke admission (4.6% vs 4.8%; P=.12) in HRRs where cardiologists performed most of the stenting procedures compared with HRRs where other specialists performed most of the carotid stenting procedures. Cardiologists were more likely to perform carotid stenting in patients with Elixhauser comorbidities related to cardiovascular conditions but less likely to do so in patients with neurologic conditions. In conclusion, the researchers stated that, “Carotid stenting is being performed by operators from diverse specialties. Hospital referral regions where cardiologists perform most procedures have higher population-based utilization rates with similar outcomes.”