AIM: Various specialties want in on carotid stenting

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After covered stent deployment, lateral view, demonstrating Jostent covered stent in cavernous segment of internal carotid artery along guide wire.
Image source: Korean J Radiol 2010;11(6):603–611.

As indications for carotid artery stenting (CAS) continue to change and its use grows, the procedure is being performed by operators from many diverse specialties, Michigan researchers found in a study published online Aug. 8 in Archives of Internal Medicine. Additionally, hospital referral regions where cardiologists perform the most procedures have higher population-based utilization rates with similar outcomes.

“Nearly 100,000 Americans undergo carotid endarterectomy [CEA] each year with the goal of reducing their risk of stroke. This operative procedure is performed by surgeons, traditionally following diagnostic carotid and cerebral angiography by radiologists,” Brahmajee K. Nallamothu, MD, MPH, of the VA Health Services Research and Development Center of Excellence in Ann Arbor, Mich., and colleagues wrote.

In May, the FDA expanded indications for CAS, which now include patients at standard risk for surgery. “Since its initial approval in late 2004, use of carotid stenting has grown rapidly across the U.S., with enthusiastic adoption by operators from several diverse physician specialties including surgery, radiology and cardiology,” Nallamothu and colleagues wrote.

But even as CAS usage expands, understanding how physician specialty relates to utilization rates or outcomes remains uncertain.

Nallamothu and colleagues performed an observational analysis of fee-for-service Medicare beneficiaries who were 65 years or older and undergoing CAS procedures between Jan. 1, 2005, and Dec. 31, 2007 in 306 hospital referral regions (HRRs). The researchers determined how often CAS was performed by various specialists within each HRR and then used a multivariable regression model to compare population-based utilization rates and 30-day outcomes across each HRR.

The results showed that within the 272 HRRs where at least 15 procedures were performed, 28,700 CAS procedures were performed by 2,588 operators. Cardiologists made up nearly one-third of these operators and were responsible for 52 percent of procedures. Of the 14,919 total procedures, 27.3 percent were performed by surgeons, 17.8 percent were performed by radiologists and 3.2 percent were performed by specialists within the neurology and internal medicine field.

Of the total CAS procedures performed, 34.9 percent were by cardiologists, 33.4 percent by surgeons, 27.8 percent by radiologists and 3.9 percent by other specialists. Among the surgeons, 62.4 percent were vascular surgeons, 20.8 percent were general surgeons, 7.9 percent were neurosurgeons and 7.9 percent were cardiothoracic surgeons.

The researchers reported many differences between the characteristics of patients treated by cardiologists compared with other specialties, including higher rates of invasive cardiac procedures and lower rates of acute stroke or transient ischemic attacks prior to CAS procedures.

“After accounting for the number of operators, geographic region and baseline rates of carotid endarterectomy in 2004, HRRs where cardiologists performed most carotid stenting had significantly higher adjusted utilization rates relative to HRRs where most were done by other specialists or a mix of specialists but no differences in risk-standardized outcomes. Population-based utilization rates were higher in HRRs were cardiologists performed the most procedures,” the authors wrote.

“Unlike many medical procedures, carotid stenting is a 'cross-disciplinary' technology that is performed by operators from several, diverse physician specialties,” the authors wrote. “These groups have widely different clinical opportunities and incentives for performing it, which could lead to important differences in how patients are selected for carotid stenting.”

The researchers offered that because surgeons are the only operators involved in CAS who also perform CEA, they may be less likely to view CAS as a “first-line therapy and restrict their use to select cases.” Additionally, the authors wrote that educational training could play a part in when specialists decide which treatment to perform.

While Nallamothu and colleagues concluded that more studies will be necessary to understand whether multidisciplinary decision-making by specialist teams could enhance this procedure, currently, cardiologists perform the