NEW YORK – The rates of carotid artery revascularization with either endarterectomy or stenting declined precipitously over a recent 15-year period, at least among Medicare fee-for-service beneficiaries, according to data presented at a symposium on vascular and endovascular issues sponsored by the Cleveland Clinic Foundation.
A reduction in carotid endarterectomies (CEA) largely accounted for the decline during 1999-2014 although there was a cumulative decline in all carotid revascularization procedures when rates of CEA and stenting were combined, according to, professor of surgery, University of Maryland Medical System, Baltimore.
In 1999, when enthusiasm for CEA appears to have peaked, 81,306 patients received this procedure, but a steady decline was observed until 2014, when 36,325 patients were being treated annually in the Medicare database. When calculated as endarterectomies per 100,000 beneficiaries, the rate declined from 298 to 128 (57%; P less than .001) over this 15-year period.
The number of stenting procedures had not reached its peak in 1999, when 10,416 were performed. Rather, the number performed annually nearly doubled to, 22.865 by 2006. However, it then began to decline and reached 10,208 by 2014, which was slightly fewer than in 1999, according to Dr. Lal.
These trends have been observed even though outcomes are getting better, at least for CEA, according to Dr. Lal. From the same pool of data, there was a 31% (1.1% vs. 1.6%) reduction from 1999 to 2014 in mortality at 30 days following CEA. For a composite of ischemic stroke and all-cause mortality, the rate fell 29.5% (3.1% vs. 4.4%). Both reductions were called statistically significant by Dr. Lal.
The improvements in CEA outcomes were observed even though “the treated patients got sicker when looking at comorbidities and risk factors, particularly hypertension, renal insufficiency, and diabetes,” Dr. Lal said.
Outcomes also improved among patients undergoing carotid stenting in general, although the patterns were described as “more complex.” In general, there was steady improvement on outcomes during 1999-2006, but there was no further gain and some lost ground during 2006-2014. For example, ischemic stroke or death fell from 7.0% in 1999 to 4.8% in 2006, but it had climbed back to 7.0% by 2014 with no net change when the first and last year were compared.
However, with risk adjustment, there was a reduction in in-hospital mortality (1.13% vs. 2.78%) over the study period for patients undergoing carotid stenting, according to Dr. Lal, who said this reached statistical significance. Like the CEA group, there was more comorbidity among those treated with stenting at the end, relative to the early part of the study period.
In the stenting group, patients with symptomatic carotid disease rose from 14.4% in 1999 to 25.9% in 2014. This tracks with Medicare policy, which required patients after 2005 to have symptomatic disease for reimbursement, according to Dr. Lal. Prior to 2005, reimbursement was granted for patients participating in clinical trials only.
The rates of carotid revascularization are not evenly distributed geographically in the United States, according to the Medicare data. Endarterectomy in particular has been more common in the south and Midwest than on either coast. This was true in 1999 and remained so in 2014. The distribution was similar for stenting, although it was also relatively common in the southwest in the early part of the study period.
In the beginning of the study, the increased rate of stenting might have contributed to the decline in endarterectomy, but there are several other factors that are implicated in the observed trends, according to Dr. Lal. He suggested that decreasing reimbursement for the performance of these procedures, better clinical management of risk factors, and advances in medical therapy. He cited a physician survey that showed a growing preference for medical management over invasive procedures in patients with high-grade stenosis and indicated that this last factor might be a particularly important driver of the decline in revascularization referrals for asymptomatic carotid disease.
The degree to which these Medicare data are representative of overall trends in the United States is unclear, but Dr. Lal called for further work to understand the forces that these data suggest are driving the changing patterns of carotid revascularization.