Mortality Data for CAS Can Tease Out Poorly Performing Medicare Hospitals

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Thirty-day mortality rates after carotid artery stenting (CAS) vary widely among US hospitals certified by the Centers for Medicare and Medicaid Services to perform the procedure, reports a paper published online June 3, 2014, ahead of print in Circulation: Cardiovascular Quality and Outcomes.

Researchers led by Peter W. Groeneveld, MD, MS, of the University of Pennsylvania (Philadelphia, PA), suggest that the metric “could enhance Medicare’s ability to identify hospitals that are questionable candidates for recertification.” Currently, the biannual process relies on hospitals self-reporting details about their CAS programs and submitting registry data on baseline characteristics and short-term procedural complications.

The crude 30-day mortality rate was 2.0% overall, and adjusted mortality rates ranged from 1.1% to 5.1% (P < .001). In all, 69% of hospitals had a risk-standardized 30-day mortality rate above the national mean of 2.0% and 31% fell below that threshold.

Some hospitals had 95% confidence intervals for adjusted 30-day mortality that excluded the national mean on either end of the spectrum (table 1).

Table 1. Hospitals with Mortality Significantly Different from National Mean of 2.0%

Nine of the 13 poor performers (69.2%) were low-volume hospitals with fewer than 8 cases and 11 (84.6%) were academic medical centers. Of the hospitals with low mortality, all were nonacademic and located in the South. 

Because some deaths were likely avoidable, “it could be argued that the appropriate national benchmark mortality rate for acceptable quality should be lower,” the researchers add. Changing the cutoff to 1.75%, the number of hospitals with excessively high mortality rose to 51 (683 CAS procedures). A cutoff of 1.5% brought the total to 111 hospitals (1,849 CAS procedures).

“As even in the highly optimized settings of clinical trials, the mortality and morbidity rates after CAS were nontrivial, and because optimal use of CAS requires clinical expertise, institutional experience, and an extensive array of advanced technologies, efforts to restrict reimbursements solely to the hospitals that provide high-quality CAS seem justified,” Dr. Groeneveld and colleagues conclude. 

“These findings,” they add, “could easily and inexpensively be incorporated into Medicare’s recertification process to further refine the selection and certification of hospitals that are providing CAS with sufficient quality.” Lower-performing hospitals “may be appropriate targets for increased scrutiny at the time of recertification,” the investigators advise. 

In addition, while the current study echoes earlier research indicating a relationship between CAS procedure volume and 30-day mortality, it does “not suggest any discernible pattern to the geographic location or urban/rural status of hospitals” with poor outcomes, they note.

Epstein AJ, Yang L, Yang F, Groeneveld PW. A comparison of clinical outcomes from carotid artery stenting among US hospitals. Circ Cardiovasc Qual Outcomes. 2014;Epub ahead of print.

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