Trends in CABG, PCI Rates Suggest Many Are Not Treated Optimally



The rate of coronary artery bypass grafting in U.S. hospitals declined by approximately one-third between 2001 and 2008, according to an analysis of the Agency for Healthcare Research and Quality database reported in the May 4 issue of JAMA.

During the same period, the rate of percutaneous coronary interventions (PCIs) showed a far more modest decrease. "Our data imply a sizeable shift in cardiovascular clinical practice patterns away from surgical treatment toward percutaneous, catheter-based interventions," said Andrew J. Epstein, Ph.D., of the Philadelphia Veterans Affairs’ Center for Health Equity Research and Promotion and the University of Pennsylvania, and his associates.

Given that coronary artery bypass grafting remains the better choice for patients with previously untreated three-vessel or left main coronary artery disease, according to the results of the SYNTAX trial (N. Engl. J. Med. 2009;360:961-72), it appears that CABG is being underused, the authors wrote. It seems likely that in recent years, "patients who would have been optimally treated with CABG surgery were instead treated with PCI," they noted.

To assess temporal trends in coronary revascularization procedures, the investigators examined a nationally representative sample of hospitalization claims using an Agency for Healthcare Research and Quality database. The database includes discharge data from approximately 1,000 nonfederal hospitals in 42 states, which covers 20% of U.S. hospitals and allows accurate estimates for the entire population of hospitalized patients, regardless of payer or insurance status.

Between 2001 and 2008, the total number of coronary revascularizations decreased "modestly," by approximately 15%.

There was a "substantial," statistically significant, 38% decrease in the annual rate of CABG surgery, from 1,742 per million adults in the first year of the study period to 1,081 per million in the final year. This decline was roughly linear throughout the 8-year study period, suggesting that it "was not triggered by any single event occurring during the past decade, such as the introduction of competing technologies, advances in CABG surgical techniques, publication of clinical trials, or issuance of clinical guidelines."

CABG procedures decreased across all sex, age, racial, and regional subgroups.

In contrast, the PCI rate remained fairly constant, showing a "modest" 4% decrease from 3,827 per million adults per year in the first year of the study to 3,667 in the final year.

"Projected to the entire U.S. population, these rate changes implied that 130,000 fewer CABG surgeries were performed in 2008 compared to 2001," Dr. Epstein and his colleagues noted (JAMA 2011;305:1769-76).

The data did not allow the researchers to distinguish which patients may have been more appropriate candidates for CABG than for PCI, so "it cannot be known with certainty whether physicians were increasingly substituting PCI for CABG surgery during the past decade. ... [But] our findings suggest the possibility that several thousand patients who underwent PCI in 2008 would have undergone CABG surgery had patterns of care not changed markedly," they said.

The preferences of patients were also not discernible from the data, lead investigator Dr. Peter W. Groeneveld said in an interview. "However, if patient preference [for PCI vs. CABG] was the driving factor, there would have to be some reason that PCI was even more preferable to patients in 2008 than it was in 2001. This scenario seems unlikely since the procedures haven’t changed that much," said Dr. Groeneveld, assistant professor of medicine at the University of Pennsylvania and staff physician at the Philadelphia Veterans Affairs Medical Center.

Another important finding was that during this interval, the number of hospitals providing CABG increased. Combined with the drop in the number of CABG surgeries, this resulted in a 28% decline in the median caseload per hospital, "and a substantial increase in the number of hospitals that provided fewer than 100 CABG surgeries per year."

Whether or not low-volume centers inherently have worse CABG outcomes can be debated, but either way "our findings highlight the increasing role of low-volume hospitals in the provision of CABG surgery," Dr. Epstein and his associates said.

The final trend in coronary revascularizations revealed in these data was the marked surge in PCI procedures using drug-eluting stents soon after two devices were approved by the Food and Drug Administration in 2003. By mid-2005, 90% of PCI procedures involved drug-eluting stents, reflecting "a high level of clinician enthusiasm" for the devices.

This peak was soon followed by a marked decline after the publication of safety concerns such as late in-stent thrombosis, "as well as increasing clinician awareness of the imperative for ... adherence to long-duration antiplatelet therapy." By the beginning of 2008, only 61% of PCI procedures involved placement of drug-eluting stents, but that rate increased steadily during that year, which also saw the adoption of second-generation stents that carried lower restenosis rates.


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