Researchers from the University of Pennsylvania School of Medicine in Philadelphia found a substantial decrease in CABG surgery utilization rates, but PCI utilization rates remained unchanged in U.S. hospitals between 2001 and 2008, according to a serial cross-sectional study published in the May 3 edition of the Journal of the American Medical Association.
It is “uncertain” how new revascularization technologies, new clinical evidence from trials and updated clinical guidelines have influenced the volume and distribution of coronary revascularizations over the past decade, according to the study authors. Therefore, Andrew J. Epstein, PhD, from Penn Medicine’s department of medicine, and colleagues examined the U.S. time trends in the rates and types of coronary revascularizations.
The researchers gathered their data from the Healthcare Cost and Utilization Project's Nationwide Inpatient Sample (NIS), which reports inpatient coronary revascularizations. These data were supplemented by Medicare outpatient hospital claims.
The investigators observed a 15 percent decrease in the annual rate of coronary revascularizations from 2001 to 2002 to 2007 to 2008. The annual CABG surgery rate decreased steadily from 1,742 CABG surgeries per million adults per year in 2001 to 2002 to 1,081 CABG surgeries per million adults per year in 2007 to 2008, but PCI rates did not significantly change (3,827 PCI per million adults per year in 2001 to 2002 vs. 3,667 PCI per million adults per year in 2007 to 2008).
Between 2001 and 2008, the number of hospitals in the NIS providing CABG surgery increased by 12 percent, and the number of PCI hospitals increased by 26 percent. The median CABG surgery caseload per hospital decreased by 28 percent and the number of CABG surgery hospitals providing fewer than 100 CABG surgeries per year increased from 11 percent in 2001 to 26 percent in 2008.
The drop in CABG surgery rates was observed across sex, age, racial and regional subgroups. The decrease in CABG surgeries occurred as a roughly linear trend throughout the sample time period, according to the authors, suggesting that the decrease was not triggered by any single event, such as the introduction of a particular new technology or a clinical guideline.
"There has been a substantial decline in CABG surgery during the past decade without a commensurate decline in PCI, suggesting the likelihood that a coronary artery disease patient receives PCI versus CABG has markedly changed," said the study’s senior author Peter W. Groeneveld, MD, assistant professor of medicine at Penn Medicine.
Interestingly, the researchers also found that despite the decline in CABG surgery rates between 2001 and 2008, the number of hospitals in the sample providing CABG surgery actually increased by 12 percent, while the number of PCI hospitals increased by 26 percent.
"Our data imply a sizeable shift in cardiovascular clinical practice patterns away from surgical treatment toward percutaneous, catheter-based interventions," said Groeneveld. "This is concerning given that recent data from a national trial indicated CABG surgery remains the better choice for patients with previously untreated three-vessel or left main coronary artery disease.
“Our analysis of Medicare claims indicated the rate of repeat revascularization did in fact decrease during the DES [drug-eluting stent] era; therefore, an overall decrease in PCI rates subsequent to the introduction of DES would have been unsurprising,” the authors wrote. “However, the stability of the PCI rate, combined with our findings from Medicare claims of decreasing rates of repeat PCI, suggests that there are increasing numbers of patients receiving PCI over time.”
Between 2001 and 2008, the rate of PCI did not significantly change; however, there were continual changes in the frequency of stent types used for PCI.
As a limitation, the authors noted that the NIS does not include detailed information about patient clinical characteristics, such as coronary anatomy, angina class, ejection fraction, medications, surgical risk or smoking status, which could explain some of the changes over time in utilization of CABG surgery or PCI.