Antianginal Therapy Use Before PCI in Stable CAD Appears Low, Inconsistent
Despite appropriate use criteria advocating the importance of trying 2 or more antianginal drugs prior to invasive treatment of coronary artery disease (CAD), up to one-third of patients undergoing elective percutaneous coronary intervention (PCI) for stable CAD in the United States never receive even 1 antianginal drug, according to a study published online August 6, 2013, ahead of print in Circulation: Cardiovascular Interventions.
William B. Borden, MD, of Weill Cornell Medical College (New York, NY), and colleagues analyzed antianginal therapy use prior to 300,772 PCI procedures for stable CAD in the National Cardiovascular Data Registry CathPCI Registry, using data from the Dartmouth Atlas to assess regional variation. PCIs were performed at 1,164 hospitals from January 2009 through March 2011. The Dartmouth Atlas arranges the health care market in the United States into 306 hospital referral regions (HRRs), 282 of which were included in the study.
Substantial Variation in Antianginal Use
Approximately one-third of patients (32.8%) were not tried on any antianginal drugs in the 2 weeks prior to PCI, while 18.9% received 2 or more such drugs over the same time period.
Urban hospitals had higher median rates of providing 2 or more antianginal drugs before PCI compared with rural hospitals (18.0% vs. 12.8%; P < 0.0001), as did hospitals with vs. without graduate medical education programs (17.9% vs. 14.3%; P < 0.0001). Sensitivity analyses of various patient populations did not change HRR patterns, nor did regression analyses including CABG and total revascularization rates.
When antianginal drugs were used, beta-blockers were the most frequent type (59.4%) followed by calcium-channel blockers (15.9%) and long-acting nitrates (12.5%).
When HRRs were compared, substantial variation was seen in use of 2 or more antianginal drugs, with a range of 0 to 42.0% and an interquartile range of 0.3% to 36.0%. Rates of appropriate use in the 2 weeks before PCI were not related to the rates of PCI by region (P = 0.64). Approximately a quarter of HRRs fell into each of the following scenarios:
- Below median rates of both ≥ 2 antianginal medications and PCI: 24.1%
- Below median rates of ≥ 2 antianginal medications but above-median PCI rates: 25.9%
- Higher than median rates of ≥ 2 antianginal medications but below-median PCI: 25.9%
- Higher than median rates of both ≥ 2 antianginal medications and PCI: 24.1%
Findings Hint at Regional Practice Pattern Differences
“The lack of correlation between the rates of antianginal therapy and PCI suggests that other variables, besides medical therapy, explain the variability in rates of PCI,” the study authors write.
In addition, Dr. Borden and colleagues say the substantial variation across HRRs suggests that regional practice patterns may affect medical therapy use. Of interest, they add, is the finding of high rates of antianginal therapy and low rates of PCI, which suggest that the practice patterns in these regions “may provide insights into strategies that seem to preferentially reserve PCI for patients who fail medical therapy.”
On the other hand, in regions with high rates of PCI despite high rates of medical therapy, practice patterns are more difficult to discern, the researchers note. Among the possible explanations is that aggressive antianginal therapy and intense follow-up may lead to more PCI due to greater detection of angina.
Future studies should examine other variables such as physician knowledge and attitudes toward relevant clinical trials and factors related to local and regional health systems, they add.
“It is likely that the relationship between antianginal therapy and PCI is multifactorial,” the authors conclude. “By examining the interaction between various elements that have previously been studied independently, the medical community can more fully understand variations in care.”
Patients receiving 2 or more antianginal drugs before PCI were more symptomatic, were older, had more comorbid conditions, were more likely to be receiving Medicare, and were less likely to be current or recent smokers.
Borden WB, Spertus JA, Mushlin AI, et al. Antianginal therapy before percutaneous coronary intervention. Circ Cardiovasc Interv. 2013;Epub ahead of print.
- Dr. Borden reports serving as a senior advisor in the US Department of Health and Human Services.