Study Examines Normal Coronary Rates for Elective Angiography
Coronary angiography has an important role in the diagnosis of coronary artery disease (CAD), but proper patient selection to avoid unnecessary procedural risk and cost of angiography is critical to high-quality care. Rates of normal coronary angiography have been proposed as a measure of the quality of patient selection for the procedure. Recent studies found that 39% of patients undergoing elective angiography in the U.S. have normal coronaries, however, little is known about normal coronary artery rates in integrated healthcare systems like VA. This study sought to determine if VA is selective and consistent in the use of angiography, as reflected by normal coronary rates. Investigators evaluated overall rates, as well as hospital-level variation in these rates, using data from 22,538 Veterans who underwent elective coronary angiography from 10/07 to 9/10 at one of 66 VA cardiac catheterization labs. Investigators also assessed patient demographics and clinical risk factors, as well as indications for diagnostic angiography and revascularization within 90 days of the index angiogram. Veterans with a prior history of myocardial infarction, percutaneous coronary intervention, coronary-artery bypass surgery, cardiac transplantation, or valvular surgery were excluded, as were VA facilities performing fewer than 50 elective diagnostic angiograms annually.
- Among Veterans undergoing elective coronary angiography in the VA healthcare system, about 1 in 5 patients (21%) had normal coronaries. This is a lower average rate of normal coronaries, compared with previous findings from other U.S. hospitals (39%).
- Across VA hospitals, the median proportion of normal angiograms among Veterans who had undergone elective coronary angiography ranged from 6% to 49%. Categorized as hospital quartiles, the median proportion of normal coronaries in the lowest quartile was 11%, compared with 19% in the second lowest quartile, 23% in the second highest quartile, and 30% in the highest quartile.
- Veterans at hospitals with lower normal coronary rates were more likely to undergo stress testing prior to angiography compared with hospitals with higher rates of normal results, and rates of obstructive CAD and subsequent revascularization were higher at hospitals with lower rates of normal coronaries.
- There were no notable trends in patient demographics or cardiovascular risk factors by hospital quartile of normal coronaries.
- Investigators were unable to identify stress tests performed outside VA or Medicare. Moreover, the specific results of stress tests (e.g., amount and distribution of ischemia) were unknown for a large number of patients.
- Investigators lacked reliable data on patient symptom burden.
These findings suggest inconsistent patient selection for invasive diagnostic coronary angiography across VA cath labs. Future work is needed to optimize patient selection for these procedures to minimize patient risk and maximize patient benefit.
Drs. Bradley and Maddox are supported by HSR&D Career Development Awards. Along with Drs. Ho, Peterson, and Rumsfeld, they also are part of VA/HSR&D's Ischemic Heart Disease Quality Enhancement Research Initiative (IHD-QUERI).
Bradley S, Maddox T, Stanislawski M, O’Donnell C, Grunwald G, Tsai T, Ho P, Peterson E, and Rumsfeld J. Normal Coronary Rates for Elective Angiography in the VA Health Care System: Insights from the VA CART Program. Journal of the American College of Cardiology October 18, 2013;e-pub ahead of print.