Study Sheds Light on Use of Stress Testing Post-PCI in VA System

Nearly 4 in 10 patients treated within the VA healthcare system undergo repeat stress testing in the 2 years after PCI, according to a study published online July 21, 2015, ahead of print in Circulation: Cardiovascular Quality and Outcomes. Yet the VA’s use of stress tests is much more in line with the expected rate of recurrent symptoms than what has been seen in fee-for-service systems. 

“One common assumption is that the way in which care is reimbursed leads to overuse,” said Steven M. Bradley, MD, MPH, of the VA Eastern Colorado Health Care System (Denver, CO) in a telephone interview with TCTMD. “In this study we took reimbursement out of the equation, [but] we still see variation at the facility level that we don’t quite understand.”

The 2013 Appropriate Use Criteria developed by the American College of Cardiology, American Heart Association, and other groups describes stress testing within 2 years after PCI as “inappropriate” in the absence of new or progressive symptoms.

Dr. Bradley and colleagues looked at patterns in stress testing using data from the VA Clinical Assessment, Reporting, and Tracking (CART) program on 10,293 Medicare-ineligible veterans who underwent PCI at 55 hospitals between October 2007 and June 2010.

Variation Seen Among Facilities

Overall, 21.8% of VA patients had a stress test within a year and 37.9% had one within 2 years. Stress testing was performed with nuclear imaging in nearly 80%.   

Patients who did and did not undergo stress testing within 2 years were similar, although a higher rate of concurrent depression was seen in the stress test group (45.3% vs 40.8%; P < .001).

In patients who had a stress test, repeat coronary angiography and repeat PCI were performed before stress testing at rates of 14.2% and 6.9%, respectively. In the 90 days after a follow-up stress test, 19.3% of patients underwent coronary angiography and 9.1% underwent PCI.

The median rate of stress testing in the 2 years after PCI was 38.3%, with use ranging from 26.5% to 59.0%. When hospitals were divided into quartiles by lowest to highest use of stress testing, the median rates were 29%, 37%, 41%, and 47%, respectively. After risk adjustment, stress testing rates varied from 28.5% to 55.2%, and about a quarter of hospitals had risk-standardized use that differed significantly from the average (14.5% of hospitals below and 10.9% above).

From 60 days to 2 years after PCI, rates of all-cause death and MI were 5.1% and 4.5%, respectively. Facility-level, risk-standardized rates of stress testing did not correlate with facility-level, risk-standardized mortality (P = .08) or MI (P = .14).  

Reasons for Variation Unclear

According to Dr. Bradley and colleagues, previous studies of stress testing after PCI in fee-for-service settings show that rates of testing are not consistent with the rate of recurrent symptoms, with more than 35% of patients undergoing stress testing within 1 year and nearly 60% undergoing testing within 2 years of PCI.

The observed VA rates are lower than those of fee-for-service systems and closer to reported rates of recurrent symptoms after PCI. A report from the Dynamic Registry showed that the rate of recurrent symptoms in routine clinical practice at 1 year after PCI is approximately 20%.

As for the variation among hospitals seen in the current study, Dr. Bradley cited the influence of cultural factors, lack of familiarity with guidelines, and differences in provider training and habits as possible contributors—all of which may be at work whether or not systems are fee-for-service. Additionally, while issues of patient preference and exceptions made for certain patients could potentially drive some of the stress testing in this population, they are not enough to account for “variations to this extent,” he added.

Implications for Other Systems?

While some studies in the fee-for-service setting have shown “a diagnostic to therapeutic cascade” in which higher rates of testing are associated with greater therapeutic intervention, including PCI, the VA findings show an inverse relationship between facility rates of stress testing and subsequent use of coronary angiography and PCI.

“These findings suggest a diagnostic to therapeutic cascade for CAD management is less prevalent within the VA,” they write “Furthermore, coronary angiography and PCI before stress testing [were] more common at facilities with lower rates of stress testing use. These findings suggest invasive diagnostic strategies may partially replace noninvasive approaches at VA facilities with lower rates of stress testing use; however, the rates of coronary angiography and PCI were not high enough to explain the entirety of lower stress testing use at these facilities.”

Importantly, Dr. Bradley and colleagues say, the study leaves open the question of whether the facility-level differences in stress testing after PCI reflect overuse or underuse of care.

“These findings suggest that opportunities to optimize the use of stress testing are still present in integrated healthcare systems,” they conclude.   

 “Systems like the VA and others that are already integrated provide a lot of insight into where we might end up as the healthcare system as a whole moves away from fee-for-service,” Dr. Bradley observed. “Studies like ours provide an opportunity to [foresee] how we might continue to improve beyond changing reimbursement structures.”

Source: 
Bradley SM, Hess E, Winchester DE, et al. Stress testing after percutaneous coronary intervention in the Veterans Affairs healthcare system: insights from the Veterans Affairs clinical assessment, reporting, and tracking program. Circ Cardiovasc Qual Outcomes. 2015;Epub ahead of print. 

Disclosures:

• The study was supported by awards from VA Health Services Research and Development.
• Dr. Bradley reports no relevant conflicts of interest. 

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