Abstract 800: Downstream Care and Outcomes Following Outpatient Stress Testing in the United States: How Low is Too Low Risk?
Background: Non-invasive stress testing has its greatest value when used in those with at least intermediate risk for CAD. While millions of Americans undergo outpatient non-invasive diagnostic testing, their subsequent courses of care and outcomes have not been well characterized.
Methods: We examined claims data from July 1, 2004 to June 30, 2007 from a large, national health insurer. We report 6- and 12-month rates of cardiac catheterization, revascularization, and cardiovascular events among all outpatient women ≥50 years old and men ≥45 years old presenting with chest pain and undergoing stress testing within 30 days. Patients with a prior history of CAD or CHF were excluded.
Results: The analysis included 98,872 patients; mean age was 56 years (±7 yr) and 46% were female. The majority, 79%, underwent initial testing with imaging (61% stress nuclear perfusion, 18% stress echo, 0.03%; MRI) while 21% had exercise ECG testing alone. Within a year of the initial stress test, <15% went on to cardiac catheterization while only 5% received coronary revascularization. Clinical event rates were also very low, with the rate of the composite of death, MI and stroke being only 1% (see Table⇓). Rates were significantly lower in those referred for ECG stress testing without imaging than in those referred for imaging stress tests (p<0.05 for all).
Conclusions: In this large national insured cohort, the majority of those referred for non-invasive evaluation were at very low risk for CAD; only 1 in 20 subsequently required coronary revascularization and event rates were at or below historical levels for age-matched peers. Further research is needed to define optimal patient selection and proper utilization of stress testing to evaluate patients with chest pain in the ambulatory setting.