Implications of Inconclusive Noninvasive Test Results in Stable Patients With Suspected Coronary Artery Disease: Insights From the PROMISE Trial

Introduction: Clinically, inconclusive (IC) noninvasive diagnostic tests (NITs) are not infrequent in patients with suspected coronary artery disease, but the actual prevalence and impact of such tests are unclear.Methods: The PROMISE trial randomized 4677 patients to CT angiography (CTA) and 4533 patients to functional stress testing. All positive tests were considered to be conclusive. Inconclusive test results were defined as a non-positive test considered by the site to be non-diagnostic or uninterpretable, or if <85% target heart rate was achieved on exercise stress. We assessed relationships between IC test results, NIT type, subsequent testing, and a composite outcome of death, myocardial infarction, and unstable angina using logistic and Cox proportional hazards models.Results: Overall, 8% of patients had an IC result (6% CTA, 10% stress; Table); for stress testing this was predominantly driven by submaximal exercise heart rate. IC CTA patients were older, more obese, diabetic, hypertensive, and with higher CV risk (all p<0.01) compared with conclusive CTA; IC stress patients had few differentiating factors vs conclusive stress. After adjustment for NIT type and patient characteristics, exercise ECG (OR 4.78, 95% CI 3.69-6.20, p<0.001) and stress echo (OR 2.11, 95% CI 1.68-2.66, p<0.001) were more likely to produce IC results than CTA, but not stress nuclear. Patients with IC tests were more likely to have a second NIT (OR 2.59, 95% CI 2.14-3.13; p<0.001) but not cath. There was no difference in outcomes between the IC and conclusive groups (HR 1.22, 95% CI 0.83-1.80; p=0.3).Conclusions: Among patients with stable angina undergoing NIT, an inconclusive test result is more common with exercise ECG or stress echo than with CTA, most commonly due to inadequate exercise stress. Individuals with inconclusive results are more likely to undergo subsequent NITs but catheterization rates and clinical outcomes are similar. These results may help guide NIT selection.Author Disclosures: N. Pagidipati: Other; Modest; Freedom Health, Physician Partners, RXAdvance, Florida Medical Associates. L. Hill: None. A. Coles: None. J.E. Udelson: Consultant/Advisory Board; Modest; Lantheus Medical Imaging, GlaxoSmithKline. Other; Modest; Abbott Laboratories, Editor - Circulation Heart Failure, Pfizer/Merck. M.H. Picard: None. P.A. Pellikka: None. K.L. Lee: None. U. Hoffmann: None. P.S. Douglas: Research Grant; Significant; GE, HeartFlow.

Duke Scholars

Author Pamela Susan Douglas Medicine, Cardiology