Abstract 17461: Prognostic Value of Multidetector Coronary Computed Tomographic Angiography in Patients with Equivocal or Mildly Abnormal Non-Invasive Cardiac Stress Tests
Background: Patients with low/intermediate pretest probability of significant coronary artery disease (CAD) and equivocal or mildly abnormal non-invasive cardiac stress tests represent a frequent management challenge.
Methods: We evaluated 513 consecutive adults with suspected CAD and an equivocal or mildly abnormal exercise electrocardiography (n = 230), stress SPECT perfusion scans (n = 270), stress echocardiography (n = 11) or stress cardiac MRI (n = 2). All patients underwent 64-slice coronary computed tomographic angiography (CCTA) and CAD severity was graded as: 1-normal coronary arteries, 2-non-obstructive plaques (<30% stenosis), 3-mild stenosis (30–49%), 4-moderate stenosis (50–69%) or 5-severe coronary stenosis (≥ 70%). Patients were also classified as having non-significant (<50% stenosis) or significant CAD (>50% stenosis). The composite endpoint of all-cause mortality and non-fatal myocardial infarction (MI) was evaluated by risk-adjusted multivariable Cox proportional hazards models.
Results: During a mean follow-up of 32 ± 10 months there were 20 deaths (3.9%) and 17 non-fatal MIs (3.3%). Event-free survival was 98% for normal coronaries (n = 191), 93% for non-obstructive (n = 97), 87% for mild (n = 61), 84% for moderate (n = 60) and 83% for severe stenosis (n = 104) (P < 0.0001). When compared to the group with normal coronaries, the risk-adjusted hazards ratios (HR) were: non-obstructive plaques (HR = 3.0, 95%CI 0.5–16.9, P = 0.20), mild (HR = 6.8, 95%CI 1.3–34.6, P = 0.02), moderate (HR = 6.5, 95%CI 1.3–32.8, P = 0.02) and severe stenosis (HR = 7.6, 95%CI 1.6–36.1, P = 0.01). Patients with non-significant CAD (n = 349) demonstrated better event-free survival than those with significant CAD (n = 164): 95% versus 83%, P < 0.0001. The risk-adjusted HR of patients with significant CAD as compared to those without was 2.4 (95%CI 1.1–5.4, P = 0.03).
Conclusion: The majority of patients with suspected CAD and equivocal or mildly abnormal non-invasive cardiac stress tests did not display significant CAD when evaluated by CCTA. In this patient population, a normal CCTA was associated with a very low risk for subsequent adverse events. Higher degrees of CAD severity as demonstrated by CCTA predicted major adverse events in intermediate-term follow-up.
- © 2010 by American Heart Association, Inc.