Abstract 1639: Clinical Utility Of Cardiac Ct Angiography: 40 Month Follow Up Of Ambulatory Patients
Introduction: Cardiac CT coronary angiography (CTA) has been largely validated to accurately detects stenosis in patients undergoing coronary arteriography, but its prognostic accuracy in clinical symptomatic outpatients with intermediate risk is less evaluated. This study analyzed CTA in an outpatient cohort and examined 40-month clinical outcomes.
Methods: 493 consecutive symptomatic patients with an intermediate likelihood of CAD who were referred for CTA evaluation in an outpatient setting were followed. Patients with known CAD, prior cardiovascular events and/or prior revascularizations were excluded. Patients were followed up for a mean of 40 +/− 9 months. Cardiac events were defined as a myocardial infarction or cardiovascular death.
Results: In this study, 32%(157) had a normal study, 41%( 204) had non-obstructive disease, 19%(93) had obstructive disease and 8 %(39) had at least one major non-diagnostic segment. The mean age was 58 +/− 15 years and 69% male. Follow up demonstrated 20 myocardial infarctions in patients with obstructive disease, 1 in the non-diagnostic group and no MIs in the group without obstructive disease. In addition 89% of obstructive disease patients and 12% of non-diagnostic studies underwent catheterization. 40 month event free survival was 100% for normal and non-obstructive disease (<50% stenosis), 97.5% for non-diagnostic studies and 79% for individuals with obstructive disease by CTA. After adjustment for age, gender, risk factors and CAC, the stepwise multivariate model showed that the obstructive diseased was independent predictor of cardiac events and had significant incremental value over clinical risk factors and CAC (HR=16.6, 95%CI=4.9–55.2, p=0.0001).
Conclusions: In symptomatic patients with intermediate risk, the CTA findings of normal and non-obstructive disease was associated with a 40 month event free survival of 100%. Larger cohorts and longer follow-up is necessary. CTA is a noninvasive method to detect and rule out CAD and provides incremental information over clinical risk factors and CAC.