Prognostic performance of low-dose coronary CT angiography with prospective ECG triggering

OBJECTIVE: To assess the prognostic value of low-dose 64-slice coronary CT angiography (CCTA) using prospective ECG triggering in a patient population with known or suspected coronary artery disease (CAD). DESIGN: Longitudinal follow-up study. SETTING: Tertiary referral cardiac imaging centre. PATIENTS: 434 consecutive patients who were referred for evaluation of CAD by CCTA. METHODS: The presence, distribution and severity of coronary lesions (non-obstructive <50% vs obstructive ≥50% luminal narrowing) were recorded by low-dose prospective ECG-triggered CCTA for each patient. The prognostic value of low-dose CCTA to predict major adverse cardiac events, defined as cardiac death, non-fatal myocardial infarction, or the need for revascularisation, was assessed using multivariate Cox regression analysis. Each person was followed up by telephone interviews and/or on the basis of clinical records. Thirty-eight early revascularised patients were excluded from outcome analysis. RESULTS: Completely normal coronary arteries were documented in 171 patients (47%), while exclusively non-obstructive lesions were found in 66 (18%), and obstructive coronary lesions were diagnosed in 130 patients (35%). A mean follow-up of 47±16 weeks was obtained. The first-year event rate was 0% in patients with normal coronary arteries on CCTA but increased to 3% and 26% in patients with non-obstructive and obstructive coronary artery lesions, respectively. In multivariate Cox regression analysis, a significant predictor of events was the presence of obstructive or any coronary lesions. Mean effective radiation dose was 1.8±0.6 mSv. CONCLUSIONS: These data document an excellent prognostic performance of low-dose CCTA.