Abstract 2596: Integrated Myocardial Perfusion Imaging/Computed Tomography Coronary Angiography for the assessment of coronary artery lesions in patients with non-ST-elevation acute coronary syndromes
Background: Computed tomography coronary angiography (CTCA) has a high negative predictive value for significant coronary stenoses. The role of CTCA in patients (pts) with non-ST-elevation acute coronary syndromes (NSTE-ACS) is unclear. In these pts, CTCA may detect multiple coronary plaques and trigger referral to invasive coronary angiography.
Methods: We studied the usefulness of a hybrid myocardial perfusion imaging (MPI)/CTCA device in 65 pts with NSTE-ACS (25 with non-ST-elevation infarction). The Thrombolysis in Myocardial Infarction (TIMI) risk score for pts with NSTE-ACS was used to classify pts as low-or high-risk (score ≥ 3). Fused MPI/CTCA images were used to detect clinically significant lesions (potentially requiring intervention), defined as >50% stenosis by CTCA and reversible perfusion defects in the same territory.
Results: A high TIMI risk score was present in 34 pts (52%). CTCA demonstrated at least 1 lesion with >50% stenosis in 24 of these pts (71%). However, only 10 of all pts with high TIMI risk score (29%) had clinically significant lesions. The sensitivity and specificity of a CTCA was 100% and 42%, respectively. Of the 31 pts with low-risk TIMI score, 10 had at least 1 lesion with >50% stenosis (32%) by CTCA, and only 4 pts (3%) had clinically significant lesions. MPI was negative in 98% of pts with negative CTCA regardless of TIMI risk score. The TIMI risk score had a moderate sensitivity (71%) and low specificity (53%) for detecting clinically significant lesions.
Conclusion: In pts with NSTE-ACS, a negative CTCA indicates that referral for coronary angiography is unnecessary even in the presence of high TIMI risk score. However, a positive CTCA has a low specificity for myocardial ischemia even in pts with high-risk TIMI score. Hybrid MPI/CTCA imaging may provide an objective decision making tool regarding the need for invasive procedures.