Abstract 2622: Prognosis by Coronary Computed Tomographic Angiography: A Comparison with Myocardial Perfusion SPECT
Background: Outcomes data are crucial to developing new technology. Coronary computed tomographic angiography (CTA) is rapidly gaining acceptance for assessing coronary artery disease (CAD) extent and severity. This study’s aim was to compare prognosis by CTA to a matched cohort undergoing myocardial perfusion SPECT (MPS).
Methods: We prospectively enrolled 1,138 patients (pts.) referred to CTA (16 slice multidetector CT, GE Healthcare) with suspected or progressive CAD (47% intermediate likelihood [LK]), assessed with the Duke CAD index (validated angiographic score subsetting proximal, extensive, and left main CAD). This cohort was matched to 7,849 pts. undergoing MPS from which % ischemic myocardium was defined with a 20-segment model. Death from all-causes was estimated using Cox proportional hazards models adjusting for pretest LK.
Results: For CTA, 39 deaths were observed at 1.5 years of follow-up; a rate similar to MPS (annual mortality: CTA=1.16% vs.MPS=1.13%). The Duke index was highly predictive of death (p<0.0001). Pts. with <50% stenosis had 99.7% survival. Survival worsened from 96% for pts. with 2 moderate stenoses or 1 ≥70% stenosis (p=0.01) to 85% for pts. with ≥50% left main stenosis (p<0.0001). Comparing CTA to MPS, (Figure⇓) annual mortality was similar by the Duke index and ischemic myocardium (range=0.1%−11.7%). CTA identified a risk gradation in less extensive CAD.
In conclusion, CTA findings are prognostically accurate, similar to that of MPS. Preliminary findings suggest that CTA may be effective in stratifying minimal CAD. These results require additional validation with longer-term follow-up using cardiovascular events and diverse pt. subsets.