Predictors of high-risk coronary artery disease in subjects with normal SPECT myocardial perfusion imaging

While uncommon, normal stress spect myocardial perfusion imaging (mpi) can be seen in patients with high-risk coronary artery disease (cad) by invasive coronary angiography (ica).the predictors of high-risk cad in patients with normal spect-mpi have not been described. we studied 580 patients (age 64 ± 12 years, 49% men) without known cad who underwent stress-gated spect-mpi [exercise (41%) or vasodilator (59%)] <2 months before ica and had summed stress score (sss) <4. high-risk cad was defined as 3 vessels with ≥70% stenosis, 2 vessels with ≥70% stenosis including proximal left anterior descending, or left main with ≥50% stenosis. obstructive non-high-risk cad was defined by the presence of a ≥70% stenosis but without having other high-risk criteria. tenfold cross-validated receiver operating characteristic (roc) estimates were obtained to assess the predictors of high-risk cad. forty-two subjects (7.2%) had high-risk cad and 168 (29.0%) had obstructive non-high-risk cad. variables associated with high-risk cad were pretest probability of cad ≥66% (odds ratio [or] 3.63, 95% ci 1.6-8.3, p = .002), sss > 0 (or 7.46, 95% ci 2.6-21.1, p < 0.001), and abnormal tid (or 2.16, 95% ci 1.0-4.5, p = 0.044). when substituted for tid, ef change was also predictive of high-risk cad (or 0.93, 95% ci 0.9-1.0, p = 0.023). the prevalence of high-risk cad increased as the number of these predictors increased. in a sub-analysis of patients in whom quantitative total perfusion deficit (tpd) was available, tpd > 0 was also a predictor of high-risk cad (or 6.01, 95% ci 1.5-22.2, p = 0.011). several clinical, stress, and spect-mpi findings are associated high-risk cad among patients with normal spect-mpi. consideration of these factors improve the overall assessment of the likelihood of high-risk cad in patients undergoing stress spect-mpi.