Purpose: To assess the prevalence, extent, severity, and risk of coronary artery disease (CAD) in patients suspected of having CAD but with no medically modifiable risk factors.
Materials and methods: Institutional review board approval or waiver of consent was obtained at each center. This study was HIPAA compliant. From an international multicenter cohort study of 27 125 subjects undergoing coronary computed tomographic (CT) angiography from 12 centers, 5262 patients without known CAD and without modifiable risk factors were identified. CAD severity was defined as none (0%), mild (1%-49%), or obstructive (≥ 50%) on a per-patient, per-vessel, and per-segment basis. CAD presence, extent, and severity were related to incidence of major adverse cardiovascular event (MACE) by using Cox proportional hazards models.
Results: At a mean follow-up of 2.3 years ± 1.2 (standard deviation), MACE occurred in 106 patients. CAD was common for nonobstructive (n = 1452, 27%) and obstructive (n = 629, 12%) CAD. In risk-adjusted analysis, per-patient obstructive CAD (hazard ratio [HR], 6.64; 95% confidence interval [CI]: 3.68, 12.00; P ≤ .001) was related to MACE. MACE was associated with a dose-response relationship to the number of vessels exhibiting obstructive CAD, increasing risk for obstructive one-vessel (HR, 6.11; 95% CI: 3.22, 11.6; P ≤ .001), two-vessel (HR, 5.86; 95% CI: 2.75, 12.5; P ≤ .0001), or three-vessel or left main (HR, 11.69; 95% CI: 5.38, 25.4; P ≤ .001) CAD. The increased hazard for MACE of obstructive disease holds true for symptomatic (HR, 11.9; 95% CI: 4.81, 29.6; P ≤ .001) and asymptomatic (HR, 6.3; 95% CI: 2.4, 16.7; P ≤ .001) patients. No CAD at coronary CT angiography was associated with a low annualized MACE rate: 0.31% versus 2.06% with obstructive disease.
Conclusion: Among individuals suspected of having CAD but without modifiable risk factors, CAD is common, with significantly increased hazards for MACE and mortality.