Objective: The ability of coronary artery calcium (CAC) to predict coronary events has been shown in several studies. We aimed to investigate the hypothesis that CAC as assessed by dual slice spiral computed tomography (DSCT), is an independent risk factor for cardiovascular events in hypertensive patients.
Methods: We followed 446 participants of INSIGHT (International Nifedipine Study Intervention as Goal for Hypertension Therapy) calcification study, for the incidence of cardiovascular events as a function of CAC and other factors. All were hypertensive, without coronary artery disease (CAD), ages > 55 years and with at least one more major cardiovascular risk factor. All underwent a baseline DSCT and were followed for a mean period of 3.8 +/- 0.4 years. All events were documented while the scheduled visits and confirmed by the INSIGHT critical event committee.
Results: Follow-up was conducted on all participants. 294 patients (66%) had CAC at baseline. Forty-seven patients experienced a first cardiovascular event: acute myocardial infarction (MI), 16; sudden cardiac death, two; unstable angina resulting in revascularization, 14; stroke, 15. The incidence of first cardiovascular events was 3.7 times higher among those who had CAC at baseline than among those who had no CAC (14.5% (41 of 294) versus 3.9% (6 of 152)). Patients who experienced an event were more likely to be males, had had higher prevalence of peripheral vascular disease, longer duration of hypertension, and had higher levels of systolic blood pressure (SBP), glucose, creatinine and uric acid. Adjusting for these covariates, CAC (total coronary calcium score (TCS) > 0) independently predicted cardiovascular events with an odds ratio (OR) of 2.76 [95% confidence interval (CI) 1.09-6.99, P = 0.032].
Conclusion: The presence of CAC predicts cardiovascular events in high-risk asymptomatic hypertensive patients.