Impact of mitral annular calcification on cardiovascular events in a multiethnic community: the Northern Manhattan Study.

OBJECTIVES

We sought to determine the magnitude of the association between mitral annular calcification (MAC) and vascular events in a multiethnic cohort.

BACKGROUND

Mitral annular calcification is common in the elderly and is associated with atherosclerotic risk factors. Its impact on the risk of cardiovascular events is controversial.

METHODS

The study cohort consisted of 1,955 subjects, ages >or=40 years, and free of prior myocardial infarction (MI) and ischemic stroke (IS). Mitral annular calcification was assessed by transthoracic 2-dimensional echocardiography. The association between MAC and MI, IS, and vascular death (VD) was examined by Cox proportional hazard models with adjustment for established cardiovascular risk factors. The effect of MAC thickness was also analyzed.

RESULTS

The mean age of the cohort was 68.0 +/- 9.7 years and the majority of subjects were Hispanics (56.8%). A total of 519 subjects (26.6%) had MAC. Of 498 patients with MAC thickness measurements available, 253 (13.1%) had mild to moderate MAC (1 to 4 mm) and 245 (12.7%) severe MAC (>4 mm). During a mean follow-up of 7.4 +/- 2.5 years, MI occurred in 100 (5.1%) subjects, IS in 104 (5.3%) subjects, and VD in 155 (8.0%) subjects. After adjustment for other cardiovascular risk factors, MAC was associated with an increased risk of MI (adjusted hazard ratio [HR]: 1.75; 95% confidence interval [CI]: 1.13 to 2.69, p = 0.011) and VD (adjusted HR: 1.53; 95% CI: 1.09 to 2.15, p = 0.015), but not IS (adjusted HR: 1.34; 95% CI: 0.87 to 2.05, p = 0.18). Further analysis revealed that the impact of MAC was related to its thickness, with MAC >4 mm being a strong and independent predictor of MI (adjusted HR: 1.89; 95% CI: 1.13 to 3.17, p = 0.008) and VD (adjusted HR: 1.81; 95% CI: 1.21 to 2.72, p = 0.002), and showing borderline association with IS (adjusted HR: 1.59; 95% CI: 0.95 to 2.67, p = 0.084).

CONCLUSIONS

In this multiethnic cohort, MAC was a strong and independent predictor of cardiovascular events, especially MI and VD. The risk increase was directly related to MAC severity.