Aortic and mitral annular calcifications are predictive of all-cause and cardiovascular mortality in patients with type 2 diabetes

OBJECTIVE

To examine the association of aortic valve sclerosis (AVS) and mitral annulus calcification (MAC) with all-cause and cardiovascular mortality in type 2 diabetic individuals.

RESEARCH DESIGN AND METHODS

We retrospectively analyzed the data from 902 type 2 diabetic outpatients, who had undergone a transthoracic echocardiography for clinical reasons during the years 1992–2007. AVS and MAC were diagnosed by echocardiography, and a heart valve calcium (HVC) score was calculated by summing up the AVS and MAC variables. The study outcomes were all-cause and cardiovascular mortality.

RESULTS

At baseline, 477 (52.9%) patients had no heart valves affected (HVC-0), 304 (33.7%) had one valve affected (HVC-1), and 121 (13.4%) had both valves affected (HVC-2). During a mean follow-up of 9 years, 137 (15.2%) patients died, 78 of them from cardiovascular causes. Compared with patients with HVC-0, those with HVC-2 had the highest risk of all-cause and cardiovascular mortality, whereas those with HVC-1 had an intermediate risk (P < 0.0001 by the log-rank test). After adjustment for sex, age, BMI, systolic blood pressure, diabetes duration, A1C, LDL cholesterol, estimated glomerular filtration rate, smoking, history of myocardial infarction, and use of antihypertensive and lipid-lowering drugs, the hazard ratio of all-cause mortality was 2.3 (95% CI 1.1–4.9; P < 0.01) for patients with HVC-1 and 9.3 (3.9–17.4; P < 0.001) for those with HVC-2. Similar results were found for cardiovascular mortality.

CONCLUSIONS

Our findings indicate that AVS and MAC, singly or in combination, are independently associated with all-cause and cardiovascular mortality in type 2 diabetic patients.Aortic valve sclerosis (AVS) is a common finding at echocardiography in the elderly population (1). AVS is defined as focal or diffuse calcification and thickening of a trileaflet aortic valve in the absence of obstruction of ventricular outflow. Approximately 30% of adults >65 years of age have AVS in Western countries. Until recently, AVS was considered an incidental echocardiographic finding of no clinical significance, as it does not significantly obstruct left ventricular outflow. However, AVS shows epidemiologic and histopathologic similarities to coronary atherosclerosis (2,3). In addition, recent large prospective studies have suggested a strong association between AVS and cardiovascular disease (CVD) outcomes both in the general population (1,4–6) and in nondiabetic high-risk patient populations such as patients with hypertension (7), coronary artery disease (8), and chronic kidney disease (9).Mitral annulus calcification (MAC) is also a common echocardiographic finding in the elderly (10). Similar to AVS, MAC is strongly associated with an increased risk of CVD morbidity and mortality, mainly in nondiabetic populations (11,12). Notably, a recent large community-based cohort study involving 2,081 German individuals aged ≥45 years (∼11% of patients with diabetes) showed that AVS and MAC were associated with a fourfold to fivefold increased risk of all-cause and CVD mortality and that the combination of AVS and MAC with a heart valve sclerosis score improved the predictability with respect to mortality (5). Similarly, patients with AVS were approximately four times more likely to develop incident coronary heart events than were those without AVS among the 2,279 middle-aged African American participants of the Jackson Atherosclerosis Risk in Community cohort (6), whereas AVS was found to be independently associated with an increase of ~50–60% in the risk of CVD events and death among the 5,621 elderly participants of the Cardiovascular Heart Study (1).To our knowledge, no large observational studies are available on the relationship of AVS and MAC with the risk of all-cause and CVD mortality in patients with type 2 diabetes. The aim of this observational study was to evaluate the association of AVS and MAC, singly or in combination, with the risk of all-cause and CVD mortality in a sample of type 2 diabetic individuals referred for clinically indicated echocardiograms.