Usefulness of Subclinical Left Ventricular Midwall Dysfunction to Predict Cardiovascular Mortality in Patients With Type 2 Diabetes Mellitus

Abstract

In this study, we tested the hypothesis that impaired midwall shortening predicts cardiovascular (CV) mortality in patients with type 2 diabetes mellitus (DM). In patients with DM without overt cardiac disease, systolic left ventricular (LV) function analyzed by midwall shortening may be impaired although LV ejection fraction is preserved. Impaired midwall shortening is an early independent prognosticator of adverse clinical outcome in patients with arterial hypertension. We analyzed the echocardiographic data from 360 outpatients with DM collected during the years 1990 to 2007. Patients had no history or symptoms attributable to cardiac disease. Stress-corrected midwall shortening (sc-MS) was taken as index of systolic LV function and considered impaired if <89%. The study outcome was CV mortality. At baseline, impaired sc-MS was detected in 140 patients (39%). During a mean follow-up period of 11 years, 54 patients (15%) died, 31 (8.6%) of them from CV causes. CV deaths occurred in 21 of 140 patients (15%) with impaired sc-MS and in 10 of 220 patients (4.5%) with normal sc-MS (p=0.006). Multivariate Cox regression analysis revealed that impaired sc-MS (hazard ratio 1.03, 95% confidence interval 1.01 to 1.08, p=0.039), together with lower estimated glomerular filtration rate (hazard ratio 0.96, 95% confidence interval 0.93 to 0.99, p=0.004), was independently associated with CV mortality even after adjustment for age, diabetes duration, hemoglobin A1c, left atrial diameter, and heart valve calcium. In conclusion, subclinical systolic LV dysfunction as measured by sc-MS occurs frequently in patients with DM without overt cardiac disease and independently predicts long-term CV mortality in such patients together with lower estimated glomerular filtration rate.