Isolated and Combined Influences of Diabetes and Hypertension on the Myocardial Function and Geometry

ABSTRACT

BACKGROUND AND OBJECTIVES: Because hypertension and left ventricular hypertrophy (LVH) frequently coexist with diabetes, in this study we sought to compare the myocardial functional and structural changes in diabetic patients who were with or without hypertension with those myocardial functional and structural changes in non-diabetic subjects with hypertension (essential hypertension), in order to identify the role of diabetes alone, in relation to the myocardial dysfunction. SUBJECTS AND METHODS: We studied 50 patients with essential hypertension (HTN, 20 men and 30 women; mean age 59+/-12 years), 54 diabetes mellitus patients without hypertension (DM, 24 men and 30 women; mean age 60+/-9 years), 53 diabetes mellitus patients with hypertension (DM+HTN, 23 men and 30 women; mean age 61+/-7 years), and 49 normal subjects (22 men and 27 women; mean age 56+/-13 years). We used echocardiography that was comprised of the standard 2-dimensional and conventional Doppler imaging for estimating the left ventricular mass index (LVMI), the relative wall thickness (RWT) and the Doppler-derived myocardial performance index (MPI, Tei index). Subjects were considered to have normal geometry (NG) if both the LVMI and RWT were normal (LVMI < or = 104 g/m2 in females, LVMI < or = 116 g/m2 in males, RWT < or = 0.43), concentric hypertrophy (CH) if both were elevated, eccentric hypertrophy (EH) if the LVMI was elevated and the RWT was normal, and concentric remodeling (CR) if the LVMI was normal and the RWT was elevated. RESULTS: The Tei index was significantly higher in the patients with essential hypertension and diabetes, especially in the DM+HTN group (HTN=0.48+/-0.13; DM=0.41+/-0.09; DM+HTN=0.53+/-0.11), as compared to the controls (0.31+/-0.11, p<0.05). The LVMI and RWT were significantly higher in the patients with essential hypertension and diabetes, and especially in the DM+HTN group (HTN=132.2+/-44.4 g/m2 and 0.45+/-0.11; DM=125.9+/-34.4 g/m2 and 0.44+/-0.07; DM+HTN=153.9+/-42.9 g/m2 and 0.48+/-0.07), as compared to the controls (108.9+/-22.2 g/m2 and 0.39+/-0.05, p<0.05). CONCLUSION: Our study demonstrated the early appearance of adverse myocardial functional and geometric changes in the diabetic patients, and the study also showed that the contributory effects of diabetes to the myocardial impairment and LV hypertrophy were produced by the presence of hypertension. The Tei index is a very sensitive method for the detection and evaluation of myocardial impairment in diabetic patients.