OBJECTIVE: To investigate the effect of angiotensin converting enzyme inhibition (ACE-I) or angiotensin receptor blockade (ARB), and their combination, on both diabetic autonomic neuropathy (DAN) and left ventricular (LV) diastolic dysfunction (LVDD) in asymptomatic patients with diabetes mellitus (DM).
MATERIALS AND METHODS: Sixty-two patients (34 women) with long-term DM (24 with Type 1) and DAN, aged 51.7+/-13.9 years, free of coronary artery disease (CAD) or arterial hypertension (HT) at baseline, were studied for a 12-month period. Diagnosis of DAN was established if two or more of the standard cardiovascular reflex tests (CRT) were abnormal. Patients were randomly allocated to quinapril (20 mg/day), losartan (100 mg/day), or quinapril plus losartan (20 mg/day+100 mg/day). LV systolic and diastolic function was assessed using radionuclide ventriculography (RNV) at baseline and after 12 months of treatment.
RESULTS: In all three treatment groups, abnormal CRT values were improved. In the quinapril group, the first third filling fraction (1/3FF, 48.9+/-17.8% vs. 39.2+/-12.9% at baseline, P=.005) was increased and the atrial contribution to ventricular filling (25.1+/-6.3 vs. 30.1+/-7.8, P=.027) was reduced in the losartan group; the peak filling rate (PFR) was improved (3.41+/-.62 vs. 3.11+/-.44 volumes/s, P=.05), and in the combination group, the 1/3FF (39.4+/-11.8% vs. 29.6+/-11.9%, P=.018) was markedly increased, while the time to peak filling (TPF; 147+/-42 vs. 184+/-33 ms, P=.02) and the TPF/filling time (TPF/FT; 32.5+/-6.2% vs. 38.2+/-5.7%, P=.016) were reduced.
CONCLUSIONS: Early ACE-I or ARB improve both DAN and LVDD in asymptomatic patients with Type 1 or 2 DM, after 1 year of treatment. Their combination may be slightly better than monotherapies on DAN and LVDD. The clinical importance of these effects should be validated by larger studies.