A randomized trial of the impact of strict glycaemic control on myocardial diastolic function and perfusion reserve: a report from the DADD (Diabetes mellitus And Diastolic Dysfunction) study

Abstract

Myocardial diastolic dysfunction (MDD) and impaired coronary flow reserve (CFR) are early signs of myocardial involvement in patients with diabetes. The important question of whether this may be reversed by glucose normalization has not been tested in a controlled clinical trial. We hypothesized that strict glycaemic control, particularly if insulin based, will improve MDD and CFR. Thirty-nine type 2 diabetes patients (mean age 61.0 +/- 7 years) with signs of diastolic dysfunction were randomly assigned to strict metabolic control by insulin (I-group; n = 21) or oral glucose lowering agents (O-group; n = 18). MDD and CFR were studied with Doppler-echocardiography including Tissue Doppler Imaging and myocardial contrast enhanced echocardiography. Fasting glucose (I-group = -2.2 +/- 2.1; O-group -1.5 +/- 0.8 mmol/L) and HbA(1c) were normalized (-0.6 +/- 0.4 and -0.7 +/- 0.4%, respectively) in both groups, but this did not significantly improve MDD in either of the groups (P = 0.65). There was no difference in CFR before and after improved glycaemic control. The hypothesis that strict glycaemic control would reverse early signs of MDD and improve CFR in patients with type 2 diabetes could not be confirmed, despite achieved normalization. Whether it is possible to influence a more pronounced diastolic dysfunction, particularly in less well-controlled diabetic patients, remains to be established.