The relationship between early left ventricular myocardial alterations and reduced coronary flow reserve in non-insulin-dependent diabetic patients with microvascular angina

AIMS: To evaluate left ventricular (LV) systolic and diastolic myocardial function, and their relation to coronary flow reserve in patients with non-insulin-dependent diabetes mellitus (DM) and microvascular angina. METHODS AND RESULTS: We selected a population of 45 normotensive patients with DM (56.3 ± 8.2 years; 25 males) with LV ejection fraction >50% and microvascular angina (anginal pain, positive imaging stress test and normal coronary angiography). Thirty-five age- and sex-matched healthy controls were also enrolled. All the patients underwent standard echocardiography, Tissue Doppler (TDI), two-dimensional strain (2DSE) imaging, and coronary flow reserve (CFR) measurement. LV myocardial early diastolic peak velocities (E(m)) and peak systolic 2DSE were reduced in both interventricular septum (IVS) and LV lateral wall (p<0.01) in DM, as well as CFR (1.89 ± 0.7 vs 2.55 ± 0.56, p<0.0001) compared with controls. By multivariate analysis, the independent determinants of E(m) were glycated haemoglobin (β coefficient=-0.36; p<0.01) and age (β=-0.46, p<0.001), while global longitudinal strain was predicted by glycated haemoglobin (β=0.48, P<0.001) and by the duration of the disease (β=0.38, P<0.005). An independent association between LV global longitudinal strain and CFR (β coefficient=-0.47, p<0.001) in DM patients was also evidenced. CONCLUSIONS: TDI, 2DSE and CFR are valuable non-invasive and easy-repeatable tools for detecting LV myocardial and coronary function in DM patients with microvascular angina.