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.