The relationship between flow-mediated dilatation and left ventricular function in type 2 diabetic patients with microalbuminuria

Abstract

Objective: The aim of this study was to assess the relationship between flow-mediated dilatation (FMD) and left ventricular (LV) systolic and diastolic function in type 2 diabetic patients with or without microalbuminuria.

Research design and methods: We prospectively evaluated 68 consecutive patients (36 women, 32 men; mean age 57 +/- 11 yr) with type 2 diabetes mellitus (DM). Patients were divided into two groups according to whether or not they had microalbuminuria: group 1 (n = 29, mean age 58 +/- 10 yr) with microalbuminuria and group 2 (n = 39, mean age 56 +/- 10 yr) without microalbuminuria. LV function was assessed by classical methods and Doppler tissue imaging (DTI). Left ventricular ejection fraction (EF), interventricular (IVS) and posterior wall (PW) thickness, peak early (E) and late (A) transmitral filling velocities, their ratio (E/A) and deceleration time of the mitral E wave (DT), LV isovolumetric relaxation time (IVRT), flow propagation of velocity (Vp), and E/Vp were evaluated by conventional echocardiography. Early diastolic (Em), late diastolic (Am), and peak systolic (Sm) mitral annular velocities were measured. Em/Am and the ratio of early diastolic mitral inflow velocity to Em (E/Em), which is a reasonably good index for predicting elevated LV filling pressure, were calculated by DTI. Endothelial function, measured as flow-mediated dilatation of the brachial artery using ultrasound, was calculated in two groups.

Results: FMD was lower in those with microalbuminuria than those without (8.8 +/- 6.44% vs 12.6 +/- 7.24%, p = 0.03). Group 1 had longer DT (223 +/- 39 ms vs 199 +/- 37 ms, p = 0.01) and longer IVRT (109 +/- 13 ms vs 100 +/- 13 ms, p = 0.03) than that of group 2 with conventional echocardiography. Group 1 had significantly lower Em/ Am (0.79 +/- 0.27 cm/s vs 1.02 +/- 0.44 cm/s, p = 0.01), lower Vp (40.4 +/- 9.98 vs 50.4 +/- 19.01 cm/s, p = 0.01) than that of group 2. Group 1 had significantly higher serum creatinine (1 +/- 0.33 mg/dL vs 0.7 +/- 0.19, p = 0.001). In logistic regression analysis, FMD was the only variable independently related to microalbuminuria. FMD was positively correlated with EF (r = 0.43, p = 0.02) and E/A (r = 0.40, p = 0.03), and negatively correlated with E/Em (r = 0.41, p = 0.04) and E/Vp (r = 0.41, p = 0.04) only in patients with microalbuminuria.

Conclusion: It was found that left ventricular diastolic function and FMD are impaired in type 2 diabetic patients with microalbuminuria. FMD may be related to LV diastolic dysfunction only in patients with microalbuminuria.