Impaired mechanics of left ventriculo-atrial coupling in patients with diabetic nephropathy

Abstract

Background: Diabetic nephropathy is independently associated with longitudinal systolic dysfunction of the left ventricle (LV) in asymptomatic diabetes mellitus (DM) patients with preserved LV ejection fraction (LVEF). However, the effect of diabetic nephropathy on left atrial (LA) function remains unknown. Methods and Results: We studied 198 asymptomatic DM patients (LVEF ≥50%). Diabetic nephropathy was defined as a protein level higher than for micro-albuminuria. LV global longitudinal strain (GLS) and LA strain were analyzed by 2D speckle-tracking; 69 age-, sex-, and LVEF-matched controls were also studied. GLS and LA strain in systole (LAS-s) decreased significantly from normal controls to DM patients without (n=137) and with nephropathy (n=61), in that order. Furthermore, GLS, LAS-s, and LA strain in late diastole (LAS-a) were significantly lower in DM patients with macro-albuminuria (n=19) than in those with micro-albuminuria (n=42). Although 1 multivariate regression analysis identified albuminuria as an independent determinative factor of LAS-s among other relevant clinical background factors (β=−0.16, P=0.002), another multivariate regression model for LAS-s+GLS (β=0.40, P<0.001) showed that albuminuria was not a significant factor (β=−0.02, P=0.68). Similarly, another multivariate regression model including GLS (β=0.32, P<0.001) demonstrated that clinical features relevant for LAS-a, except for age, were not independent determinants of LAS-a. Conclusions: The cross-linked association of LA strain with GLS and albuminuria may be important for better understanding the development of diabetic cardiomyopathy.