Left Ventricular Strain and Relaxation Are Independently Associated with Renal Cortical Perfusion in Hypertensive Patients.

Abstract

Renal perfusion, which depends on cardiac function, is a factor conditioning the work of kidneys. The objective of the study was to assess the influence of cardiac function, including left ventricular contractility and relaxation, on renal cortical perfusion in patients with hypertension and chronic kidney disease treated pharmacologically. There were 63 patients (7F and 56M; aged 56±14) with hypertension and stable chronic kidney disease enrolled into the study. Serum cystatin C, with estimated glomerular filtration rate (eGFR), ambulatory blood pressure monitoring, carotid intima-media thickness (cIMT), echocardiography with speckle tracking imaging and the calculation of global longitudinal strain (GLS), diameter of vena cava inferior (VCI), and an ultrasound dynamic tissue perfusion measurement of the renal cortex were performed. We found that the renal cortical perfusion correlated significantly with age, renal function, cIMT, GLS, left ventricular ejection fraction (LVEF), left ventricular mass index (LVMI), diastolic peak values of early (E) and late (A) mitral inflow velocities ratio (E/A) and E to early diastolic mitral annular tissue velocity (E/E'), but not with VCI, or the right ventricle echocardiographic parameters. In multivariable regression analysis adjusted to age, only eGFR, E/E', and GLS were independently related to renal cortical perfusion (r 2=0.44; p<0.001). In conclusion, the intensity of left ventricular strain and relaxation independently influence renal cortical perfusion in hypertensive patients with chronic kidney disease. A reduction in left ventricular global longitudinal strain is superior to left ventricular ejection fraction in the prediction of a decline in renal cortical perfusion.