Impact of Ambulatory Blood Pressure on Early Cardiac and Renal Dysfunction in Hypertensive Patients without Clinically Apparent Target Organ Damage

Abstract

PURPOSE: Impaired left ventricular (LV) global longitudinal strain (GLS) and the presence of microalbuminuria indicate early cardiac and renal dysfunction. We aimed to determine the relationships among 24-h ambulatory blood pressure (BP) variables, LV GLS, and urine albumin creatinine ratio (UACR) in hypertensive patients. MATERIALS AND METHODS: A total of 130 hypertensive patients (mean age 53 years; 59 men) underwent 24-h ambulatory BP monitoring, measurements of peripheral and central BPs, and transthoracic echocardiography. Patients with apparent LV systolic dysfunction (LV ejection fraction <50%) or chronic kidney disease were not included. LV GLS was calculated using two-dimensional speckle tracking, and UACR was analyzed from spot urine samples. RESULTS: In simple correlation analysis, LV GLS showed the most significant correlation with mean daytime diastolic BP (DBP) (r=0.427, p<0.001) among the various BP variables analyzed. UACR revealed a significant correlation only with night-time mean systolic BP (SBP) (r=0.253, p=0.019). In multiple regression analysis, daytime mean DBP and night-time mean SBP were independent determinants for LV GLS (beta=0.35, p=0.028) and log UACR (beta=0.49, p=0.007), respectively, after controlling for confounding factors. Daytime mean DBP showed better diagnostic performance for impaired LV GLS than did peripheral or central DBPs, which were not diagnostic. Night-time mean SBP showed satisfactory diagnostic performance for microalbuminuria. CONCLUSION: There are different associations for daytime and night-time BP with early cardiac and renal dysfunction. Ambulatory BP monitoring provides more relevant BP parameters than do peripheral or central BPs regarding early cardiac and renal dysfunction in hypertensive patients.