The Association of Smoothness Index of Central Blood Pressure With Ambulatory Carotid Femoral Pulse Wave Velocity After 20-week Treatment With Losartan in Combination With Amlodipine Versus Hydrochlorothiazide

Abstract

Objectives: The aim of this study was to identify associations between the smoothness index of central SBP (CSBP) and changes of ambulatory carotid femoral pulse wave velocity in response to 20-week treatments with losartan and amlodipine vs. losartan and hydrochlorthiazide combinations.

Methods: For 142 (losartan and hydrochlorthiazide: 72, losartan and hydrochlorthiazide: 70) patients examined with ambulatory central blood pressure (BP) monitoring device, we calculated smoothness indices and trough-to-peak ratios of brachial SBP, CSBP, ambulatory pulse pressure amplification (APPA), ambulatory augmentation index at heart rate 75 beats per minute (AAIx75) and ambulatory carotid femoral pulse wave velocity (AcfPWV).

Results: Mean age was 58.9 ± 12.3 years, and women accounted for 25.9%. Changes in office SBP/DBP were not different between groups (losartan and hydrochlorthiazide: -15.2 ± 15.0/-7.8 ± 8.0 vs. losartan and amlodipine: -14.9 ± 13.7/-9.2 ± 7.5 mmHg). Reduction of 24-h CSBP was not significantly different (losartan and hydrochlorthiazide: 6.4 ± 1.1 vs. losartan and amlodipine: 9.2 ± 1.1 mmHg, P = 0.074). Reduction in nocturnal AcfPWV was greater in the losartan and amlodipine group (losartan and hydrochlorthiazide: 0.09 ± 0.05 vs. losartan and amlodipine: 0.26 ± 0.05 m/s, P = 0.0216). Intraindividual SIs for CSBP were higher in the losartan and amlodipine group (0.40 ± 0.57 vs. 0.65 ± 0.74, P = 0.022). In multivariable regression analysis, smoothness index of CSBP was independently associated with the losartan and amlodipine group. In model additionally considering the changes in arterial stiffness, decrease in AcfPWV instead of the treatment group was independently associated with smoothness indices. In mediation analysis, smoothness index was fully mediated by reduction in night-time AcfPWV.

Conclusion: Losartan and amlodipine combination was superior to the losartan and hydrochlorthiazide combination in terms of achieving higher smoothness index for CSBP after 20-week treatments. The effect of losartan and amlodipine on smoothness index was fully mediated by reduction of night-time AcfPWV.