PP.33.10] AMBULATORY HEMODYNAMIC TRENDS IN HYPERTENSION AND AGING

Abstract

Objective: To compare 24-hour ambulatory blood pressure monitoring with existing laboratory methods, and to investigate the impact of BP and age on systemic hemodynamics. Design and method: Cardiac output (CO) and systemic vascular resistance (SVR) were analyzed in 3 sub studies. Sub study A: 24-hour PWA (MobilOGraph, IEM, Stolberg, DE) was performed in a convenience sample (n = 66) stratified into 3 groups by systolic BP levels (<120, 120–139, >139 mmHg) and separately stratified by age (<55, >/ = 55 years). Sub study B: Each individual PWA was analyzed for within individual trends in CO and SVR. These trends were compared to the trends obtained from Sub study A. Sub study C: supine hemodynamics and echocardiographic parameters measured in a reference population developed in our laboratory (n = 78) were compared to 24-hour PWA means(Sub study A). Results: BP was independent of CO in all 3 sub studies, overall and for each BP subgroup. Thus, there are very strong inverse relationships between 24-hour SVR and 24-hour CO for each BP group (p < 0.000 each) in each sub study, with a parallel upward-rightward shift of the respective SVR-CO isobars as BP increases. Figure 1 (left panel) shows the SVR-CO isobars for each BP group in Sub study A. Nearly identical relationships were also found in sub studies B and C. Figure 1 (right panel) demonstrates respective SVR-CO isobars for younger and older individuals, demonstrating only a rightward shift in the SVR-CO isobar.Conclusions: 1) Hemodynamic analysis using 24-hour ambulatory PWA is feasible. 2) Sustained hypertension is associated with an upward-rightward shift of the SVR-CO isobar in proportion to the degree of BP elevation, indicating that the underlying hemodynamic abnormality in hypertension at any stage is both inappropriately high CO and inappropriate high SVR. 3) Age effects on hemodynamics are more complex.