Abstract 15955: Central Arterial Hemodynamics of Hypertension at High Altitude: The INTERVENCION Trial
Background: Altitude above sea level is a key regulator of cardiovascular function. Whereas much is known about the short-term cardiovascular effects of altitude, data are lacking about the differences in the patterns of hypertension between populations living at low and high altitude. Hemodynamic patterns of hypertension can provide important clues about vascular status. Mean arterial pressure is dependent on microvascular resistance and cardiac output, whereas pulsatile hemodynamics are dependent on large and medium-sized conduit artery function.
Methods: We performed an analysis of the baseline measurements in the INTERVENCION study, a prospective randomized multicenter trial which enrolled subjects with untreated hypertension at low altitude (LA, <2000 m), intermediate altitude (IA, 2000-3500 m) and high altitude (HA, >3500 m) in Peru. At each altitude level, enrollment was stratified by age group and gender to achieve an equal distribution. Central pressure profiles were measured with carotid high-fidelity arterial tonometry (Millar tonometer and Sphygmocor device).
Results: Age, gender and body mass index in the sample did not differ between altitude levels. Despite similar mean arterial pressure (LA: 106.3±1.9; IA: 107.9±1.3; HA: 104.3±1.1; P=0.12), central systolic pressure was progressively lower with increasing altitude (SL: 144.8±3.3; IA: 139.2±2.2; HA: 133.7±1.7; P=0.007). This was due to both a lower amplitude of the first systolic peak (forward pressure) (LA=47.8±1.7; IA=42.2±1.4; HA: 38.1±1.3 mmHg; P<0.0001), and lower augmented pressure (LA=16±1.8; IA=10.5±1.2; HA=10.5±1.4 mmHg; P=0.025). Peripheral systolic pressure also decreased with increasing altitude (SL=149.2±2.7; IA=142.8±1.6; HA=138.6±1.4; P=0.001). Augmentation index and pulse pressure amplification were not significantly different between the altitude levels.
Conclusions: Despite similar levels of mean pressure, we demonstrate for the first time, marked altitude-related differences in central hemodynamics in hypertension. Hypertensives living chronically at increasing altitude demonstrated less adverse pulsatile hemodynamics, which may translate in differences in cardiovascular risk and response to therapy.
Author Disclosures: J. Medina-Lezama: None. O. Narvaez Guerra: None. K. Herrera Enriquez: None. M. Zapata Ponze De Leon: None. A.J. Rondon Rodríguez: None. S. Pérez Moscoso: None. J.A. Chirinos: Research Grant; Significant; NIH, American College of Radiology Network, Fukuda Denshi, Bristol Myers Squibb, Microsoft and CVRx Inc. Other Research Support; Modest; Fukuda Denshi, Withings, Atcor Medical. Consultant/Advisory Board; Modest; Fukuda Denshi, Microsoft Research, Merck and Vital Labs. Consultant/Advisory Board; Significant; Bristol Myers Squibb, OPKO Healthcare.
- © 2016 by American Heart Association, Inc.