Abstract 15955: Central Arterial Hemodynamics of Hypertension at High Altitude: The INTERVENCION Trial

BackgroundAltitude 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.MethodsWe 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, 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).ResultsAge, gender and body mass index in the sample did not differ between altitude levels. Despite similar mean arterial pressure (LA106.3±1.9; IA107.9±1.3; HA104.3±1.1; P=0.12), central systolic pressure was progressively lower with increasing altitude (SL144.8±3.3; IA139.2±2.2; HA133.7±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; HA38.1±1.3 mmHg; P