Cardiac function and pulmonary hypertension in Central Asian highlanders at 3250 m

THE QUESTION ADDRESSED BY THE STUDY Chronic exposure to hypoxia increases pulmonary artery pressure (PAP) in highlanders, but the criteria for diagnosis of high-altitude pulmonary hypertension (HAPH) are debated. We assessed cardiac function and PAP in highlanders at 3250 m and explored HAPH prevalence using different definitions. PATIENTS AND METHODS Central Asian highlanders free of overt cardiorespiratory disease, permanently living at 2500-3500 m compared to age-matched lowlanders living <800 m. Participants underwent echocardiography close to their altitude of residence (at 3250 m versus 760 m). RESULTS 173 participants (97 highlanders, 76 lowlanders), mean±sd age 49±9 years (49% females) completed the study. Results in lowlanders versus highlanders were systolic PAP (23±5 versus 30±10 mmHg), right ventricular fractional area change (42±6% versus 39±8%), tricuspid annular plane systolic excursion (2.1±0.3 versus 2.0±0.3 cm), right atrial volume index (20±6 versus 23±8 mL·m$^{-2}$), left ventricular ejection fraction (62±4% versus 57±5%) and stroke volume (64±10 versus 57±11 mL); all between-group comparisons p