Brenner Roman, Pratali Lorenza, Rimoldi Stefano F, Murillo Jauregui Carla Ximena, Soria Rodrigo, Rexhaj Emrush, Salinas Salmón Carlos, Villena Mercedes, Romero Catherine, Sartori Claudio, Allemann Yves, Scherrer Urs
Department of Cardiology and Clinical Research, University Hospital Bern, Bern, Switzerland.
Institute of Clinical Physiology, Pisa, Italy.
Chest. 2015 Apr;147(4):1072-1079. doi: 10.1378/chest.14-1353.
There is considerable interindividual variability in pulmonary artery pressure among high-altitude (HA) dwellers, but the underlying mechanism is not known. At low altitude, a patent foramen ovale (PFO) is present in about 25% of the general population. Its prevalence is increased in clinical conditions associated with pulmonary hypertension and arterial hypoxemia, and it is thought to aggravate these problems.
We searched for a PFO (transesophageal echocardiography) in healthy HA dwellers (n = 22) and patients with chronic mountain sickness (n = 35) at 3,600 m above sea level and studied its effects (transthoracic echocardiography) on right ventricular (RV) function, pulmonary artery pressure, and vascular resistance at rest and during mild exercise (50 W), an intervention designed to further increase pulmonary artery pressure.
The prevalence of PFO (32%) was similar to that reported in low-altitude populations and was not different in participants with and without chronic mountain sickness. Its presence was associated with RV enlargement at rest and an exaggerated increase in right-ventricular-to-right-atrial pressure gradient (25 ± 7 mm Hg vs 15 ± 9 mm Hg, P < .001) and a blunted increase in fractional area change of the right ventricle (3% [-1%, 5%] vs 7% [3%, 16%], P = .008) during mild exercise.
These findings show, we believe for the first time, that although the prevalence of PFO is not increased in HA dwellers, its presence appears to facilitate pulmonary vasoconstriction and RV dysfunction during a mild physical effort frequently associated with daily activity.
ClinicalTrials.gov; No.: NCT01182792; URL: www.clinicaltrials.gov.
高海拔（HA）居住者的肺动脉压存在相当大的个体间差异，但其潜在机制尚不清楚。在低海拔地区，约25%的普通人群存在卵圆孔未闭（PFO）。在与肺动脉高压和动脉低氧血症相关的临床情况下，其患病率会增加，并且被认为会加重这些问题。
我们在海拔3600米处对健康的HA居住者（n = 22）和慢性高山病患者（n = 35）进行经食管超声心动图检查以寻找PFO，并通过经胸超声心动图研究其对静息和轻度运动（50瓦）时右心室（RV）功能、肺动脉压和血管阻力的影响，轻度运动是一种旨在进一步升高肺动脉压的干预措施。
PFO的患病率（32%）与低海拔人群报告的患病率相似，并且在有和没有慢性高山病的参与者中没有差异。其存在与静息时RV扩大以及右心室与右心房压力梯度的过度增加（25±7毫米汞柱对15±9毫米汞柱，P <.001）以及轻度运动期间右心室面积变化分数的增加减弱（3%[-1%，5%]对7%[3%，16%]，P =.008）有关。
我们认为这些发现首次表明，尽管HA居住者中PFO的患病率没有增加，但其存在似乎在日常活动常见的轻度体力活动期间促进肺血管收缩和RV功能障碍。
ClinicalTrials.gov；编号：NCT01182792；网址：www.clinicaltrials.gov。
