| dc.description.abstract | Background: Chronic mountain sickness (CMS) is a major public health problem characterized by
exaggerated hypoxemia and erythrocytosis. In more advanced stages, patients with CMS often
present with functional and structural changes of the pulmonary circulation, but there is little
information on the systemic circulation. In patients with diseases associated with chronic hypoxemia at low altitude, systemic vascular function is altered. We hypothesized that patients with
CMS have systemic vascular dysfunction that may predispose them to increased systemic cardiovascular morbidity.
Methods: To test this hypothesis, we assessed systemic endothelial function (by flow-mediated
dilation [FMD]), arterial stiffness, and carotid intima-media thickness and arterial oxygen saturation
(SaO2) in 23 patients with CMS without additional classic cardiovascular risk factors and
27 age-matched healthy mountain dwellers born and permanently living at 3,600 m. For some
analyses, subjects were classified according to baseline SaO2 quartiles; FMD of the highest quartile
subgroup (SaO2 90%) was used as a reference value for post hoc comparisons.
Results: Patients with CMS had marked systemic vascular dysfunction as evidenced by impaired
FMD (CMS, 4.6% 1.2%; control subjects, 7.6% 1.9%; P,.0001), greater pulse wave velocity
(10.6 2.1 m/s vs 8.4 1.0 m/s, P,.001), and greater carotid intima-media thickness (690 120 mm
vs 570 110 mm, P5.001). A positive relationship existed between SaO2 and FMD (r50.62,
P,.0001). Oxygen inhalation improved (P,.001) but did not normalize FMD in patients with
CMS, although it normalized FMD in hypoxemic control subjects (SaO2,90%) and had no detectable
effect in normoxemic control subjects (SaO2 90%).
Conclusions: Patients with CMS show marked systemic vascular dysfunction. Structural and functional alterations contribute to this problem that may predispose these patients to premature
cardiovascular disease. | |
