CLINICAL INVESTIGATION Increased lung vasoreactivity in children from Leadville, Colorado, after recovery from high-altitude pulmonary edema

Cardiac catheterization was performed on seven children after recovery from highaltitude pulmonary edema. All were life-long residents at elevations above 10,000 feet. Three of the seven had developed pulmonary edema without antecedent travel to low altitude but had an upper respiratory infection. Response of pulmonary arterial pressure to 16% inspired oxygen in all seven was compared with that in six well children who resided at a similar altitude and had no history of highaltitude pulmonary edema. With hypoxia the susceptible patients had a greater mean pulmonary arterial pressure (56.3 + 23.8) than the nonsusceptible children (18.8 + 3.9, p < .05). Comparison with historical hemodynamic responses in children at high altitudes showed a similar greater mean pulmonary arterial pressure in the susceptible children. Thus, in children from high altitudes, increased pulmonary vasoreactivity to hypoxia may play a role in the pathogenesis of high-altitude pulmonary edema. The development of pulmonary edema in high-altitude residents with upper respiratory infections and no antecedent low-altitude journey is consistent with the presence of other factors such as inflammation, which may play a role in the pathogenesis of the edema. The finding of right ventricular hypertrophy on an electrocardiogram in children from high altitudes may be predictive of their susceptibility to high-altitude pulmonary edema. Circulation 72, No. 5, 957-962, 1985. HIGH-ALTITUDE PULMONARY EDEMA in Colorado residents of areas of high altitude occurs predominantly in children." 2 Characteristically the children develop pulmonary edema on return to high altitude after a visit to low altitude. Some children have repeated episodes of high-altitude pulmonary edema, suggesting that they are particularly susceptible. However, the mechanisms of the edema are unknown. It is known that during the acute episode both children and adults have acutely elevated pulmonary arterial pressure, suggesting that pulmonary hypertension may be a factor in the pathogenesis of the edema.3 Increased pulmonary vasoconstriction to acute hypoxia has been found at low altitude in some adults after recovery from high-altitude pulmonary edema.45 Increased pulmonary vasoreactivity could contribute to excessive pulmonary hypertension in susceptible From the Department of Pediatrics and the Cardiovascular Pulmonary Research Laboratory, University of Colorado School of Medicine, Denver. Supported by NIH grants HL 14985 and HL 07171. Address for correspondence: J. W. Fasules, M.D., Pediatric Cardiology, University of Colorado Health Sciences Center, 4200 East Ninth Ave., C220, Denver, CO 80262. Received Feb. 15, 1985; revision accepted July 25, 1985. Vol. 72, No. 5, November 1985 subjects ascending to high altitude. We can find only two reported instances in which hypoxic pulmonary vasoreactivity was measured in children who had recovered from high-altitude pulmonary edema, and both appeared to have large increases in pulmonary arterial pressure during the hypoxic challenge.3 However, at cardiac characterization in one of the two children 1 year later, the hyperresponsiveness was decreased. We hypothesized that increased vasoconstriction in response to hypoxia plays a role in the pathogenesis of high-altitude pulmonary edema in children who reside at high altitudes. If so, children living at high elevations who have a history of high-altitude pulmonary edema should have larger hypoxic pulmonary pressor responses than do children without such history. To address this question we measured pulmonary vascular responses to acute hypoxia in children from high-altitude areas who were referred to us for heart catheterization between 1978 and 1984. The seven children without other heart and lung disease who had a history of prior high-altitude pulmonary edema and the six normal, or near-normal, children without such history constitute the basis of this report. The measurements of 957 by gest on A ril 4, 2017 http://ciajournals.org/ D ow nladed from