Exaggerated exercise‐induced pulmonary vasoconstriction in reentry pulmonary edema‐prone subjects and in offspring of preeclampsia

Abstract

Offspring of mothers suffering from preeclampsia and subjects with a history of reentry high‐altitude pulmonary edema (re‐entry HAPE) display sustained hypoxic pulmonary hypertension when living at high altitude and a predisposition to pulmonary edema. The underlying mechanisms are unknown. We hypothesized that the predisposition to pulmonary edema could be caused by capillary stress failure related to exaggerated pulmonary hypertension. We, therefore, estimated the pulmonary artery pressure response (Doppler echocardiography) to mild exercise in 18 re‐entry HAPE‐prone subjects, 12 offspring of preeclampsia and 29 controls, all born and living in La Paz, Bolivia (3600 m). As expected, mean±SD systolic pulmonary artery pressure at rest was higher in re‐entry HAPE prone subjects and offspring of preeclampsia than in controls (42±7 and 37±8 vs. 30±7 mm Hg, P<0.001). Most importantly, the exercise‐induced increase in pulmonary artery pressure was 50 percent larger in the two groups of subjects at risk than in controls (21±8 and 21±10 vs. 14±7 mm Hg, P=0.02). These data provide the first evidence for a markedly exaggerated pulmonary vasoconstrictor response to exercise in high altitude dwellers known to have an augmented susceptibility to develop pulmonary edema. We speculate that this exaggerated response may predispose them to pulmonary edema by causing capillary stress failure.