Pulmonary Vascular Pressure Response to Acute Cold Exposure in Kyrgyz Highlanders

Sydykov, Akylbek, Abdirashit Maripov, Kubatbek Muratali Uulu, Nadira Kushubakova, Aleksandar Petrovic, Christina Vroom, Meerim Cholponbaeva, Melis Duishobaev, Samatbek Satybaldyev, Nurgul Satieva, Argen Mamazhakypov, Meerim Sartmyrzaeva, Nazgul Omurzakova, Zhainagul Kerimbekova, Nursultan Baktybek, Oleg Pak, Lan Zhao, Norbert Weissmann, Akpay Sarybaev, Sergey Avdeev, Hossein Ardeschir Ghofrani, Ralph Theo Schermuly, and Djuro Kosanovic. Pulmonary vascular pressure response to acute cold exposure in kyrgyz highlanders. High Alt Med Biol 00:000-000, 2019. Background/Aims: Long-term high altitude residence leads to a sustained increase in pulmonary vascular resistance and elevation of pulmonary artery pressure due to chronic alveolar hypoxia. However, living at high altitude is also associated with other environmental factors such as cold. There is still little experimental evidence suggesting detrimental effects of low temperatures on the pulmonary vasculature. Therefore, our objective was to investigate acute effects of cold exposure on the pulmonary circulation in Kyrgyz high altitude natives. Methods: Responses of the pulmonary circulation during acute exposure to controlled cold conditions (4 degrees C-6 degrees C) for 60 minutes were measured in highlanders using Doppler echocardiography. Based on the Doppler echocardiography-derived tricuspid regurgitant systolic pressure gradient (TRG), subjects with TRG >= 40 mmHg were allocated into the pulmonary hypertension (PH) group. Participants from the PH group were compared with volunteer control subjects with TRG <40 mmHg. All baseline measurements were evaluated in a warm room during 60 minutes (22 degrees C-28 degrees C). Following baseline echocardiography, the subjects were assigned to either warm or cold exposure for an additional 60 minutes. Results: Acute cold exposure significantly increased TRG both in the control (Delta TRG, 4.93 mmHg) and in the PH (Delta TRG, 8.15 mmHg) group, compared to the respective warm exposure conditions (Delta TRG, -0.14 and -0.05 mmHg). No changes in cardiac output were observed upon cold exposure. Conclusion: Thus, acute exposure to cold leads to elevation of pulmonary artery pressure in high altitude residents.