We read with profound interest the article titled “Vascular endothelial function assessed by post-ischemic diastolic blood pressure is associated with acclimatization and acute mountain sickness” published in Volume 17 of High Altitude Medicine and Biology (He et al., 2016). A noninvasive, simple, and inexpensive parameter like postischemic diastolic blood pressure (DBP) for risk prediction of acute mountain sickness (AMS) will indeed be a clinically useful addition to the existing modalities for early identification of individuals at risk of developing the condition. AMS occurs within 6–12 hours of ascent to more than 2500 m and symptoms usually subside within 1–2 days (Bärtsch and Swenson, 2013). However, in this study, subjects underwent a standard physical exercise regime at training base located at altitude of 3200 m and ascended with 20 kg load to a mountain with altitude of 4300 m for 20 minutes. Thereafter, after a stay of 3 days at 3200 m, they were evaluated for AMS after their descent to 1380 m in an automobile motorized vehicle. Symptoms of AMS are exacerbated after physical exertion at high altitude (Bärtsch and Swenson, 2013). It would have been nice if the subjects were also evaluated for AMS on the morning of the first day of stay at 3200 m before indulging in the physical activity of hand-to-hand combat training and after attaining summit at 4300 m. This would have enabled the authors to identify more individuals with AMS at high altitude as descent of 300 to 1000 m results in resolution of symptoms of AMS (Luks et al., 2014) and reliability on recall could underestimate symptoms or severity The possibly higher scores of AMS due to administration of AMS questionnaire at 3200/4300 m could have strengthened the association observed between postischemic DBP decline and mean AMS score.
Authors have used Chinese AMS score for comparison, but it has been reported that use of Chinese AMS score, in comparison with globally used Lake Louise scoring system (LLS) based on self-reported questionnaire, results in reporting of higher incidence of AMS (West, 2010). As physiologists with experience of working in the field of high altitude (HA) medicine, we were interested in knowing whether the outcome of study would be different if authors had used LLS instead of or along with the Chinese AMS scoring system. Probably, this would have enabled a wider application of outcome of this study in the field of HA medicine and facilitated comparison with other studies.
Authors have compared the AMS score of sea-level and moderate-altitude groups. However, they have inadvertently not reported the actual incidence of AMS. Reporting of incidence of AMS in each group and association of incidence with mean postischemic DBP decline in sea-level and moderate-altitude groups could have possibly elucidated further the role of vascular endothelium dysfunction in the pathogenesis of AMS.
