The Relationship Of Aggravated Tricuspid Regurgitation And Acute Mountain Sickness In Healthy Young Men After Acute High Altitude Exposure

Background:Tricuspid regurgitation (tricuspid regurgitation, TR) is a common clinicalphenomenon, commonly present in healthy people. The incidence of tricuspidregurgitation is higher in men than in women. The incidence of tricuspidregurgitation is reported from30%to89%in abroad. In China, it is approximate50%. More than70%of them are trace or small amount of regurgitation. Justbecause of this, the research and treatment of TR have been overlooked for a longtime. Lately studies have found that even trace amounts of TR could affect theprognosis of correlate diseases such as pulmonary hypertension, heart failure, mitralvalve disease, and so on, which suggests that we should strengthen the research andtreatment of tricuspid regurgitation (even trace amounts of regurgitation).Nearly40million people acute ascend to the plateau from the plains in theworld every year. More than one third of them appeared tricuspid regurgitation.Therefore, it is very important to clear the clinical features of TR after acute ascentto high altitude. Several studies mention that TR pressure gradient increased afteracute high altitude exposure. But the exact extent and time phrase of the increasedTR after acute high altitude exposure are still unclear. Meanwhile the clinicalrelevance of increased TR after acute high altitude exposure remains unknown. Sothis study focuses on the increased TR after rapidly ascend to high altitude anddesigns to explore the pathogenesis of it.Acute mountains sickness (AMS) is a symptom complex appearing6-12hoursafter arrival at high altitude. Mild AMS usually remits by rest or short-timeacclimatized to the highland. Severe AMS needs treatment urgently with oxygen ormedicine. Occasionally some people with AMS will evolve high altitude cerebral oedema or pulmonary oedema. So it is very important to diagnose and classfy theAMS exactly at the early time. Currently, there are some tools to evaluate AMS,such as lake Louise Standard Scoring (LLSS), Visual Analogue Scale (VAS),Environmental Symptoms Questionnaire (ESQ) and so on. But all of them aresubjective and easily confused with viral infection, alcohol hangover, exhaustion,fever or dehydration. Therefore, to search objective clinical tools to diagnose AMSis very essential. Although several studies have tried to explore some newparameters such as oximetry and heart rate variability to diagnose AMS, noobjective examination findings or investigations has shown good value indiagnosing AMS. Our previous works have found that TR increase after acute highaltitude exposure and many subjects with increased TR suffer from AMS. So thisstudy also intends to investigate the correlation of TR and AMS, and to explore thenew objective parameter based on TR to diagnose the AMS.Objectives: To investigate the clinical relevance of tricuspid regurgitation inhealthy young men after acute ascended to high altitude. To investigate thecorrelation of TR and AMS, and to explore the new objective parameter based onTR in diagnosis of AMS.Study design:Part11.179healthy Chinese young men aged22（18-30）years were consecutivelyevaluated for TR by echocardiography from September2011to September2013.54subjects lived at an altitude of450m (low altitude),60subjects ascended to3700mfrom450m within24hour (acute exposure), and65subjects ascended and stayed at3700m for2weeks (acclimatization). Subjects of acute exposure group were furtherdivided into subjects with TR and subjects without TR.2. The TR and cardiac function was assessed by echocardiography and theAMS was assessed by the LLSS.3. Analyze the difference of the TR, basic physical signs and cardiac functionin the three groups (low altitude, acute exposure, acclimatization) and screen therisk factors of TR by SPSS16.0software package. Part21.60healthy Chinese young men aged22（18-30）years who ascended to3700m from450m within24hours were consecutively evaluated for TR byechocardiography from July2012to September2012. Subjects were further dividedinto3subgroups according to TR pressure gradient (group1: TR pressure gradient=0mmHg; group2:0<TR pressure gradient≤30mmHg; group3: TR pressuregradient>30mmHg).2. The TR was assessed by echocardiography and the AMS was assessed by theLLSS.3. Analyze the relationship of the TR and AMS by SPSS16.0software package.Assess the diagnosis value of TR to AMS.Results:Part11. The morbidity of TR was48%,67%and51%respectively in low altitude,acute exposure and acclimatization. Compared to the low altitude group, TRpressure gradient was increased significantly in the acute exposure group(26.64±4.36mmHg vs18.84±4.22mmHg, p<0.05), but was comparable toacclimatization group (19.45±3.78mmHg vs18.84±4.22mmHg, p>0.05).2. The subjects with TR showed lower SaO2than subjects withoutTR(87.40±2.64%vs89.65±2.23%，p＜0.05), but there was no difference betweenthe two groups in mean pulmonary artery pressure (mPAP), right ventricular Teiindex, tricuspid valve E/A, right ventricular size and so on.3. Logistic regression analysis showed that increased TR was correlated withAMS(OR=3.667,95%CI, P<0.05) and SaO2(OR=0.692,95%CI, P<0.05) but notrelated to mPAP, right ventricular Tei index, tricuspid valve E/A and rightventricular size.Part21. The subjects with TR pressure gradient more than30mmHg showed highermorbidity and severity of AMS than those without TR or with TR pressure gradientless than30mmHg.2. TR pressure gradient showed a remarkable linear positive correlation withAMS score(r=0.462). 3. With LLSS as the gold standard, the TR pressure gradient (cut off value:30mmHg) showed high positive predictive value (90%) and negative predictive value(64%) in predicted and diagnosed the severe AMS.Conclusions:Acute high altitude exposure aggravated TR in the healthy young man.Increased TR pressure gradient was correlated with the incidence and severity ofAMS and could assist to diagnosis of AMS.