Prognostic significance of day-by-day in-hospital blood pressure variability in COVID-19 patients with hypertension.

Hypertension is the most common comorbidity in patients with coronavirus disease 2019 (COVID-19) and increases in-hospital mortality. Day-by-day blood pressure (BP) variability (BPV) is associated with clinical outcomes in hypertensive patients. However, little information is available on the association of BPV with the outcomes of COVID-19 patients with hypertension. This study aimed to demonstrate whether day-by-day in-hospital BPV had prognostic significance in these patients. The authors included 702 COVID-19 patients with hypertension from Huoshenshan Hospital (Wuhan, China), who underwent valid in-hospital BP measurements on at least seven consecutive days. Day-by-day BPV was assessed by standard deviation (SD), coefficient of variation (CV), and variation independent of mean (VIM). Overall, patients with severe COVID-19 and non-survivors had higher BPV than moderate cases and survivors, respectively. Additionally, higher BPV was correlated with greater age and higher levels of C-reactive protein, procalcitonin, high-sensitive cardiac troponin I, and B-type natriuretic peptide. In multivariable Cox regression, SD of systolic BP (SBP) was predictive of mortality [hazard ratio (HR) 1.17, 95% confidence interval (CI) 1.05-1.30] as well as acute respiratory distress syndrome (ARDS) (HR 1.09, 95% CI 1.01-1.16). Similar trends were observed for CV and VIM of SBP, but not indices of diastolic BP variability. The authors demonstrated that day-by-day in-hospital SBP variability can independently predict mortality and ARDS in COVID-19 patients with hypertension. And high BPV might be correlated with severe inflammation and myocardial injury. Further studies are needed to clarify whether early reduction of BPV will improve the prognosis of these patients.

A novel echocardiographic parameter to identify individuals susceptible to acute mountain sickness.

BACKGROUND: Acute mountain sickness (AMS) may cause life-threatening conditions. This study aimed to screen echocardiographic parameters at sea level (SL) to identify predictors of AMS development. METHODS: Overall, 106 healthy men were recruited at SL and ascended to 4100 m within 7 days by bus. Basic characteristics, physiological data, and echocardiographic parameters were collected both at SL and 4100 m above SL. AMS was identified by 2018 Lake Louise Questionnaire Score. RESULTS: After acute high altitude exposure (AHAE), 33 subjects were diagnosed with AMS and exhibited lower lateral mitral valve tissue motion annular displacement (MV TMADlateral) at SL than AMS-free subjects (13.09 vs. 13.89 mm, p = 0.022). MV TMADlateral at SL was significantly correlated with AMS occurrence (OR = 0.717, 95% CI: 0.534-0.964, p = 0.028). The MV TMADlateral<13.30-mm group showed over 4-fold risk for AMS development versus the MV TMADlateral≥13.30-mm group. After AHAE, the MV TMADlateral<13.30-mm group had increased HR (64 vs. 74 bpm, p = 0.001) and right-ventricular myocardial performance index (0.54 vs. 0.69, p = 0.009) and decreased left ventricular global longitudinal strain (-21.50 vs. -20.23%, p = 0.002), tricuspid valve E/A ratio (2.11 vs. 1.89, p = 0.019), and MV E-wave deceleration time (169.60 vs. 156.90 ms, p = 0.035). CONCLUSION: MV TMADlateral at SL was a potential predictor of AMS occurrence and might be associated with differential alterations of ventricular systolic and diastolic functions in subjects with different MV TMADlateral levels at SL after AHAE.

Cardiovascular Indicators of Systemic Circulation and Acute Mountain Sickness: An Observational Cohort Study.

Background: Acute high-altitude (HA) exposure results in blood pressure (BP) and cardiac function variations in most subjects, some of whom suffer from acute mountain sickness (AMS). Several previous studies have found that cardiovascular function indicators are potentially correlated with AMS. Objectives: This study aims to examine HA-induced cardiovascular adaptations in AMS patients and compare them with healthy subjects. It also aims to investigate the relationship between cardiovascular function indicators and AMS, as well as to provide some insightful information about the prevention and treatment of AMS. Methods: Seventy-two subjects were enrolled in this cohort study. All the subjects ascended Litang (4,100 m above sea level). They were monitored by a 24-h ambulatory blood pressure (ABP) device and underwent echocardiography examination within 24 h of altitude exposure. The 2018 Lake Louise questionnaire was used to evaluate AMS. Results: Acute mountain sickness group consisted of more women (17 [60.7%] vs. 10 [22.7%], p = 0.001) and fewer smokers (5 [17.9%] vs. 23 [52.3%], p = 0.003). Compared with subjects without AMS, subjects with AMS had lower pulse pressure (PP) (daytime PP, 45.23 ± 7.88 vs. 52.14 ± 4.75, p < 0.001; nighttime PP, 42.81 ± 5.92 vs. 49.39 ± 7.67, p < 0.001) and lower effective arterial elastance (Ea) (1.53 ± 0.24 vs. 1.73 ± 0.39, p = 0.023). Multivariate regression indicated that female sex (OR = 0.23, p = 0.024), lower daytime PP (OR = 0.86, p = 0.004), and lower Ea (OR = 0.03, p = 0.015) at low altitude (LA) were independent risk factors for AMS. Combined daytime PP and Ea at LA had a high predictive value for AMS (AUC = 0.873; 95% CI: 0.789-0.956). Correlation analysis showed that AMS-induced headache correlated with daytime PP (R = -0.401, p < 0.001) and nighttime PP at LA (R = -0.401, p < 0.001). Conclusion: Our study demonstrated that AMS patients had a lower PP and Ea at LA. These baseline indicators of vasodilation at LA were closely associated with AMS, which may explain the higher headache severity in subjects with higher PP at LA.

Echocardiographic Right Ventricular Outflow Track Notch Formation and the Incidence of Acute Mountain Sickness.

Yuan, Fangzhengyuan, Zhexue Qin, Chuan Liu, Shiyong Yu, Jie Yang, Jun Jin, Shizhu Bian, Xubin Gao, Jihang Zhang, Chen Zhang, Mingdong Hu, Jingbin Ke, Yuanqi Yang, Jingdu Tian, Chunyan He, Wenzhu Gu, Chun Li, Rongsheng Rao, and Lan Huang. Echocardiographic right ventricular outflow track notch formation and the incidence of acute mountain sickness. High Alt Med Biol. 22:263-273, 2021. Background: High-altitude exposure causes acute mountain sickness (AMS) and increases pulmonary arterial pressure (PAP). The notching of echocardiographic right ventricular outflow tract flow velocity envelope (right ventricular outflow tract [RVOT] notching), is related to increased PAP. We speculate that acute high-altitude exposure may trigger RVOT notching, which may be associated with AMS. Methods: All 130 subjects, ascended to 4,100 m from low altitude by bus within 7 days, underwent physiological and echocardiographic testing. The subjects with a total score of 3 or above and in the presence of a headache were diagnosed with AMS according to Lake Louise criteria. Results: After high-altitude exposure, the incidence of RVOT notching and AMS was 20% and 28.5%, respectively. The subjects with AMS had a higher incidence (37.8%) of RVOT notching than those without AMS (12.9%). Multivariate logistic regression analysis showed that RVOT notching was associated with systolic pulmonary artery pressure (SPAP) (odds ratio [OR], 1.11; 95% confidence interval [CI], 1.05-1.17; p < 0.001) and the occurrence of AMS (OR, 5.48; 95% CI, 1.96-15.35; p = 0.001). Although linear regression analysis showed a weak correlation between SPAP and Lake Louise AMS score in the overall population (r = 0.20, p = 0.020), this correlation was more pronounced in the subpopulation with RVOT notching (r = 0.44, p = 0.023) and SPAP was not related to Lake Louise AMS score in the subpopulation without RVOT notching (r = 0.03, p = 0.698). Among AMS symptoms, the incidence of headache and fatigue were higher in subjects with RVOT notching than those in subjects without RVOT notching. Conclusions: We first observe that high-altitude exposure triggers RVOT notching formation, which is associated with AMS occurrence. Clinical Trials.gov ID: ChiCTR-RCS-12002232.

Sex-Dependent Association Between Early Morning Ambulatory Blood Pressure Variations and Acute Mountain Sickness.

BACKGROUND: Acute high altitude (HA) exposure elicits blood pressure (BP) responses in most subjects, and some of them suffer from acute mountain sickness (AMS). However, a 24-h ambulatory BP (ABP) change and the correlation with the occurrence of AMS in different sexes are still unclear. OBJECTIVES: This prospective study aimed to investigate HA induced BP responses in males and females and the relationship between AMS and 24-h ABP. METHODS: Forty-six subjects were matched according to demographic parameters by propensity score matching with a ratio of 1:1. All the subjects were monitored by a 24-h ABP device; the measurement was one period of 24 h BP. 2018 Lake Louise questionnaire was used to evaluate AMS. RESULTS: Both the incidence of AMS (14 [60.9%] vs. 5 [21.7%], P = 0.007) and headache (18 [78.3%] vs. 8 [34.8%], P = 0.003) were higher in females than in males. All subjects showed an elevated BP in the early morning [morning systolic BP (SBP), 114.72 ± 13.57 vs. 120.67 ± 11.10, P = 0.013]. The elevation of morning SBP variation was more significant in females than in males (11.95 ± 13.19 vs. -0.05 ± 14.49, P = 0.005), and a higher morning BP surge increase (4.69 ± 18.09 vs. -9.66 ± 16.96, P = 0.005) was observed after acute HA exposure in the female group. The increase of morning SBP was associated with AMS occurrence (R = 0.662, P < 0.001) and AMS score (R = 0.664, P = 0.001). Among the AMS symptoms, we further revealed that the incidence (R = 0.786, P < 0.001) and the severity of headache (R = 0.864, P < 0.001) are closely correlated to morning SBP. CONCLUSIONS: Our study demonstrates that females are more likely to suffer from AMS than males. AMS is closely associated with elevated BP in the early morning period, which may be correlated to higher headache incidence in subjects with higher morning SBP.

The Association Between Notching of the Right Ventricular Outflow Tract Flow Velocity Doppler Envelope and Impaired Right Ventricular Function After Acute High-Altitude Exposure.

INTRODUCTION: Pulmonary artery pressure (PAP) is increased and right ventricular (RV) function is well preserved in healthy subjects upon exposure to high altitude (HA). An increase in PAP may trigger notching of the right ventricular outflow tract Doppler flow velocity envelope (RVOT notch), which is associated with impaired RV function in patients with pulmonary hypertension. However, whether HA exposure can induce RVOT notch formation and the subsequent impact on cardiac function in healthy subjects remains unclear. METHODS: A total of 99 subjects (69 males and 30 females) with a median age of 25 years were enrolled in this study; they traveled from 500 to 4100 m by bus over a 2-day period. All subjects underwent a comprehensive physiological and echocardiographic examination 1 day before ascension at low altitude and 15 ± 3 h after arrival at HA. The RVOT notch was determined by the presence of a notched shape in the RVOT Doppler flow velocity envelope. The systolic PAP (SPAP) was calculated as Bernoulli equation SPAP = 4 × (maximum tricuspid regurgitation velocity)2+5 and mean PAP (mPAP) = 0.61 × SPAP+2. Cardiac output was calculated as stroke volume × heart rate. Pulmonary capillary wedge pressure (PCWP) was calculated as 1.9+1.24 × mitral E/e'. Pulmonary vascular resistance (PVR) was calculated as (mPAP-PCWP)/CO. RESULTS: After HA exposure, 20 (20.2%) subjects had an RVOT notch [notch (+)], and 79 (79.8%) subjects did not have an RVOT notch [notch (-)]. In the multivariate logistic regression analysis, the SPAP, right ventricular global longitude strain (RV GLS), and tricuspid E/A were independently associated with the RVOT notch. The SPAP, mPAP, PVR, standard deviations of the times to peak systolic strain in the four mid-basal RV segments (RVSD4), peak velocity of the isovolumic contraction period (ICV), and the peak systolic velocity (s') at the mitral/tricuspid annulus were increased in all subjects. Conversely, the pulse oxygen saturation (SpO2), RV GLS, and tricuspid annulus plane systolic excursion (TAPSE)/SPAP were decreased. However, the increases of SPAP, mPAP, PVR, and RVSD4 and the decreases of SpO2, RV GLS, and TAPSE/SPAP were more pronounced in the notch (+) group than in the notch (-) group. Additionally, increased tricuspid ICV and mitral/tricuspid s' were found only in the notch (-) group. CONCLUSION: HA exposure-induced RVOT notch formation is associated with impaired RV function, including no increase in the tricuspid ICV or s', reduction of RV deformation, deterioration in RV-pulmonary artery coupling, and RV intraventricular synchrony.

Sex Differences in the Incidence and Risk Factors of Myocardial Injury in COVID-19 Patients: A Retrospective Cohort Study.

Male novel coronavirus disease (COVID-19) patients tend to have poorer clinical outcomes than female patients, while the myocardial injury is strongly associated with COVID-19-related adverse events. Owing to a lack of corresponding data, we aimed to investigate the sex differences in the incidence of myocardial injury in COVID-19 patients and to identify the potential underlying mechanisms, which may partly account for the sex bias in the incidence of adverse events. This retrospective study included 1,157 COVID-19 patients who were hospitalized in Huoshenshan Hospital from 12 March 2020 to 11 April 2020. Data on the patients' demographic characteristics, initial symptoms, comorbidities and laboratory tests were collected. Totally, 571 (49.4%) female and 586 (50.6%) male COVID-19 patients were enrolled. The incidence of myocardial injury was higher among men than women (9.2 vs. 4.9%, p = 0.004). In the logistic regression analysis, age, and chronic kidney disease were associated with myocardial injury in both sexes. However, hypertension [odds ratio (OR) = 2.25, 95% confidence interval (CI) 1.20-4.22], coronary artery disease (OR = 2.46, 95% CI 1.14-5.34), leucocyte counts (OR = 3.13, 95% CI 1.24-7.86), hs-CRP (OR = 4.45, 95% CI 1.33-14.83), and D-dimer [OR = 3.93 (1.27-12.19), 95% CI 1.27-12.19] were independent risk factors only in the men. The correlations of hs-CRP and D-dimer with hs-cTnI and BNP were stronger in the men. The incidence of myocardial injury in COVID-19 patients is sex-dependent, predominantly in association with a greater degree of inflammation and coagulation disorders in men. Our findings can be used to improve the quality of clinical management in such settings.

Blood pressure and left ventricular function changes in different ambulatory blood pressure patterns at high altitude.

Acute high-altitude (HA) exposure induces physiological responses of the heart and blood pressure (BP). However, few studies have investigated the responses associated with dipper and non-dipper BP patterns. In this prospective study, 72 patients underwent echocardiography and 24-h ambulatory BP testing at sea level and HA. Patients were divided into dipper and non-dipper groups according to BP at sea level. Acute HA exposure elevated 24-h systolic and diastolic BP and increased BP variability, particularly in the morning. Moreover, acute exposure increased left ventricular torsion, end-systolic elastance, effective arterial elastance, and untwisting rate, but reduced peak early diastolic velocity/late diastolic velocity and peak early diastolic velocity/early diastolic velocity, implying enhanced left ventricular systolic function but impaired filling. Dippers showed pronounced increases in night-time BP, while non-dippers showed significant elevation in day-time BP, which blunted differences in nocturnal BP fall, and lowest night-time and evening BP. Dippers had higher global longitudinal strain, torsion, and untwisting rates after acute HA exposure. Variations in night-time systolic BP correlated with variations in torsion and global longitudinal strain. Our study firstly demonstrates BP and cardiac function variations during acute HA exposure in different BP patterns and BP increases in dippers at night, while non-dippers showed day-time increases. Furthermore, enhanced left ventricular torsion and global longitudinal strain are associated with BP changes. Non-dippers showed poor cardiac compensatory and maladaptive to acute HA exposure. However, the exact mechanisms involved need further illumination.

Blood Pressure Load: An Effective Indicator of Systemic Circulation Status in Individuals With Acute Altitude Sickness.

Background: Acute high altitude (HA) exposure results in blood pressure (BP) variations in most subjects. Previous studies have demonstrated that higher BP is potentially correlated with acute mountain sickness (AMS). The BP load may be of clinical significance regarding systemic circulation status. Objectives: This study aimed to examine HA-induced BP changes in patients with AMS compared to those in healthy subjects. Further, we provided clinical information about the relationship between variations in 24-h ambulatory parameters (BP level, BP variability, and BP load) and AMS. Methods: Sixty-nine subjects were enrolled and all participants ascended Litang (4,100 m above sea level). They were monitored using a 24-h ambulatory blood pressure device and underwent echocardiography within 24 h of altitude exposure. The 2018 Lake Louise questionnaire was used to evaluate AMS. Results: The AMS group comprised more women than men [15 (65.2%) vs. 13 (28.3%), P < 0.001] and fewer smokers [4 (17.4%) vs. 23 (50.0%), P = 0.009]. The AMS group exhibited significant increases in 24-h BP compared to the non-AMS group (24-h SBP variation: 10.52 ± 6.48 vs. 6.03 ± 9.27 mmHg, P = 0.041; 24-h DBP variation: 8.70 ± 4.57 vs. 5.03 ± 4.98 mmHg, P = 0.004). The variation of mean 24-h cBPL (cumulative BP load) (mean 24-h cSBPL: 10.58 ± 10.99 vs. 4.02 ± 10.58, P = 0.016; 24-h mean cDBPL: 6.03 ± 5.87 vs. 2.89 ± 4.99, P = 0.034) was also obviously higher in AMS subjects than in non-AMS subjects after HA exposure. 24-h mean cSBPL variation (OR = 1.07, P = 0.024) and 24-h mean cDBPL variation (OR = 1.14, P = 0.034) were independent risk factors of AMS. Moreover, variation of 24-h mean cSBPL showed a good correlation with AMS score (R = 0.504, P < 0.001). Conclusions: Our study demonstrated that patients with AMS had higher BP and BP load changes after altitude exposure than healthy subjects. Excessive BP load variations were associated with AMS. Thus, BP load could be an effective indicator regarding systemic circulation status of AMS.

Impairment of sirtuin 1-mediated DNA repair is involved in bisphenol A-induced aggravation of macrophage inflammation and atherosclerosis.

Bisphenol A (BPA), an environmental pollutant, has received considerable attention worldwide for its hazardous effects of promoting atherosclerosis and increasing the risk of cardiovascular diseases (CVDs). However, the mechanisms involved are unclear. We aimed to investigate the mechanisms underlying BPA-aggravated atherosclerosis and potential preventive treatments. Four-week-old male Ldlr-/- C57BL/6 mice were administered 250 µg/L BPA via drinking water for 30 weeks with or without a Western diet and/or resveratrol (RESV) for 12 weeks. Chronic BPA exposure significantly aggravated atherosclerosis, enhanced the production of inflammatory cytokines but not lipid levels, promoted macrophage infiltration into plaque areas. Moreover, peritoneal macrophages isolated from BPA-exposed mice exhibited a more pro-inflammatory phenotype in response to cholesterol crystal treatment than those from control mice. The comet assay revealed that the DNA repair capacity of BPA-exposed macrophages was impaired, and western blotting showed that sirtuin 1 and Nijmegen breakage syndrome 1 (NBS1) expression was reduced. However, restoring sirtuin 1 by RESV administration significantly blocked the BPA-induced decrease in NBS1 and subsequently attenuated the BPA-induced impairment of DNA repair and apoptosis, as indicated by phosphorylated H2AX expression and staining and PARP expression. Moreover, RESV administration significantly ameliorated BPA-aggravated NOD-like receptor pyrin domain 3 and caspase 1 activation and interleukin-1ß production, which were abolished by NBS1 knockdown. Furthermore, RESV administration prevented BPA-induced aggravation of atherosclerosis. Our findings indicate that impairment of sirtuin 1-mediated DNA repair is involved in BPA-induced aggravation of macrophage inflammation and atherosclerosis and that RESV might be a promising preventive and therapeutic agent for BPA-related CVDs.

Association between physiological responses after exercise at low altitude and acute mountain sickness upon ascent is sex-dependent.

BACKGROUND: Acute mountain sickness (AMS) is the mildest form of acute altitude illnesses, and consists of non-specific symptoms when unacclimatized persons ascend to elevation of ≥2500 m. Risk factors of AMS include: the altitude, individual susceptibility, ascending rate and degree of pre-acclimatization. In the current study, we examined whether physiological response at low altitude could predict the development of AMS. METHODS: A total of 111 healthy adult healthy volunteers participated in this trial; and 99 (67 men and 32 women) completed the entire study protocol. Subjects were asked to complete a 9-min exercise program using a mechanically braked bicycle ergometer at low altitude (500 m). Heart rate, blood pressure (BP) and pulse oxygen saturation (SpO2) were recorded prior to and during the last minute of exercise. The ascent from 500 m to 4100 m was completed in 2 days. AMS was defined as ≥3 points in a 4-item Lake Louise Score, with at least one point from headache wat 6-8 h after the ascent. RESULTS: Among the 99 assessable subjects, 47 (23 men and 24 women) developed AMS at 4100 m. In comparison to the subjects without AMS, those who developed AMS had lower proportion of men (48.9% vs. 84.6%, P < 0.001), height (168.4 ± 5.9 vs. 171.3 ± 6.1 cm, P = 0.019), weight (62.0 ± 10.0 vs. 66.7 ± 8.6 kg, P = 0.014) and proportion of smokers (23.4% vs. 51.9%, P = 0.004). Multivariate regression analysis revealed the following independent risks for AMS: female sex (odds ratio (OR) =6.32, P < 0.001), SpO2 change upon exercise at low altitude (OR = 0.63, P = 0.002) and systolic BP change after the ascent (OR = 0.96, P = 0.029). Women had larger reduction in SpO2 after the ascent, higher AMS percentage and absolute AMS score. Larger reduction of SpO2 after exercise was associated with both AMS incidence (P = 0.001) and AMS score (P < 0.001) in men but not in women. CONCLUSIONS: Larger SpO2 reduction after exercise at low altitude was an independent risk for AMS upon ascent. Such an association was more robust in men than in women. TRIAL REGISTRATION: Chinese Clinical Trial Registration, ChiCTR1900025728 . Registered 6 September 2019.

Influence of blood pressure control and application of renin-angiotensin-aldosterone system inhibitors on the outcomes in COVID-19 patients with hypertension.

Hypertension is proved to be associated with severity and mortality in coronavirus disease 2019 (COVID-19). However, little is known about the effects of pre-admission and/or in-hospital antihypertension treatments on clinical outcomes. Thus, this study aimed to investigate the association between in-hospital blood pressure (BP) control and COVID-19-related outcomes and to compare the effects of different antihypertension treatments. This study included 2864 COVID-19 patients and 1628 were hypertensive. Patients were grouped according to their BP during hospitalization and records of medication application. Patients with higher BP showed worse cardiac and renal functions and clinical outcomes. After adjustment, subjects with pre-admission usage of renin-angiotensin-aldosterone system (RAAS) inhibitors (HR = 0.35, 95%CI 0.14-0.86, P = .022) had a lower risk of adverse clinical outcomes, including death, acute respiratory distress syndrome, respiratory failure, septic shock, mechanical ventilation, and intensive care unit admission. Particularly, hypertension patients receiving RAAS inhibitor treatment either before (HR = 0.35, 95%CI 0.13-0.97, P = .043) or after (HR = 0.18, 95%CI 0.04-0.86, P = .031) admission showed a significantly lower risk of adverse clinical outcomes than those receiving application of other antihypertensive medicines. Furthermore, consecutive application of RAAS inhibitors in COVID-19 patients with hypertension showed better clinical outcomes (HR = 0.10, 95%CI 0.01-0.83, P = .033) than non-RAAS inhibitors users. We revealed that COVID-19 patients with poor BP control during hospitalization had worse clinical outcomes. Compared with other antihypertension medicines, RAAS inhibitors were beneficial for improving clinical outcomes in COVID-19 patients with hypertension. Our findings provide direct evidence to support the administration of RAAS inhibitors to COVID-19 patients with hypertension before and after admission.

Pulmonary function tests at low altitude predict pulmonary pressure response to short-term high altitude exposure.

BACKGROUND: Travelling to high altitude (HA) presents a risk of the high levels of pulmonary artery pressure (PAP) at altitude, which is associated with impaired exercise capacity and fatal HA pulmonary oedema. However, prediction of high levels of PAP at altitude is still unclear. METHODS: Echocardiography and pulmonary function tests were performed on 121 healthy men at low altitude (LA) and 4100 m (5 ± 2 h after a 7 day ascent). RESULTS: HA exposure increased the levels of FEV1/FVC ratio, FEF25%, 50%, 75%, MMEF, mPAP, total pulmonary vascular resistance (PVR) and systolic pulmonary arterial pressure (SPAP). More smokers and lower forced expiratory flow at 25% of forced vital capacity (FEF25%) at LA were observed in subjects with mPAP≥30 mmHg than those with mPAP<30 mmHg at HA. Multivariate logistic regression identified that FEF25% at LA [odds ratio (OR) 0.50, 95%CI 0.33-0.76, p = 0.001] and smoking (OR 3.09, 95%CI 1.31-7.27, p = 0.010) were the independent predictors for identifying subjects with mPAP≥30 mmHg at HA. Moreover, FEF25% at LA was linearly correlated with mPAP at HA (r = -0.31, p < 0.001), which mainly existed in smokers. Compared to subjects with FEF25% ≥7.55 L/sec at LA, those with FEF25% <7.55 L/sec at LA showed higher levels of mPAP, and total PVR, and a multivariable OR of 11.16 (95%CI, 3.48-35.81) for developing mPAP ≥ 30 mmHg at HA. However, there was no significant difference in the incidences of AMS and its related clinical symptoms in subjects with different levels of FEF25%. CONCLUSIONS: Thus, these findings suggest that subjects with low FEF25% values at LA are susceptible to high levels of PAP at altitude but not the incidence of AMS following short-term HA exposure, especially in smokers.

EPAS1 and VEGFA gene variants are related to the symptoms of acute mountain sickness in Chinese Han population: a cross-sectional study.

BACKGROUND: More people ascend to high altitude (HA) for various activities, and some individuals are susceptible to HA illness after rapidly ascending from plains. Acute mountain sickness (AMS) is a general complaint that affects activities of daily living at HA. Although genomic association analyses suggest that single nucleotide polymorphisms (SNPs) are involved in the genesis of AMS, no major gene variants associated with AMS-related symptoms have been identified. METHODS: In this cross-sectional study, 604 young, healthy Chinese Han men were recruited in June and July of 2012 in Chengdu, and rapidly taken to above 3700 m by plane. Basic demographic parameters were collected at sea level, and heart rate, pulse oxygen saturation (SpO2), systolic and diastolic blood pressure and AMS-related symptoms were determined within 18-24 h after arriving in Lhasa. AMS patients were identified according to the latest Lake Louise scoring system (LLSS). Potential associations between variant genotypes and AMS/AMS-related symptoms were identified by logistic regression after adjusting for potential confounders (age, body mass index and smoking status). RESULTS: In total, 320 subjects (53.0%) were diagnosed with AMS, with no cases of high-altitude pulmonary edema or high-altitude cerebral edema. SpO2 was significantly lower in the AMS group than that in the non-AMS group (P = 0.003). Four SNPs in hypoxia-inducible factor-related genes were found to be associated with AMS before multiple hypothesis testing correction. The rs6756667 (EPAS1) was associated with mild gastrointestinal symptoms (P = 0.013), while rs3025039 (VEGFA) was related to mild headache (P = 0.0007). The combination of rs6756667 GG and rs3025039 CT/TT further increased the risk of developing AMS (OR = 2.70, P < 0.001). CONCLUSIONS: Under the latest LLSS, we find that EPAS1 and VEGFA gene variants are related to AMS susceptibility through different AMS-related symptoms in the Chinese Han population; this tool might be useful for screening susceptible populations and predicting clinical symptoms leading to AMS before an individual reaches HA. TRIAL REGISTRATION: Chinese Clinical Trial Registration, ChiCTR-RCS-12002232 . Registered 31 May 2012.

Preliminary Study of Right Ventricular Dyssynchrony Under High-Altitude Exposure: Determinants and Impacts.

The aims of this study were to explore the effect of high-altitude (HA) exposure on the incidence, determinants, and impacts of right ventricular dyssynchrony (RVD). In our study, 108 healthy young men were enrolled, and physiological and echocardiographic variables were recorded at both sea level and 4,100 m. By using two-dimensional speckle-tracking echocardiography, RVD was evaluated by calculating the R-R interval-corrected standard deviation of the time-to-peak systolic strain for the four mid-basal RV segments (RVSD4) and defined by RVSD4 > 18.7 ms. After HA exposure, RVSD4 was significantly increased, and the incidence of RVD was approximately 32.4%. Subjects with RVD showed lower oxygen saturation (SaO2) and RV global longitudinal strain and higher systolic pulmonary artery pressure than those without RVD. Moreover, myocardial acceleration during isovolumic contraction was increased in all subjects and those without RVD, but not in those with RVD. Multivariate logistic regression revealed that SaO2 is an independent determinant of RVD at HA (odds ratio: 0.72, 95% CI: 0.56-0.92; P = 0.009). However, the mean pulmonary artery pressure was linearly correlated with the magnitude of RVD in the presence of Notch. No changes were found in RV fractional area change, tricuspid annular motion, or tricuspid s' velocity between subjects with and without RVD. Collectively, we demonstrated for the first time that HA exposure could induce RVD in healthy subjects, which may be mainly attributed to the decline in SaO2 as well as RV overload; the incidence of RVD was associated with reduced RV regional function and blunted myocardial acceleration.