Right ventricular morphology and function in chronic obstructive pulmonary disease patients living at high altitude

Prevalence of pulmonary hypertension in COPD patients living at high altitude

BACKGROUND

Pulmonary hypertension (PH) is associated with poor prognosis for patients with chronic obstructive pulmonary disease (COPD). Most of the knowledge about PH in COPD has been generated at sea level, with limited information associated with high altitude (HA).

OBJECTIVES

To assess the prevalence and severity of PH in COPD patients living in a HA city (2,640 m).

METHODS

Cross-sectional study in COPD patients with forced expiratory volume in the first second / forced vital capacity ratio (FEV1/FVC) post-bronchodilator <0,7. Transthoracic echocardiography (TTE), spirometry, carbon monoxide diffusing capacity, and arterial blood gasses tests were performed. Patients were classified according to the severity of airflow limitation. PH was defined by TTE as an estimated systolic pulmonary artery pressure (sPAP) > 36 mmHg or indirect PH signs; severe PH as sPAP > 60 mmHg; and disproportionate PH as an sPAP > 60 mmHg with non-severe airflow limitation (FEV1 > 50% predicted).

RESULTS

We included 176 COPD patients. The overall estimated prevalence of PH was 56.3% and the likelihood of having PH increased according to airflow-limitation severity: mild (31.6%), moderate (54.9%), severe (59.6%) and very severe (77.8%) (p = 0.038). The PH was severe in 7.3% and disproportionate in 3.4% of patients.

CONCLUSIONS

The estimated prevalence of PH in patients with COPD at HA is high, particularly in patients with mild to moderate airflow limitation, and greater than that described for COPD patients at low altitude. These results suggest a higher risk of developing PH for COPD patients living at HA compared to COPD patients with similar airflow limitation living at low altitude.

Clinical characteristics and predictors of pulmonary hypertension in chronic obstructive pulmonary disease at different altitudes

BACKGROUND

Pulmonary hypertension (PH) is a common complication in patients with chronic obstructive pulmonary disease (COPD) and is closely associated with poor prognosis. However, studies on the predictors of PH in COPD patients are limited, especially in populations living at high altitude (HA).

OBJECTIVES

To investigate the differences in the clinical characteristics and predictors of patients with COPD/COPD and PH (COPD-PH) from low altitude (LA, 600 m) and HA (2200 m).

METHODS

We performed a cross-sectional survey of 228 COPD patients of Han nationality admitted to the respiratory department of Qinghai People's Hospital (N = 113) and West China Hospital of Sichuan University (N = 115) between March 2019 and June 2021. PH was defined as a pulmonary arterial systolic pressure (PASP) > 36 mmHg measured using transthoracic echocardiography (TTE).

RESULTS

The proportion of PH in COPD patients living at HA was higher than that in patients living at LA (60.2% vs. 31.3%). COPD-PH patients from HA showed significantly different in baseline characteristics, laboratory tests and pulmonary function test. Multivariate logistic regression analysis indicated that the predictors of PH in COPD patients were different between the HA and LA groups.

CONCLUSIONS

The COPD patients living at HA had a higher proportion of PH than those living at LA. At LA, increased B-type natriuretic peptide (BNP) and direct bilirubin (DB) were predictors for PH in COPD patients. However, at HA, increased DB was a predictor of PH in COPD patients.

Association of right ventricle diastolic diameter with pulmonary function, exercise tolerance and exacerbation period in patients with chronic obstructive pulmonary disease: A prospective study

BACKGROUND

The echocardiogram is a useful method for monitoring the cardiovascular complications of chronic obstructive pulmonary disease (COPD), but it is not clear if morphological and functional cardiac variables are able to identify patients with unfavorable COPD progression.

OBJECTIVE

The aim of this study was to investigate morphological and functional echocardiographic variables associated with exacerbation of the disease, pulmonary function parameters and functional capacity evaluation in COPD patients.

METHOD

A longitudinal observational study including 91 patients diagnosed with COPD, who were stratified in two groups according to their basal right ventricle diastolic diameter (RVDD) measuring greater and less than 35 mm. They underwent clinical evaluation, echocardiography, spirometry and 6-minute walking-test (6MWT).

RESULTS

The study found that patients with RVDD greater than 35 mm showed worse functional capacity in the 6MWT (p = 0.05) and more exacerbation of the disease during the one-year follow-up (p = 0.05). There were correlations of greater RVDD vs forced vital capacity (R = -0.27; p = 0.02) and distance in the 6MWT (R = 0.55; p = 0.03) in patients with exacerbation. In the univariate regression analysis, the RVDD was responsible for 55% of the variation in distance in the 6MWT (-0.75 m) in COPD patients.

CONCLUSION

The RV dilation is associated with unfavorable prognostic markers in COPD, such as the worsening of the functional capacity and more frequent exacerbations. The echocardiogram may be a useful tool to identify patients who need more aggressive strategies to control the evolution of the disease with potential impact in pulmonary rehabilitation.

Effect of Nocturnal Oxygen Therapy on Daytime Pulmonary Hemodynamics in Patients With Chronic Obstructive Pulmonary Disease Traveling to Altitude: A Randomized Controlled Trial

INTRODUCTION

We investigated whether nocturnal oxygen therapy (NOT) mitigates the increase of pulmonary artery pressure in patients during daytime with chronic obstructive pulmonary disease (COPD) traveling to altitude.

METHODS

Patients with COPD living below 800 m underwent examinations at 490 m and during two sojourns at 2,048 m (with a washout period of 2 weeks < 800 m between altitude sojourns). During nights at altitude, patients received either NOT (3 L/min) or placebo (ambient air 3 L/min) via nasal cannula according to a randomized crossover design. The main outcomes were the tricuspid regurgitation pressure gradient (TRPG) measured by echocardiography on the second day at altitude (under ambient air) and various other echocardiographic measures of the right and left heart function. Patients fulfilling predefined safety criteria were withdrawn from the study.

RESULTS

Twenty-three COPD patients [70% Global Initiative for Chronic Obstructive Lung Disease (GOLD) II/30% GOLD III, mean ± SD age 66 ± 5 years, FEV1 54% ± 13% predicted] were included in the per-protocol analysis. TRPG significantly increased when patients traveled to altitude (from low altitude 21.7 ± 5.2 mmHg to 2,048 m placebo 27.4 ± 7.3 mmHg and 2,048 m NOT 27.8 ± 8.3 mmHg) difference between interventions (mean difference 0.4 mmHg, 95% CI -2.1 to 3.0, p = 0.736). The tricuspid annular plane systolic excursion was significantly higher after NOT vs. placebo [2.6 ± 0.6 vs. 2.3 ± 0.4 cm, mean difference (95% confidence interval) 0.3 (0.1 - 0.5) cm, p = 0.005]. During visits to 2,048 m until 24 h after descent, eight patients (26%) using placebo and one (4%) using NOT had to be withdrawn because of altitude-related adverse health effects (p < 0.001).

CONCLUSION

In lowlanders with COPD remaining free of clinically relevant altitude-related adverse health effects, changes in daytime pulmonary hemodynamics during a stay at high altitude were trivial and not modified by NOT.

CLINICAL TRIAL REGISTRATION

www.ClinicalTrials.gov, identifier NCT02150590.

Evaluation of right ventricular performance and impact of continuous positive airway pressure therapy in patients with obstructive sleep apnea living at high altitude

Obstructive sleep apnea syndrome (OSAS) can lead to alterations in right ventricular (RV) performance and pulmonary vascular haemodynamics. Additionally, altitude-related hypoxia is associated with pulmonary vasoconstriction, and the effect of high-altitude on the pulmonary circulation in OSAS patients can be further altered. We sought to assess alterations in RV morphology and function in OSAS patients living at high altitude by way of 2-dimensional speckle tracking echocardiography (2D-STE), real-time 3- dimensional echocardiography (RT-3DE) and cardiac biomarkers. We also evaluate the impact of continuous positive airway pressure (CPAP) treatment on RV performance. Seventy-one patients with newly diagnosed OSAS and thirty-one controls were included in this study. All individuals were assessed for cardiac biomarkers as well as underwent 2D-STE and RT-3DE. Forty-five OSAS patients underwent CPAP therapy for at least 24 weeks and were studied before and after CPAP treatment. RT-3DE was used to measure RV volume, and calculate RV 3D ejection fraction (3D RVEF). Peak systolic strain was determined. Cardiac biomarkers, including C-reactive protein (CRP), N-terminal pro-B-type natriuretic peptide, and cardiac troponin T were also measured. Right atrium volume index, RV volume, RV volume index, systolic pulmonary artery pressure (sPAP), pulmonary vascular resistance (PVR) and level of serum CRP were significantly higher in OSAS group, while OSAS patients showed lower 3D RVEF and RV longitudinal strains. Compared to the patients with sPAP < 40 mmHg, RV longitudinal strains in patients with sPAP ≥ 40 mmHg were lower. Both RV global longitudinal strain and sPAP were associated with apnea–hypopnea index. Patients treated with 6 months of CPAP therapy had significant improvement in RV geometry and performance. RV structural abnormalities and RV function impairments were observed in OSAS patients living at moderate high altitude compared to control highlanders. The reversibility of these changes after application of CPAP were further confirmed.

Echocardiographic assessment of right ventricular functions in healthy subjects who migrated from the sea level to a moderate altitude

Objective:

The aim of this study was to evaluate right ventricle (RV) functions using echocardiography in healthy subjects who migrated from the sea level to moderate altitude (1890 m).

Methods:

The prospective observational in this study population consisted of 33 healthy subjects (23 men; mean age 20.4±3.2 years) who migrated from the sea level to a moderate altitude (Erzurum city centre, 1890 m above sea level) for long-term stay. Subjects underwent echocardiographic evaluation within the first 48 h of exposure to the moderate altitude and at the sixth month of arrival. Conventional echocardiographic parameters such as RV sizes and areas, systolic, and diastolic functional indices [fractional area change (FAC), tricuspid flow velocities, myocardial performance index (MPI), and tricuspid annular plane systolic excursion (TAPSE)] were obtained. Systolic (S) and diastolic (E’, A’) velocities were acquired from the apical four-chamber view using tissue Doppler imaging. Kolmogorov–Smirnov test, student’s t-test, Wilcoxon test, and chi-square test were used in this study.

Results:

There were no significant changes in RV size, FAC, MPI, TAPSE, inferior inspiratory vena cava collapse, tricuspid E velocity, and tricuspid annulus E’ velocity. Compared with the baseline, there was a significant increase in mean pulmonary artery pressure (p=0.001); RV end systolic area (p=0.014); right atrial end diastolic area (p=0.021); tricuspid A velocity (p=0.013); tricuspid annulus S and A’ velocity (p=0.031 and p=0.006, respectively); and RV free wall S, E’, and A’ velocity (p=0.007, p<0.001, and p=0.007 respectively) at the sixth month. Also, there was a significant decrease in tricuspid E/A ratio (1.61±0.3 vs. 1.45±0.2, p=0.038) and tricuspid annulus E’/A’ ratio (1.52±0.5 vs. 1.23±0.4, p=0.002) at the sixth month.

Conclusion:

Our study revealed that right ventricular diastolic function was altered while the systolic function was preserved in healthy subjects who migrated from the sea level to a moderate altitude. (Anatol J Cardiol 2016; 16: 779-83)

Protective Effects of Sheng-Mai-San on Right Ventricular Dysfunction during Chronic Intermittent Hypoxia in Mice

Right ventricular (RV) dysfunction and failure contribute to the increasing morbidity and mortality of cardiovascular diseases; however, current treatment strategies are grossly inadequate. Sheng-Mai-San (SMS) has been used to treat heart diseases for hundreds of years in China, and its protective effects on RV have not been observed. The present study was to investigate the protective effects of SMS aqueous extract on RV dysfunction in chronic intermittent hypoxia (CIH) mice model. The results showed that CIH mice model presented RV dysfunction and maladaptive compensation after 28-day-CIH and SMS treatment significantly reversed these changes. Diastolic function of RV was restored and systolic dysfunction was attenuated, including elevation of RV stroke volume and fractional shortening, as well as pulmonary circulation. Structurally, SMS treatment inhibited RV dilation, cardiomyocytes vacuolization, ultrastructure abnormalities, and the expression of cleaved caspase-3. Of importance, SMS showed remarkable antioxidant activity by decreasing the levels of malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE), increasing the levels of superoxide dismutase (SOD) and heme oxygenase-1 (HO-1), as well as inhibiting the overexpression of 3-NT in RV. Our results indicate that SMS preserve RV structure and function in CIH-exposed mice by involving regulation in both ROS and Reactive Nitrogen Species (RNS) production.

Right ventricular geometry and mechanics in patients with obstructive sleep apnea living at high altitude

PURPOSE

Repetitive obstruction of larynx during sleep can lead to daytime pulmonary hypertension and alterations in right ventricular morphology and function in a small fraction of obstructive sleep apnea syndrome (OSAS) patients. Environmental effects, particularly high altitude, can modify the effects of OSAS on pulmonary circulation, since altitude-related hypoxia is related with pulmonary vasoconstriction. This potential interaction, however, was not investigated in previous studies.

METHODS

A total of 41 newly diagnosed OSAS patients were included in this study after pre-enrolment screening. Two-dimensional, three-dimensional, and Doppler echocardiographic data were collected after polysomnographic verification of OSAS. Three-dimensional echocardiograms were analyzed to calculate right ventricular volumes, volume indices, and ejection fraction.

RESULTS

Systolic pulmonary artery pressure (38.35 ± 8.60 vs. 30.94 ± 6.47 mmHg; p = 0.002), pulmonary acceleration time (118.36 ± 16.36 vs. 103.13 ± 18.42 ms; p = 0.001), right ventricle (RV) end-diastolic volume index (48.15 ± 11.48 vs. 41.48 ± 6.45 ml; p = 0.009), and RV end-systolic volume index (26.50 ± 8.11 vs. 22.15 ± 3.85; p = 0.01) were significantly higher in OSAS patients, with similar RV ejection fraction (EF) between groups. No significant differences were noted in other two-dimensional, Doppler or speckle-tracking strain, measurements. Both RVEF and pulmonary acceleration time were predictors of disease severity.

CONCLUSIONS

A greater degree of RV structural remodeling and higher systolic pulmonary pressure were observed in OSAS patients living at high altitude compared to healthy highlanders. The reversibility of these alterations with treatment remains to be studied.