Right and Left Heart Function in Lowlanders with COPD at Altitude: Data from a Randomized Study

Lichtblau, Mona; Latshang, Tsogyal D.; Furian, Michael; Müller-Mottet, Séverine; Küest, Silke M.; Tanner, Felix C.; Grünig, Ekkehard; Bloch, Konrad E.; Ulrich, Silvia

doi:10.1159/000492898

Cited by 20 publications

(24 citation statements)

References 30 publications

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“…In the same study population, exposure to moderate altitude was shown to be associated with a reduced oxygen uptake and reduced cerebral tissue oxygenation when compared to low altitude 35. Echocardiography in this population revealed a reduction of parameters assessing right ventricular function and an increase in calculated mean pulmonary artery pressure in response to moderate altitude that were mainly interpreted as a consequence of hypoxic pulmonary vasoconstriction 36. Of possible pathophysiologic importance to the BP increase at moderate altitude is the development of moderate to severe central sleep apnea at 2,590 m, additionally resulting in increased sympathetic activity due to the intermittent hypoxia and disturbed sleep 24.…”

Section: Discussionmentioning

confidence: 68%

<p>Blood pressure response to exposure to moderate altitude in patients with COPD</p>

Schwarz¹,

Latshang²,

Furian³

et al. 2019

COPD

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Purpose:Patients with COPD might be particularly susceptible to hypoxia-induced autonomic dysregulation. Decreased baroreflex sensitivity (BRS) and increased blood pressure (BP) variability (BPV) are markers of impaired cardiovascular autonomic regulation and there is evidence for an association between decreased BRS/increased BPV and high cardiovascular risk. The aim of this study was to evaluate the effect of short-term exposure to moderate altitude on BP and measures of cardiovascular autonomic regulation in COPD patients. Materials and methods: Continuous morning beat-to-beat BP was noninvasively measured with a Finometer ® device for 10 minutes at low altitude (490 m, Zurich, Switzerland) and for 2 days at moderate altitude (2,590 m, Davos Jakobshorn, Switzerland) -the order of altitude exposure was randomized. Outcomes of interest were mean SBP and DBP, BPV expressed as the coefficient of variation (CV), and spontaneous BRS. Changes between low altitude and day 1 and day 2 at moderate altitude were assessed by ANOVA for repeated measurements with Fisher's exact test analysis. Results: Thirty-seven patients with moderate to severe COPD (mean±SD age 64±6 years, FEV 1 60%±17%) were included. Morning SBP increased by +10.8 mmHg (95% CI: 4.7-17.0, P=0.001) and morning DBP by +5.0 mmHg (95% CI: 0.8-9.3, P=0.02) in response to altitude exposure. BRS significantly decreased (P=0.03), whereas BPV significantly and progressively increased (P,0.001) upon exposure to altitude. Conclusion: Exposure of COPD patients to moderate altitude is associated with a clinically relevant increase in BP, which seems to be related to autonomic dysregulation. Clinical trial registration: ClinicalTrials.gov (NCT01875133). Plain language summaryWhy was the study done? Hypoxia is a potent stressor for the cardiovascular system and patients with COPD might be particularly susceptible to hypoxia-induced autonomic dysregulation. What did the researchers do and find? When patients with moderate to severe COPD were exposed to hypobaric hypoxia at moderate altitude, they reacted with a clinically relevant increase of both blood pressure and heart rate accompanied by an increased blood pressure variability and a decreased baroreflex sensitivity. What do these results mean? Disturbed autonomic cardiovascular regulation and increase in blood pressure and heart rate in response to hypoxia have important clinical implications for patients with COPD for altitude and air traveling and could explain part of the underlying pathophysiology of the observed risk of cardiovascular events during an acute exacerbation of COPD.

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Section: Discussionmentioning

confidence: 68%

<p>Blood pressure response to exposure to moderate altitude in patients with COPD</p>

Schwarz¹,

Latshang²,

Furian³

et al. 2019

COPD

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“…Forty patients with moderate to severe COPD (median FEV 1 59% predicted) have been assessed in a randomized crossover trial ascending to 2,590 m, and a 24% incidence of altitude-related adverse health effects was reported, confirming the increased susceptibility in COPD patients exposed to moderate hypobaric hypoxia ( 29 ). In the same trial, left and right heart function was assessed by echocardiography, revealing an increase in pulmonary artery pressure and slight reduction in right ventricular function as well as an increase in diastolic dysfunction at altitude ( 15 ). At such altitudes, adverse events requiring medical treatment or descent have not been reported in healthy volunteers or in patients with obstructive sleep apnea syndrome ( 30 , 31 ).…”

Section: Discussionmentioning

confidence: 99%

“…Echocardiography was performed in Zurich and on day 2 (after the first night) at altitude according to previously published studies and included assessments of right ventricular function (right ventricular fractional area change (RV-FAC), tricuspid annular plane systolic excursion (TAPSE), and peak systolic right ventricular to right atrial pressure gradient (RV/RA gradient) ( 15 ). Echocardiographic recordings were performed with a real-time, phased array sector scanner (CX 50, Philips, Philips Respironics, Zofingen, Switzerland) with an integrated Color Doppler system and a transducer containing crystal sets for imaging (1–5 MHz) and for continuous-wave Doppler.…”

Section: Methodsmentioning

confidence: 99%

Altitude Travel in Patients With Pulmonary Hypertension: Randomized Pilot-Trial Evaluating Nocturnal Oxygen Therapy

et al. 2020

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Introduction: Stable patients with pulmonary arterial or chronic thromboembolic pulmonary hypertension (PH) wish to undergo altitude sojourns or air travel but fear disease worsening. This pilot study investigates health effects of altitude sojourns and potential benefits of nocturnal oxygen therapy (NOT) in PH patients. Methods: Nine stable PH patients, age 65 (47; 71) years, 5 women, in NYHA class II, on optimized medication, were investigated at 490 m and during two sojourns of 2 days/nights at 2,048 m, once using NOT, once placebo (ambient air), 3 L/min per nasal cannula, according to a randomized crossover design with 2 weeks washout at <800 m. Assessments included safety, nocturnal pulse oximetry (SpO 2 ), 6-min walk distance (6 MWD), and echocardiography. Results: At 2,048 m, two of nine patients required medical intervention, one for exercise-induced syncope, one for excessive nocturnal hypoxemia (SpO 2 < 75% for >30 min). Both recovered immediately with oxygen therapy. Two patients suffered from acute mountain sickness. In 6 patients with complete data, nocturnal mean SpO 2 and cyclic SpO 2 dips reflecting sleep apnea significantly differed from 490 to 2,048 m with placebo, and 2,048 m with NOT (medians, quartiles): SpO 2 93 (91; 95)%, 89 (85; 90)%, 97 (95; 97)%; SpO 2 dips 10.4/h (3.1; 26.9), 34.0/h (5.3; 81.3), 0.3/h (0.1; 2.3). 6 MWD at 490, 2,048 m without and with NOT was 620 m (563; 720), 583 m (467; 696), and 561 m (501; 688). Echocardiographic indices of heart function and PH were unchanged at 2,048 m with/without NOT vs. 490 m. Conclusions: 7/9 PH patients stayed safely at 2,048 m but revealed hypoxemia, sleep apnea, and reduced 6 MWD. Hemodynamic changes were trivial. NOT improved oxygenation and sleep apnea. The current pilot trial is important for designing further studies on altitude tolerance of PH patients.

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“…COPD-patients also have a lower respiratory reserve compared to healthy, who use an increased breathing rate as a compensatory mechanism at altitude. COPD-patients additionally may reveal pulmonary hypertension already at low altitude, but even more in a hypoxic environment at high altitude, which further strains the right ventricular reserve to ischemia, due to increased load [6,7]. The mentioned adaptive responses are accentuated during exercise.…”

Section: Introductionmentioning

confidence: 99%

ECG changes at rest and during exercise in lowlanders with COPD travelling to 3100 m

Carta

Bitos

Furian

et al. 2021

International Journal of Cardiology

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Background: The incidence and magnitude of cardiac ischemia and arrhythmias in patients with chronic obstructive pulmonary disease (COPD) during exposure to hypobaric hypoxia is insufficiently studied. We investigated electrocardiogram (ECG) markers of ischemia at rest and during incremental exercise testing (IET) in COPDpatients travelling to 3100 m. Study design and methods: Lowlanders (residence <800 m) with COPD (forced volume in the first second of expiration (FEV 1 ) 40-80% predicted, oxygen saturation (SpO 2 ) ≥92%, arterial partial pressure of carbon dioxide (PaCO 2 ) <6 kPa at 760 m) aged 18 to 75 years, without history of cardiovascular disease underwent 12-lead ECG recordings at rest and during cycle IET to exhaustion at 760 m and after acute exposure of 3 h to 3100 m. Mean ST-changes in ECGs averaged over 10s were analyzed for signs of ischemia (≥1 mm horizontal or downsloping ST-segment depression) at rest, peak exercise and 2-min recovery. Results: 80 COPD-patients (51% women, mean ± SD, 56.2 ± 9.6 years, body mass index (BMI) 27.0 ± 4.5 kg/m 2 , SpO 2 94 ± 2%, FEV 1 63 ± 10% prEd.) were included. At 3100 m, 2 of 53 (3.8%) patients revealed ≥1 mm horizontal ST-depression during IET vs 0 of 64 at 760 m (p = 0.203). Multivariable mixed regression revealed minor but significant ST-depressions associated with altitude, peak exercise or recovery and rate pressure product (RPP) in multiple leads. Conclusion:In this study, ECG recordings at rest and during IET in COPD-patients do not suggest an increased incidence of signs of ischemia with ascent to 3100 m. Whether statistically significant ST changes below the standard threshold of clinical relevance detected in multiple leads reflect a risk of ischemia during prolonged exposure remains to be elucidated.

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Right and Left Heart Function in Lowlanders with COPD at Altitude: Data from a Randomized Study

Cited by 20 publications

References 30 publications

<p>Blood pressure response to exposure to moderate altitude in patients with COPD</p>

<p>Blood pressure response to exposure to moderate altitude in patients with COPD</p>

Altitude Travel in Patients With Pulmonary Hypertension: Randomized Pilot-Trial Evaluating Nocturnal Oxygen Therapy

ECG changes at rest and during exercise in lowlanders with COPD travelling to 3100 m

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