High-Altitude Exposure in Patients with Cardiovascular Disease: Risk Assessment and Practical Recommendations

doi:10.1016/j.pcad.2010.03.005

Progress in Cardiovascular Diseases

Volume 52, Issue 6, May–June 2010, Pages 512-524

https://doi.org/10.1016/j.pcad.2010.03.005 Get rights and content

Abstract

Because of the development of modern transportation facilities, an ever rising number of individuals including many patients with preexisting diseases visit high-altitude locations (>2500 m). High-altitude exposure triggers a series of physiologic responses intended to maintain an adequate tissue oxygenation. Even in normal subjects, there is enormous interindividual variability in these responses that may be further amplified by environmental factors such as cold temperature, low humidity, exercise, and stress. These adaptive mechanisms, although generally tolerated by most healthy subjects, may induce major problems in patients with preexisting cardiovascular diseases in which the functional reserves are already limited. Preexposure assessment of patients helps to minimize risk and detect contraindications to high-altitude exposure. Moreover, the great variability and nonpredictability of the adaptive response should encourage physicians counseling such patients to adapt a cautionary approach. Here, we will briefly review how high-altitude adjustments may interfere with and aggravate/decompensate preexisting cardiovascular diseases. Moreover, we will provide practical recommendations on how to investigate and counsel patients with cardiovascular disease desiring to travel to high-altitude locations.

Section snippets

Coronary artery disease

Increased myocardial oxygen demand due to elevated heart rate, myocardial contractility, and ventricular afterload are the major determinants of myocardial ischemia in patients with coronary artery disease (CAD) exposed to high altitude. The mismatch between O₂ demand and supply may further be aggravated by inappropriate paradoxical hypoxia-induced coronary vasoconstriction¹⁹ triggered by high altitude-induced respiratory alkalosis or coronary spasms.²⁰ In these patients, the capacity of the

High altitude and cardiovascular diseases, practical recommendations

Because of the paucity of existing studies, evidence-based recommendations for unacclimatized patients with cardiovascular disease who are considering high-altitude exposure are not possible. The following recommendations, summarized in Table 2, Table 3, are based on the available data and our own experience and should reasonably ensure the patients' safety.

Conditions that represent contraindications for high-altitude exposure are summarized in Table 2. Several factors other than the

Conclusions

High altitude has become a popular leisure time destination that is visited not only by healthy individuals but also by increasing numbers of patients with preexisting diseases. The low ambient oxygen triggers a series of physiologic adaptations intended to maintain adequate organ oxygen supply. There is enormous interindividual variability in these responses that may be further amplified by external factors such as cold temperature, low humidity, exercise, and stress. These adjustments,

Statement of Conflict of Interest

All authors declare that there are no conflicts of interest.

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ECG changes at rest and during exercise in lowlanders with COPD travelling to 3100 m
2021, International Journal of Cardiology
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 COPD-patients travelling to 3100 m.
Lowlanders (residence <800 m) with COPD (forced volume in the first second of expiration (FEV₁) 40–80% predicted, oxygen saturation (SpO₂) ≥92%, arterial partial pressure of carbon dioxide (PaCO₂) <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.
80 COPD-patients (51% women, mean ± SD, 56.2 ± 9.6 years, body mass index (BMI) 27.0 ± 4.5 kg/m², SpO₂ 94 ± 2%, FEV₁ 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.
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.
Epidemiology of Cardiac Events During Prehospital Care in Mountain Rescues Conducted in Aragón
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Cardiac events are one of the leading causes of death in the Spanish population. Given the increase in the nontraumatic medical conditions found in mountain rescues, the objective of this study was to report on the heart conditions of patients rescued in the mountains of Aragón in the Spanish Pyrenees.
We conducted a retrospective observational study based on data collected from patients’ medical histories for rescues undertaken in from 2010 to 2016 (at altitudes between 500 m [1640 ft] and 3404 m [11,168 ft]).
Of the 2079 individuals rescued from 2010 to 2016, 34 (2%) were diagnosed with heart conditions, accounting for 21% of all nontraumatic medical conditions. The data showed a statistically significant increase in the age of the rescued patients with heart conditions (55±15 y) and those with acute coronary syndrome/sudden death (60±8 y). Eighty-five percent of the rescued patients with heart conditions were men, 62% were rescued above 2000 m (6500 ft), 42% had acute coronary syndrome (of whom 56% had inferior infarction), and 35% died suddenly.
Aragón mountain rescues show an increase in patient age in recent years. The most common medical case among rescued individuals with heart conditions was a hiker over the age of 50 y with cardiovascular risk factors, inferior infarction, and occurrence at an altitude above 2000 m. Based on our observations, appropriate training should be undertaken, especially by older hikers, who may also benefit from cardiac screening, and rescue vehicles/personnel and mountain huts should be equipped with semiautomatic external defibrillators.
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Travel is associated with health risks, particularly for those with underlying medical conditions. In most cases these risks can be anticipated and mitigated with special attention to the underlying disease as well as travel risks. In addition to the regular travel medicine preparation, travelers with underlying diseases need to plan where and when to get medical attention, ensure fitness to fly, travel with all needed medications and supplies, have adequate insurance, and, ideally, have a contact at home in case there is a medical issue that arises during travel. Early consultation with a travel medicine provider is key. There are numerous organizations designed for those with many medical conditions that support a lifestyle that includes travel.
The Environment and High Blood Pressure
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Acute changes in cardiac dimensions, function, and longitudinal mechanics in healthy individuals with and without high-altitude induced pulmonary hypertension at 4559 m
2024, Echocardiography
Associations between Land-Use Patterns and Cardiovascular Disease Mortality in the Beijing—Tianjin–Hebei Megacity Region
2023, Land

View all citing articles on Scopus

: Statement of Conflict of Interest: see page 522.

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High-Altitude Exposure in Patients with Cardiovascular Disease: Risk Assessment and Practical Recommendations

Abstract

Section snippets

Coronary artery disease

High altitude and cardiovascular diseases, practical recommendations

Conclusions

Statement of Conflict of Interest

Respir Physiol Neurobiol

Am J Cardiol

Am J Cardiol

Am J Cardiol

Am J Cardiol

J Wilderness Med

Wilderness Environ Med

Lancet

Am J Med

J Am Coll Cardiol

Wilderness Environ Med

Respir Physiol Neurobiol

Chest

J Am Coll Cardiol

Augmented sympathetic activation during short-term hypoxia and high-altitude exposure in subjects susceptible to high-altitude pulmonary edema

Circulation

Sympathetic neural overactivity in healthy humans after prolonged exposure to hypobaric hypoxia

J Physiol

Cardiac output in man in rest and work during and after acclimatization to 3,800 m

J Appl Physiol

Cardiopulmonary responses of resting man during early exposure to high altitude

J Appl Physiol

Impact of acute hypoxic pulmonary hypertension on LV diastolic function in healthy mountaineers at high altitude

Am J Physiol Heart Circ Physiol

Control of coronary blood flow during hypoxemia

Adv Exp Med Biol

Adrenergic contribution during acclimatization to high altitude: perspectives from Pikes Peak

Exerc Sport Sci Rev

How well do older persons tolerate moderate altitude?

West J Med

Who should not go high: chronic disease and work at altitude during construction of the Qinghai-Tibet railroad

High Alt Med Biol

Salmeterol for the prevention of high-altitude pulmonary edema

N Engl J Med

Inhaled nitric oxide for high-altitude pulmonary edema

N Engl J Med

Effect of altitude on the heart and the lungs

Circulation

Regulation of cerebral blood flow in mammals during chronic hypoxia: a matter of balance

Exp Physiol

Patent foramen ovale and high-altitude pulmonary edema

JAMA

Atherosclerosis influences the vasomotor response of epicardial coronary arteries to exercise

J Clin Invest

Coronary arterial spasm and Prinzmetal's variant form of angina induced by hyperventilation and Tris-buffer infusion

Circulation

The collateral circulation of the heart