Table 3: Recommendations and pre-exposure assessments according to cardiovascular disease. |
Clinical condition | | Proposed pre-exposure assessment and recommendations for patients |
CAD
| Asymptomatic revascularisation
<6 mo | Consider exercise testing according to coronary status |
Asymptomatic revascularisation
>6 mo | Exercise testing If not conclusive → exercise testing with imaging modality |
Asymptomatic reduced LVEF | Exercise testing and transthoracic echocardiography at rest If not conclusive → exercise testing with imaging modality |
Stable angina and ischaemic
threshold of more than 6 METs | Exposure up to 3500 m can be considered, in particular if passive ascent is planned. Limit physical activity (<70% of maximal heart rate achieved during exercise testing) If angina occurs, patients should not further ascend, limit physical activity, and
take anti-anginal medication. Immediate descent if symptoms persist or worsen |
Reduced LVEF
(any cause) | Exercise testing Transthoracic echocardiography at rest Consider CPX and Holter-ECG in selected patients Adhere to low altitude recommendations such as restricting salt intake, as well as close monitoring of body weight, avoid dehydration and diarrhoea (loss of potassium) Instructions for adjustment of medication (diuretics) if signs of heart failure In the case of signs and symptoms of pulmonary congestion, immediate descent to lower altitude and seeking medical advice are mandatory. In the absence of medical help,
take 1 or 2 supplemental doses of loop diuretic. If no improvement is achieved within 4 to 6 hours, initiate HAPE treatment with a CCB (slow-release nifedipine, 20 mg, every 6 hours) |
Arterial
hypertension | If not well controlled → ABPM Instructions for self-monitoring of BP and adjustment of medication if poor BP control or hypotension develop Favour CCB owing to a beneficial effect on HAPE |
Pulmonary
hypertension
| Exposure contraindicated if marked pulmonary hypertension or if functional class >I (see table 2) Echocardiographic assessment of RV function and of pulmonary artery pressure under simulated high altitude (FIO2: 12%; if RV-RA gradient >42 mm Hg at rest or >53 mmg Hg during exercise patients should be strongly discouraged) or TTE and symptom-limited exercise test including monitoring of arterial oxygen saturation Prophylaxis for HAPE with nifedipine 30 mg twice daily Travel up to 3000 m can be considered if normal test results |
Valvular heart
disease
| Symptomatic and/or severe | Exposure contraindicated |
Mild aortic or mitral regurgitation | Exercise testing, transthoracic echocardiography at rest Instructions for self-monitoring of BP and adjustment of medication if uncontrolled hypertension or hypotension develop Instructions for self-monitoring of international normalised ratio and dose adjustment If anticoagulation, avoid activities at risk for traumatic injury at high altitude Avoid exaggerated physical activity and keep fluid balance equilibrated |
Congenital heart
disease
| Acyanotic or cyanotic | Exposure contraindicated if functional class >I CPX and echocardiographic assessment of left and RV function, and pulmonary pressure under simulated high altitude (FIO2, 12%; if RV-RA gradient >40 mm Hg patients should be strongly discouraged) Consider cardiac magnetic resonance imaging and Holter-ECG in selected patients Consider ABPM in patient with aortic coarctation A short-term trip with passive ascent up to 3400 m may be considered with a proper pre-exposure assessment and planning of prophylactic and emergency measures
including oxygen supplement and pulmonary vasodilatators in selected patients. |
Heart transplant
| <1 year | Avoid high altitude in remote areas |
>1 year | Transthoracic echocardiography at rest and exercise test Echocardiographic assessment of RV function and of pulmonary artery pressure under simulated high altitude (FIO2: 12%; if RV-RA gradient >42 mm Hg at rest or >53 mmg Hg during exercise patients should be strongly discouraged) Control blood pressure and renal function Consider exercise test and Holter-ECG to identify arrhythmia and to evaluate BP under stress. |
Arrhythmia
| Associated with CAD/CHF | Exercise testing (no ECG changes indicating myocardial ischaemia and no ventricular arrhythmia) |
Pacemaker | Testing only if VVIR, DDDR, or AAIR mode to adapt PM rates (in particular for exercise
at high altitude) |
| Supraventricular tachycardia/atrial
flutter Atrial fibrillation | Consider catheter ablation before high-altitude exposure Exercise testing and Holter-ECG Instructions for heart rate self-monitoring and adjustment of medication in the event of insufficient rate control (>90 beats per min at rest) |
Symptomatic ventricular or atrial
premature beats, or non-sustained
tachycardia | Ad hoc adaptation of the treatment should be discussed (e.g. higher doses in cases of chronic prophylactic treatment or “Pill-in-the-Pocket” approach) |
ICD | ICD follow-up Contact the manufacturer or the device-treating physician prior to an expedition to extreme altitudes. |
Cerebrovascular disease | All conditions | Avoid trekking or climbing alone |
Ischaemic stroke or TIA
<90 d ago | Avoid traveling to higher altitudes (>2000–2500 m) Avoid air travel |
Ischaemic stroke or TIA <90 d ago, thorough workup of the stroke has
been performed and risk factors are treated adequately | Avoid extreme altitude >4500 m |
Stenosis or occlusion of a major
extra- or intracranial cerebral artery | Avoid traveling to altitude >2000–2500 m
|
Hypertensive haemorrhage | Travel to high altitude only if BP is controlled and not before 90 d after the event |
Haemorrhage as a result of amyloid angiopathy | Avoid high altitude |
Known cerebral aneurysm, arteriovenous malformation,
or cerebral cavernoma | Check BP. Avoid extreme altitude >4500 m
|
Abbreviations: MET, metabolic equivalent of task; BP, blood pressure; CCB, calcium channel blocker; HAPE, high altitude pulmonary oedema; CPX, cardiopulmonary exercise testing; ABPM, 24-hour ambulatory blood pressure monitoring; RV, right ventricular; VVIR, ventricular pacing, ventricular sensing, inhibition response, and rate-adaptive; DDDR, atrial and ventricular pacing, atrial and ventricular sensing, dual response, and rate-adaptive; AAIR, atrium paced, atrium sensed, and pacemaker inhibited in response to sensed atrial beat and rate-adaptive; min, minute; ICD, implantable cardioverter defibrillator; TIA, transient ischaemic attack, modified from [64] with permission of Elsevier. |