Table 2.

Recommendation for ischaemic patients ascending to high altitude

Patient risk class	Recommendations	Class of evidence	Level of evidence	References
General recommendations for all cardiovascular patients	Patients should continue pre-existing medications at HA. All therapy changes, especially dual anti-antiplatelet therapy after drug-eluting stent implantation, must be discussed with a doctor before enacting. Individuals who do not engage in physical exertion at low altitude should not engage in physical activity at HA.	I	C
	Acetazolamide administration seems to reduce the risk of subendocardial ischaemia at HA in healthy subjects, and thus use of acetazolamide for AMS prevention might be helpful. No data are available, however, in patients with CAD.	IIa	C	28
After AMI/CABG	Patients should wait at least 6 months after uncomplicated ACS episode as well as after revascularization before HA exposure.	I	C	5,12,30
After stenting	Patients should wait at least 6–12 months after coronary stenting before HA exposure.	IIa	C	12,31,33,30S
Low risk (CCS 0-I)	May safely ascend to HA, up to 4200 m asl, and practice light-to-moderate physical exertion.	IIa	C	12,31
Moderate risk CAD (CCS II-III)	May carefully ascend up to 2500 m, but physical exercise heavier than light is contraindicated.	IIa	C	22
High risk (CCS IV)	Should not ascend to HA.	I	C

The strength of these recommendations is to be weighted in the light of the limited evidence available.

AMI, acute myocardial infarction; CABG, coronary artery bypass grafting; CAD, coronary artery disease; CCS, Canadian Cardiovascular Society; HA, high altitude.