Table 1. Functional and cardiopulmonary exercise test (CPET) parameters in risk assessment.

	Low risk (< 5%)	Intermediate risk (5-10%)	High risk (> 10%)
WHO functional class	I, II	III	IV
6MWD	> 440 m	165-440 m	< 165 m
CPET parameters
Peak VO2, mL·kg-1·min-1	> 15	44880	< 11
Peak VO2, % predicted	> 65	65-35	< 35
VE/VCO2 slope	< 36	36-45	> 45

6MWD, 6-minute walking distance; VO2, oxygen uptake; VCO2, carbon dioxide production; VE, minute ventilation; VE/VCO2 slope, slope of the relationship between VE and VCO2.