Table 6

Paediatric functional classification of pulmonary hypertension

Age functional class	0–0.5 years	0.5–1 years	1–2 years	2–5 years	5–16 years
I	Asymptomatic, growing along own centiles and developing normally, no limitation of physical activity
I	Gains head control and increases body tone from 0 to 3 months, then rolls over and has no head lag. Sitting with support	Mobile, sitting, grasping, starting to stand, crawling, playing	Standing, starting to walk/walking, climbing	Regular school/nursery attendance, playing sports with his/her classmates
II	Slight limitation of physical activity, unduly dyspnoeic and fatigued. Falling behind physical developmental milestones/delayed physical development. Comfortable at rest. Continues to grow along own centiles
II				Nursery/school attendance 75% normal. No chest pain
IIIa	Marked limitation of physical activity, unduly fatigued. Regression of learned physical activities. Comfortable at rest. Less than ordinary activity causes undue fatigue or syncope and/or pre-syncope (or chest pain)
	Quiet and needs frequent naps. Growth compromised. Poor appetite. Requires excessive medical attention			Nursery/schooling compromised, <50% normal attendance
		Hesitant and unadventurous.
		Stops crawling	Reluctant to play	Not climbing stairs, reluctant to play with friends	No attempt at sports
IIIb	Growth severely compromised. Poor appetite. Supplemental feeding. Less than ordinary activity causes undue fatigue or syncope (or chest pain). Plus features of Class IIIa
IIIb				Unable to attend nursery/school, but mobile at home. Wheelchair needed outside home
IV	Unable to carry out any physical activity without undue dyspnoea, fatigue or syncope (or chest pain), not interacting with family. Syncope and/or right heart failure. Plus features of class III
IV				Unable to attend nursery/school, wheelchair dependant, not interacting with friends

Modified from Lammers et al.17