The association between resting and mild-to-moderate exercise pulmonary artery pressure

The mean pulmonary artery pressure (P(pa)) achieved on mild-to-moderate exercise is age related and its haemodynamic correlates remain to be documented in patients free of pulmonary hypertension (PH). Our retrospective study involved patients free of PH investigated in our centre for possible pulmonary vascular disease between January 1, 2007 and October 31, 2009 who underwent right heart catheterisation at rest and during supine exercise up to 60 W. The 38 out of 99 patients aged <50 yrs were included and a P(pa) of 30 mmHg was considered the upper limit of normal on exercise. The 24 subjects who developed P(pa)>30 mmHg on exercise had higher resting P(pa) (19±3 versus 15±4 mmHg) and indexed pulmonary vascular resistance (PVRi; 3.4±1.5 versus 2.2±1.1 WU·m(2); p<0.05) than the remaining 14 subjects. Resting P(pa) >15 mmHg predicted exercise P(pa) >30 mmHg with 88% sensitivity and 57% specificity. The eight patients with resting P(pa) 22-24 mmHg all had exercise P(pa) >30 mmHg. In subjects aged <50 yrs investigated for possible pulmonary vascular disease and free of PH, patients with mild-to-moderate exercise P(pa) >30 mmHg had higher resting PVRi and higher resting P(pa), although there was no resting P(pa) threshold value that could predict normal response on mild-to-moderate exercise. The clinical relevance of such findings deserves further long-term follow-up studies.