title: Respiratory muscle dysfunction in idiopathic pulmonary arterial hypertension.
abstract: Idiopathic pulmonary arterial hypertension (IPAH) is a pulmonary vasculopathy of unknown aetiology. Dyspnoea, peripheral airway obstruction and inefficient ventilation are common in IPAH. Data on respiratory muscle function are lacking. This prospective single-centre study included 26 female and 11 male patients with IPAH in World Health Organization functional classes II-IV. Mean+/-SD pulmonary artery pressure was 48.6+/-16.9 in females and 53.1+/-22.9 mmHg in males; cardiac output was 3.7+/-1.3 and 4.2+/-1.7 L x min(-1). Maximal inspiratory pressure (PI,max) was lower in the female patients than in 20 controls (5.3+/-2.0 versus 8.2+/-2.0 kPa). In the male patients, PI,max was lower than in 25 controls (6.8+/-2.2 versus 10.5+/-3.7 kPa). Maximal expiratory pressure (PE,max) was lower in the female patients than in controls (6.2+/-2.6 versus 9.5+/-2.1 kPa), and in male patients as compared to controls (7.1+/-1.6 versus 10.3+/-3.9 kPa). There was no correlation between PI,max or PE,max and parameters of pulmonary haemodynamics or exercise testing. The ratio of mouth occlusion pressure within the first 0.1 s of inspiration and PI,max was higher in IPAH than in controls (females 0.067+/-0.066 versus 0.021+/-0.008; males 0.047+/-0.061 versus 0.023+/-0.016). In conclusion, this study provides the first evidence of inspiratory and expiratory muscle weakness in idiopathic pulmonary arterial hypertension. The pathomechanisms and the prognostic significance should be further investigated.
authors.affiliation: Dept of Cardiology and Respiratory Medicine, University Hospital, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany. joachim_meyer@med.uni-heidelberg.de
authors.forename: F J
authors.initials: FJ
authors.lastname: Meyer
authors.forename: D
authors.initials: D
authors.lastname: Lossnitzer
authors.forename: A V
authors.initials: AV
authors.lastname: Kristen
authors.forename: A M
authors.initials: AM
authors.lastname: Schoene
authors.forename: W
authors.initials: W
authors.lastname: Kübler
authors.forename: H A
authors.initials: HA
authors.lastname: Katus
authors.forename: M M
authors.initials: MM
authors.lastname: Borst
mesh_terms: D000328:Adult; D000368:Aged; D001784:Blood Gas Analysis; D016022:Case-Control Studies; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis* / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000175:diagnosis*; D010807:Physical Endurance; D011336:Probability; D011446:Prospective Studies; D011659:Pulmonary Gas Exchange; D012016:Reference Values; D012129:Respiratory Function Tests; D012132:Respiratory Muscles / Q000503:physiopathology*; D018570:Risk Assessment; D012720:Severity of Illness Index; D014109:Total Lung Capacity