No abstract

Dyspnea and exercise limitation are common in patients with idiopathic pulmonary arterial hypertension (IPAH). Recently, a reduction in inspiratory and expiratory muscle strength has been observed in IPAH. However, it has not been investigated whether this respiratory muscle weakness might be part of a general muscle dysfunction as observed in congestive left heart failure. Therefore, in 24 consecutive IPAH patients (16 female; age 58.7+/-16.2; WHO class II-III; systolic pulmonary artery pressure during echocardiography at rest (sPAP) 65.0+/-20.6 mmHg, and 6-min-walk test (6-MWT) 473.6+/-127.7 m), the maximal isometric forearm muscle strength (best of three hand grip manoeuvres), maximal inspiratory and expiratory mouth occlusion pressures (Pimax, Pemax) were prospectively evaluated. The isometric forearm muscle strength was significantly lower in IPAH patients (281.7+/-102.6N) than in matched 24 healthy controls (397.1+/-116.8 N; p=0.03). In IPAH patients, there was a correlation between maximal isometric forearm muscle strength and 6-MWT (r=0.67; p=0.0007) and both, Pimax (r=0.69; p=0.0003) and Pemax (r=0.63; p=0.01), respectively. There was no correlation between forearm muscle strength and sPAP (r=0.30; p=0.16). The present skeletal muscle dysfunction is a novel finding in patients with IPAH. The correlation with respiratory muscle dysfunction and severity of disease might indicate a generalised "myopathy" in IPAH.

BackgroundRegulators and clinical experts increasingly recognize the importance of incorporating patient-reported outcomes (PROs) in clinical studies of therapies for pulmonary arterial hypertension (PAH). No PAH-specific instruments have been developed to date in accordance with the 2009 FDA guidance for the development of PROs as endpoints in clinical trials. A qualitative research study was conducted to develop a new instrument assessing PAH symptoms and their impacts following the FDA PRO guidance.MethodsA cross-sectional study was conducted at 5 centers in the US in symptomatic PAH patients aged 18–80 years. Concept elicitation was based on 5 focus group discussions, after which saturation of emergent concepts was reached. A PRO instrument for PAH symptoms and their impacts was drafted. To assess the appropriateness of items, instructions, response options, and recall periods, 2 rounds of one-on-one cognitive interviews were conducted, with instrument revisions following each round. Additional interviews tested the usability of an electronic version (ePRO). PRO development considered input from an international Steering Committee, and translatability and lexibility assessments.ResultsFocus groups comprised 25 patients (5 per group); 20 additional patients participated in cognitive interviews (10 per round); and 10 participated in usability interviews. Participants had a mean ± SD age of 53.1 ± 15.8 years, were predominantly female (93 %), and were diverse in race/ethnicity, WHO functional class (FC I/II: 56 %, III/IV: 44 %), and PAH etiology (idiopathic: 56 %, familial: 2 %, associated: 42 %). The draft PRO instrument (PAH-SYMPACT®) was found to be clear, comprehensive, and relevant to PAH patients in cognitive interviews. Items were organized in a draft conceptual framework with 16 symptom items in 4 domains (respiratory symptoms, tiredness, cardiovascular symptoms, other symptoms) and 25 impact items in 5 domains (physical activities, daily activities, social impact, cognition, emotional impact). The recall period is the past 24 h for symptoms, and the past 7 days for impacts.ConclusionsThe PAH-SYMPACT® was shown to capture symptoms and their impacts relevant to PAH patients, demonstrating content saturation, concept validity, and ePRO usability. Final content and psychometric validation of the instrument will be based on the results of an ongoing Phase IIIb clinical trial in PAH patients.Electronic supplementary materialThe online version of this article (doi:10.1186/s12931-016-0388-6) contains supplementary material, which is available to authorized users.

PAH (pulmonary arterial hypertension) is the leading cause of fatal right ventricular failure. However, rarely detectable, cTnT [cardiac TnT (troponin T)] is a significant prognostic marker. Therefore the aim of the present study was to evaluate the usefulness of a novel high-sensitive cTnT (hsTnT) assay as a parameter for functional and prognostic evaluation of PAH patients. In 55 PAH patients (idiopathic, n=20; chronic thromboembolic, n=30; and interstitial lung disease, n=5) with a mean pulmonary artery pressure of 45+/-18 mmHg, cTnT was measured by a fourth-generation conventional assay and a novel hsTnT assay with a lower detection limit at 2 pg/ml [total imprecision <10% at the 99th percentile value (13.4 pg/ml)]. In 90.9% of patients, cTnT was detectable using the hsTnT assay and in 30.9% using the fourth-generation assay. Concentrations >99th percentile were observed in 27.3% using hsTnT compared with 10.9% using the fourth-generation assay. A total of five out of six patients with cTnT values >30 pg/ml (fourth-generation assay) or >29.5 pg/ml (hsTnT assay) died during the 12-month follow-up. There was a correlation between hsTnT and 6-min walk distance (r=-0.92, P=0.0014), right ventricular systolic strain (r=0.95, P=0.0018) and strain rate (r=0.82, P=0.0021). In AUC (area under the curve) analysis, hsTnT predicted death at least as effectively as hFABP (heart-type fatty-acid-binding protein) or NT-proBNP (N-terminal pro-brain natriuretic protein). Moreover, hsTnT predicted a WHO (World Health Organization) functional class >II better than NT-proBNP or hFABP. In conclusion, in PAH patients, the novel biomarker hsTnT is associated with death and advanced WHO functional class, and is related to systolic right ventricular dysfunction and an impaired 6-min walk distance.