Idiopathic pulmonary arterial hypertension (IPAH) is a rare but fatal disease diagnosed by right heart catheterisation and the exclusion of other forms of pulmonary arterial hypertension, producing a heterogeneous population with varied treatment response. Here we show unsupervised machine learning identification of three major patient subgroups that account for 92% of the cohort, each with unique whole blood transcriptomic and clinical feature signatures. These subgroups are associated with poor, moderate, and good prognosis. The poor prognosis subgroup is associated with upregulation of the ALAS2 and downregulation of several immunoglobulin genes, while the good prognosis subgroup is defined by upregulation of the bone morphogenetic protein signalling regulator NOG, and the C/C variant of HLA-DPA1/DPB1 (independently associated with survival). These findings independently validated provide evidence for the existence of 3 major subgroups (endophenotypes) within the IPAH classification, could improve risk stratification and provide molecular insights into the pathogenesis of IPAH.

Background:Paediatric heart transplantation in Australia is centralised at The Royal Children’s Hospital, Melbourne. Survival to adulthood is improving but the ongoing need for complex medical therapy, surveillance, and potential for late complications continues to impact on quality of life. Quality of life in adults who underwent heart transplantation in childhood in Australia has not been assessed.Methods:Cross-sectional quality of life data were collected from paediatric heart transplant survivors >18 years of age using Rand 36-Item Health Survey. Self-reported raw scores were transformed to a 0–100 scale with higher scores indicating better quality of life. Mean scores were compared to National Health Survey Short Form-36 Population Norms data using the independent sample t-test.Results:A total of 64 patients (64/151) who underwent transplantation at The Royal Children’s Hospital between 1988 and 2016 survived to adulthood. In total 51 patients (51/64, 80%) were alive at the time of the study and 27 (53%) responded with a mean age of 25 ± 6 years, being a median of 11 years (interquartile range 7–19) post-transplantation. Most self-reported quality of life subscale scores were not significantly different from the Australian normative population data. However, self-reported ‘General Health’ was significantly worse than normative data (p = 0.02). Overall, 93% (25/27) reported their general health as being the same or better compared to 1-year ago.Conclusion:Adult survivors after paediatric heart transplantation in Australia report good quality of life in multiple domains and demonstrate independence in activities of daily living and employment. However, lifelong medical treatment may affect perceptions of general health.

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