Causes and outcomes of ICU hospitalisations in patients with pulmonary arterial hypertension

Rationale Pulmonary arterial hypertension (PAH) is a rare disease characterised by limited survival despite remarkable improvements in therapy. The causes, clinical burden and outcomes of patients admitted to the intensive care unit (ICU) remain poorly characterised. The aim of this study was to describe patient characteristics, causes of ICU hospitalisation, and risk factors for ICU and 1-year mortality. Methods Data from patients enrolled in the Johns Hopkins Pulmonary Hypertension Registry were analysed for the period between January 2010 and December 2020. Clinical, functional, haemodynamic and laboratory data were collected. Measurements and main results 102 adult patients with 155 consecutive ICU hospitalisations were included. The leading causes for admission were right heart failure (RHF, 53.3%), infection (17.4%) and arrhythmia (11.0%). ICU mortality was 27.1%. Mortality risk factors included Na <136 mEq·mL⁻¹ (OR: 3.10, 95% CI: 1.41–6.82), elevated pro-B-type natriuretic peptide (proBNP) (OR: 1.75, 95% CI: 1.03– 2.98), hyperbilirubinaemia (OR: 1.40, 95% CI: 1.09–1.80), hyperlactaemia (OR: 1.42, 95% CI: 1.05– 1.93), and need for vasopressors/inotropes (OR: 5.29, 95% CI: 2.28–12.28), mechanical ventilation (OR: 3.76, 95% CI: 1.63–8.76) and renal replacement therapy (OR: 5.57, 95% CI: 1.25–24.76). Mortality rates at 3, 6 and 12 months were 17.5%, 27.6% and 39.0%, respectively. Connective tissue disease-associated PAH has lower 1-year survival compared to idiopathic PAH (51.4% versus 79.8%, log-rank test p=0.019). Conclusions RHF is the most common cause for ICU admission. In-hospital and 1-year mortality remain exceedingly high despite improved ICU care. Recognising specific risk factors on admission can help identifying patients at risk for poor outcomes.