Trevor J. Williams

Background and objective: Chronic thromboembolic pulmonary hypertension (CTEPH) is a serious condition occurring in 2%–4% of patients after acute pulmonary embolism. Pulmonary endarterectomy (PEA) is a potential cure for technically operable disease. The epidemiology and long‐term outcomes of CTEPH have not been previously described in Australia and New Zealand.Methods: Data were extracted from the Pulmonary Hypertension Society of Australia and New Zealand (PHSANZ) registry for patients diagnosed with CTEPH between January 2004 and March 2020. Baseline characteristics, treatment strategies, outcome data and long‐term survival are reported.Results: A total of 386 patients were included with 146 (37.8%) undergoing PEA and 240 (62.2%) in the non‐PEA group. PEA patients were younger (55 ± 16 vs. 62 ± 16 years, p < 0.001) with higher baseline 6‐min walk distance (6MWD; 405 ± 122 vs. 323 ± 146 m, p = 0.021), whilst both groups had similar baseline pulmonary haemodynamics. Pulmonary hypertension‐specific therapy was used in 54% of patients post‐PEA and 88% in the non‐PEA group. The 1‐, 3‐ and 5‐year survival rates were 93%, 87% and 84% for the PEA group compared to 86%, 73% and 62%, respectively, for the non‐PEA group (p < 0.001). Multivariate survival analysis showed baseline 6MWD was an independent predictor of survival in both operated and medically managed patients.Conclusion: In this first multicentre report of CTEPH in Australia and New Zealand, long‐term survival is comparable to that in other contemporary CTEPH registries. However, PEA was only performed in a minority of CTEPH patients (37.8%) and significantly less than overseas reports. Greater awareness of PEA and improved patient access to experienced CTEPH centres are important priorities.

See related article

Pulmonary vascular resistance (PVR) >3 Wood units is a criterion of the haemodynamic definition of pulmonary arterial hypertension (PAH). However, this cut-off is conservative and arbitrarily defined. Data is lacking on the natural history, response to therapy and survival of patients diagnosed with precapillary pulmonary hypertension (PH) with mild or borderline elevation of PVR.In Australia, PAH therapy could be prescribed solely on mean pulmonary arterial pressure (PAP) and pulmonary arterial wedge pressure (PAWP) criteria. Using the Australian and New Zealand Pulmonary Hypertension Registry, we aimed to study a population diagnosed with PAH between January 2004 and December 2017 with the pre-defined haemodynamic characteristics of mean PAP ≥25 mmHg, PAWP ≤15 mmHg and PVR <3 Wood units.Eighty-two patients met the pre-defined haemodynamic inclusion criteria (mean age 63±11 years; 67 females). Underlying aetiologies included idiopathic disease (n=39), connective tissue disease (CTD; n=42) and HIV infection (n=1). At diagnosis, mean PAP was 27 mmHg (interquartile range (IQR) 25–30 mmHg), PAWP 13 mmHg (IQR 11–14 mmHg) and PVR 2.2 Wood units (IQR 1.9–2.7 Wood units). Baseline 6-min walk distance (6MWD) was 352 m (IQR 280–416 m) and 77% of subjects were in New York Heart Association (NYHA) functional class 3 or 4. All patients were commenced on initial monotherapy with an endothelin receptor antagonist (ERA; n=66) or phosphodiesterase type-5 inhibitor (PDE5i; n=16). At first re-evaluation, 6MWD increased by 46 m (IQR 7–96 m) and 35% of subjects demonstrated improvement in NYHA functional class. After a median follow-up of 65 months (IQR 32–101 months), 18 out of 82 subjects (22.0%) had died, with estimated 1-year and 5-year survival rates of 98% and 84%, respectively. Death attributed to PAH occurred in six out of these 18 patients (33.3%, 7% of total cohort).Patients with precapillary PH and “borderline” PVR falling outside the current definition have adverse outcomes. Such patients appear to respond to PAH therapy; however, this requires further study in randomised trials.

We report two patients with relapsing remitting multiple sclerosis (RRMS) on interferon (IFN) beta-1a treatment for more than 7 years who developed pulmonary arterial hypertension (PAH). Patient 1 developed severe PAH requiring lung transplantation. Histology showed typical proliferative lesions including plexiform lesions consistent with PAH. Patient 2 ceased IFN beta-1a, and their symptoms stabilised. Both cases highlight IFN beta-1a treatment as a potential risk factor for PAH. PAH needs to be considered as a diagnosis in patients on long-term IFN beta-1a treatment who develop new-onset respiratory symptoms.