Cardiac index (CI), stroke volume index (SVI), pulmonary vascular resistance (PVR), and pulmonary arterial compliance (PCa) at follow-up on right heart catheterization (RHC) are associated with transplant-free survival in patients with systemic sclerosis and pulmonary arterial hypertension (PAH), according to a study published in the European Respiratory Journal.

Treatment-naive patient data from the French Pulmonary Arterial Hypertension Network registry were retrospectively reviewed (n=513). Patients included in the analysis had a confirmed diagnosis of systemic sclerosis, as well as newly diagnosed group 1 precapillary PAH (ie, resting mean pulmonary artery pressure ≥ 25 mm Hg; PVR >3 Wood unit) on RHC.

Within a 12-month period after diagnosis, researchers evaluated baseline and first-follow-up RHC hemodynamic variables, including right atrial pressure, mean pulmonary artery pressure, cardiac output, CI, PVR, mixed venous oxygen saturation, SVI, and PCa. Death or lung transplantation made up the primary outcome.

During a median follow-up time of 2.09 years (interquartile range, 0.96-3.69 years), a total of 256 (49.9%) patients died and 12 (2.3%) received lung transplants. The median transplant-free survival, defined from the initial RHC date until a primary outcome event occurred for baseline, and from the first RHC follow-up “until the occurrence of a primary outcome event for the follow-up analysis,” was 3.42 years (41 months).

Follow-up RHC was performed in 353 patients within 1 year of diagnosis (median interval, 4.6 months; interquartile range, 3.9-6.4 months). Significant improvements were observed in patients who were characterized in the New York Heart Association Functional Class I or II groups (24% vs 43.5%; P <.001) and median 6-minute walking distance (300 vs 318 m; P <.001).

The 6-minute walking distance was associated with transplant-free survival in the multivariable analysis that included age, body mass index, 6-minute walking distance, New York Heart Association Functional Class, right atrial pressure, mean pulmonary artery pressure, and CI, SVI, PVR, or PCa (adjusted hazard ratio, 0.97 per 10 m; 95% CI, 0.95-0.99 per 10 m; P <.001). In addition, follow-up measurements of CI, SVI, PVR, and PCa were associated with the primary outcome in the multivariable analysis. An increasing number of low-risk criteria at baseline were associated with better outcomes at 1-year follow-up (area under the curve, 0.63; 95% CI, 0.56-0.69), as well as at first follow-up (area under the curve, 0.71; 95% CI, 0.64-0.78).

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The investigators reported that a substantial proportion of the study was affected by missing data, which may limit the conclusively of the findings.

On the basis of their findings, the investigators suggested that, “while RHC remains mandatory for the diagnosis of PAH, non-invasive measures of RV function would be preferred during follow-up” in patients with systemic sclerosis and PAH.

Reference

Weatherald J, Boucly A , Launay D, et al. Haemodynamics and serial risk assessment in systemic-sclerosis associated pulmonary arterial hypertension [published online September 12, 2018]. Eur Respir J. doi:10.1183/13993003.00678-2018