Pulmonary arterial compliance (PAC) was found to be strongly associated with all-cause mortality and clinical worsening in patients with systemic lupus erythematosus (SLE)–associated pulmonary arterial hypertension (PAH), according to a study published in Hypertension.
In this study, 120 consecutive patients (mean age, 33.5 ± 8.5; 97.5% women) who were diagnosed with SLE-associated PAH based on right heart catheterization were enrolled between February 2012 and December 2016. Of 120 participants, 47 patients had PAC ≥1.39 mL/mm Hg, and 73 had PAC <1.39 mL/mm Hg. The study’s end point was a composite of all-cause mortality and clinical worsening.
During a median follow-up of 48.0 months (interquartile range [IQR], 40.0-60.8), 49 patients (41%) experienced the composite end point after 15.0 months (IQR, 8.5-24.0). Patients with a PAC <1.39 mL/mm Hg vs PAC ≥1.39 mL/mm Hg a 3.09-fold higher risk of experiencing end point events (95% CI, 1.54-6.20, P =.001).
Stratified right ventricular afterload was found to be the only independent predictor for the study’s end point (hazard ratio, 2.009; 95% CI, 1.390-2.904; P <.001) in a multivariable Cox regression analysis. Participants with the highest right ventricular afterload (ie, PAC <1.39 mL/mm Hg and pulmonary vascular resistance [PVR] ≥10.3 Wood Unit) had the greatest risk of experiencing the end point (P <.014).
“The combination of PAC and PVR, which reflects the right ventricular afterload more precisely than PVR alone, has great value in improving the risk stratification of patients with SLE-associated PAH,” noted the study authors. “A low PAC (PAC <1.39 mL/mm Hg) with high PVR (>10.3 Wood Unit) indicates that the patients are at a particularly high risk of poor prognosis.”
Study limitations include a limited sample size, and the fact that the ratio of stroke volume to pulmonary artery pulse pressure measured with right heart catheterization may underestimate compliance, as it does not account for blood flow from the pulmonary circulation into the capillary bed during systole.
“Our study suggests that the calculated PAC provides relevant prognostic insights in SLE-associated PAH,” the researchers concluded.
Guo X, Lai J, Wang H, et al. Predictive value of pulmonary arterial compliance in systemic lupus erythematosus patients with pulmonary arterial hypertension [published online August 10, 2020]. Hypertension. doi:10.1161/HYPERTENSIONAHA.120.15682