Right Heart Score for Predicting Outcome in Idiopathic, Familial, or Drug- and Toxin-Associated Pulmonary Arterial Hypertension

Objectives: This study sought to determine whether a simple score combining indexes of right ventricular (RV) function and right atrial (RA) size would offer good discrimination of outcome in patients with pulmonary arterial hypertension (PAH).

Background: Identifying a simple score of outcome could simplify risk stratification of patients with PAH and potentially lead to improved tailored monitoring or therapy.

Methods: We recruited patients from both Stanford University (derivation cohort) and VU University Medical Center (validation cohort). The composite endpoint for the study was death or lung transplantation. A Cox proportional hazard with bootstrap CI adjustment model was used to determine independent correlates of death or transplantation. A predictive score was developed using the beta coefficients of the multivariable models.

Results: For the derivation cohort (n = 95), the majority of patients were female (79%), average age was 43 ± 11 years, mean pulmonary arterial pressure was 54 ± 14 mm Hg, and pulmonary vascular resistance index was 25 ± 12 Wood units × m(2). Over an average follow-up of 5 years, the composite endpoint occurred in 34 patients, including 26 deaths and 8 patients requiring lung transplant. On multivariable analysis, RV systolic dysfunction grade (hazard ratio [HR]: 3.4 per grade; 95% confidence interval [CI]: 2.0 to 7.8; p < 0.001), severe RA enlargement (HR: 3.0; 95% CI: 1.3 to 8.1; p = 0.009), and systemic blood pressure <110 mm Hg (HR: 3.3; 95% CI: 1.5 to 9.4; p < 0.001) were independently associated with outcome. A right heart (RH) score constructed on the basis of these 3 parameters compared favorably with the National Institutes of Health survival equation (0.88; 95% CI: 0.79 to 0.94 vs. 0.60; 95% CI: 0.49 to 0.71; p < 0.001) but was not statistically different than the REVEAL (Registry to Evaluate Early and Long-Term PAH Disease Management) score c-statistic of 0.80 (95% CI: 0.69 to 0.88) with p = 0.097. In the validation cohort (n = 87), the RH score remained the strongest independent correlate of outcome.

Conclusions: In patients with prevalent PAH, a simple RH score may offer good discrimination of long-term outcome.