TAPSE/sPAP Ratio to Improve Risk Assessment in Pulmonary Arterial Hypertension

Background: Right ventricular functional adaptation to afterload is a major determinant of outcome in pulmonary arterial hypertension (PAH). We aimed to investigate if right ventricular-PA coupling evaluated by the ratio of tricuspid annular plane systolic excursion (TAPSE) to systolic pulmonary artery pressure (sPAP) improves risk assessment scores for survival prediction. Methods: A total of 677 consecutive patients with PAH (55% idiopathic) were prospectively enrolled with follow-up clinical, right heart catheterization, and echocardiographic evaluations within 12 months (interquartile range, 180-344 days) after initiation of targeted therapies in 11 Italian centers. European Society of Cardiology/European Respiratory Society guidelines-derived risk scores and REVEAL 2.0 (US Registry to Evaluate Early and Long-Term PAH Disease Management 2.0) risk scores were collected at baseline and follow-up. 254 consecutive patients with PAH retrospectively enrolled in a German reference center served as a validation cohort. Results: A low-risk status at a median of 3.7 years (interquartile range, 1.2-6.8) follow-up was significantly associated with each unit (0.1 mm/mm Hg) increase in TAPSE/sPAP under targeted therapies (European Society of Cardiology/European Respiratory Society score: odds ratio, 1.78; P≤0.001; REVEAL 2.0 score: odds ratio, 1.43; P≤0.001). At follow-up, the TAPSE/sPAP ratio increased the prognostic information of each risk stratum of the European Society of Cardiology/European Respiratory Society risk score, except the highest risk stratum, with 0.5 mm/mm Hg, 0.35 mm/mm Hg, and 0.30 mm/mm Hg, from the lowest to the intermediate-high risk score, identified as the best cutoff value. TAPSE/sPAP ratio increased the prognostic information of the REVEAL 2.0 score at follow-up, with 0.35 mm/mm Hg identified as the best cutoff value to discriminate within a score of 5 to 8, with no added value for scores <5 and >8. These results were confirmed in the validation cohort. Conclusions: Assessment of right ventricular-PA coupling by the TAPSE/sPAP ratio in PAH improves risk assessment scores except in the lowest or most advanced stage of the disease.