Right ventricular to pulmonary artery coupling and outcome in patients with cardiac amyloidosis

Aims: To investigate the prognostic value of the right ventricle-to-pulmonary artery (RV-PA) coupling in patients with either transthyretin (ATTR) or immunoglobulin light-chain (AL) cardiac amyloidosis (CA). Methods and results: Overall, 283 patients with CA from 3 Italian high-volume centres were included (median age 76 years; 63% males; 53% with ATTR-CA, 47% with AL-CA). The RV-PA coupling was evaluated by using the tricuspid annular plane systolic excursion/pulmonary artery systolic pressure (TAPSE/PASP) ratio. The median value of TAPSE/PASP was 0.45 (0.33-0.63) mm/mmHg. Patients with a TAPSE/PASP ratio <0.45 were older, had lower systolic blood pressure, more severe symptoms, higher cardiac troponin and N-terminal pro-B-type natriuretic peptide levels, greater left ventricular (LV) thickness, and worse LV systolic and diastolic function. A TAPSE/PASP ratio <0.45 was independently associated with a higher risk of all-cause death or heart failure (HF) hospitalization [hazard ratio (HR) 1.98, 95% confidence interval (CI) 1.32-2.96; P = 0.001] and all-cause death (HR 2.18, 95% CI 1.31-3.62; P = 0.003). The TAPSE/PASP ratio reclassified the risk of both endpoints [net reclassification index 0.46 (95% CI 0.18-0.74) P = 0.001 and 0.49 (0.22-0.77) P < 0.001, respectively], while TAPSE or PASP alone did not (all P > 0.05). The prognostic impact of the TAPSE/PASP ratio was significant both in AL-CA patients (HR for the composite endpoint 2.47, 95% CI 1.58-3.85; P < 0.001) and in ATTR-CA (HR 1.81, 95% CI 1.11-2.95; P = 0.017). The receiver operating characteristic curve showed that the optimal cut-off for predicting prognosis was 0.47 mm/mmHg. Conclusion: In patients with CA, RV-PA coupling predicted the risk of mortality or HF hospitalization. The TAPSE/PASP ratio was more effective than TAPSE or PASP in predicting prognosis.