Prevalence and clinical significance of right ventricular pulmonary arterial uncoupling in cardiac amyloidosis

This study aims to evaluate the prevalence and the clinical significance of the right ventricular pulmonary arterial (RV-PA) uncoupling in patients with cardiac amyloidosis (CA).The study population consisted in 92 consecutive patients with CA (age 71.1 ± 12.2 years, 71% males; 47% with immunoglobulin light chain (AL), 53% with transthyretin [ATTR]). A pre-specified tricuspid anulus plane systolic excursion on pulmonary arterial systolic pressure (TAPSE/PASP) value <0.31 mm/mmHg was used to define RV-PA uncoupling and to dichotomize the study population.Thirty-two patients (35%) showed RV-PA uncoupling at baseline evaluation (15/44 [34%] AL and 17/48 [35%] ATTR). Patients with RV-PA uncoupling, in both AL and ATTR, showed worse NYHA functional class, lower systemic blood pressure, and more pronounced left ventricular and RV systolic dysfunction than those with RV-PA coupling. During a median follow-up of 8 months (IQR 4-13), 26 patients (28%) experienced cardiovascular death. Patients with RV-PA uncoupling showed lower survival at 12 months follow-up than those with RV-PA coupling (42.7% [95%CI 21.7-63.7%] vs. 87.3% [95%CI 78.3-96.3%], p-value<0.001). Multivariate analysis identified high-sensitivity troponin I values (HR 1.01 [95%CI 1.00-1.02] per 1 pg/mL increase; p-value 0.013) and TAPSE/PASP (HR 1.07 [95%CI 1.03-1.11] per 0.01 mm/mmHg decrease; p-value 0.002) as independent predictors of cardiovascular death.RV-PA uncoupling is common among patient with CA, and it is a marker of advanced disease and worse outcome. This study suggest that TAPSE/PASP ratio has the potential to improve risk stratification and guide management strategies in patients with CA of different etiology and advanced disease.