Right Ventricular-Pulmonary Artery Coupling as a Prognostic Marker in Cardiac Amyloidosis: A Comprehensive Review

Background: Cardiac amyloidosis (CA) is characterized by progressive myocardial infiltration leading to restrictive cardiomyopathy and heart failure. While left ventricular assessment has traditionally dominated prognostic evaluation, right ventricular (RV) dysfunction and RV-pulmonary artery (PA) coupling have emerged as critical determinants of outcomes. Objectives: This review synthesizes current evidence on RV-PA coupling as a prognostic marker in cardiac amyloidosis, examining measurement methodologies, prognostic significance, pathophysiological mechanisms, and clinical applications. Methods: We comprehensively reviewed the recent literature on RV-PA coupling in CA, focusing on studies published from 2020 to 2025, including both AL and ATTR subtypes. We analyzed data from multicenter cohorts, prospective registries, and validation studies examining the relationship between RV-PA coupling indices and clinical outcomes. Results: RV-PA coupling, most commonly assessed using the tricuspid annular plane systolic excursion to pulmonary artery systolic pressure (TAPSE/PASP) ratio, consistently demonstrates strong independent prognostic value for mortality and heart failure outcomes in CA patients. Impaired coupling (TAPSE/PASP < 0.45 mm/mmHg) identifies high-risk patients with hazard ratios ranging from 1.98 to 4.17 for adverse outcomes. In a multicenter cohort of 283 patients, TAPSE/PASP < 0.45 mm/mmHg was independently associated with death or heart failure hospitalization (HR 1.98, 95% CI 1.32-2.96, p = 0.001) and significantly improved risk reclassification (NRI 0.46-0.49). In ATTR-specific populations receiving disease-modifying therapy, impaired coupling (TAPSE/PASP ≤ 0.382 mm/mmHg) predicted three-year mortality with an adjusted HR of 2.99. The coupling index provides incremental value over individual RV parameters by accounting for afterload conditions and demonstrates consistent prognostic performance across both AL and ATTR subtypes. Conclusions: RV-PA coupling represents a robust, easily obtainable prognostic marker that should be routinely assessed in CA patients for risk stratification and clinical decision-making. The TAPSE/PASP ratio can be calculated from standard echocardiographic examinations without additional cost or time, making it practical for widespread implementation. Future research should focus on standardizing measurement protocols, establishing disease-specific thresholds, evaluating coupling trajectories with novel therapies, and integrating coupling assessment into staging systems and management algorithms. The strong prognostic signal, pathophysiological relevance, and ease of measurement position RV-PA coupling as an essential component of comprehensive cardiac amyloidosis evaluation.