Abstract Body (Do not enter title and authors here): Background:
Cardiac amyloidosis (CA) is a progressive infiltrative cardiomyopathy associated with poor prognosis. CA is commonly due to transthyretin (ATTR) or light chain (AL) amyloid deposition. Tricuspid regurgitation (TR) is a common echocardiographic finding in CA; however, its prognostic relevance remains unclear. We aimed to evaluate the association between TR severity and clinical outcomes in patients with CA.

Methods:
We conducted a retrospective cohort study of adults with CA referred to a specialized Cardiac Amyloidosis Clinic between January 2014-April 2024. TR severity was assessed by transthoracic echocardiography completed within 6 months of CA diagnosis and categorized as less-than-moderate versus moderate or greater. Multivariable Cox proportional hazards models were used to evaluate the association between TR severity and survival, adjusting for baseline characteristics including age, New York Heart Association (NYHA) class, estimated glomerular filtration rate (eGFR), natriuretic peptide levels (BNP or NT-proBNP), and disease stage.

Results:
Among 416 patients (mean age 64.8 years, 27% AL subtype), ≥moderateTR was present in 69 (16.6%). Compared to those In adjusted Cox models, TR remained independently associated with mortality in the overall cohort (hazard ratio (HR) 1.84, P<0.0001), ATTR subgroup (HR 1.77, P = 0.0023), and AL subgroup (HR 2.18, P <0.0001).

Conclusion:
≥moderateTR is independently associated with worse survival in patients with CA, regardless of amyloid subtype. These findings support routine TR severity assessment for risk stratification and to identify individuals who may benefit from closer follow-up or tailored interventions.