Objective:

To assess disease-specific echocardiographic thresholds for tricuspid regurgitation in patients with transthyretin amyloid cardiomyopathy and compare prognostic discrimination with existing guidelines.

Approach:

• Study Design: Enrolled 1,124 patients with newly diagnosed transthyretin amyloid cardiomyopathy across 8 centers in Europe, excluding those with prior tricuspid valve intervention or severe aortic conditions.
• Echocardiographic Assessment: Conducted standardized transthoracic echocardiography with centralized assessment of tricuspid regurgitation using specific metrics.
• Cohorts: Divided into derivation cohort (745 patients) and validation cohort (379 patients) for establishing and confirming prognostic thresholds.
• Follow-up: Median follow-up of 25 months to assess all-cause mortality and heart failure hospitalizations.

Key Findings:

• Identified intermediate-risk thresholds: 3 mm for vena contracta width, 0.15 cm² for effective regurgitant orifice area, and 10 mL for regurgitant volume, with 324 patients (29%) dying and 251 (22%) experiencing at least 1 heart failure hospitalization during follow-up.
• High-risk thresholds were established at 5 mm, 0.25 cm², and 20 mL; extreme-risk thresholds at 8 mm, 0.50 cm², and 40 mL.
• The proposed framework classified 413 patients (37%) as low risk, 377 (34%) as intermediate risk, 234 (21%) as high risk, and 100 (9%) as extreme risk.
• The framework showed significantly greater discrimination for mortality and heart failure hospitalization compared to existing guidelines.

Limitations:

• Developed thresholds are for prognostic assessment, not for determining eligibility for intervention.
• Causal conclusions cannot be drawn due to the observational nature of the study.
• Residual confounding may affect results.
• Tricuspid regurgitation measurements were limited to baseline assessments.

Sources:

• JAMA Cardiology