Temporal Shifts in Diagnostic Testing for Cardiac Amyloidosis Across U.S. Health Systems

Purpose: To evaluate temporal trends in diagnostic testing for cardiac transthyretin amyloidosis (ATTR-CM) across U.S. health systems in the contemporary era. Methods: We conducted a retrospective, descriptive analysis using the TriNetX U.S. Collaborative Network, identifying patients diagnosed with wild-type or hereditary ATTR-CM between January 2017 and November 2025. ATTR-specific ICD-10 codes were combined with evidence of cardiac involvement, and patients with light-chain amyloidosis or plasma cell dyscrasias were excluded. Diagnostic testing, including technetium-99m (Tc-99m) bone scintigraphy, cardiac magnetic resonance imaging (CMR), and biopsy, was assessed within an extended diagnostic ascertainment window spanning 24 months before and 12 months after diagnosis. Results: The number of patients diagnosed with ATTR-CM increased markedly over time. Use of Tc-99m scintigraphy and CMR rose substantially in absolute terms, while biopsy utilization declined steadily. Dual-modality imaging increased modestly, and invasive histologic confirmation became progressively less common, indicating a shift toward imaging-based diagnosis. Conclusion: Between 2017 and 2025, diagnostic evaluation of ATTR-CM shifted decisively toward noninvasive imaging, with declining reliance on biopsy. Although imaging volume increased, proportional adoption did not keep pace with expanding case identification, underscoring the need for broader implementation of guideline-recommended diagnostic pathways.