Abstract 4372096: Reappraising left ventricular wall thickness in transthyretin cardiac amyloidosis: A survey of the diagnostic journeys of patients with normal posterior wall thickness

Background: Transthyretin cardiac amyloidosis (ATTR-CM) is becoming a more prominent and recognized etiology for diastolic heart failure. The debut of disease-modifying therapies have emphasized the importance of early diagnosis in disease course. Screening criteria have highlighted increased left ventricular wall thickness (LVWT) over 1.2 cm as a threshold to suspect cardiac amyloidosis. However, we previously demonstrated that left ventricular wall thickness may be an unreliable screening marker in these patients and highly variable. We aimed to 1) characterize the diagnostic journey of patients with ATTR-CM with LVWT ≤ 1.2 cm and 2) determine alternative screening pathways to better capture more patients with ATTR-CM. Methods: Our study extracted a cohort from a database of all patients diagnosed with ATTR-CM at single large academic center from January 2006 to March 2024. For each of these 1845 patients, dimensions were abstracted from the echocardiogram closest to the diagnosis date. A cohort of 319 (17.2%) patients diagnosed with ATTR-CM with normal posterior wall thickness (≤ 1.2 cm) were sub-selected and evaluated by manual chart abstraction to categorize pre-specified diagnostic pathways. Data were then evaluated to compare the prevalence of various diagnostic pathways. Results: Among 319 patients with diagnosed ATTR-CM, 198 (62.1%) patients were diagnosed with routine evaluation for restrictive cardiomyopathy and 37 (11.6%) were diagnosed as a part of our mandated ATTR-CM screening for TAVR (Table 1). Seventy-two patients were diagnosed with tissue pathology (8.8% with carpal tunnel pathology, 4.4% with intraoperative cardiac pathology, and 3.4% with other noncardiac pathology). Conclusion: Wall thickness may be an unreliable marker in screening patients with ATTR-CM. Clinicians should maintain a high degree of suspicion of and vigilance among select patients with undifferentiated heart failure and lower thresholds for upfront evaluation with imaging or biopsy.