Utility of the IWT score for cardiac amyloidosis screening in patients with unexplained left ventricular hypertrophy

Abstract Background Timely diagnosis of cardiac amyloidosis (CA) is essential for initiating disease-modifying therapies and improving prognosis. The European Society of Cardiology suggests an Increased Wall Thickness (IWT) echocardiographic score ≥8 to identify CA in patients with suspected disease. However, its role as a screening tool in an unselected left ventricular hypertrophy (LVH) population is unknown. Purpose We aimed to assess the utility of the IWT score as a screening tool for the early diagnosis of CA in patients with unexplained LVH. Methods Consecutive patients with unexplained LVH ≥12 mm referred to 12 cardiac imaging units for echocardiographic evaluation between November 2023 and November 2024 were included. Exclusion criteria were incomplete clinical or echocardiographic data and refusal to provide consent. The IWT score was calculated for all the participants. In IWT score ≥8, further diagnostic testing was performed to rule out CA. Results A total of 581 patients (mean age 71±13 years, 63% male) were included. The most common previous diagnoses were aortic stenosis (21%), restrictive cardiomyopathy (14%), hypertensive cardiomyopathy (12%), and heart failure with preserved ejection fraction (5%). Presenting symptoms included dyspnea (37%), chest pain (15%), and syncope (5%). The mean maximum wall thickness was 15±2.7 mm. An IWT score ≥8 was observed in 53 patients (9%), of whom 22 (42%) were diagnosed with CA following further evaluation. Among these, 20 patients had wild-type transthyretin amyloidosis (ATTRwt), 1 had hereditary transthyretin amyloidosis (ATTRv), and 1had light-chain (AL) amyloidosis. The median time from cardiac symptom onset to diagnosis using this screening approach was 2.5 months (IQR: 0-4). Conclusions The IWT score may be a useful screening tool in unselected patients with unexplained LVH≥12 mm, enabling early identification of CA in 4% of cases. Nearly half of positive score patients were confirmed to have the disease in our cohort. These findings support the integration of the IWT score into routine echocardiographic assessment in patients with LVH. Further studies with larger cohorts are warranted to confirm its diagnostic performance in the general population.Screening workflow using IWT score