Prospective Systematic Screening for Transthyretin Amyloid Cardiomyopathy in Cardiology Inpatients With Left Ventricular Hypertrophy: the IMPACT Study.

BACKGROUND: Transthyretin cardiac amyloidosis (ATTR-CM) is an underdiagnosed severe cardiomyopathy in older adults. Current diagnostic strategies rely on clinical "red flags", but data on systematic screening in minimally selected populations remain limited. We aimed to describe the prevalence of ATTR-CM among cardiology inpatients with left ventricular hypertrophy (LVH) and to identify parameters associated with its diagnosis. METHODS AND RESULTS: This prospective single-center study included consecutive patients aged ≥60 years hospitalized in cardiology with echocardiographic LVH (wall thickness ≥12 mm), irrespective of etiology. Patients with known amyloidosis, prior heart transplantation, or contraindication to scintigraphy were excluded. All patients underwent immunologic testing and technetium-99m scintigraphy. ATTR-CM was diagnosed by cardiac uptake (Perugini grade ≥2) without significant monoclonal gammopathy. Multivariable logistic regression identified independent associations and receiver-operating characteristic curve analysis assessed diagnostic performance. Between October 2021 and June 2023, ATTR-CM was diagnosed in 29 of 400 patients (7.3%). Four variables were independently associated with ATTR-CM: basal longitudinal strain (BLS) (odds ratio [OR] 0.84, 95% CI 0.74-0.95), non-sinus rhythm (OR 3.85, 95% CI 1.30-11.11), bilateral carpal tunnel syndrome (OR 3.48, 95% CI 1.09-11.14), and history of stroke (OR 8.67, 95% CI 2.65-28.34). BLS showed the highest discrimination for ATTR-CM (AUC 0.81). During a median follow-up of 3.31 years, all-cause mortality did not significantly differ between ATTR-CM and non-ATTR-CM patients (p=0.137). CONCLUSION: In a minimally selected cardiology population with LVH, systematic screening identified a substantial prevalence of ATTR-CM. BLS may help prioritize diagnostic testing in routine practice and facilitate earlier identification and management of ATTR-CM.