Early Diagnosis of Age-Linked CArdiac TransThyRetin Amyloidosis by Selective Screening in Spinal Stenosis Surgery: the Multi-centric ALCATTRASS-study.

Background: Transthyretin amyloid cardiomyopathy (ATTR-CM) is an underdiagnosed, severe, yet treatable disease. Lumbar spinal stenosis (SS) in elderly is a red flag for ATTR-CM, often preceding cardiac diagnose by many years. Yet, optimal screening strategies for early ATTR-CM detection at time of SS diagnosis are underused.

Study aim: Multi-centric validation of the diagnostic yield of a standard-of-care prospective screening strategy for early ATTR-CM detection in the elderly, based on ligamentum flavum biopsy assessment at SS surgery.

Design: International, multi-centre, prospective, observational, multi-disciplinary, diagnostic registry.

Methods: All consecutive patients ≥60 years old undergoing standard-of-care ligamentum flavum biopsy as part of symptomatic SS surgery within 12 heart centres are included. The burden of ATTR amyloid deposition (positive Congo-red and pre-albumin staining) is assessed semi-quantitatively by visual Westermark grading. Patients with significant ATTR amyloid burden (grade 3 (≥5-10%) or 4 (>10%) ATTR amyloid on biopsy specimen) undergo standard-of-care work-up to exclude ATTR-CM, conform state-of-the-art clinical practice and ESC recommendations (i.e. baseline cardiac biomarkers, ECG, transthoracic echocardiography, monoclonality assessment and bone-scintigraphy with SPECT; additional CMR and/or endomyocardial biopsy as needed). The diagnostic yield of this biopsy-based strategy will be evaluated.

Conclusion: This trial will validate the diagnostic yield of selective ligamentum flavum biopsy analysis in SS surgery patients as a simple and valuable prospective screening strategy for early ATTR-CM detection.