Device-pocket subcutaneous fat sampling for amyloid screening in elderly patients undergoing cardiac device implantation
T Capovilla, M Pozzan, C Indennidate, R Bussani, E Dal Bo, C Carriere, M Zecchin, M Merlo, G Sinagra, A PorcariAbstract
Background
Abdominal fat fine-needle aspiration is widely used as a minimally invasive screening biopsy for amyloidosis, but its diagnostic yield varies according to amyloid subtype [1,2]. Elderly patients undergoing permanent cardiac device implantation represent a population with an increased prevalence of cardiac amyloidosis (CA), particularly transthyretin-related disease. Deep subcutaneous adipose tissue can be obtained during device pocket creation, yet its clinical value as a screening biopsy in this setting remains unexplored.
Purpose
To evaluate the feasibility, safety, and diagnostic yield of deep subcutaneous fat sampling obtained from the cardiac device pocket for amyloid detection in elderly patients undergoing permanent cardiac device implantation.
Methods
This prospective, single-center study enrolled consecutive unselected patients aged ≥70 years undergoing clinically indicated new permanent cardiac device implantation. During device pocket creation, deep subcutaneous adipose tissue was collected and analyzed using Congo red staining. All patients underwent standardized clinical evaluation, laboratory testing, and transthoracic echocardiography. Procedural feasibility, safety, and histological results were assessed.
Results
Fifty patients were enrolled (mean age 81 ± 6 years, 50% female). Device implantation indications included advanced atrioventricular block (56%), sinoatrial dysfunction or brady–tachy syndrome (20%), atrial fibrillation with symptomatic bradycardia (12%), and other causes (12%). Subcutaneous fat sampling was successfully performed in all patients, with adequate tissue obtained in every case and no intra- or post-procedural complications, including among patients receiving anticoagulant therapy. Clinical features associated with increased CA risk were common: 52% had a history of heart failure, 40% had increased left ventricular wall thickness (≥12 mm), 6% had carpal tunnel syndrome or spinal canal stenosis, and 12% had a detectable serum monoclonal protein. Despite this, Congo red staining did not identify amyloid deposition in any sample.
Conclusion
Deep subcutaneous fat sampling from the cardiac device pocket during permanent device implantation is safe and feasible but shows no diagnostic yield for amyloid detection in elderly patients, including those with a high pre-test probability of cardiac amyloidosis. These findings suggest that this approach is insufficient as a stand-alone screening strategy in elderly patients undergoing permanent cardiac device implantation. Comprehensive multimodal diagnostic pathways remain essential for CA identification.Characteristics of the study populationFor image description, please refer to the figure legend and surrounding text.