Safety, diagnostic yield and clinical utility of endomyocardial biopsy in patients with suspected cardiac amyloidosis: a 10-year consecutive single-centre experience
J Mansell, J Coghlan, T Kotecha, J Gilbertson, A Sheikh, B Thillainathan, S Kakhi, C Whelan, S Hatipoglu, A Martinez Naharro, L Venneri, P N Hawkins, M Fontana, J D Gillmore, W MoodyAbstract
Introduction
Cardiac amyloidosis (CA) is most commonly transthyretin-type (ATTR-CA) or immunoglobulin light chain type (AL-CA). These two amyloid types have very different disease courses and are treated with completely different amyloid-specific disease-modifying therapy.1–3 Although ATTR-CA can frequently be diagnosed without recourse to histology,4 histological typing of amyloid remains necessary to distinguish between ATTR-CA and AL-CA in a significant proportion of patients with CA. We evaluated diagnostic performance and complication rates associated with endomyocardial biopsy (EMB) for investigation of CA.
Methods
A retrospective analysis of consecutive EMBs performed between January 2015 and December 2025 among patients referred to the UK National Amyloidosis Centre (NAC) with suspected or established but untyped CA. Biopsy specimens were formalin-fixed, paraffin-embedded and stained with Congo Red followed by an immunohistochemistry (IHC) panel. Mass spectrometry was undertaken when amyloid subtyping was inconclusive on the basis of IHC. Diagnostic performance and periprocedural complication rates were evaluated.
Results
A total of 247 EMBs were performed in 246 patients. One patient required a repeat EMB due to challenging RV access and resultant insufficient tissue for laboratory analysis. Five EMBs were rebooked after being abandoned due to haemodynamic instability (n=2), challenging anatomical access (n=2) and prolapse of a right atrial pacemaker lead through the tricuspid valve (n=1). 239 (96.8%) EMBs were obtained from the RV interventricular septum and 8 from the LV approach including 3 following prior unsuccessful RV attempts. Baseline demographics, biopsy indication and histological diagnoses are shown in Table 1. Periprocedural complications occurred in 9 patients, 6 (2.4%) considered major; 3 deaths occurred within 30 days of EMB, none of which were considered to be procedure-related (Table 2). EMB established a definitive diagnosis in >95% cases; 12 patients (4.9%) had samples that were insufficient for analysis (n=3), untypable (n=3) or reported as negative for amyloid despite a high clinical suspicion of CA (n=6).
Discussion
In this large, elderly cohort undergoing EMB for investigation of CA, EMB demonstrated high diagnostic yield with a very low complication rates. These data support the role of EMB as a safe and effective diagnostic tool in patients with suspected or untyped CA.