Abstract 4115801: Assessing Prevalence of Cardiac Amyloidosis at the Time of Spinal Laminectomy for Spinal Stenosis

Introduction: Cardiac amyloidosis (CA) involves deposition of amyloid fibrils within cardiac myocardium, resulting in heart failure. Recent studies have shown an association between amyloid deposition in the ligamentum flavum (LF) and development of CA. Our study aims to investigate the prevalence of CA in patients identified with amyloid deposition in their LF at the time of spinal laminectomy for spinal stenosis, employing a comprehensive approach integrating multi-modality imaging and laboratory testing. Methods: This is a retrospective study of patients age >50 years old who underwent spinal laminectomy for non-congenital spinal stenosis or spondyloarthropathy. LF tissue samples obtained during surgery were examined histologically for amyloid deposition. Patients with positive findings underwent testing, including serum markers, echocardiography, and 99mtechnetium pyrophosphate (99mTcPYP) scintigraphy. Additionally, cardiac magnetic resonance imaging (cMRI) was obtained when clinically appropriate to assess for CA. Results: Among the 197 enrolled patients, 39 (19.3%) exhibited amyloid deposition in LF tissue. Patient demographics and clinical characteristics did not significantly differ between the positive and negative groups (Table 1). Of the 39 amyloid positive specimens, subtyping using mass spectrometry identified 1 (3%) light-chain, 28 (72%) transthyretin (TTR), and 10 (25%) were unable to be subtyped. Of the 28 TTR positive patients, 8 were of the wild type genotype. Furthermore, 18 of the 28 TTR patients underwent 99mTcPYP scintigraphy, of which none had cardiac uptake consistent with TTR amyloidosis; the other 10 declined work up. Of the 10 untyped patients, 6 had 99mTcPYP scintigraphy with none of the patients having cardiac uptake. Adjunctive cMRI in select positive patients showed findings inconsistent with amyloid deposition. Serum NT-proBNP, Troponin T, and serum pre-albumin levels were similar between groups. Conclusion: Amyloid deposition in LF tissue did not correlate with cardiac manifestations of amyloidosis at the time of surgery. Longitudinal investigation is ongoing to better understand the relationship between amyloid deposition in LF tissue and the development of CA over time.