Primary objective: To identify older adults with transthyretin cardiac amyloidosis (ATTR-CA) early in the course of the illness, at a time when disease modifying therapies are most effective. The specific aims of this epidemiologic investigation include: 1. To identify subjects with previous lumbar spinal stenosis (LSS) Surgery who have evidence of transthyretin (TTR) amyloid deposits in spinal specimens and could be at risk for ATTR cardiac amyloidosis. 2. To evaluate for ATTR-CA among those with localized TTR in the spinal tissue. The study will also explore the following: 1. The prevalence of amyloid in lumbar spinal stenosis specimens by Congo Red staining. 2. The prevalence of TTR deposits among subjects with amyloid as determined by mass spectrometry. 3. Evaluation of a novel artificial intelligence technique for that can identify amyloid histologically with standard H\&E staining. 4. Difference in ATTR-CA prevalence between subjects with TTR and indeterminate amyloid deposits in subject's spine by myocardial uptake of technetium pyrophosphate scan (Tc99-PYP).