Background: Degenerative aortic stenosis (AS) and transthyretin cardiac amyloidosis (ATTR-CM), particularly wild-type ATTR (ATTRwt), are age-associated disorders that frequently converge in elderly patients. Their coexistence may obscure diagnosis, amplify heart-failure burden, and complicate risk stratification before and after aortic valve replacement. Methods: This narrative review was conducted using a structured literature search focused on ATTR-CM, AS, transcatheter aortic valve implantation/replacement (TAVI/TAVR), and nuclear cardiology. Priority was given to cohort studies, systematic reviews, consensus documents, and guideline statements. Main findings: Across observational cohorts and meta-analyses, ATTR-CM is consistently identified in a clinically meaningful minority of older patients with severe AS, especially among those referred for TAVI. Reported prevalence varies with age, referral pathway, diagnostic protocol, and whether equivocal grade 1 uptake is included, but most contemporary TAVI-oriented cohorts place definite ATTR-CM in the high single-digit to mid-teen percentage range. Clinical suspicion should increase in patients with disproportionate left-ventricular wall thickening, low-flow low-gradient AS, restrictive physiology, elevated cardiac biomarkers, conduction disease, atrial fibrillation, or extracardiac ATTR clues such as bilateral carpal tunnel syndrome. Conclusions: Bone-avid tracer scintigraphy with 99mTc-pyrophosphate, 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid, or 99mTc-hydroxymethylene diphosphonate, interpreted with SPECT or SPECT/CT and combined with mandatory exclusion of a monoclonal protein, enables robust non-biopsy diagnosis of ATTR-CM. In severe AS, nuclear diagnosis should be embedded in a pragmatic, multidisciplinary pathway that identifies patients likely to benefit from valve intervention, ATTR-specific therapy, genetic testing, and tailored follow-up.