Aortic Stenosis and Amyloidosis: Role of MRI and CT in the Diagnosis of a Sneaky Association

Abstract

Abstract Purpose of the Review In this narrative review, we focus on the latest updates on CA–AS diagnosis, the implementation of CMR, and CT in the diagnostic algorithm and their future prospectives. Recent Findings Aortic stenosis (AS) is the most common valvular heart disease (VHD) worldwide. In recent years, the association between Cardiac amyloidosis (CA) and AS has emerged as a not uncommon and sneaky association. Trans-thyretin (TTR) and immunoglobulin light chain (AL) are the two most common different types of misfolded amyloid proteins infiltrating the heart. AS–CA shares some anatomical features with CA, but the association leads to worse outcome. Nearly 30% of patients undergoing TAVR suffers from CA. Differentiating CA–AS from lone AS is of great importance to tailorize pharmaceutical therapy and/or surgery. Nowadays, bone scintigraphy and urine/serum analyses are crucial to assess which type of amyloid excess there is, but to represent anatomical changes of the myocardium cardiac magnetic resonance (CMR) and computed tomography cardiac angiography (CTCA), they are the best non-invasive tools. Moreover, extracellular expansion can be quantified via CMR, but new promising studies assessing extracellular volume (ECV) via CT are emerging. Furthermore, AS–CA is a sneaky pathology afflicting elderly patients. Seen the comorbidities of the typical patient, Transcatheter Aortic Valve Replacement (TAVR) should be the indicated procedure. CT is the best imaging modality for TAVR planning with its excellent anatomical resolution. Summary CMR and CT could be integrated in the CA algorithm. Both can assess myocardium anatomical changes. Moreover, ECV is a precious tool to suggest the presence of amyloid in the myocardium.