Transthyretin amyloidosis in aortic stenosis: clinical and therapeutic implications

About one in seven elderly patients with severe calcific aortic stenosis (AS) also have ATTR amyloid cardiomyopathy (AC-TTR). The reasons for this close association are not fully known, but the two entities are not only related by common epidemiology. For example, it is possible to hypothesize that an amyloidotic infiltration of the aortic valve, even partial, can act as a trigger for the development of endothelial damage and subsequent calcification. Another hypothesis is the increased myocardial strain induced by AS may locally favour the process of amyloidogenesis and tissue infiltration. In a patient with AS, the coexistence of AC-TTR can be suspected by careful analysis of the echocardiogram and the ECG, especially if a clinical history of carpal tunnel syndrome coexists. Bone tracer scintigraphy allows a diagnosis of certainty. Recently, several studies have evaluated the prognostic implications of the coexistence of the two entities in candidates for percutaneous aortic valve replacement, showing how amyloidosis would not significantly impact the results of the procedure, but would only be associated with a greater risk of distant heart failure. In patients with AS associated with AC-TTR, valve replacement should not be ruled out in the presence of the usual clinical-haemodynamic indications.