Transthyretin amyloid cardiomyopathy in aortic stenosis patients scheduled for transcatheter aortic valve implantation.

Objective: The prevalences of aortic stenosis (AS) and transthyretin amyloid cardiomyopathy (ATTR-CM) increase with age. Identification of occult ATTR-CM in patients with AS can help explain out-of-proportion myocardial dysfunction, aid in prognostication and prompt initiation of disease-modifying treatment. Studies have suggested that many patients referred for transcatheter aortic valve implantation (TAVI) have concomitant ATTR-CM, but some have included unverified ATTR-CM in patients with ambiguous scintigrams. We aimed to assess the co-occurrence of ATTR-CM in patients scheduled for TAVI.

Methods: In patients accepted for TAVI for severe AS, we used bone scintigraphy to screen for ATTR-CM. We defined ATTR-CM as a cardiac tracer uptake ≥ Perugini Grade 2 in the absence of abnormal monoclonal protein or abnormal free light chain ratio. We offered bioptic verification to patients with Grade 1 or ambiguous DPD uptake.

Results: We included 171 consecutive patients aged 79 ± 7 years, 57% were male. Six patients (3.5%) had cardiac bone tracer uptake ≥ Perugini Grade 2 and no abnormal monoclonal protein/free light chains. Endomyocardial biopsies confirmed the diagnosis in two additional patients (1.2%), whereas five patients with low-grade uptake did not have ATTR-CM. In total, 8/171 patients (4.7%) were diagnosed with concomitant AS and ATTR-CM. Most of the patients with concomitant ATTR-CM had low-flow low-gradient (LFLG) AS, and 25% had a history of carpal tunnel syndrome.

Conclusions: We found concomitant AS and ATTR-CM in 5% of our TAVI patients. Carpal tunnel syndrome and LFLG AS suggest concomitant ATTR.