Abstract
Background : The diagnosis of cardiac transthyretin (ATTR) amyloidosis is frequently delayed or missed because of its nonspecific echocardiographic features and the need for histological confirmation through biopsy. We evaluated the prevalence of cardiac ATTR amyloidosis diagnosed noninvasively by the combination of the positive cardiac uptake on technetium (99mTc)-labeled pyrophosphate (PYP) scintigraphy and the absence of monoclonal protein among elderly heart failure patients. We also demonstrated the clinical features of cardiac ATTR amyloidosis.
Methods : We prospectively enrolled 38 consecutive patients, aged 70 years and older, who were treated for heart failure at our hospital between October 2017 and September 2018 and consented to undergo 99mTc-PYP scintigraphy. Experienced radiologists scored the cardiac uptake from grade 0 to 3, and grades 2 and 3 were defined as positive uptake. The clinical, echocardiographic, and electrocardiographic characteristics were recorded, and monoclonal protein studies were performed.
Results : Four patients showed positive cardiac uptake on the 99mTc-PYP scan, and two of them demonstrated grade 2 or 3 uptake and negative monoclonal protein. As one patient with grade 3 uptake and monoclonal protein was proven to have cardiac ATTR amyloidosis histologically, the proportion of cardiac ATTR amyloidosis was 7.9％ (3/38). We compared parameters including clinical, blood test and imaging characteristics between cardiac ATTR amyloidosis patients and others. The electrocardiographic voltage of the R-wave in the precordial leads was lower in cardiac ATTR amyloidosis.
Conclusions : This study indicated that cardiac ATTR amyloidosis should not be regarded as a rare cause of heart failure in elderly patients.
