Prevalence of positive 99 mTc-DPD scintigraphy as an indicator of the prevalence of wild-type transthyretin amyloidosis in the elderly

Abstract

Senile or wild-type transthyretin (wtTTR) amyloidosis is an age-related disease caused by the deposition of wtTTR amyloid protein. In contrast to light chain amyloidosis,99 mTc-DPD scintigraphy (DPD scan) is a useful diagnostic modality for wtTTR amyloidosis. We retrospectively analyzed patients older than 30 years who underwent DPD scanning for non-cardiac reasons at our hospital between June 2014 and March 2017 (n = 9,581). Transthoracic echocardiography was used to assess left ventricular hypertrophy (LVH), as well as systolic and diastolic function. A positive DPD scan was observed in only six patients (0.06%). All six of these patients were older than 70 years, and they constitute only 0.4% of patients in this age group (6/1652). Among the patients with a positive DPD scan, four showed concentric LVH and two showed a normal wall thickness. With respect to the severity of diastolic dysfunction and pulmonary artery pressure, patients with a positive DPD scan showed the expected E’ and pulmonary artery systolic pressure for their age. Even considering the limited sensitivity of a positive DPD scan detecting wtTTR amyloidosis, the incidence of a positive DPD scan in non-cardiac patients indicated that wtTTR amyloid deposition does not seem to be a major cause for age-related diastolic dysfunction, nor does appear to have a high incidence in patients with heart failure with preserved EF in the elderly.