Prevalence and prognosis of cardiac amyloidosis in patients who underwent diphosphonate scintigraphy for non-cardiological reasons

Abstract

Transthyretin cardiac amyloidosis is a rare and currently underdiagnosed disease. Untreated, median survival since diagnosis is estimated to be between 3 and 5 years. Diphosphonate scintigraphy is one of the earliest positive examinations well before biological or clinical signs. The objective of this study is to determine the prevalence of cardiac involvement in patients who underwent disphophonate scintigraphy for non-cardiological reasons and to follow their prognosis. Our study is a retrospective, descriptive, monocentric study carried out at the university hospital of Poitiers. Collection of all scintigraphy with Technetium 99m-labelled disodium Hydroxymethylene Diphosphonate (HMDP-99mTc), performed at the Poitiers University Hospital between January 1, 2006 and January 1, 2012. 725 patients were included and all scintigraphy were reanalyzed and we retained only the Perugini 2 and 3 stage for the diagnosis of amyloidosis. The study focuses on the prevalence and the overall and detailed mortality of these patients at 5 years. In all, 20 scintigraphy showed Perugini scores of 2 or 3, i.e., a prevalence of about 1% in the study. The prevalence by age group was also studied: there is an age-related gradient: among patients over 70 years of age, it is calculated at 2.7% (20/725 patients); among patients over 80 years of age, it is calculated at 4.4% (14/316) (Fig. 1); and among patients over 90 years of age, it is calculated at 16.7% (4/24). No fixation was found in patients under 70-years-old. The overall 5-year mortality rate was calculated at 85%, the majority of which was due to cancer. The discovery of Perugini stage 2 and 3 cardiac staining on scintigraphy for non-cardiological reasons among the 725 patients analyzed is uncommon (1%). There is an age-related prevalence gradient (up to 16.7% over 90 years). Radiologists should refer patients to amyloidosis specialists for specific management, which would allow amyloidosis to be managed at an early stage to probably decrease hospitalizations and mortality.