Although cardiac amyloidosis was previously believed to be rare, more recent diagnostic advances and awareness have led to an increasing number of cases.
New research has found that approximately 3% of all bone scan patients have markers of cardiac amyloidosis, which can lead to heart failure and increased mortality. The study, published in The Journal of Nuclear Medicine, is among the first of its kind to identify the prevalence and outcomes of cardiac amyloidosis among the general population, according to the authors.
Cardiac amyloidosis is a disease in which amyloid deposits take the place of normal heart tissue, causing the heart to become thick and stiffen. Although it was previously believed to be rare, more recent diagnostic advances and awareness have led to an increasing number of cases.
Treatment of cardiac amyloidosis is more effective when administered at earlier stages of disease and if left untreated, it can lead to heart failure and death.
“Patients undergoing bone scintigraphy (a nuclear medicine bone scan) may present with high levels of cardiac radiotracer (known as DPD) uptake as an incidental finding, which point to the presence of cardiac amyloidosis,” said Christian Nitsche, MD, PhD, a cardiologist in training and intermediate research fellow at the Medical University of Vienna in Austria and the University College in London, in a press release. “In this large-scale study, we sought to estimate the prevalence of cardiac amyloidosis in the general population based on bone scans and to investigate the associated outcomes.”
Investigators analyzed a total of 17,387 scans from 11,527 subjects, including both cardiac and non-cardiac referrals. All patients underwent DPD bone scintigraphy, and the scans were analyzed by nuclear medicine professionals. Visual assessments classified the scans as grade 0 (no DPD uptake), grade 1 (low-grade DPD uptake), and grade 2/3 (confirmed cardiac amyloidosis).
Among all of the subjects, 3.3% had some level of DPD uptake. Specifically, 1.8% had grade 1 and 1.5% had grade 2/3. A prevalence of 1 in 50 among non-cardiac and 1 in 5 among cardiac referrals was reported. There was a significant increase in the prevalence of DPD uptake with incremental age, and comorbidities associated with age were also more prevalent in patients with DPD uptake.
After a median follow-up of 6 years, nearly 30% of subjects died, with cardiovascular death accounting for 8.9% of mortality. Additionally, 1.5% of patients were hospitalized for heart failure during the follow-up period. Patients with grade 2/3 DPD uptake had a 3.5 times higher risk of heart failure hospitalization as compared to those with grade 0 uptake.
“Facing worse outcomes and given the availability of novel treatment options for cardiac amyloidosis, efforts should be maximized to reliably diagnose DPD uptake,” said Andreas Kammerlander, MD, PhD, a cardiologist at the Medical University of Vienna in Austria, in the press release. “Patients with DPD uptake should then be referred to a cardiology specialist for further assessment, as an early diagnosis may offer a window of opportunity to initiate cardiac amyloidosis treatments.”
Methods for detection may be improved in the future, with the development of automated detection tools. Kammerlander noted that researchers are developing novel tracers with high diagnostic accuracy, which could diagnose cardiac amyloidosis non-invasively.
Nuclear Medicine Bone Scan Study Identifies Prevalence and Outcomes of Cardiac Amyloidosis. News release. Society of Nuclear Medicine and Molecular Imaging; January 3, 2023. Accessed January 10, 2023. http://www.snmmi.org/NewsPublications/NewsDetail.aspx?ItemNumber=42868