SNMMI: Scanning for cardiac amyloid could help predict heart attacks

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 - heart geometry

While amyloid imaging is typically discussed with regard to diagnosing Alzheimer’s disease, a team of French researchers, presenting at the Society of Nuclear Medicine and Molecular Imaging (SNMMI) 2015 annual meeting, have found that amyloid scans of the heart can predict major cardiac events.

Amyloid can build up throughout the body, and the specific condition targeted in the study was transthyretin-type (TTR) amyloidosis, which in the heart can cause hypertension, abnormal heartbeat and chronic heart failure.

Axel Van Der Gucht, MD, and colleagues from Henri Mondor Hospital in Créteil, France, used myocardial scintigraphy with the radiotracer technetium-99m hydroxymethylene diphosphonate (Tc-99m HMDP). While Tc-99m HMDP is typically used to image bone, it also binds to amyloid in the heart.

“To our knowledge, this is the first study revealing the prognostic value of Tc-99m HMDP myocardial scintigraphy in patients with TTR amyloidosis,” said Axel Van Der Gucht in a press release.

Fifty-five patients were diagnosed with TTR amyloidosis and included in the study, all undergoing both whole-body and cardiac Tc-99m HMDP scintigraphy at 10 minutes and three hours after injection. Forty-seven were positive for cardiac amyloidosis.

Quantitative analysis of heart-to-skull ratios for agent retention showed that patients with a lower heart-to-skull score experienced better survival rates. At six months, those with a heart-to-skull ratio of less than 1.94 had 95 percent major adverse cardiac event (MACE) free survival compared with 60 percent in those with a heart-to-skull ratio greater than 1.94.

Van Der Gucht and colleagues were able to identify prognostic groups ranging from 100 percent MACE-free survival to 44 percent by combining heart-to-skull imaging agent retention ratios with New York Heart Association classification.

“Given the clinical, diagnostic and therapeutic potential of Tc-99m HMDP myocardial scintigraphy based on these results, all patients with suspected cardiac amyloidosis should undergo a minimally invasive scan as a standard of clinical evaluation,” said Van Der Gucht.