For individuals undergoing bone scintigraphy, positive 99m Tc-3,3-diphosphono-1,2-propanodicarbo-xylic-acid (99m Tc-DPD), indicative of cardiac amyloidosis (CA), is associated with poor outcomes, according to a study published in the Journal of Nuclear Medicine. Christian Nitsche, MD, PhD, and colleagues examined CA prevalence among individuals undergoing 99m Tc-DPD
bone scintigraphy. Low-grade 99m Tc-DPD up-take defined Perugini grade 1, while grades 2 and 3 indicated confirmed CA. A total of 17,387 scans from 11,527 patients were analyzed. 99m Tc-DPD positivity had a prevalence of 3.3% overall, with higher prevalence seen among cardiac than non-cardiac referrals (18.2% vs 1.7%). Progression from grade 1 to grades 2 or 3 was seen among individuals with more than one scan. The portion of light-chain CA was significantly higher in grade 1 than in grades 2 and 3 among those with biopsy-proven CA (73.3% vs 15.4%). Clinical event rates were 29.4% for mortality, 2.6% for cardiovascular death, and 1.5% for heart failure hospitalization after a median of 6 years; all were independently predicted by 99m Tc-DPD.
