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Role of 99mTc-DPD Scintigraphy in Diagnosis and Prognosis of Hereditary Transthyretin-Related Cardiac Amyloidosis

2011; Elsevier BV; Volume: 4; Issue: 6 Linguagem: Inglês

10.1016/j.jcmg.2011.03.016

1936-878X

Claudio Rapezzi, Candida Cristina Quarta, Pier Luigi Guidalotti, Cinzia Pettinato, Stefano Fanti, Ornella Leone, Alessandra Ferlini, Simone Longhi, Massimiliano Lorenzini, Maria Letizia Bacchi Reggiani, Christian Gagliardi, Pedro Gallo, Caterina Villani, Fabrizio Salvi,

Medical Imaging and Pathology Studies

In a cohort of patients with hereditary transthyretin-related amyloidosis (ATTR), we aimed to assess the role of 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (99mTc-DPD) in detecting myocardial amyloid infiltration across a wide spectrum of cardiac involvement and in predicting major adverse cardiac events (MACE). Hereditary transthyretin-related amyloidosis is a challenging and underdiagnosed condition where both early diagnosis and prognosis remain problematic. We evaluated 63 patients with ATTR: 40 with and 23 without echocardiographically diagnosed amyloidotic cardiomyopathy (AC). Myocardial uptake of 99mTc-DPD scintigraphy was semiquantitatively and visually assessed at 5 min and 3 h. All patients with AC showed moderate-to-severe myocardial tracer uptake (i.e., visual score ≥2). Within the subgroup without AC, only 4 patients (with Ala36Pro, Gly47Ala, Thr49Ala, and Glu89Gln transthyretin mutations) showed myocardial tracer uptake and abnormal heart/whole body retention (H/WB) values: in all these cases endomyocardial biopsies showed amyloidotic infiltration. The H/WB was positively correlated with left ventricular (LV) mean wall thickness (Pearson's r = 0.695, p < 0.001) and negatively with LV ejection fraction (r = −0.368, p = 0.004). The H/WB was an unfavorable predictor of MACE-free survival at Cox univariate analysis and contributed to the multivariate model. Notably, LV wall thickness >12 mm in combination with H/WB >7.5 was associated with the highest event rate. In ATTR, 99mTc-DPD scintigraphy can identify myocardial infiltration across a wide spectrum of morphologic/functional cardiac involvement, allowing an early diagnosis of the disease (even before the appearance of echocardiographic abnormalities). The 99mTc-DPD myocardial uptake is a prognostic determinant of “cardiac” outcome in ATTR, either alone or in combination with LV wall thickness.