title: Role of (99m)Tc-DPD scintigraphy in diagnosis and prognosis of hereditary transthyretin-related cardiac amyloidosis.
abstract: OBJECTIVE
  In a cohort of patients with hereditary transthyretin-related amyloidosis (ATTR), we aimed to assess the role of (99m)Tc-3,3-diphosphono-1,2-propanodicarboxylic acid ((99m)Tc-DPD) in detecting myocardial amyloid infiltration across a wide spectrum of cardiac involvement and in predicting major adverse cardiac events (MACE).
  
  
  BACKGROUND
  Hereditary transthyretin-related amyloidosis is a challenging and underdiagnosed condition where both early diagnosis and prognosis remain problematic.
  
  
  METHODS
  We evaluated 63 patients with ATTR: 40 with and 23 without echocardiographically diagnosed amyloidotic cardiomyopathy (AC). Myocardial uptake of (99m)Tc-DPD scintigraphy was semiquantitatively and visually assessed at 5 min and 3 h.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  In ATTR, (99m)Tc-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 (99m)Tc-DPD myocardial uptake is a prognostic determinant of "cardiac" outcome in ATTR, either alone or in combination with LV wall thickness.
authors.affiliation: Institute of Cardiology, University of Bologna and S. Orsola-Malpighi Hospital, Bologna, Italy. claudio.rapezzi@unibo.it
authors.forename: Claudio
authors.initials: C
authors.lastname: Rapezzi
authors.forename: Candida C
authors.initials: CC
authors.lastname: Quarta
authors.forename: Pier Luigi
authors.initials: PL
authors.lastname: Guidalotti
authors.forename: Cinzia
authors.initials: C
authors.lastname: Pettinato
authors.forename: Stefano
authors.initials: S
authors.lastname: Fanti
authors.forename: Ornella
authors.initials: O
authors.lastname: Leone
authors.forename: Alessandra
authors.initials: A
authors.lastname: Ferlini
authors.forename: Simone
authors.initials: S
authors.lastname: Longhi
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Lorenzini
authors.forename: Letizia Bacchi
authors.initials: LB
authors.lastname: Reggiani
authors.forename: Christian
authors.initials: C
authors.lastname: Gagliardi
authors.forename: Pamela
authors.initials: P
authors.lastname: Gallo
authors.forename: Caterina
authors.initials: C
authors.lastname: Villani
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Salvi
mesh_terms: D000328:Adult; D000368:Aged; D028226:Amyloidosis, Familial / Q000150:complications / Q000235:genetics* / Q000401:mortality; D001706:Biopsy; D009202:Cardiomyopathies / Q000000981:diagnostic imaging* / Q000235:genetics / Q000401:mortality / Q000503:physiopathology; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D004164:Diphosphonates; D018572:Disease-Free Survival; D018619:Echocardiography, Doppler, Pulsed; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007558:Italy; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology*; D015609:Organotechnetium Compounds; D011228:Prealbumin / Q000235:genetics*; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D013318:Stroke Volume; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon; D016277:Ventricular Function, Left
chemical_list: D004164:Diphosphonates; D015609:Organotechnetium Compounds; D011228:Prealbumin; D019275:Radiopharmaceuticals; C033905:technetium Tc 99m 1,1-diphosphonopropane-2,3-dicarboxylic acid