title: Technetium-99m pyrophosphate/thallium-201 dual-isotope SPECT imaging predicts reperfusion injury in patients with acute myocardial infarction after reperfusion.
abstract: OBJECTIVE
  Microcirculatory failure after reperfusion is clinically indicated to cause reperfusion injury whereas excessive intracellular calcium ion overload is experimentally proved as a key mechanism of reperfusion injury. We hypothesized that technetium-99m ((99m)Tc) pyrophosphate (Tc-PYP) uptake in injured but viable infarct-related myocardium with preserved myocardial perfusion after reperfusion estimated by thallium-201 ((201)Tl) uptake would be associated with final functional recovery.
  
  
  METHODS
  Dual-isotope Tc-PYP/(201)Tl single-photon emission computed tomography (SPECT) was performed 2 days after successful reperfusion therapy in patients with first acute myocardial infarction, and 50 patients (63 +/- 13 years old, female 22%) with preserved (201)Tl uptakes of > or = 50% in reperfused myocardium was followed for 1 month. Tc-PYP uptake was assessed as the heart-to-sternum (H/S) ratio. Two-dimensional echocardiography was also performed 2 days and 1 month after reperfusion to evaluate functional recovery.
  
  
  RESULTS
  High Tc-PYP uptake, defined as the H/S ratio > or = 0.81, was predictive of chronic phase no functional recovery (73.7% in 14 of 19 patients with high uptake vs 16.1% in five of 31 patients without those, p < 0.0001). After adjustment for potential confounding variables, including electrocardiographic persistent ST segment elevation at 1 h after reperfusion, high Tc-PYP uptake remained independently predictive of no functional recovery with odds ratio of 8.7 (95% confidential interval = 2 to 38.7; p = 0.005).
  
  
  CONCLUSIONS
  High Tc-PYP uptake in reperfused but viable infarct-related myocardium was a powerful predictor of no functional recovery, which may reflect excessive intracellular calcium ion overload caused by reperfusion injury. Tc-PYP/(201)Tl dual-isotope SPECT imaging can provide prognostic information after reperfusion.
authors.affiliation: Division of Cardiology, Department of Medicine, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawaku, Tokyo, 142-8666, Japan. hzn01233@s02.itscom.net
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Akutsu
authors.forename: Kyouichi
authors.initials: K
authors.lastname: Kaneko
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kodama
authors.forename: Hui-Ling
authors.initials: HL
authors.lastname: Li
authors.forename: Hideki
authors.initials: H
authors.lastname: Nishimura
authors.forename: Yuji
authors.initials: Y
authors.lastname: Hamazaki
authors.forename: Jumpei
authors.initials: J
authors.lastname: Suyama
authors.forename: Akira
authors.initials: A
authors.lastname: Shinozuka
authors.forename: Takehiko
authors.initials: T
authors.lastname: Gokan
authors.forename: Youichi
authors.initials: Y
authors.lastname: Kobayashi
mesh_terms: D006801:Humans; D009203:Myocardial Infarction / Q000503:physiopathology / Q000601:surgery*; D015428:Myocardial Reperfusion Injury / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D020127:Recovery of Function; D016698:Technetium Tc 99m Pyrophosphate / Q000378:metabolism; D013794:Thallium Radioisotopes / Q000378:metabolism; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
chemical_list: D013794:Thallium Radioisotopes; D016698:Technetium Tc 99m Pyrophosphate
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