Technetium-99m pyrophosphate/thallium-201 dual-isotope SPECT imaging predicts reperfusion injury in patients with acute myocardial infarction after reperfusion.
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.
Akutsu
Yasushi
Y
Division of Cardiology, Department of Medicine, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawaku, Tokyo, 142-8666, Japan. hzn01233@s02.itscom.net
Kaneko
Kyouichi
K
Kodama
Yusuke
Y
Li
Hui-Ling
HL
Nishimura
Hideki
H
Hamazaki
Yuji
Y
Suyama
Jumpei
J
Shinozuka
Akira
A
Gokan
Takehiko
T
Kobayashi
Youichi
Y
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*
D013794:Thallium Radioisotopes; D016698:Technetium Tc 99m Pyrophosphate
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