title: Accelerated (99m)Tc-sestamibi clearance associated with mitochondrial dysfunction and regional left ventricular dysfunction in reperfused myocardium in patients with acute coronary syndrome.
abstract: BACKGROUND
  Accelerated clearance of (99m)technetium-sestamibi (MIBI) has been observed after reperfusion therapy in patients with acute coronary syndrome (ACS), but the mechanisms have not been fully investigated. MIBI retention may depend on mitochondrial function. The clearance rate of (11)carbon-acetate reflects such mitochondrial functions as oxidative metabolism. The purpose of this study was to examine the mechanisms of accelerated MIBI clearance in ACS. We therefore compared it to oxidative metabolism estimated using (11)C-acetate positron emission tomography (PET).
  
  
  METHODS
  Eighteen patients [mean age 69.2 ± 8.7 years, 10 males (56 %)] with reperfused ACS underwent MIBI single-photon emission computed tomography (SPECT), echocardiography, and (11)C-acetate PET within 3 weeks of the onset of ACS. MIBI images were obtained 30 min and 3 h after MIBI administration. Regional left ventricular (LV) function was evaluated by echocardiography. The measurement of oxidative metabolism was obtained through the mono-exponential fitting of the (11)C-acetate time-activity curve (k mono).
  
  
  RESULTS
  Among 95 segments of reperfused myocardium, MIBI SPECT showed 64 normal segments (group N), 14 segments with accelerated MIBI clearance (group AC), and 17 segments with fixed defect (group F). Group AC showed lower k mono than group N (0.041 ± 0.009 vs 0.049 ± 0.010, p = 0.02). Group F showed lower k mono than group N (0.039 ± 0.012 vs 0.049 ± 0.010, p = 0.01). However, k mono was similar in group AC and group F (p = 0.99).
  
  
  CONCLUSIONS
  Segments with accelerated MIBI clearance showed reduced oxidative metabolism in ACS. Loss of MIBI retention may be associated with mitochondrial dysfunction.
authors.affiliation: Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.|Department of Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan.
authors.forename: Atsuro
authors.initials: A
authors.lastname: Masuda
authors.affiliation: Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan. yoshinaga.keiichiro@qst.go.jp.|Molecular Imaging Research Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-Ku, Chiba, 263-8555, Japan. yoshinaga.keiichiro@qst.go.jp.
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Yoshinaga
authors.affiliation: Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Masanao
authors.initials: M
authors.lastname: Naya
authors.affiliation: Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Manabe
authors.affiliation: Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yamada
authors.affiliation: Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Iwano
authors.affiliation: Department of Natural Sciences, Fukushima Medical University, Fukushima, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Okada
authors.affiliation: Department of Health Sciences, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Chietsugu
authors.initials: C
authors.lastname: Katoh
authors.affiliation: Department of Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan.
authors.forename: Yasuchika
authors.initials: Y
authors.lastname: Takeishi
authors.affiliation: Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsutsui
authors.affiliation: Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Nagara
authors.initials: N
authors.lastname: Tamaki
keywords: Acute coronary syndrome; Clearance; Metabolism; Sestamibi