Evaluation of Salvaged Myocardium After Acute Myocardial Infarction Using Single Photon Emission Computed Tomography After 201Tl-Glucose-Insulin Infusion

Abstract

he prognosis of patients with acute myocardial infarction (AMI) has improved with reperfusion therapy, 1-12 but even with successful reperfusion therapy, the myocardium may be stunned and regional wall motion (RWM) at the infarcted area decreased. [13][14][15] In patients with AMI, it is clinically important to distinguish viable from nonviable myocardium to predict whether the RWM will eventually improve. Positron emission tomography (PET) is considered the gold standard for assessing myocardial viability, but alternative procedures based on radionuclide imaging have been proposed. 201 Tl myocardial scintigraphy has been widely used to detect myocardial viability using either a late redistribution 16 or a reinjection imaging technique 17,18 in patients with coronary artery disease. A recent study by Tartagni et al describes a new method for cardiac imaging after infusion of 201 Tl, insulin, and potassium in a glucose solution, which improved the detection of viable myocardium. 19 Insulin augments the myocardial uptake of potassium through translocation of Na-K ATPase from the cytosol to the sarcolemma. 20,21 Likewise, 201 Tl is taken up by myocardium through Na-K ATPase, 22,23 and its uptake is also enhanced by insulin. We compared the efficacy of resting 201 Tl imaging with resting 201 Tl imaging after glucose -insulin -potassium infusion for detecting viable myocardium after AMI. Methods PatientsThirty-seven patients with AMI who had undergone successful percutaneous transluminal coronary angioplasty (PTCA) or stenting within 6 h of the onset of symptoms were recruited. The diagnosis of AMI was based on the following criteria: acute chest pain lasting more than 30 min, serum creatine kinase (CK) concentration greater than 500 IU, and development of abnormal Q waves on electrocardiogram.Patients who fulfilled the following criteria were included in the statistical analysis: successful PTCA or coronary stenting (or both) with angiographic confirmation of <25% residual stenosis, no significant stenosis in other vessels, good image quality on all radiotracer studies during subacute and chronic phases, and patency without restenosis on follow-up coronary angiography 6 months after AMI. Restenosis was defined as a decrease in lumen diameter by >50% compared with after reperfusion therapy. Patients with diabetes or glucose intolerance were excluded from the study. Glucose intolerance was defined when fasting glucose concentration was more than 110 mg/dl and less than 126 mg/dl, or the glucose concentration at 2 h after 75 g glucose loading was more than 140 mg/dl and less than 200 mg/dl. The final study population comprised 25 patients (13 men, 12 women; age 41-82 years, mean age 67±13 years). The infarct-related vessel

123I-MIBG imaging can be used to evaluate microvascular disturbance caused by embolization by microdebris after rotational atherectomy

“…The activated burr (size 1.25-2.0 mm), rotating at 170 000 rpm, was then slowly advanced across the lesion. The rotablator was passed several times (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) within the stenotic segment. Where necessary, burrs of increasing size were used to achieve a burr size/artery diameter ratio м0.7.…”

“…The myocardial SPECT image set of each patient was divided into 20 segments ( Fig. 1), using a previously described method [13][14][15]. The short axis images at the basal, middle, and apical ventricular levels were divided into six segments each.…”

Prediction of Functional Improvement of Ischemic Myocardium With 123I-BMIPP SPECT and 99mTc-Tetrofosmin SPECT Imaging-A Study of Patients With Large Acute Myocardial Infarction and Receiving Revascularization Therapy-

“…Mean time from onset of infarction to reperfusion was 5±6 h (range 0. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Coronary stents were implanted in all patients (MULTI-LINK in 2 cases, GFX in 1 case, and NIR in 8 cases).…”

“…In total the SPECT or PET image was divided into 20 segments, using a previously described method. 15,16 All SPECT and PET images were analyzed by 2 experienced evaluators with no knowledge of the patients' clinical histories. Semiquantitative visual analysis was performed by assigning regional tracer defect scores using a 4-point scale (defect score; DS; 0= normal uptake, 1= mildly reduced uptake, 2= severely reduced uptake, and 3= defect).…”

“…17 Segments were analyzed for systolic wall thickening and endocardial wall motion using QGS, and were graded as dyskinesis (-1) or as showing akinesis (0), severe hypokinesis (1), moderate hypokinesis (2), mild hypokinesis (3), or normokinesis (4) as the wall motion score (WMS). 15,[18][19][20] Improvement of wall motion was defined as an increase of 1 point or more in WMS over the 6 months. Mismatched segments were defined as those in which the 123 I-BMIPP SPECT defect score exceeded the 18 F-FDG PET or 99m Tc-TF SPECT defect score by 1 point or more, and also the 99m Tc-TF SPECT defect score exceeded the 18 F-FDG PET defect score by 1 point or more.…”