title: Adenosine technetium-99m sestamibi single-photon emission tomography for the assessment of jeopardized myocardium early after acute myocardial infarction. Paradoxical scintigraphic underestimation of jeopardized myocardium in patients with a severe infarct-related stenosis.
abstract: This study investigated the value of technetium-99m sestamibi scintigraphy in identifying patients at risk for post-infarct ischaemia (=jeopardized myocardium), especially within the reperfused infarct region. In 51 patients with a recent (<1 month) myocardial infarction, adenosine 99mTc-sestamibi single-photon emission tomography (SPET) and dobutamine stress echocardiography (DSE) were performed and correlated with the presence of significant coronary artery stenosis [% diameter stenosis (DS) >50%] on quantitative coronary angiography. Regional perfusion activity was analysed semi-quantitatively (score 0-4) on a 13-segment left ventricular model. DSE was used for the estimation of the infarct size (low-dose DSE) and for concomitant evaluation of ischaemia (high-dose DSE). A reversible perfusion defect within the infarct region was observed in 20 of the 37 patients with a significant infarct-related lesion (sensitivity of 54%) and only in one patient without a significant infarct-related lesion (specificity of 93%). Further analysis revealed that the scintigraphic assessment of jeopardized myocardium was fairly good in patients with a moderate (DS 51%-64%) infarct-related stenosis but was inadequate in patients with a severe (DS>/=65%) infarct-related stenosis (sensitivity of 80% vs 36%, P<0.01), while the echocardiographic detection of ischaemia was not influenced by stenosis severity (sensitivity of 73% in both subgroups). This scintigraphic underestimation of jeopardized myocardium was mainly related to a severely impaired myocardial perfusion under baseline conditions, as was evidenced by a significantly more severe rest perfusion score in the infarct region in patients with a severe stenosis as compared to those with a moderate stenosis (average score: 1.5+/-0.7 vs 2.1+/-0.6, P<0.01), while infarct size on echocardiography was similar for both subgroups. It may be concluded that early after an acute myocardial infarction, adenosine 99mTc-sestamibi SPET may underestimate reperfused but still jeopardized myocardium, particularly in patients with a severe infarct-related stenosis. In these patients the evaluation of the ischaemic burden on rest-stress scintigraphy is hampered by the presence of a severely impaired myocardial perfusion in resting conditions.
authors.affiliation: Department of Cardiology, Antwerp University Hospital, Edegem, Belgium.
authors.forename: M J
authors.initials: MJ
authors.lastname: Claeys
authors.forename: P P
authors.initials: PP
authors.lastname: Blockx
authors.forename: F E
authors.initials: FE
authors.lastname: Rademakers
authors.forename: C J
authors.initials: CJ
authors.lastname: Vrints
authors.forename: J P
authors.initials: JP
authors.lastname: Snoeck
mesh_terms: D000241:Adenosine; D016022:Case-Control Studies; D017023:Coronary Angiography; D003327:Coronary Disease / Q000175:diagnosis / Q000000981:diagnostic imaging*; D004280:Dobutamine; D004452:Echocardiography; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000000981:diagnostic imaging*; D017202:Myocardial Ischemia / Q000175:diagnosis / Q000000981:diagnostic imaging; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon; D014665:Vasodilator Agents
chemical_list: D019275:Radiopharmaceuticals; D014665:Vasodilator Agents; D004280:Dobutamine; D017256:Technetium Tc 99m Sestamibi; D000241:Adenosine