title: Variability of myocardium at risk for acute myocardial infarction.
abstract: The objective of this study was to assess the variability in myocardium at risk and relate this to coronary angiographic variables. One hundred ninety-seven patients with > or = 1-mm ST-segment elevation in 2 contiguous electrocardiographic leads, without prior myocardial infarction, were injected with technetium-99m sestamibi acutely before reperfusion therapy. The perfusion defect was quantified to determine myocardium at risk for infarction. Patients underwent coronary angiography to determine the infarct-related artery and to classify the occlusion as proximal or not proximal. Collateral and anterograde (Thrombolysis In Myocardial Infarction [TIMI] trial) flow were assessed in a subset of 83 patients with angiography before direct angioplasty. Myocardium at risk for infarction in the distribution of the left anterior descending coronary artery was significantly greater (p <0.0001) than that in the circumflex or right coronary artery. In the left anterior descending coronary artery distribution, myocardium at risk for infarction was significantly larger for proximal occlusions (p <0.0001). There was a trend toward greater myocardium at risk for infarction of proximal occlusions (p = 0.14) of the left circumflex but not for proximal occlusions in the right coronary artery distribution (p = 0.47). Multivariate analysis revealed that the infarct-related artery (p <0.0001), TIMI flow (p = 0.0002), and proximal location (p = 0.09) in the infarct-related artery were independent predictors of myocardium at risk for infarction. Thus, infarct-related artery, TIMI flow, and proximal location of occlusion in the infarct-related artery influence the myocardium at risk for infarction, which is highly variable for given location of occlusion.
authors.affiliation: Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA.
authors.forename: K W
authors.initials: KW
authors.lastname: Klarich
authors.forename: T F
authors.initials: TF
authors.lastname: Christian
authors.forename: S T
authors.initials: ST
authors.lastname: Higano
authors.forename: R J
authors.initials: RJ
authors.lastname: Gibbons
mesh_terms: D015906:Angioplasty, Balloon, Coronary; D017023:Coronary Angiography; D003937:Diagnosis, Differential; D004562:Electrocardiography; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000628:therapy; D011237:Predictive Value of Tests; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D012307:Risk Factors; D017256:Technetium Tc 99m Sestamibi; D015912:Thrombolytic Therapy; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D005343:Fibrinolytic Agents; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi