Variability of myocardium at risk for acute myocardial infarction.
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.
Klarich
K W
KW
Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA.
Christian
T F
TF
Higano
S T
ST
Gibbons
R J
RJ
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
D005343:Fibrinolytic Agents; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi