Technetium-99m MIBI to assess coronary collateral flow during acute myocardial infarction in two closed-chest animal models.
Collateral flow is an independent determinant of infarct size in both animal and clinical studies of myocardial infarction. The purpose of this study was to quantitatively evaluate, in a closed-chest animal model, a noninvasive method of measuring coronary collateral flow over a wide spectrum of collateral flow rates from a tracer that can be injected during occlusion but measured after reperfusion.


METHODS
Fourteen animals underwent 40 min of coronary occlusion using a closed-chest technique. Two closed-chest models representing different rates of collateral flow were used: canine and porcine. Coronary blood flow was measured by radiolabeled microspheres. Collateral blood within the risk zone was estimated from the severity of 99mTc-sestamibi tomographic perfusion defect.


RESULTS
Collateral blood flow was significantly higher in the canine model than it was in the porcine model. There was close agreement (r = 0.90) between absolute collateral flow by microspheres and the severity of the tomographic perfusion defect.


CONCLUSIONS
These results suggest that an accurate noninvasive estimate of collateral blood flow can be provided by an intravenous injection of 99mTc-sestamibi.
Christian
T F
TF
Department of Nuclear Medicine, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA.
O'Connor
M K
MK
Schwartz
R S
RS
Gibbons
R J
RJ
Ritman
E L
EL
D000818:Animals; D003097:Collateral Circulation / Q000502:physiology; D003326:Coronary Circulation / Q000502:physiology*; D004285:Dogs; D006321:Heart / Q000000981:diagnostic imaging; D008863:Microspheres; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000503:physiopathology; D009206:Myocardium / Q000473:pathology; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D013552:Swine; D017256:Technetium Tc 99m Sestamibi
D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi