Ameroid constrictor: uniform closure rates and a calibration procedure.

The Ameroid constrictor device, when placed around a coronary artery, induces gradual occlusion of that vessel. The limitations of this technique for producing myocardial infarction in animals are: I) the variable closure rates (sometimes incomplete) from one de-vice to the next and 2) the lack of a suitable calibration procedure to monitor daily flow reduction. The results of this study have shown that, by careful fabrication of the device and by drying of the Ameroid material, uniform results are obtainable. To calibrate the devices, a simulated coronary vessel (polyethylene tubing) is placed in the slot of the Ameroid constrictor and connected daily to a fluid perfusion apparatus (perfusion pressure 100.0 mm Hg). With this procedure, calibration curves were constructed for non-coated and silicone-coated Ameroid constrictors, This procedure will allow for greater predictability of flow reduction to the myo-cardium when the above technique is applied.