The new nitroderivative ITF 296 improves collateral blood flow in a canine model of coronary thrombosis.

The actions of ITF 296 and isosorbide dinitrate (ISDN), 20, 70, and 200 g/kg/min, on myocardial transmural blood flow distribution during acute thrombotic occlusion of the left circumflex coronary artery (LCX) have been evaluated in seven and three anesthetized open-chest dogs, respectively, and compared with four animals receiving vehicle. Occlusion of LCX was achieved in 14 +/- 2 min by the insertion of a copper coil. This caused transmural myocardial ischemia in the LCX area, while leaving blood flow in the left anterior descending coronary artery (control area) unaffected. Infusion of ITF 296 (200 g/kg/min) increased transmural coronary flow in the border zone and in the control area without affecting blood flow in the central ischemic area. ISDN, given in the same dose, reduced systemic blood pressure but did not affect LCX blood flow. In three dogs with residual perfusion in the LCX central area ITF 296 also increased blood flow. These results confirm that ITF 296 promotes an increase of flow to the border zone, thus possibly reducing the area of myocardial infarction.