Search for author "A. Michael Lincoff"

Figure 1. Schematic diagram of experimental protocol. Thrombus formation is induced by passage of 100-μA continuous anodal current through the coronary electrode. Twenty minutes after thrombus formation, dogs received either AR-C69931MX (4 μg · kg⁻¹ · min⁻¹) or saline. Ten minutes afterward, t-PA was given to all animals for a 20-minute period (phase I, 1 mg/kg; phase II, 0.5 mg/kg). Colored microspheres were injected directly into the left atrium before thrombus formation, as control, during the occlusion, and at the end of adjunctive treatment administration. MCE was performed before thrombus formation, during occlusion, 20 minutes after t-PA infusion, and at the end of adjunctive treatment administration. All animals from both phases received heparin (80 U/kg as a bolus, 17 U · kg⁻¹ · min⁻¹ IV).

Figure 2. Myocardial TBF as assessed by colored microspheres at baseline, during occlusion, and at the end of adjunctive treatment administration. At baseline, myocardial TBF in the risk area was similar in both groups (P=NS). During occlusion, a significant reduction in myocardial TBF within the risk area was observed, and there was no difference between the 2 groups. However, by 120 minutes after initiation of the study drug, myocardial TBF with AR-C69931MX improved greatly, whereas myocardial TBF with placebo remained at a level similar to that during occlusion (P<0.05).

Figure 4. Examples of MCE performed in an AR-C69931MX–treated dog (top) and in a control dog (bottom) at baseline, during occlusion, 20 minutes after t-PA infusion, and at the end of adjunctive treatment administration. In both groups, myocardial opacification was uniform at baseline. During occlusion, risk area was clearly delineated as an area of absent contrast opacification. However, at 20 minutes after t-PA infusion and at the end of adjunctive treatment administration, risk area from controls was still incompletely refilled by contrast, whereas it was uniformly opacified in AR-C69931MX–treated animals, indicating preserved myocardial microvascular flow.

TABLE 3. Myocardial Area at Risk and Effect of AR-C69931MX on Infarct Size