[The coronary flow reserve during reperfusion in myocardial infarction]. / A reserva circulatória coronária durante a reperfusão no infarto do miocárdio.

PURPOSE: The study of coronary flow reserve on the reperfused myocardium damaged by 90 minutes of severe ischemia. MATERIAL AND METHODS: Nine mongrel dogs of either sex, weighing 12 to 17 kg were studied. Each dog was anesthesiated with 30 mg of pentobarbital and ventilated with room air. A thoracotomy was done and the left descendent coronary artery was isolated. Aorta and right atria pressures was measured using a Siemmens-Elema transducers and mingograf recording-804 (Siemmens Instruments). Coronary blood flow was measures with a Caroline Medical Electromagnetic flowmeter, 501D. The index studied was the coronary resistance, calculated as the quotient of the diastolic aortic pressure and the diastolic blood flow. The coronary reserve was studied during reactive hyperemia produced by 10 seconds of coronary occlusion in the 5, 10, 15 and 20 minutes of reperfusion. The infarcted area was detected by TTC (triphenyltetrazolium) method. RESULTS: All the hearts examined showed infarcted area. The diastolic coronary resistance during the reactive hyperemia in the 20 minutes of reperfusion was higher than the control value. CONCLUSION: The coronary vascular reserve was decreased during reperfusion, in the myocardial infarction.