MYOCARDIAL PROTECTION DURING CORONARY ANGIOPLASTY WITH AUTOPERFUSION AND FORCED PERFUSION - AN IN-VITRO COMPARISON

During coronary angioplasty, perfusion distal to the inflated angiopla sty balloon can be maintained with autoperfusion balloon catheters and coronary perfusion pumps. The blood flow rates through the autoperfus ion balloon catheters and the flow rates achieved with a perfusion pum p were compared in vitro with fresh human blood at 37 degrees C. In a specially designed system, blood flow rates through StackTM autoperfus ion balloon catheters were measured at 40, 60 and 80 mmHg continuous p ressure. In another system, driving pressures were measured during per fusion with the pump, through a specially designed forced perfusion ca theter at 20, 40 and 60 ml/min flow. The pressure applied in the autop erfusion experiments was converted into atmospheres (atm) to facilitat e comparison with the driving pressures measured during pumping (1 mmH g = 1.316 x 10(-3) atm). Mean flow rates through the autoperfusion bal loon catheters were: 46 ml/min at 0.05 atm, 66 ml/min at 0.09 atm and 75 ml/min at 0.1 atm. Mean pressures during pumping were: 1.8 atm at 2 0 ml/min, 3.5 atm at 40 ml/min, 5 afm at 60 ml/min. Due to the phasic nature of coronary blood flow, the flow through autoperfusion balloons is generally lower than the minimum required for adequate myocardial protection (= 60 ml/min). Thus, autoperfusion balloon catheters are si mpler and cheaper devices than perfusion pumps, but generally they are not able to provide adequate myocardial protection.