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Myocardial protection during coronary angioplasty with autoperfusion and forced perfusion: an in vitro comparison
E D de Muinck1, B J Verkerke, G Rakhorst
1Department of Cardiology, University Hospital, Groningen, The Netherlands.
Insights
Autoperfusion balloon catheters offer simpler, cheaper coronary angioplasty perfusion than pumps. However, their lower blood flow rates may not ensure adequate myocardial protection during the procedure.
Area of Science:
- Cardiovascular interventions
- Medical device engineering
- Hemodynamics
Background:
- Maintaining distal perfusion during coronary angioplasty is crucial.
- Autoperfusion balloon catheters and coronary perfusion pumps are used for this purpose.
Purpose of the Study:
- To compare the in vitro blood flow rates of autoperfusion balloon catheters and perfusion pumps.
- To assess the adequacy of myocardial protection offered by each device.
Main Methods:
- In vitro comparison using fresh human blood at 37°C.
- Measurement of blood flow rates through autoperfusion catheters at varying pressures (40-80 mmHg).
- Measurement of driving pressures during pump perfusion at varying flow rates (20-60 ml/min).
Main Results:
- Autoperfusion catheters achieved mean flow rates of 46-75 ml/min at pressures of 0.05-0.1 atm.
- Perfusion pumps generated pressures of 1.8-5 atm at flow rates of 20-60 ml/min.
- Autoperfusion flow rates were often below the 60 ml/min threshold for adequate myocardial protection.
Conclusions:
- Autoperfusion balloon catheters are simpler and less expensive than perfusion pumps.
- Perfusion pumps provide higher flow rates, potentially offering better myocardial protection.
- Autoperfusion catheters may not consistently deliver sufficient blood flow for optimal myocardial protection during coronary angioplasty.
Abstract:
During coronary angioplasty, perfusion distal to the inflated angioplasty balloon can be maintained with autoperfusion balloon catheters and coronary perfusion pumps. The blood flow rates through the autoperfusion balloon catheters and the flow rates achieved with a perfusion pump were compared in vitro with fresh human blood at 37 degrees C. In a specially designed system, blood flow rates through Stack autoperfusion balloon catheters were measured at 40, 60 and 80 mmHg continuous pressure. In another system, driving pressures were measured during perfusion with the pump, through a specially designed forced perfusion catheter at 20, 40 and 60 ml/min flow. The pressure applied in the autoperfusion experiments was converted into atmospheres (atm) to facilitate comparison with the driving pressures measured during pumping (1 mmHg = 1.316 x 10(-3) atm). Mean flow rates through the autoperfusion balloon 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 20 ml/min, 3.5 atm at 40 ml/min, 5 atm 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 simpler and cheaper devices than perfusion pumps, but generally they are not able to provide adequate myocardial protection.