Pulsatile flow for improved myocardial protection
The potential importance of pulsatile cardiopulmonary bypass (CPB) has been reemphasized within the past few years by Berger and Pappas. A new valveless pulsatile assist device (PAD®) has been developed which converts roller pump flow into synchronized atraumatic pulsatile flow. In addition, the PAD can also be used as an arterial counterpulsator before and after CPB in a manner similar to the intra-aortic balloon pump. The PAD is inserted into the arterial line close to the aortic root. The device consists of a flexible, valveless balloon conduit through which the arterial blood flows. The balloon is contained within a rigid plastic housing which is connected to a standard intraaortic balloon pump.
The PAD has been employed in 200 adult patients undergoing elective open heart surgery for coronary artery and/or valvular heart disease at the Columbia-Presbyterian Medical Center during the last 2 years. One hundred forty of these patients were either NYHA Class III or IV preoperatively, or had ejection fractions of less than 0.3 or left ventricular end-diastolic pressures of 18 mm Hg or higher on their preoperative cardiac catheterization. One hundred twenty-three patients had multiple coronary bypasses alone, 43 had valve replacements alone, 6 had ventricular aneurysm resections alone, 17 had combined coronary bypass grafting in conjunction with aortic valve replacement, and 11 had combined ventricular aneurysm resection and coronary artery bypass surgery. The device functioned as a hemodynamically effective arterial counterpulsator before and after CPB. During CPB pulse pressures of 40 to 50 mm Hg were readily obtained.