Recently, several types of centrifugal pumps have been widely used as the main pumps for cardiopulmonary bypass (CPB). However, according to the results of our experimental studies, after cardiogenic shock, pulsatile flow was effective in maintaining the functions and microcirculations of end organs, especially those of the liver and kidney. To estimate the effectiveness of pulsatility during CPB, cytokine and endothelin and other metabolic parameters were measured in clinical pulsatile and nonpulsatile CPB cases. From March to May 1997, CPB was performed in 18 elective cases (14 ischemic and 4 valvular disease). In 9 cases, pulsatile perfusion was achieved by the Jostra HL20, which is a newly developed CPB pump (Group P). A nonpulsatile centrifugal pump was used in 9 patients (Group NP). In both groups, as chemical and metabolic mediators, interleukin-8 (IL-8), endothelin-1 (ET-1), and plasma free hemoglobin were measured before and during CPB, and 0.5, 3, 6, 9, 18 h after weaning from CPB. This pulsatile CPB pump could be very simply and easily controlled and could easily produce pulsatile flow. There were no significant differences in CPB time (CPBT), aortic cross clamp time (ACCT), mean aortic pressure, or pump flow during CPB between the both groups. The ET-1 level of Group P was significantly (p < 0.05) lower than that of Group NP 9 h after CPB weaning. The IL-8 level of Group P also showed a lower value than that of Group NP. As for plasma free hemoglobin, there were no significant differences between the groups. These results suggested that even in conventional CPB, pulsatility was effective to reduce endothelial damage and suppress cytokine activation. It may play a important role in maintaining the functions and microcirculations of end organs during CPB.

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We evaluated the efficacy and problems of circulatory support with percutaneous cardiopulmonary support (PCPS) for severe cardiogenic shock and discussed our strategy of mechanical circulatory assist for severe cardiopulmonary failure. We also described the effects of an alternative way of PCPS as venoarterial (VA) bypass from the right atrium (RA) to the ascending aorta (Ao), which was used recently in 3 patients. Over the past 9 years, 30 patients (20 men and 10 women; mean age: 61 years) received perioperative PCPS at our institution. Indications of PCPS were cardiopulmonary bypass weaning in 13 patients, postoperative low output syndrome (LOS) in 14 patients, and preoperative cardiogenic shock in 3 patients. Approaches of the PCPS system were the femoral artery to the femoral vein (F-F) in 21 patients, the RA to the femoral artery (RA-FA) in 5 patients, the RA to the Ao (RA-Ao) in 3 patients, and the right and left atrium to the Ao in 1 patient. Seventeen (56.7%) patients were weaned from mechanical circulatory support (Group 1) and the remaining 13 patients were not (Group 2). In Group 1, PCPS running time was 33.1 +/- 13.6 h, which was significantly shorter than that of Group 2 (70.6 +/- 44.4 h). Left ventricular ejection fraction was improved from 34.8 +/- 12.0% at the pump to 42.5 +/- 4.6% after 24 h support in Group 1, which was significantly better than that of Group 2 (21.6 +/- 3.5%). In particular, it was 48.6 +/- 5.7% in the patients with RA-Ao, which was further improved. Two of 3 patients with RA-Ao were discharged. Thrombectomy was carried out for ischemic complication of the lower extremity in 5 patients with F-F and 1 patient with RA-FA. One patient with F-F needed amputation of the leg due to necrosis. Thirteen patients (43.3%) were discharged. Hospital mortality indicated 17 patients (56.7%). Fifteen patients died with multiple organ failure. In conclusion, our alternate strategy of assisted circulation for severe cardiac failure is as follows. In patients with postcardiotomy cardiogenic shock or LOS, PCPS should be applied first under intraaortic balloon pumping (IABP) assist for a maximum of 2 or 3 days. In older aged patients particularly, the RA-Ao approach of PCPS is superior to control flow rate easily, with less of the left ventricular afterload and ischemic complications of the lower extremity. If native cardiac function does not recover and longer support is necessary, several types of ventricular assist devices should be introduced, according to end-organ function and the expected support period.

In recent years, several types of centrifugal pumps have been widely used as the main pumps for cardiopulmonary bypass (CPB) and postcardiotomy cardiac support. From April 1990 to March 1997, a percutaneous cardiopulmonary support (PCPS) system was used in 20 patients with an average age of 58 years (13 males and 7 females). They comprised 11 ischemic, 6 valvular, 2 aortic, and 1 congenital heart disease patients. Our PCPS system consists of a centrifugal pump (BioMedicus BP-80), an oxygenator, and a reservoir. The entire blood contacting surface, including that of the thin wall cannulas, is coated by heparin bonded materials. As a result of this new technology, this system can be used for the long term without systemic heparinization. No major critical thrombi were revealed inside the pumps or circuits. Of the 20 patients, 7 (35%) (Group 1) could be weaned from PCPS, and the remaining 13 (Group 2) could not. In Group 1 although 2 patients suffered from renal failure and pneumonia, respectively, both were discharged from our hospital. The long-term survival rate was 35%. In Group 2 cerebral vascular damage was recognized in 3 patients, renal failure in 4, multiple system organ failure in 4, bleeding in 2, arrhythmia in 1, and leg ischemia in 2. Pulse pressure was significantly elevated due to the recovery of the native heart in Group 1, 2 days after support. However, in Group 2, it did not elevate, and the left ventricular ejection fraction was less than 30%, associated with high left atrial pressure. In conclusion, this heparin coated PCPS system was very simple and easy to control. It demonstrated long-term biocompatibility and was very effective in recovering deteriorated cardiac function. Quicker application of this system can play an important role in preventing severe complications and obtaining better clinical results. If long-term support is necessary, a ventricular assist device (VAD), which is more powerful, durable, and biocompatible, has to be applied instead of PCPS.