Cardiopulmonary bypass (CPB) involves the use of either an occlusive roller pump or centrifugal pump. Damage to blood elements, including haemolysis, may arise from occlusion when using a roller pump; the appropriate degree of occlusion has not yet been determined scientifically. Centrifugal and nonocclusive roller pumps are reputed to reduce haemolysis. The objective of this study was to compare haemolysis caused by a standard roller pump with a dynamically set nonocclusive roller pump and with a centrifugal pump. We prospectively randomized 60 patients undergoing routine coronary artery surgery into three groups: standard roller pump (STD, n = 20), dynamically set roller pump (DYN, n = 20), or centrifugal pump (CEN, n = 20). The level of plasma free haemoglobin (FHb) was measured preoperatively, and the rate of formation of FHb (in mg/dl/min) was determined at the end of the ischaemic phase and at the end of CPB. Cardiotomy suction blood was isolated for the ischaemic phase and returned before the end of CPB. It was found that there were no differences between the groups in demographic or operative variables. The rate of formation of FHb at the end of the ischaemic phase was similar for all groups (STD 0.108 +/- 0.10, DYN 0.117 +/- 0.08, CEN 0.129 +/- 0.07). At the end of CPB, after return of the cardiotomy suction blood, there was a significant (< 0.001) increase in the rate of formation of FHb in all groups. The increase was similar for each of the groups (STD 0.424 +/- 0.17, DYN 0.481 +/- 0.20, CEN 0.471 +/- 0.18). We conclude that the rates of haemolysis are similar for each of the pump types, and no benefit is conferred by the use of either a dynamically set roller pump or a centrifugal pump compared with the standard roller pump. The return of the cardiotomy suction blood to the circulation is the principal source of plasma free haemoglobin.

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Between April 1969 and November 1973 103 patients underwent isolated mitral replacement with three-cusp stented tissue valves. Autologous fascia lata was used in 50 patients, homologous fascia lata in 21, and heterologous pericardium in 32. The early mortality rate (14.6%) was influenced by age, the extent of preoperative cardiac disability, and low cardiac output. The survivors were followed up for periods varying from 8 to 60 months (average 37 months). In general, a factor in late death (13.6%) was high preoperative pulmonary artery pressure. In the autologous fascial series valve failure and infective endocarditis were significantly related to late mortality. The results with homologous fascia and pericardium were better than with autologous fascia valves. The incidence of postoperative mitral regurgitation was singificantly lower in the homologous fascial and pericardial series and none of these grafts had to be removed. The incidence of thromboembolism was low without anticoagulants. Actuarial analysis showed a survival rate at five years of 82.2 per cent. We no longer use autologous fascial valves. Though better results have been obtained with both homologous fascia and pericardium we prefer the physical characteristics of heterologous pericardium and it is easy to obtain.