Ömer Bayezid

Cardiopulmonary Bypass Using Centrifugal Pump

Centrifugal pumps are nonocclusive pumps that offer centrifugal blood pumping known as the constrained force vortex principle. Of 2405 open heart procedures, 370 (15.4%) were performed with a centrif ugal pump (CP). In the rest of the cases extracorporeal circulation (ECC) was established with conventional roller pump (RP). The operations performed with a CP were: 34 reoperations, 11 ascending aortic aneurysms + coronary artery bypass graft (CABG), 47 multivalve replacements, 125 CABG + left ventricu lar aneurysmectomies, and 153 CABGs alone. This prospective study consisted of two groups, each group including 50 patients undergoing CABG surgery. In group I ECC was established with a CP and in group II with a conventional RR The two selected groups of patients were considered to be similar in terms of clinical, hemodynamic, and angio graphic data. Hemodynamic study concerned flow rate, systemic vascular re sistance (SVR), and urinary output. No difference was found between the CP and RP hemodynamically. Nevertheless, the alteration of the flow rate in re sponse to variation of SVR is accepted as an advantage. As for hemolytic effect during ECC of CP compared with RP: Plasma free hemoglobin, hemotocrit, platelet count, platelet factor 4, and fibrinogen levels, were investigated. These parameters revealed that there was significant hemoly sis and trauma to the blood components in the RP group when compared with the CR (p < 0.05, p < 0.01). There was no significant difference in psychoneurologic complications, but behavioral and sensory disorders were encountered sevenfold more in the RP group. This might be due to spoliation of the tubing set or to microair embo lism. Compared with the conventional RP the CP proved to have no hemodynamic advantage. The effects on blood components showed significant trauma to the RP group. Postoperative drainage verified this observation (p < 0.05). In this study the CP appears to be superior to the RP especially in compli cated and prolonged ECC.

Results of 300 bileaflet mechanical valve implanatations

Three hundred bileaflet mitral or aortic mechanical prosthetic heart valves were implanted in 250 patients over a four-year period at Kosuyolu Heart and Research Center: 96 patients underwent mitral valve replacement (MVR), 81 aortic valve replacement (AVR), and 73 AVR + MVR. Seven of the mitral, 8 of the aortic, and 2 of the double valve replacements involved additional cardiac proce dures. Sex ratio was 63% females, 37% males. The youngest patient was nine, the oldest was seventy-six, and the average age was thirty-nine years; 59% of the patients had atrial fibrillation, 66% were in NYHA functional Class III-IV, and 61% were in congestive heart failure. Hospital mortality was 9.6% and late mortality was 4%. The predictors of survival were evaluated. Preoperatively and postoperatively 17 variables were studied by statistical analysis. Factors identified as influencing survival were: female sex, advanced age, NYHA Class more than III, increased cardiothoracic ratio, congestive heart failure, diabetes mellitus, giant left atrium, and prosthet ic valve endocarditis. Eleven patients developed endocarditis, and 21 had throm boembolic episodes. The authors conclude that the bileaflet mechanical prosthetic heart valve is a good candidate for mechanical valve replacement among the currently availa ble choices.

Surgical Treatment of Multivalvular Rheumatic Heart Disease

Of 632 valvular heart disease patients 187 were operated on because of multivalvular rheumatic lesions. The operative mortality was 10.1% and late mortality 4.9%. Left ventricular dysfunction was the common cause in the early operative period. Prosthetic valve endocarditis and thromboembolism were the other common causes of mortality, 5.9% and 6.4% respectively. NYHA Class III-IV, pulmonary hypertension, ejection fraction less than 40%, aortic stenosis and elevated left ventricular end diastolic pressure were significant predictors of poor-prognosis. Tricuspid regurgitation due to right heart decompensation is also another grave sign. The type of the prosthetic valve or additional annuloplasties to double valve replacement did not influence the outcome. Optimal timing of the operation is essential. Urgent operations should always be avoided if possible. Earlier surgical intervention, improved perioperative myocardial preservation, and alternate support methods, and improved surgical techniques may lower the operative mortality and morbidity.