Myocardial Protection and Cardiopulmonary Bypass in Pediatric Cardiac Surgery. Biomechanical and Structural Properties of Neonatal Coronary Arteries. Summary of the Doctoral Thesis

Abstract

The aim of this promotional work was to improve the quality of myocardial protection and cardiopulmonary bypass in pediatric cardiac surgery as well as to determine the optimal parameters for application of cardioplegic solution in neonates taking into account immaturity and fragility of the wall of coronary arteries. It consists of three basic parts. In the first part of the work the analysis of literature regarding the myocardial protection in pediatric cardiac surgery was made and compared with experience of the Clinic for Pediatric Cardiology and Cardiac Surgery, Children’s University Hospital, Riga, Latvia. To compare cold crystalloid and blood cardioplegia in pediatric cardiac surgery the blood samples from artery and coronary sinus were collected before and after aortic occlusion, and the level of lactates was analyzed. Results were compared with the echocardiographic grading of left ventricular function in early postoperative period. In addition, the level of Troponin I was analysed early and late postoperatively. When cardioplegic solution is injected into coronary arteries with a pump in order to ensure myocardial protection, it is necessary to determine the correct delivery pressure to avoid damage of the heart. Therefore biomechanical and structural properties of neonatal coronary artery wall were investigated experimentally in vivo as the second part of the work. In the third part of the work blood samples were drawn from packed red blood cells (PRBC) used in cardiopulmonary bypass before added to the priming solution. It was done to evaluate the effect of length of storage of PRBC on the concentration of potassium, sodium, lactate, glucose and pH in PRBC used in pediatric cardiac surgery. Taking into account the results of the promotional work the recomendations were made regarding the choise of method for myocardial protection in pediatric cardiac surgery and the use of PRBC in pediatric cardiopulmonary bypass. In addition, strong monitoring of the delivery pressure was recomended when cardioplegic solution is injected into neonatal coronary arteries, and it should not exceed 100 mmHg. The promotional work has been written in Latvian. It consists of introduction, aim and objectives of the study, scientific and practical novelty, summary of literature, materials and methods, results, discussion, conclusions, recomendations. The total amount of work is 139 pages, including 21 tables and 28 pictures. There are 170 references included.