Myocardial Protection for Open Heart Operation in Infancy; Experimental and Clinical Studies

After the experimental study in annimals，我们开始使用回trograde coronary sinus perfusion (RCSP) with the cardioplegic解决方案（4 - C St Thomas Hospital solution） for myocardial protection in these particular patientswith aortic valve operation in which conventional selective coronary perfusion might be technicallydifficult. This method has made the operative procedures extremely easy and brought much bettersurgical results. Our present studies are aiming further application of这个方法to the infantopen heart operationsparticularly the anatomic correction of TGA in which operative procedures are morecomplicated, bringing inevitably more difficult myocardial protection.Using the mongrel dogs，myocardial ischemia was induced by aortic crossclamping and obstruction of the left main coronaryartery under CPB. After 90 minutes of ischemia，coronary arteries were reperfused by releasing the aortic crossclamp and left coronary obstruction. .Myocardial temperature, Pco, pH，oxygen and lactate uptake and ATP were measured. RCSP-group showed a better myocardial cooling thangroup with conventional antegrade perfusion. the rest of the experimental results alsodemonstrated satisfactory perfusion of the left ventricular myocardium in RCSP-group.Thus，this method will be an excellent alternative for myocardial protection in particular open heartoperation . however,occasional insufficient perfusion of the right ventricular myocardium been pointed out to be adrawback of this method. We studied right ventricular functions of the dogs in 1) RCSP with topicalcooling of the right ventricle，2) RCSP without topical cooling和3)conventional antegrade perfusion. Right ventricular functionafter 60 minutes of ischemia deminished significantly in the group of dogs in RCSP without topicalcooling. This means the importance of right ventricular topical cooling at the time of RCSP。

After the experimental study in annimals, we started the clinical use of retrograde coronary sinus perfusion (RCSP) with the cardioplegic solution (4゜C St Thomas Hospital solution) for myocardial protection in these particular patients with aortic valve operation in which conventional selective coronary perfusion might be technically difficult. This method has made the operative procedures extremely easy and brought much better surgical results. Our present studies are aiming further application of this method to the infant open heart operations, particularly the anatomic correction of TGA (Jatene) in which operative procedures are more complicated, bringing inevitably more difficult myocardial protection.Using the mongrel dogs, myocardial ischemia was induced by aortic crossclamping and obstruction of the left main coronary artery under CPB. After 90 minutes of ischemia, coronary arteries were reperfused by releasing the aortic crossclamp and left coronary obstruction. Myocardial temperature, Pco , pH, oxygen and lactate uptake and ATP were measured. RCSP-group showed a better myocardial cooling than the group with conventional antegrade perfusion. The rest of the experimental results also demonstrated satisfactory perfusion of the left ventricular myocardium in RCSP-group.Thus, this method will be an excellent alternative for myocardial protection in particular open heart operation. However, occasional insufficient perfusion of the right ventricular myocardium has been pointed out to be a drawback of this method. We studied right ventricular functions of the dogs in 1) RCSP with topical cooling of the right ventricle, 2) RCSP without topical cooling and 3) conventional antegrade perfusion. Right ventricular function after 60 minutes of ischemia deminished significantly in the group of dogs in RCSP without topical cooling. This means the importance of right ventricular topical cooling at the time of RCSP.