Comparison of Pulsatile and Non-Pulsatile Extracorporeal Circulation on the Pattern of Coronary Artery Blood Flow / 대한흉부외과학회지

BACKGROUND: In sudden cardiac arrest, the effective maintenance of coronary artery blood flow is of paramount importance for myocardial preservation as well as cardiac recovery and patient survival. The purpose of this study was to directly compare the effects of pulsatile and non-pulsatile circulation to coronary artery flow and myocardial preservation in cardiac arrest condition. MATERIAL AND METHOD: A cardiopulmonary bypass circuit was constructed in a ventricular fibrillation model using fourteen Yorkshire swine weighing 25~35 kg each. The animals were randomly assigned to group I (n=7, non-pulsatile centrifugal pump) or group II (n=7, pulsatile T-PLS pump). Extracorporeal circulation was maintained for two hours at a pump flow of 2 L/min. The left anterior descending coronary artery flow was measured with an ultrasonic coronary artery flow measurement system at baseline (before bypass) and at every 20 minutes after bypass. Serologic parameters were collected simultaneously at baseline, 1 hour, and 2 hours after bypass in the coronary sinus venous blood. The Mann-Whitney U test of STATISTICA 6.0 was used to determine intergroup significances using a p value of <0.05. RESULT: The resistance index of the coronary artery was lower in group II and the difference was significant at 40 min, 80 min, 100 min and 120 min (p <0.05). The mean velocity of the coronary artery was higher in group II throughout the study, and the difference was significant from 20 min after starting the pump (p <0.05). The coronary artery blood flow was higher in group II throughout the study, and the difference was significant from 40 min to 120 min (p <0.05) except at 80 min. Serologic parameters showed no differences between the groups at 1 hour and 2 hours after bypass in the coronary sinus blood. CONCLUSION: In cardiac arrest condition, pulsatile extracorporeal circulation provides more blood flow, higher flow velocity and less resistance to coronary artery than non-pulsatile circulation.

A Study of Optimal Model for the Circuit Configuration of Korean Pulsatile Extracorporeal Life Support System (T-PLS) / 대한흉부외과학회지

BACKGROUND: We have hypothesized that, if a low resistant gravity-flow membrane oxygenator is used, then the twin blood sacs of TPLS can be located at downstream of the membrane oxyenator, which may double the pulse rate at a given pump rate and increase the pump output. The purpose of this study was to determine the optimal configuration for the ECLS circuits by using the concept of pulse energy and pump output. MATERIAL AND METHOD: Animals were randomly assigned to 2 groups in a total cardiopulmonary bypass model. In the serial group, a conventional membrane oxygenator was located between the twin blood sacs. In the parallel group, the twin blood sacs were placed downstream of the gravity-flow membrane oxygenator. Energy equivalent pressure (EEP) and pump output were collected at pump-setting rates of 30, 40, and 50 BPM. RESULT: At the given pump-setting rate, the pulse rate was doubled in the parallel group. Percent changes of mean arterial pressure to EEP were 13.0+/-1.7, 12.0+/-1.9 and 7.6+/-0.9% in the parallel group, and 22.5+/-2.4, 23.2+/-1.9, and 21.8+/-1.4% in the serial group at 30, 40, and 50 BPM of pump-setting rates. Pump output was higher in the parallel circuit at 40 and 50 BPM of pump-setting rates (3.1+/-0.2, 3.7+/-0.2 L/min vs. 2.2+/-0.1 and 2.5+/-0.1 L/min, respectively, p=0.01). CONCLUSION: Either parallel or serial circuit configuration of the ECLS generates effective pulsatility. As for the pump out, the parallel circuit configuration provides higher flow than the serial circuit configuration.

Early and Mid-Term Results of MIDCAB / 대한흉부외과학회지

BACKGROUND: The significance of MIDCAB is emerging topics recently as OPCAB is going to be universalized, and long-term outcome of bypass graft surgery was proved to be more excellent than balloon dilation or stent insertion. We report our MIDCAB results in 73 patients in the last three years. MATERIAL AND METHOD: Retrospective analysis of medical records was done from November 1, 2000 through November 31, 2003. There were 47 males and 26 females ranging in age from 31 years to 79 years (average 61.3+/-9.8 years). Observation periods after operative procedures were 10 to 1238 days (average 763+/-319.8 days). Left longitudinal parasternal incision as a standard procedure was done to approach the heart after dissection of the left internal thoracic artery by partial or total resection of 3rd to 5th ribs. RESULT: Of those patients, 46 patients were transferred to ICU after extubation at operation room and 58 patients were extubated within 3 hours after operation. Average ICU staying periods was 26.8+/-11.5 hours. Follow-up angiography during admission was done in 36 patients and showed 100% patency. Only one patient died on the 10th post operative day because of sudden CVA. Complications included wound problems in 4 patients, and constructing pericardial window using thoracoscopy due to continuous pericardial effusion in 1. Permanent pacemaker was inserted in one patient owing to sick sinus syndrome. In one patient with recurrence of angina 8 months after operation, stenosis at anastomic site was found and improved with balloon dilatation. CONCLUSION: We were satisfied with our results of MIDCAB in single and multi-vessel coronary artery disease. These results have made the cardiologists tried to operate positively and we expect widening operative indications including hybrid revascularization.