• Journal of Chest Surgery
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• v.41 no.4
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• pp.405-416
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• 2008

Background: Spinal cord ischemic injury during thoracic and thoracoabdominal aortic surgeries remains a potentially devastating outcome despite using various methods of protection. Neuronal voltage-dependent sodium channel antagonists are known to provide neuroprotection in cerebral ischemic models. This study was designed to compare the neuroprotective effects of phenytoin with those of hypothermia in a rabbit model of spinal cord ischemia. Material and Method: Spinal cord ischemia was induced in New Zealand white rabbits by means of infrarenal aortic cross clamping for 25 minutes. Four groups of 8 animals each were studied. The control group and the hypothermia group received retrograde infusion of saline only ($22^{\circ}C$, 2 mL/min); the normothermic phenytoin group and the hypothermicphenytoin group received retrograde infusion of 100 mg of phenytoin at different rectal temperatures ($39^{\circ}C$ and $37^{\circ}C$, respectively) during the ischemic period. The neurologic function was assessed at 24 and 72 hours after the operation with using the modified Tarlov criteria. The spinal cords were harvested after the final neurologic examination for histopathological examination to objectively quantify the amount of neuronal damage. Result: No major adverse effects were observed with the retrograde phenytoin infusion during the aortic ischemic period. All the control rabbits became severely paraplegic, Both the phenytoin group and the hypothermia group had a better neurological status than did the control group (p < 0.05). The typical morphological changes that are characteristic of neuronal necrosis in the gray matter of the control animals were demonstrated by means of the histopathological examination, whereas phenytoin or hypothermia prevented or attenuated these necrotic phenomena (p < 0.05). The number of motor neuron cells positive for TUNEL staining was significantly reduced, to a similar extent, in the rabbits treated with phenytoin or hypothermia. Phenytoin and hypothermia had some additive neuroprotective effect, but there was no statistical significance between the two on the neurological and histopathological analysis. Conclusion: The neurological and histopathological analysis consistently demonstrated that both phenytoin and hypothermia may afford significant spinal cord protection to a similar extent during spinal cord ischemia in rabbits, although no significant additive effects were noticed.

• Journal of Chest Surgery
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• v.30 no.5
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• pp.471-478
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• 1997

Introduction: The use of rabbits as a cardiopulmonary bypass(CPB) animal model is extremely dif%cult mainly due to technical problems. On the other hand, deep hypothermic circulatory arrest(CA) is used to facilitate surgical repair in a variety of cardiac diseases. Although steroids are generally known to be effective in the treatment of cerebral edema, the protective effects of steroids on the brain during CA are not conclusively established. Objectives of this study are twofold: the establishment of CPB technique in rabbits and the evaluation of preventive effect of steroid on the development of brain edema during CA. Material '||'&'||' Methods: Fifteen New Zealan white rabbits(average body weight 3.5kg) were divided into three experimental groups; control CA group(n=5), CA with Trendelenberg position group(n=5), and CA with Trendelenberg position + steroid(methylprednisolone 30 mglkg) administration group(n=5). After anesthetic induction and tracheostomy, a median sternotomy was performed. An aortic cannula(3.3mm) and a venous ncannula(14 Fr) were inserted, respectively in the ascending aorta and the right atrium. The CPB circuit consisted of a roller pump and a bubble oxygenator. Priming volume of the circuit was approximately 450m1 with 120" 150ml of blood. CPB was initiated at a flow rate of 80~85ml/kg/min, Ten min after the start of CPB, CA was established with duration of 40min at $20^{\circ}C$ of rectal temperature. After CA, CPB was restarted with 20min period of rewarming. Ten min after weaning, the animal was sacrif;cod. One-to-2g portions of the following tissues were rapidly d:ssected and water contents were examined and compared among gr ups: brain, cervical spinal cord, kidney, duodenum, lung, heart, liver, spleen, pancreas. stomach. Statistical significances were analyzed by Kruskal-Wallis nonparametric test. Results: CPB with CA was successfully performed in all cases. Flow rate of 60-100 mlfkgfmin was able to be maintained throughout CPB. During CPB, no significant metabolic acidosis was detected and aortic pressure ranged between 35-55 mmHg. After weaning from CPB, all hearts resumed normal beating spontaneously. There were no statistically significant differences in the water contents of tissues including brain among the three experimental groups. Conclusion: These results indicate (1) CPB can be reliably administered in rabbits if proper technique is used, (2) the effect of steroid on the protection of brain edema related to Trendelenburg position during CA is not established within the scope of this experiment.

• Journal of Chest Surgery
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• v.41 no.1
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• pp.34-40
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• 2008

Background: Off-pump coronary artery bypass grafting (OPCAB) shows fewer side effects than cardiopulmonary by. pass, and other benefits include myocardial protection, pulmonary and renal protection, coagulation, inflammation, and cognitive function. We analyzed the clinical results of our cases of OPCAB. Material and Method: From May 1999 to August 2007, OPCAB was performed in 100 patients out of a total of 310 coronary artery bypass surgeries. There were 63 males and 37 females, from 29 to 82 years old, with a mean age of $62{\pm}10$ years. The preoperative diagnoses were unstable angina in 77 cases, stable angina in 16, and acute myocardial infarction in 7. The associated diseases were hypertension in 48 cases, diabetes in 42, chronic renal failure in 10, carotid artery disease in 6, and chronic obstructive pulmonary disease in 5. The preoperative cardiac ejection fraction ranged from 26% to 74% (mean $56.7{\pm}11.6%$). Preoperative angiograms showed three-vessel disease in 47 cases, two-vessel disease in 25, one-vessel disease in 24, and left main disease in 23. The internal thoracic artery was harvested by the pedicled technique through a median sternotomy in 97 cases. The radial artery and greater saphenous vein were harvested in 70 and 45 cases, respectively (endoscopic harvest in 53 and 41 cases, respectively). Result: The mean number of grafts was $2.7{\pm}1.2$ per patient, with grafts sourced from the unilateral internal thoracic artery in 95 (95%) cases, the radial artery in 62, the greater saphenous vein in 39, and the bilateral internal thoracic artery in 2. Sequential anastomoses were performed in 46 cases. The anastomosed vessels were the left anterior descending artery in 97 cases, the obtuse marginal branch in 63, the diagonal branch in 53, the right coronary artery in 30, the intermediate branch in 11, the posterior descending artery in 9 and the posterior lateral branch in 3. The conversion to cardiopulmonary bypass occurred in 4 cases. Graft patency was checked before discharge by coronary angiography or multi-slice coronary CT angiography in 72 cases, with a patency rate of 92.9% (184/198). There was one case of mortality due to sepsis. Postoperative arrhythmias or myocardial in-farctions were not observed. Postoperative complications were a cerebral stroke in 1 case and wound infection in 1. The mean time of respirator care was $20{\pm}35$ hours and the mean duration of stay in the intensive care unit was $68{\pm}47$ hours. The mean amounts of blood transfusion were $4.0{\pm}2.6$ packs/patient. Conclusion: We found good clinical outcomes after OPCAB, and suggest that OPCAB could be used to expand the use of coronary artery bypass grafting.

• Journal of Chest Surgery
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• v.40 no.1 s.270
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• pp.25-31
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• 2007

Background: Cerebral protection is one of the most important procedures during aortic arch surgery. We can minimize neurological complications through short period of total circulatory arrest and resuming of brain perfusion. We evaluated 11 patients who underwent arch replacement using antegrade brain perfusion via right axillary artery. Material and Method: Between July 2004 and July 2006, 11 patients (male 9, female 2) underwent aortic arch replacement with antegrade brain perfusion via right axillary artery. Preoperative diagnosis was listed; 5 type A aortic dissections (5/11, 45.5%), 5 aortic aneurysms (5/11, 45,5%) and 1 type A IMH (intramural hematoma, 1/11, 9%). The mean age at the time of operation was $60.3{\pm}12.8$ years. For antegrade brain perfusion, we performed right axillary artery cannulation in all patients. Retrograde brain perfusion was used briefly during total circulatory arrest. Result: The mean total circulatory arrest time was $31.1{\pm}16.9$ minutes and the mean retrograde brain perfusion time was $21{\pm}17.8$ minutes. Mean antegrade brain perfusion time was $77.9{\pm}17.5\;(43{\sim}101)$ minutes. We had neither operative mortality nor permanent neurological complications. Conclusion: By means of antegrade brain perfusion via right axillary artery, that could lead to decrease circulatory arrest time and minimize damages to severely atheromatous arch vessels, we can expect to reduce neurological complications after aortic arch replacement. Further investigation with iarge patient populations will be required.

• Journal of Chest Surgery
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• v.31 no.3
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• pp.233-241
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• 1998

To define the risk factors affecting the early major morbidity and mortality after multiple- valve operations, the preoperative, intraoperative and postoperative informations were retrospectively collected on 124 consecutive patients undergoing a multiple-valve operation between October 1985 and July 1996 at the department of Thoracic and Cardiovascular Surgery of Pusan Paik Hospital. The study population consists of 53 men and 71 women whose mean age was 37.9$\pm$11.5(mean$\pm$SD) years. Using the New York Heart Association(NYHA) classification, 41 patients(33.1%) were in functional class II, 60(48.4%) in class III, and 20(16.1%) in class IV preoperatively. Seven patients(5.6%) had undergone previous cardiac operations. Atrial fibrillations were present in 76 patients(61.3%), a history of cerebral embolism in 5(4.0%), and left atrial thrombus in 13(10.5%). The overall early mortality rate and postoperative morbidity was 8.1% and 21.8% respectively. Among the 124 cases of multiple-valve operation, there were 57(46.0%) of combined mitral valve replacement(MVR) and aortic valve replacement(AVR), 48(38.7%) of combined MVR and tricuspid annuloplasty(TVA), 12(9.7%) of combined MVR, AVR and TVA, 3(2.4%) of combined MVR and aortic valvuloplasty, 2(1.6%) of combined MVR and tricuspid valve replacement, and others. The patients were classified according to the postoperative outcomes; Group A(27 cases) included the patients who had early death or major morbidity such as low cardiac output syndrome, mediastinitis, cardiac rupture, ventricular arrhythmia, sepsis, and others; Group B(97 cases) included the patients who had the good postoperative outcomes. The patients were also classified into group of early death and survivor. In comparison of group A and group B, there were significant differences in aortic cross-clamping time(ACT, group A:153.4$\pm$42.4 minutes, group B:134.0$\pm$43.7 minutes, p=0.042), total bypass time(TBT, group A:187.4$\pm$65.5 minutes, group B:158.1$\pm$50.6 minutes, p=0.038), and NYHA functional class(I:33.3%, II:9.7%, III:20%, IV:50%, p=0.004). In comparison of early death(n=10) and survivor(n=114), there were significant differences in age(early death:45.2$\pm$8.7 years, survivor:37.2$\pm$11.6 years, p=0.036), sex(female:12.7%, male:1.9%, p=0.043), ACT(early death:167.1$\pm$38.4 minutes, survivor:135.7$\pm$43.7 minutes, p=0.030), and NYHA functional class(I:0%, II:4.9%, III:1.7%, IV:35%, p=0.001). In conclusion, the early major morbidity and mortality were influenced by the preoperative clinical status and therefore the earlier surgical intervention should be recommended whenever possible. Also, improved methods of myocardial protection and operative techniques may reduce the risk in patients with multiple-valve operation.