• Journal of Chest Surgery
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• v.30 no.8
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• pp.760-769
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• 1997

This study aimed to determine factors that influence blood flow through coronary bypass grafts and to analyze relationship between the graft flow and postoperative outcome. Blood flow through 146 bypass grafts(GBF) was measured with transit-time ultrasound flowmeter during coronary artery bypass grafting operations in 50 patients. Single and multiple regression analyses were done for relationships between the GBF and four variables: internal diameter of recipient coronary artery, myocardial value of bypassed branch(es), type of graft, and finding of preoperative myocardial perfusion scan. The relationship between GBF and postoperative scan finding was also analyzed. 1. The mean GBF was significantly higher in sequential grafts than in single vein grafts or in internal thoracic artery grafts(61.5 vs. 46.9 and 42.5 ml/min). 2. Myocardial value and recipient artery diameter were found to be the factors determining GBF. There was no correlation between GHF and presence of perfusion defect in the preoperative scan. 3. Myocardial value was found to be more important than recipient artery diameter in determinintg GBF. 4. Reversible perfusion defects were more frequently found in the areas upplied by grafts with low GBP. But this fact had only mild statistical significance. These results suggest that blood flow through a bypass graft is more determined by the size of its supplyinf: myocardium than by the size of recipient artery. So, we can expect effective improvement in myocardial flow reserve after grafting of small(1~1.5mm) coronary arteries, if they supply substantial area of myocardium.

• Journal of Chest Surgery
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• v.29 no.6
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• pp.599-605
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• 1996

A total of 249 patients undergoing isolated coronary revascularization were studied for the occurrence of postoperative atrial fibrillation(AF). Possible associations of this arrhythmia with various preoperative, intraoperative and postoperative factors were studied by univariate and multivariate analysis. The overall incidence of postoperative AF was 15%, with the median time occurence of 48 hours(mean time : 59.1 $\pm$ 56.9 hours) after arrival to the intensive care unit. Cardiac index decreased significantly after occurence of AF(p=0.001). There were no in-hospital complications in those patients with AF. Univariate studies indicated preoperative ejection fract on(EF), triglyceride level, postoperative peak CKMB isoenzpme and atrial pacing to be the dominant factor promoting postoperative AF, with an increasing prevalence in lower EF(p=0.025), triglyceride(p=0.006) and peak CKMB isoenzyme(p=0.002), and in patients with atrial pacing(p=0.001). Hospital stay(p=0.001) and late mortality(p=0.003) were significantly increased in patients with postoperative AF Multivariate analysis showed that body weight and postoperative atrial pacing to be the dominant factor promoting postoperative AF, with an increasing prevalence in over- weight patients(p=0.011) and patients with atrial pacing(p=0.001). Both univariate and multivariate analy- sis showed that the age was not a significant factor but tended to promote postoperative AF respectively (p=0.053, 0.064). After 30.1 $\pm$ 11.4 months gfollow-up, those patients with AF had sinus rhythm. We think that we must try to prevent postoperative AF after ccoronary artery bypass grafting because of its deleterio s hemodynamic effect, prolonged hospital stay, and increased late mortality.

• Journal of Chest Surgery
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• v.40 no.3 s.272
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• pp.209-214
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• 2007

Background: Failed percutaneous transluminal coronary angioplasty (PTCA) is occasionally required for emergency coronary artery bypass grafting (CABG). The aim of this study was to assess the outcome of patients receiving emergency CABG after failed PTCA. Material and Method: Between May 1988 and May 2005, 5712 patients underwent PTCA, where 84 (1.4%) failed. 27 patients underwent emergency CABG after failed PTCA. The mean age was $63.7{\pm}8.9\;(46{\sim}80)$ years, with 14 male patients (51.9%). Result: All patients underwent emergent surgical revascularization within 6 hours. 22 patients underwent conventional CABG and 5 underwent off-pump CABG. The causes of PTCA failure were coronary obstruction due to new thrombi formation during the procedure (n=4), coronary dissection (n=17), coronary artery rupture (n=3) and 3 due to other causes. The rate of in-hospital operative mortality after emergent operation was 18.5% (5/27). A univariate analysis revealed that patients who died more often had left anterior descending artery disease, a preprocedural shock status, postoperative use of multiple isotropics and postoperative use of intra-aortic balloon pump. The mean follow up duration was $53.6{\pm}63.4$ months. Conclusion: Although PTCA is known to be life saving, there is still a high risk for morbidity and mortality following emergency CABG after failed PTCA, despite the advancement in PTCA techniques. This result will help identify and more effectively treat patients selected for PTCA when emergency CABG is required.

• Journal of Chest Surgery
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• v.31 no.9
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• pp.884-892
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• 1998

Background: The gastroepiploic artery is not only an alternative graft but also may be considered an important primary graft for coronary revascularization. However, the long-term patency of the gastroepiploic arterial graft is yet to be determined and the incidence of perioperative spasm and long-term patency of a coronary graft may be affected by the properties of the graft response to certain vasoactive substances. The reactivity of the gastroepiploic artery to vasoactive substances has not been studied extensively and the results of the studies are contradictory. Material and Method: This study was designed to test the reactivity of human gastroepiploic artery to four constrictors and four relaxants. The middle sections of the human gastroepiploic arteries were collected from the patients undergoing gastrectomy and the arterial rings with intact endothelium were suspended in organ baths for isometric tension recording. Result: Epinephrine, norepinephrine, and potassium chloride induced the maximum constriction to higher forces (7.0$\pm$1.1g, 6.6$\pm$0.9g, and 6.5$\pm$1.1g) than 5-hydroxytryptamine did (3.8$\pm$1.7g, p<0.05). Nitroprusside and histamine induced almost full relaxation in the gastroepiploic arteries preconstricted with norepinephrine. There was no significant difference between two relaxants regarding maximum relaxation force. Acetylcholine induced the maximum relaxation to weaker force when compared with nitroprusside and histamine (p<0.05), and isoproterenol was the weakest of the relaxants (p<0.05 compared with acetylcholine). Conclusion: The gastroepiploic artery has a strong capacity of endothelium-dependent relaxation which could have an important influence on long-term patency. The gastroepiploic artery exhibits a potent contractility to catecholamines and the enhanced contractility may facilitate vasospasm in the presence of high circulating levels of catecholamines. Nitroprusside, a potent relaxant in gastroepiploic artery, might be beneficial for the treatment of gastroepiploic arterial graft spasm. The gastroepiploic arterial graft with intact endothelium may respond weakly to beta-adrenoceptor agonist and 5-hydroxytryptamine.

• Journal of Chest Surgery
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• v.34 no.12
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• pp.901-908
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• 2001

Background : Coronary artery bypass graft(CABG) in patients with advanced left ventricular dysfunction has often been regarded as having high mortality rate, despite the great improvement in operative result of CABG. With recent advances in surgical technique and myocardial protection, surgical revascularization improved the symptom and long-term survival of these high risk patients more than the medical conservative treatment. Material and Methold : Clinical data of 31(4.1％) patients with preoperative ejection fraction less than 30% among 864 CABGs performed between January 1995 and March 1999 were retrospectively analyzed and pre- and postoperative changes of the ejection fraction on echocardiography were analyzed. There were 26 men and 5 women. The mean age was 60.7 years(range 41 to 72 years). History of myocardial infarction(30 cases, 98％) was the most common preoperative risk factor. There were seven irreversible myocardial infarction on thallium scan. Most patients had triple vessel diseases(26 cases, 84％) and first degree of Rentrop classification(16 cases, 52％) on coronary angiography. The mean number of distal anastomosis during CABG was per patient was 4.9${\pm}$0.8 sites in each patient. In addition to long saphenous veins, the internal mammary artery was used in 20 patients. Total bypass time was 244.7${\pm}$3.7 minutes(range, 117 to 567 minutes), and mean aortic cross-clamp time was 77.9 ${\pm}$ 1.6 minutes(range, 30 to 178 minutes). There were five other reparative procedures such as two left ventricular aneurysrmectomy, two mitral repair, and one aortic valve replacement. There were twelve postoperative complications such as three cardiac arrhythmia, two bleeding(re-operation), one delayed sternal closure, eleven usage of intra-aortic balloon counterpulsation for low cardiac output. Two patients died, postoperative mortality was 6.5% . Twenty-nine patients were relieved of chest pain and left ventricular ejection fraction after operation was significantly higher(38.5${\pm}$11.6%, p 0.001) as compared with preoperative left ventricular ejection fraction(25.3${\pm}$2.3%). The follow up period of out patient was 25. 3 months. Conclusion: In patients with coronary artery disease and advanced left ventricular dysfunction, coronary artery bypass grafting can be performed relatively safely with improvement in left ventricular function, but it will be necessary to study long term results.

• Journal of Chest Surgery
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• v.34 no.12
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• pp.895-900
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• 2001

Background : This study aimed to evaluate the usefulness of preoperative placement of intraaortic balloon pump(IABP) in reducing operative risk and facilitating posterior vessel OPCAB in high risk patients with left main disease( 75％ stenosis), intractable resting angina, postinfarction angina, or left ventricular dysfunction(ejection fraction 35％). Material and Method : One hundred eighty- nine consecutive patients who underwent multi-vessel OPCAB including posterior vessel revascularization were studied. The patients were divided into group I(n=74) that received preoperative or intraoperative IABP and group II(n=115) that did not receive IABP. In group I, there were 39 patients with left main disease, 40 patients with intractable resting angina, 14 patients with left ventricular dysfunction and 7 patients with postinfarction angina. Ten patients received intraoperative IABP support due to hemodynamic instability during OPCAB. Result : There was one operative mortality in group I and two mortalities in group II. The average number of distal anastomoses was not different between group I and group II(3.5$\pm$0.9 vs 3.4$\pm$0.9, p=ns). There were no significant differences in the number of posterior vessel anastomosis per patient between the two groups. There were no differences in ventilator support time, length of hospital stay, and morbidity between the two groups. There was one case of IABP-related complication in group I. Conclusion : IABP facilitates posterior vessel OPCAB in high risk patients, with comparable surgical results to low risk patients

• Journal of Chest Surgery
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• v.40 no.2 s.271
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• pp.90-96
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• 2007

Background: Postoperative atrial fibrillation is the most frequently arrhythmic complication associated with coronary artery bypass graft surgery. This study was designed to investigate the incidence of atrial fibrillation in patients undergoing OPCAB and on-pump CABG and to identify the risk factors associated with its development. Material and Method: 247 consecutive patients were evaluated among 306 patients who underwent the coronary artery bypass graft surgery between January, 2002 and December, 2005. 178 patients underwent OPCAB (OPCAB group) and 69 patients underwent On-pump CABG (On-pump CABG group). The incidence and the risk factors of atrial fibrillation in two groups were determined. Result: There were no significant differences between two groups with respect to the preoperative demographic characteristics of the patients. The incidences of postoperative atrial fibrillation were 25 cases (14%) in OPCAB group and 15 cases (21%) in On-pump CABG group. Age over 65 years, net positive fluid imbalance for postoperative 3 days, and chest tube bleeding for postoperative 3 days were independent predictive factors in OPCAB group. Age over 65 years and net positive fluid imbalance for postoperative 3 days were independent predictive factors in On-pump CABG group. In multivariate analysis, age over 65 years was the only risk factor of postoperative atrial fibrillation in both groups. Conclusion: Atrial fibrillation is a common complication after procedures of myocardial revascularization. There wasn't a low incidence of postoperative atrial fibrillation in OPCAB, compared with On-pump CABG. Age over 65 years was associated with postoperative atrial fibrillation irrespective of the use of cardiopulmonary bypass.

• Journal of Chest Surgery
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• v.41 no.5
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• pp.610-618
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• 2008

Background: There are various treatment modalities for atherosclerotic arterial obstructive disease at the lower limbs, for example, conservative physical therapy, medication, operation etc. Yet it has been established that an arterial bypass operation is the most effective treatment. The aim of this study is to evaluate the effect of arterial bypass operation within our experience and to determine the indicators of treatment. Material and Method: Ninety six patients received arterial bypass operation for atherosclerotic arterial obstructive disease from June 2002 to April 2006. We evaluated the feasibility of arterial bypass operation based on the improvement of symptoms and the ankle-brachial index (ABI) and the surgical outcomes, as based on the complications, the amputation rates and the patency rates. We also assessed the possible risk factors such as gender, age, a smoking history, co-morbidities, the anastomotic sites, the graft size and the graft type. We retrospectively reviewed the medical records of the patients. The total mean follow-up period was $29.4{\pm}13.1$ months. Result: The mean age was $65.95{\pm}9.61$ and there were 88 male patients. The most common clinical manifestation was ischemic resting pain in the lower extremities. The underlying combined diseases were hypertension (61%), diabetes (43%), cardiac problems (35%) and smoking (91.7%). The most frequent site of arterial obstruction was the superficial femoral artery (44 cases, 40%). A femoropopliteal artery bypass operation with a Polytetrafluoroethylene(PTFE) synthetic graft was done in 44 cases (40%) and the great saphenous vein graft was used in 11 cases. The postoperative ABI increased significantly from $0.30{\pm}0.11$ preoperatively to $0.63{\pm}0.11$ (p<0.001) postoperatively. In 8 cases, amputations above the ankle level were necessary. The graft patency rates were 86.4% and 68.0% after 1 and 3 years, respectively. There were 29 cases (30.21%) of patency failure; the male gender, smokers and hypertension were significantly more frequent in the failure group. Of these, hypertension was the most powerful risk factor (p=0.042). Conclusion: The arterial bypass operation is an effective treatment modality for controlling the symptoms such as pain and claudication, and for preventing major amputations for the patients with atherosclerotic arterial obstructive disease. This study suggests quitting smoking, strict blood pressure control, selection of an appropriate graft, regular outpatient follow up and proper medication would offer higher patency rates and more favorable outcomes.

• Journal of Chest Surgery
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• v.38 no.5 s.250
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• pp.349-356
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• 2005

Background: Arterial conduits using in coronary artery bypass grafting (CABG) have been known a great long term patency rates, and improved short and long term clinical outcomes. It has been reported that Off pump CABG has better clinical results than CABG using cardiopulmonary bypass. To evaluate the advantage of arterial conduits over venous conduits and to avoid the adverse effects of cardiopulmonary bypass, we performed total arterial Off pump CABG. Material and Method: From January 2001 to October 2004, Off pump CABG using only arterial conduits was performed on 325 patients with a mean age of $59.3\pm11.9$ years ($36\~83$). Mean ejection fraction was $55.4\pm14.0\%\;(15\~86).$ Angiography showed left main disease or triple-vessel disease in $81.9\%$ of the patients. Indications of using arterial conduits was stenosis $\ge50\%$ of left anterior descending artery, stenosis $\ge80\%$ of branches of left circumflex artery, and stenosis $\ge90\%$ of right coronary artery and its branches. Multi-slice computed tomography was performed on 194 patients to evaluate the short term patency rates. Result: A total of 928 distal anastomoses were performed and the average anastomoses per a patient were $2.86\pm0.78$. There was 1 operative mortality. Postoperative complications were mediastinitis in 6 patients ($1.8\%$), renal failure in 4 patients ($1.2\%$), perioperative myocardial infarction in 3 patients ($0.9\%$), reoperation for bleeding in 3 patients ($0.9\%$). There was no postoperative stroke. Patency rate of arterial conduits was $99.3\%$ (581/585). There were 4 stenoses or competitive flows in 2 radial arteries and 2 right internal mammary arteries. Conclusion: Total arterial Off pump CABG appears to be safe, showing a low surgical mortality and morbidity and excellent short term patency rates of arterial conduits.

• Journal of Chest Surgery
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• v.31 no.2
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• pp.118-124
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• 1998

Minimally invasive coronary artery bypass grafting without using cardiopulmonary bypass (CPB) is a recently accepted modality of myocardial revascularization prcedures which is particularly suitable to the patients with lesions in the left anterior descending(LAD) and the right coronary arteries. Of the consecutive 35 patients of coronary artery bypass grafting performed at Sejong General Hospital from March to August 1996, six patients underwent minimally invasive coronary artery bypass grafting without CPB. All had stenotic lesions of the LAD more than 90%. Bypass grafting of the LAD was approached through midline sternotomy in one, through ministernotomy in two, and through limited left anterior thoracotomy in three patients, respectively. The internal mammary arteries were prepared without the use of thoracoscope. The mobilized mammary arteries were connected directly to the LAD in 5 patients, and the anastomosis required interposition of a segment of the radial artery in the remaining one. The diagonal branch was revascularized with the saphenous vein graft at the same time in one patient. No blood transfusion was necessary in 2 patients, and average blood required during surgery was 800ml in 4 patients. All patients were extubated from 4 to 14 hours(mean 9 hours) after operation. Early postoperative coronary angiography in 5 patients between 7 and 10 days after surgery has proved full patency of the grafts. With these limited clinical experiences, the clinical results demonstrated that minimally invasive coronary artery bypass grafting without CPB is an useful procedure especially in patients with isolated lesion in the proximal LAD.