• Journal of Chest Surgery
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• v.32 no.4
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• pp.373-378
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• 1999

Background: Minimally invasive technique for various cardiac surgeries has become widely accepted since it has been proven to have distinct advantages for the patients. We describe here the results of our experiences of minimal incision in cardiac surgery. Material and Method: From February 1997 to November 1998, we successfully performed 31 cases of minimally invasive cardiac surgery. Male and female ratio was 17:14, and the patients age ranged from 1 to 75 years. A left parasternal incision was used in 9 patients with single vessel coronary heart disease. A direct coronary bypass grafting was done under the condition of the beating heart without cardiopulmonary bypass support(MIDCAB). Among these, one was a case of a reoperation 1 week after the first operation due to a kinked mammary artery graft. A right parasternal incision was used in one case of a redo mitral valve replacement. Mini-sternotomy was used in the remaining 21 patients. The procedures were mitral valve replacement and tricuspid annuloplasty in 6 patients, mitral valve replacement 5, double valve replacement 2, aortic valve replacement 1, removal of left atrial myxoma 1, closure of atrial septal defect 2, repair of ventricular septal defect 2, and primary closure of r ght ventricular stab wound 1. The initial 5 cases underwent a T-shaped mini-sternotomy, however, we adopted an arrow-shaped ministernotomy in the remaining cases because it provided better exposure of the aortic root and stability of the sternum after a sternal wiring. Result: The operation time, the cardiopulmonary bypass time, the aorta cross-clamping time, the mechanical ventilation time, the amount of chest tube drainage until POD#1, the chest tube indwelling time, and the duration of intensive care unit staying were in an acceptable range. There were two surgical mortalities. One was due to a rupture of the aorta cannulation site after double valve replacement on POD#1 in the mini-sternotomy case, and the other was due to a sudden ventricular arrhythmia after MIDCAB on POD#2 in the parasternal incision case. Postoperative complications were observed in 2 cases in which a cerebral embolism developed on POD#2 after a mini-sternotomy in mitral valve replacement and wound hematoma developed after a right parasternal incision in a single coronary bypass grafting. Neither mortality nor complication was directly related to the incision technique itself. Conclusion: Minimally invasive surgery using parasternal or mini-sternotomy incision can be used in cardiac surgeries since it is as safe as the standard full sternotomy incisions.

• Journal of Chest Surgery
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• v.39 no.6 s.263
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• pp.440-448
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• 2006

Background: Surgery of descending thoracic or thoracoabdominal aorta has the potential risk of causing neurological injury including spinal cord damage. This study was designed to find out the risk factors leading to spinal cord and brain damage after surgery of descending thoracic and thoracoabdominal aorta. Material and Method: Between October 1995 and July 2005, thirty three patients with descending thoracic or thoracoabdominal aortic disease underwent resection and graft replacement of the involved aortic segments. We reviewed these patients retrospectively. There were 23 descending thoracic aortic diseases and 10 thoracoabdominal aortic diseases. As an etiology, there were 23 aortic dissections and 10 aortic aneurysms. Preoperative and perioperative variables were analyzed univariately and multivariately to identify risk factors of neurological injury. Result: Paraplegia occurred in 2 (6.1%) patients and permanent in one. There were 7 brain damages (21%), among them, 4 were permanent damages. As risk factors of spinal cord damage, Crawford type II III(p=0.011) and intercostal artery anastomosis (p=0.040) were statistically significant. Cardiopulmonary bypass time more than 200 minutes (p=0.023), left atrial vent catheter insertion (p=0.005) were statistically significant as risk factors of brain damage. Left heart partial bypass (LHPB) was statistically significant as a protecting factor of brain (p=0.032). Conclusion: The incidence of brain damage was higher than that of spinal cord damage after surgery of descending thoracic and thoracoabdominal aorta. There was no brain damage in LHPB group. LHPB was advantageous in protecting brain from postoperative brain injury. Adjunctive procedures to protect spinal cord is needed and vigilant attention should be paid in patients with Crawford type II III and patients who have patent intercostal arteries.

• Journal of Chest Surgery
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• v.38 no.11 s.256
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• pp.733-738
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• 2005

Background: The possibility of incomplete revascularization and development of flow competition after revascularization of the borderline lesion made the hybrid strategy as an option for complete revascularization. Material and Method: From January f998 to July 2004, 25 $(3.2\%)$ patients underwent hybrid revascularization among 782 total OPCAB procedures. Clinical results and angiographic patencies were evalulated. Percutaneous coronary intervention (PCI) was peformed before CABG in 8 patients and after CABG in 47 patients. Result: The causes of PCIs before CABG were to achieve complete revascularization with minimally invasive surgery (n=7) and emergent PCI for culprit lesion (n=1). The indications of PCIs after CABG were high possibility of flow competition in the borderline lesion of right coronary artery territory (n=8), diffuse atheromatous lesion preventing anastomosis of graft (n=5), severe calcified ascending aorta with no more arterial grafi available (n=3), and intramyocardial coronary lesion (n=1). Mean number of distal anastomoses was $2.3\pm1.0$. Mean number of lesions treated by PCI was $1.2\pm0.4$. There was no operative or procedure-related mortality. PCI-related complication was periprocedural myocardial infarction in one patient, and complications related to CABG were transient atrial fibrillation (n=5), perioperative myocardial infarction (n=1), and transient renal dysfunction (n=1). Early postoperative coronary angiography $(1.8{pm}1.6days)$ revealed $100\%$ patency rate of grafts (57/57). The stenosis occurred in one patient performed PCI before CABG, which was successfully treated with re-ballooning. During midterm follow-up (mean; $25{\pm}26$ months), 1 patient died of congestive heart failure. All survivors (n=24) accomplished follow-up coronary angiographics, which showed .all grafts (56/57) were patent except one string sign. In-stent restenosis was developed in 2 patients who received bare metal stents. Conclusion: In selected patients, complete revascularization was achieved with low risk by taking the hybrid strategy.

• Journal of Chest Surgery
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• v.43 no.3
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• pp.246-253
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• 2010

Background: Our objective was to review the long-term prognosis of patients with preoperative mild to moderate ischemic mitral regurgitation who underwent off-pump coronary artery bypass grafting. Material and Method: We prospectively followed 1,000 consecutive and systematic off-pump coronary artery bypass grafting patients who were operated on between September 1996 and March 2004; follow-up was achieved for 97%. Sixty-seven patients (6.7%) had mild to moderate ischemic mitral regurgitation at the time of surgery. Operative mortality, actuarial survival and major adverse cardiac event free survival were compared to assess the effect of ischemic mitral regurgitation. Result: Average follow-up was $66{\pm}22$ months. Patients with ischemic mitral regurgitation were older (p<0.001), had lower ejection fractions (p<0.001) and more comorbidities. Significantly more female patients presented with ischemic mitral regurgitation (p=0.002). There was no significant difference in operative mortality and perioperative myocardial infarction in ischemic mitral regurgitation patients (p=0.25). Eight-year survival was decreased in ischemic mitral regurgitation patients ($39.6{\pm}11.8%$ vs $76.7{\pm}2.2$, p<0.001). However, after correcting for risk factors, mild to moderate ischemic mitral regurgitation was not found to be a significant independent risk factor for long-term mortality (p=0.42). Major adverse cardiac event free survival at 8 years was significantly lower in ischemic mitral regurgitation patients ($53.12{\pm}12%$ vs $77{\pm}2%$, p<0.001). After correction for risk factors, ischemic mitral regurgitation remained a significant independent cause of major adverse cardiac events (HR: 2.31), especially congestive heart failure and recurrent myocardial infarction. Conclusion: In our series, patients with preoperative mild to moderate ischemic mitral regurgitation had a higher prevalence of preoperative risk factors than patients without ischemic mitral regurgitation. They had comparable perioperative mortality and morbidity, but, in the long term, were found to be at elevated risk for recurrent cardiac events.

• Journal of Chest Surgery
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• v.39 no.10 s.267
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• pp.759-764
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• 2006

Background: We analyzed post-operative angiography performed in symptomatic patients to evaluate the patency rates and the roles of grafts. Material and Method: We reviewed 52 (15%) coronary angiograms performed for recurrent angina after prior coronary artery bypass surgery from January 1995 to June 2005. A total of 345 patients underwent coronary artery bypass surgery during this period. There were 41 men and 11 women and the mean age was $64.07{\pm}15.58$ years. The median period from operation to re-angiogram was 68.5 months (range, 1 to 126 months). The numbers of grafts and peripheral anastomoses were 42 and 43 for internal thoracic artery (ITA), 14 and 20 for radial artery (RA), and 49 and 89 for saphenous vein. The mean number of anastomosis was 2.9 per patient, Result: The patency rates of ITA, RA and saphenous vein graft (SVG) were 37/43 (86%), 17/20 (85%) and 34/89 (38.2%). The patency rate of arterial grafts was significantly higher than that of SVG (p< 0.001) and the patency rate of the RA was comparable to that of ITA (p=0.942). The patency rate of sequential SVGs was higher than that of single SVG (40.3% vs 31.8%, p=0.478) and the patency rate of proximal segments in sequential anastomosis was higher than that in single anastomsis (55.6% vs 31.8%, p=0.097), but statistically not significant. Conclusion: Arterial grafts have markedly superior patency rates than SVGs, so consideration should be given to the vigorous use of arterial grafts. The patency rate of the RA was comparable to that of ITA.

• Journal of Chest Surgery
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• v.36 no.4
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• pp.229-241
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• 2003

Background:Autogenous vein is the preferred vascular graft for patients who require coronary artery bypass surgery or peripheral arterial bypass surgery. When an autogenous vein is not available, an allograft saphenous vein can be used as an alternative conduit. Although arterial homograft has been under investigation since the beginning of this century, the viability of endothelial cells and the optimum mode of storage for the venous and arterial allografts is controversial. In addition, with the recently gained knowledge of vascular endothelial functions, such as the production of nitric oxide or thrombomodulin, the viability and antigenicity of endothelial cells are being studied again. The purpose of this study was to evaluate the viability of endothelial cells in the preserved human saphenous veins. Material and Method: The veins were stored in a $4^{\circ}C$ RPMI (Roswell Park Memorial Institute) 1640 solution including 10% fetal calf serum, for one, three, five, seven or fourteen days. After the completion of the storage period, the veins were divided into two groups: Group I: studied immediately at $4^{\circ}C$ (cold) storage (I-1, I-3, I-5, I-7, I-14), and Group II: studied after storage at $-196^{\circ}C$ liquid nitrogen tank (cryopreservation) in an RPMI 1640 solution containing 10% DMSO for two weeks (II-1, II-3, II-5, II-7, II-14). Light microscopy and scanning electron microscopy (SEM), frypan blue exclusion testing, and thrombomodulin immunohistochemistry were performed. Result: In a morphometric study using SEM, there was statistically significant increase in Gundry Score in Groups I-7, I-14, II-5, II-7, and II-14 and showed cellular destruction (p<0.05). In the thrombomodulin immunohistochemistry study, there was reactivity in Groups I-1, I-3, and I-5, but the cryopreserved group revealed decreased reactivity (p<0.05). The trypan blue exclusion testing also showed superior viability in cold storage Group I. Conclusion: Venous allografts preserved in a $4^{\circ}C$ RPMI 1640 solution showed well preserved endothelial cellular integrity and thrombomodulin expression at up to seven days of preservation. Although cryopreservation of venous allografts stored in 10% DMSO -RPMI 1640 solution maintained the endothelial cellular structure on SEM, immunohistochemistry from the thrombomodulin and trypan blue exclusion testing showed decreased viability, It remains to be seen whether the decreased thrombomodulin reactivity could be restored, and what the nature to the relationship is between thrombomodulin and long-term patency of allografts.

• Journal of Chest Surgery
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• v.39 no.1 s.258
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• pp.28-34
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• 2006

Background: There has been an increase in the number of elderly patients considered for coronary artery bypass grafting (CABG). Recently, there were many satisfactory reports of coronary artery bypass grafting (CABG) in old age due to the development in operative technique and postoperative management. We evaluated operative and follow-up results of patients 70 years of age and older compared to 60 years old. Material and Method: We retrospectively studied the cases of 74 consecutive patients 70 years or older (group A) who underwent a elective CABG from January 2000 to December 2003 and compared that of relatively young age group (group B, 60-69 years old). We compared preoperative characteristics, operation technique, postoperative results that effect outcome, also we investigated late mortality and cardiac events at follow-up periods. Result: Preoperative demographic and clinical characteristics of two groups were not different, except preoperative renal dysfunction(serum creatinine: $\geq$1.4 mg/dl) (group A 17, 23$\%$ vs group B 14, 9$\%$) (p=0.024). There was no difference of the mean number of distal anastomosis and the left ventricular ejection fraction in group A decreased significantly from 53.7$\pm$13$\%$ preoperatively to 49.9$\pm$ 12$\%$ postoperatively (p=0.02), but not changed in group B. There was no difference at operative mortality rate and postoperative major morbidity rate, but wound problem of saphenous vein harvest site was significantly higher in group A than group B (6.8$\%$ vs 0.7$\%$, p=0.02). The mean follow up duration was 24.3$\pm$13 months and the cumulative survival were 95.4$\%$ at 2 year and 79.9$\%$ at 4 year in group A and 95.4$\%$ at 2 year and 90.1$\%$ at 4 year in group B (p=ns). Conclusion: We conclude that age is not a factor of determination when we decide about operation because coronary artery bypass grafting in elderly more than 70 years old can be performed with a low mortality rate and acceptable morbidity rate.

• Journal of Chest Surgery
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• v.36 no.4
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• pp.261-266
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• 2003

Background: Surgery of abdominal aortic aneurysm revealed high operative mortality. We reviewed our 11-years' experiences of abdominal aortic aneurysm operation and wish to obtain information on the treatment. Material and Method: From Jan. 1990 to Dec. 2000, 48 patients were operated due to abdominal aortic aneurysm in Yonsei Cardiovascular Center Mean age was $62.8{\pm}12.7$ and there were 40 males and 8 females. Among 48 patients, nine patients had ruptured abdominal aortic aneurysm, and mean aneurysm diameter of non-ruptured cases was $8.8{\pm}2.4$cm. Result: There were 6 early deaths, and early mortality was 12.5%. Among 9 patients of preoperative aneurysm rupture, three patients died (33.3%), and among 39 patients of non-ruptured cases, 3 patients died (7.7%). Among preoperative variables, age (p<0.05), preoperative BUN level (p<0.05), and DM (p<0.05) were risk factors of early mortality. Among discharged 42 patients, 40 patients were followed up (f/u rate=95.2%) and mean follow up was $3.6{\pm}0.2$ years. During follow up periods, five patients died (late mortality=11.9%), and Kaplan-Meier survival analysis revealed $81.7{\pm}7.6$% survival rate at five and ten year. Linealized incidence of graft related event was 3.53% per patient-year. Conclusion: Surgical mortality of ruptured abdominal aortic aneurysm was higher than non-ruptured cases; therefore, early resection of the aneurysm can decrease the surgical mortality.

• Journal of Chest Surgery
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• v.36 no.5
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• pp.309-315
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• 2003

Background: To avoid the adverse effects of cardiopulmonary bypass and to overcome late vein graft failure we routinely peformed off-pump total arterial coronary revascularization. Material and Method: From July 2000 to August 2001, 104 consecutive patients underwent first elective off-pump total arterial coronary revascularization. Both internal mammary, radial and gastroepiploic arteries were used. Sequential and composite grafts were used to achieve complete revascularization. Perioperative adverse events and postoperative angiograms were analyzed. Result: A total of 252 arterial conduits were used with an average of 2.47 grafts per patient. A total of 326 distal anastomosis were performed with a mean of 3.13 distal anastomosis per patient. Cross over to on-pump occurred in seven patients (6.7%). Of these 4 were due to unstable hemodynamics during lateral or posterior wall stabilization as a result of cardiomegaly and 3 were due to uncontrolled bleeding during dissection of diffusely dimunitive deeply placed intramyocardial coronary arteries. There were no opeartive deaths. Two cases of perioperative myocardial infarction and transient neurologic complications occurred, respectively. Of the 312 distal anastomoses, 308 (98.7%) were compatible with Fitz-Gibboll A or B patency grading. Conclusion: Off-pump total arterial coronary revascularization was technically feasible in most elective cases with satisfactory early results. However, on-pump coronary bypass surgery should be considered in difficult circumstances, such as cardiomegaly or unfavorable anatomy of the target coronary artery.

• Journal of Periodontal and Implant Science
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• v.38 no.2
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• pp.237-246
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• 2008

Purpose: If bone grafts and guided tissue regeneration are effective individually in treating osseous defects, then the questionis, what would happen when they are combined. Bone grafts using Calcium Carbonate(Biocoral) and Guided Tissue Regeneration using Calcium Sulfate(CALMATRIX) will maximize their advantages and show the best clinical results in intrabony defects. This study was to compare the effects of a combination of CS and CC with control treated only with modified widman flap in a periodontal repair of intrabony defects. Materials and Methods: 30 patients with chronic periodontitis were used in this study. 10 patients were treated with a combination of CS and CC as the experimental group II and another 10 patients were treated with CC as the experimental group I, and the remaining 10 patients, the control group were treated only with modified widman flap. Clinical parameters including probing depth, gingival recession, bone probing depth and loss of attachment were recorded 6 months later. Results: The probing depth changes were $3.30{\pm}1.34\;mm$ in the control group, $4.2{\pm}1.55\;mm$ in the experimental group I(CC) and $5.00{\pm}1.33\;mm$ in the experimental group II(CS+CC). They all showed a significant decrease 6 months after surgery(p<0.01). There was a significant difference(p<0.05) between the control and experimental group. However there were no significant difference(p<0.05) between the experimental group I and II. The gingival recession changes w $-1.30{\pm}1.25\;mm$ in the control group, This is a significant difference(p<0.01). However, there was a $-0.50{\pm}0.53\;mm$ change in the experimental group I(CC) and $-0.60{\pm}0.97\;mm$ in the experimental group II(CS+CC). In addition, in terms of gingival recession, there was a no significance difference(p<0.05) among the groups. The clinical attachment level changes were $2.00{\pm}1.33\;mm$ in the control group, $3.60{\pm}1.58\;mm$ in the experimental group I(CC) and $4.40{\pm}1.17\;mm$ in the experimental group II(CS+CC). They all showed a significant decrease 6 months after surgery(p<0.01). There was a significant difference(p<0.05) between the control and experimental group. However there was a no significance difference(p<0.05) between the experimental group I and II. The bone probing depth changes were $0.60{\pm}0.52\;mm$ in the control group, $3.20{\pm}1.48\;mm$ in the experimental group I(CC) and $4.60{\pm}1.43\;mm$ in the experimental group II(CS+CC). All of them showed a significant decrease 6 months after surgery(p<0.01), there was a significance difference(p<0.05) among the groups. Conclusion: Treatment using a combination of CS and CC have a potential to improve periodontal parameters in intrabony defects and More efficient clinical results can be expected in intrabony defects less than 2 walls grafted with CS and CC.