• Journal of Korean Society for Quality Management
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• v.39 no.3
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• pp.391-399
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• 2011

Our study was carried out to analyze the variation factors of severity-adjusted length of stay(LOS) in coronary artery bypass graft(CABG). The subjects were 932 CABG inpatients of the Korean National Hospital Discharge In-depth Injury Survey from 2004 through 2008. The data were analyzed using $x^2$ test and the severity-adjusted model was developed using data mining technique. The results of the study were as follows: male(71.1%), older than 61 years of age(61.6%), more than 500 beds(92.8%) and admitting via ambulatory care(70.0%) appeared to have higher rate than otherwise. In-hospital mortality of CABG inpatients was 2.8%. In addition, 46.4% of the patients received their care in other residence. The angina pectoris(45.6%) was found to be the highest in principle diagnosis, followed by chronic ischemic heart disease(36.9%) and acute myocardial infarction(12.0%). We developed severity-adjusted LOS model using the variables such as gender, age and comorbidity. Comparison of adjusted values in predicted LOS revealed that there were significant variations in LOS by location of hospital, bed size, and whether patients received the care in their residences. The variations of LOS can be explained as the indirect indicator for quality variation of medical process. It is suggested that the severity-adjusted LOS model developed in this study should be utilized as a useful method for benchmarking in hospital and it is necessary that national standard clinical practice guideline should be developed.

• Journal of Chest Surgery
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• v.32 no.11
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• pp.1009-1016
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• 1999

Background: Minimally invasive direct coronary artery bypass surgery(MIDCAB) has been increasing in interest along with the new techniques in myocardial immobilization for easier and safer procedures. Until the opening of the era of new techniques, adequate accuracy and good patency of grafts were debatable. Our experiences of MIDCAB were studied according to the stages of technical developments. Material and Methods: Since March 1996, 55 patients have undergone MIDCAB procedures. The patients of off-pump CABG(no cardiopulmonary bypass under full sternotomy) were excluded from the study. In the early experience(Stage I), a left anterior small thoracotomy through the left parasternal incision was performed(n=6); then an approach through the lower partial sternotomy was used(Stage II, n=33); and recently, a chest wall elevator for harvesting the internal thoracic artery and the foot plate for myocardial immobilization have been used(USSC, Norwalk, CT)(Stage III, n=16). Result: The surgical procedures of four patients in the Stage II group have been converted to conventional bypass because of the deeply seated left anterior descending coronary artery in two patients, fracture of the calcific lesion in the right coronary artery in one patient, and a cardiogenic shock during hypothermia in the other patient with ventricular dysfunction. Two patients in stage II experienced symptomatic recurrences after surgery and restenosis was verified on angiocardiography. They were managed by interventional procedures. All the other patients were doing well without symptoms, except one patients in Stage II who underwent PTCA procedure for a lesion in the circumflex artery during the follow up period. Conclusion: The new and specialized devices are essential to the development of MIDCAB surgery. MIDCAB and the hybrid procedures in multi-vessel disease are on the way to further development. So far, our experience is limited only to a single device among the many new devices for the purpose.

• Quality Improvement in Health Care
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• v.7 no.2
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• pp.218-228
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• 2000

Background : Among 'structure', 'process' and 'outcome' approaches, outcome evaluation is considered as the most direct and best approach to assess the quality of health care providers. Risk-adjustment is an essential method to compare outcome across providers. This study has aims to judge performance of hospitals by severity adjusted mortality rates of coronary artery bypass graft (CABG) surgery. Methods : Medical records of 584 patients who got the CABG surgery in 6 general hospitals during 1996 and 1997 were reviewed by trained nurses. The MedisGroups was used to quantify severity of patients. The predictive probability of death was calculated for each patient in the sample from a multivariate logistic regression model including the severity score, age and sex. For evaluation of hospital performance, we calculated ratio of observed number to expected number of deaths and z score [(observed number of deaths - expected number of deaths)/square root of the variance in the number of deaths], and compared observed mortality rate with confidence interval of adjusted mortality rate for each hospital. Results : The overall in-hospital mortality was 7.0%, ranged from 2.7% to 15.7% by hospital. After severity adjustment the mortality by hospital was from 2.7% to 10.7%. One hospital with poor performance was distinctly divided from others with good performance. Conclusion : In conclusion, severity-adjusted mortality rate of CABG surgery might be applied as an indicator for hospital performance evaluation in Korea. But more pilot studies and improvement of methodologies has to be done to use it as quality indicator.

• Journal of Preventive Medicine and Public Health
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• v.34 no.1
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• pp.21-27
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• 2001

Objectives : To develop a model that will predict the mortality of patients undergoing Coronary Artery Bypass Graft (CABG) and evaluate the perfermance of hospitals. Methods : Data from 564 CABGs peformed in six general hospitals were collected through medical record abstraction by registered nurses. Variables studied involved risk factors determined by severity measures. Risk modeling was performed through logistic repression and validated with cross-validation. The statistical performance of the developed model was evaluated using c-statistic, $R^2$, and Hosmer-Lemeshow statistic. Hospital performance was assessed by severity-adjusted mortalities. Results : The developed model included age, sex, BUN, EKG rhythm, Congestive Heart Failure at admission. acute mental change within 24 hours, and previous angina pectoris history. The c-statistic and $R^2$ were 0.791 and 0.001, respectively. Hosmer-Lemeshow statistic was 10.3(p value=0.2415). One hospital had a significantly higher mortality rate than the average mortality rate, while others were net significantly different. Conclusion : Comparing the quality of service by severity adjusted mortality rates, there were significant differences in hospital performance. The severity adjusted mortality rate of CABG surgery may He an indicator for evaluating hospital performance in Korea.

• Journal of Chest Surgery
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• v.40 no.9
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• pp.637-640
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• 2007

Papillary fibroelastoma is a rare benign cardiac tumor with an elevated risk for embolization and most papillary fibroelastomas do not cause symptoms. In this report, we describe a case of previous undiagnosed masses of the aortic valve that were incidentally found on intraoperative transesophageal echocardiography during coronary artery bypass surgery. Upon surgery, masses were found on the left and right aortic cusps and the pathological findings were consistent with a papillary fibroelastoma.

• The Korean Journal of Nuclear Medicine
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• v.32 no.6
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• pp.497-508
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• 1998

Purpose: Using rest T1-201/dipyridamole stress gated Tc-99m-MIBI/ 24 hour delay T1-201 SPECT, we investigated the predictive values of the markers of the stress-rest reversibility (Rev), T1-201 rest perfusion (Rest), T1-201 24 hour redistribution (Del) and Tc-99m-MIBI gated systolic thickening (Thk) for wall motion improvement after coronary artery bypass surgery. Materials and Methods: In 39 patients (M;F= 34:5, age $58{\pm}8$), preoperative and postoperative (3 months) SPECT were compared. 24 hour delayed SPECT was done in 16 patients having perfusion defects at rest. Perfusion or wall motion was scored from 0 to 3 (0: normal to 3: defect or dyskinesia). Wall motion was abnormal in 142 segments among 585 segments of 99 artery territories which were surgically revascularized. Results: After bypass surgery, ejection fraction increased from $37.8{\pm}9.0%$ to $45.5{\pm}12.3%$ in 22 patients who had decreased ejection fraction preoperatively. Wall motion improved in 103 (72.5%) segments among 142 dysfunctional segments. Positive predictive values (PPV) of Rev, Rest, Del, and Thk were 83%, 76%, 43%, and 69% respectively. Negative predictive values (NPV) of Rev, Rest, Del, and Thk were 48%, 44%, 58%, and 21%, respectively. Rest/gated stress/delay SPECT had PPV of 74% and NPV of 46%. Though univariate logistic regression analysis revealed Rev (p=0.0008) and Rest (p=0.024) as significant predictors, stepwise multivariate test found Rev as the only good predictor (p=0.0008). Conclusion: Among independent predictors obtained by rest T1-201/ stress gated Tc-99m-MIBI/ delayed T1-201 myocardial SPECT for wall motion improvement after bypass surgery, stress-rest reversibility was the single most useful predictor.

• Journal of Chest Surgery
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• v.36 no.11
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• pp.828-833
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• 2003

Background: It has been reported that the recently developed intermittent antegrade warm blood cardioplegia (IAWBC) has better myocardial protective effects during coronary artery bypass surgery than cold blood cardioplegia or continuos retrograde cold blood cardioplegia. The aim of this study is to evaluate the safety and usefulness of IAWBC by comparing it retrospectively with intermittent retrograde cold blood cardioplegia (lRCBC). Material and Method: From April 2001 to Feb. 2003, fifty seven patients who underwent isolated coronary surgery were divided into two groups (IAWBC vs. IRCBC). The two group had similar demographic and angiographic characteristics. There were no statistical differences in age, sex, Canadian Cardiovascular Society Functional Classification for angina, ejection fraction, and number of grafts. Result: Aortic cross clamping time and total pump time in IAWBC (99$\pm$23 and vs. 126$\pm$32 min) were shorter than those of IRCBC (118$\pm$32 min. and 185$\pm$48 min.)(p<0.05). The reperfusion time (13$\pm$7 min) in IAWBC was shorter than that of IRCBC (62$\pm$109 min.)(p<0.05). CKMB at 12 hours and 24 hours (16$\pm$15 and 9$\pm$13) in IAWBC was lower than that of IRCBC (33$\pm$47 and 17$\pm$26)(p<0.05). The awakening time in IAWBC (2$\pm$1 hour) was shorter than that of IRCBC (4$\pm$3)(p<0.05). The number of spontaneous heart beat recovery in IAWBC (85%) was more than that of IRCBC (35%)(p<0.05). The cardiac index after discontinuing cardio-pulmonary bypass was significantly elevated in the IAWBC group. The prevalence of perioperative myocardial infarction in IAWBC (4%) was lower than that of IRCBC group (20%)(p<0.05). Conclusion: Intermittent antegrade warm blood cardioplegia is a safe, reliable, and effective technique for myocardial protection. It can also provide simpler and economic way than the retrograde cold cardioplegia by shortening of cardiopulmonary bypass time and avoiding retrograde cannulation for coronary sinus.

• Journal of Chest Surgery
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• v.38 no.7 s.252
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• pp.483-488
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• 2005

Aortic valve-sparing procedures could reduce valve-related morbidity, but may increase operative risks; therefore, these procedures could not be performed routinely. We attempted to find out the early results while focusing on the operative risks associated with these procedures in our hospital. Material and Method: From May 1996 to July 2003, 26 patients underwent these procedures including 15 patients with Marfan syndrome and 1 patient with Behcet disease. There were 17 men and 9 women with mean age of $37.9\pm19.2$ years (range: 6 months-74 years). Ten patients had ascending aortic dissection, 18 patients had more than moderate degree of aortic valve insufficiency (AI). Two types of valve-sparing procedures were performed: valve reimplantation in 14 and root remodeling in 12 patients. Associated procedures were performed as follows: aortic valve plasty in 6, mitral valve plasty in 5, hemi-arch replacement in 4, total arch replacement in 2, coronary artery bypass surgery in 1 and Maze procedure in 1 patient(s). Result: In four patients, valve-sparing procedures were converted to Bentall procedures during operation. Including these patients, there was no operative deaths, 3 patients underwent re-operation due to bleeding, 1 patient had permanent pacemaker. The median duration of ICU stay was 45.5 hours, the median duration of hospital stay was 10.5 days. In 22 patients excluding 4 converted patients, intraoperative transesophageal echocardiogram (TEE) showed less than mild degree of AI in all except one who had not received intra-operative TEE in the beginning and showed moderate degree of AI at discharge. The mean duration of follow-up was $21.2\pm27.4$ months. All patients were alive except one who died during other departmental surgery. In 3 patients, more than moderate degree of AI was recurred, but there were no reoperation. Conclusion: Aortic valve-sparing procedures could be performed relatively safely in selected patients who had annuloaortic ectasia.

• Journal of Chest Surgery
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• v.35 no.2
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• pp.102-112
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• 2002

This study was undertaken to analyze the outcome of composite valve graftreplacement(CVGR) for the treatment of aneurysms of the ascending aorta involving the aortic root. Material and Method: Between April 1995 and June 2001, 56 patients had replacement of the ascending aorta and aortic root with a composite graft valve and were reviewed retrospectively. Aortic regurgitation was present in 50 patients(89%), Marfan's syndrome in 18 patients(32%), and bicuspid aortic valve in 7(12.5%). The indications for operation were annuloaortic ectasia(AAE) in 30 patients(53.6%), aortic dissection in 13(23.2%), aneurysms of the ascending aorta involving aortic root in 11(19.6%), and aortitis in 2(3.6%). Cardiogenic shock due to the aortic rupture was present in 2 patients. Nine patients(16%) had previous operations on the ascending aorta or open heart surgery. The operative techniques used for CVGR were the aortic button technique in 51 patients(91%), the modified Cabrol technique in 4, and the classic Bentall technique in 1. The concomitant procedures were aortic arch replacement in 24 patients(43%), coronary artery bypass graft in 8(14.3%), mitral valve repair in 2, redo mitral valve replacement in 1, and the others in 7 The mean time of circulatory arrest, total bypass, and aortic crossclamp were 21$\pm$14 minutes, 186$\pm$68 minutes, and 132$\pm$42 minutes, respectively. Result: Early mortality was 1.8%(1/56). The postoperative complications were left ventricular dysfunction in 16 patients(28.6%), reoperation for bleeding in 7(12.5%), pericardial effusion in 2, and the others in 7. Fifty-three patients out of 55 hospital survivors were followed up for a mean of 23.2 $\pm$ 18.7 months(1-75 months). There were two late deaths(3.8%) including one death due to the traumatic cerebral hemorrhage, and CVGR-related late mortality was 1.9%. The 1- and 6-year actuarial survival was 98.1$\pm$1.9% and 93.2$\pm$5.1%, respectively. Two patients required reoperation for complication of CYGR(3.8%) and two other patients required subsequent operations for dissection of the remaining thoracoabdominal aorta. The 1- and 6-year actuarial freedom from reoperation was 97.8$\pm$2.0% and 65.3$\pm$26.7%, respectively.

• Journal of Chest Surgery
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• v.39 no.12 s.269
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• pp.906-912
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• 2006

Background: Ventricular septal defect(VSD) is rare but feared complication after acute myocardial infarction. The patient could survive by surgery only, but the surgical mortality is still high. We investigate the surgical result and predictors for early surgical mortality. Material and Method: Between August 1993 and February 2006, 8 patients (male, 2: female, 6) with postinfarct VSD underwent surgical repair. Seven patients had one-vessel disease of left anterior descending artery, and 6 of them had wide extension of infarction to posterior septal wall as well as anterior septal wall of both ventricles. One patient had concomitant coronary bypass grafting to a coronary lesion unrelated to the infarction. Two patients had concomitant tricuspid annuloplasty and 1 patient mitral valvuloplasty. Result: Surgical mortality was 37.5%(3 patients). They all had only one-vessel disease of left anterior descending artery, which made extended posterior septal wall infarction as well as anterior septal wall infarction of both ventricles. In preoperative M-mode echocardiographic study of left ventricle, they had lower ejection fraction than survivors($34.9{\pm}4.2\;vs.\;54.8{\pm}12.3$; p=0.036). Conclusion: Most of patients with postinfarction VSD had one-vessel disease of left anterior descending artery. Early surgical mortality occurred in the patients with poor ejection fraction of left ventricle and the wide anterior septal wall infarction extending to the posterior septum.