• Journal of Chest Surgery
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• v.16 no.4
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• pp.602-614
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• 1983

Six hundred fourteen consecutive cases of bioprosthetic cardiac valve replacement performed during the period from March 1976 through December 1982 were reviewed. A total of 748 tissue valves [534 Ionescu-Shiley valves, 144 Hancock valves, 46 Angell-Shiley, and 24 Carpentier-Edwards] were implanted in 610 patients. Of these, 477 had single valve replacements [403 mitral, 60 aortic, and 14 tricuspid] including three REDO MVR and one REDO AVR. The remaining 129 had double valve replacements [95 AVR and MVR and 34 MVR and TVR] and 8 had triple valve replacement.592 cases were evaluated. Overall early mortality rate [within 30 days of operation] was 7.1% [6.2% in single valve replacement, 10.2% in double valve replacement, and 16.7% in triple valve replacement]. Leading causes of mortality were low cardiac output or myocardial failure and ventricular arrhythmias. The follow-up period was from one month to 7 years with a cumulative follow-up of 906.6 patient-years [mean 1.53 years]. The late mortality was 1.6%, 3.9%, 0%, 2.6%, 6.6% and 2.0% per patient-year for MVR, AVR, TVR or triple valve replacement, AVR+MVR, MVR+TVR and total, respectively. Actuarial analysis of late results including early mortalities indicates an expected survival rate of 87.6+1.8% at 3 years and 85.92.4% at 7 years for all cases. We also analyzed actuarial survival rate between groups of each valve replacement [AVR, TVR, Double valve, and Triple valve] and the tissue valve groups in MVR. We experienced 7 cases [0.77% per patient-year] of confirmed endocarditis, two of which were fatal. Valve failure-free rates calculated according to the confirmed cases were 97.5% at 4 years, 87.5% at 7 years, and 88.3% at 6 years for Ionescu-Shiley, Hancock and Angell-Shiley valves, respectively. The occurrence rate of thromboembolism was 2.0% per patient-year in total cases, although almost all the patients were given anticoagulant therapy for one year. The occurring rate in MVR was 1.5% and 2.7% per patient-year for Ionescu-Shiley and Hancock valve groups, respectively. The difference in actuarial rate free from thromboemboli between Ionescu-Shiley and Hancock groups was statistically significant [P value less than 0.001]. Thromboembolic events beyond the period of anticoagulation therapy mainly occurred in patients with atrial fibrillation. The actuarial thromboemboli free survival was 95.71.4% at 3 years and 80.17.3% at 7 years. The incidence of hemorrhagic complications was 1.2% per patient-year [fatality 0.55% per patient-year] for anticoagulated patients. Although our clinical data favorably compares with results from other reports, our results suggest that anticoagulant therapy be given on a short-term basis or not at all to hemodynamically stable patients. Long-term therapy with antiplatelet drugs is probably inevitable with patients who have thromboembolic risk factors [such as atrial fibrillation].

• Journal of Chest Surgery
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• v.25 no.5
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• pp.494-503
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• 1992

The durability of the xenograft cardiac substitute valves is of a great concern on the clinical grounds. Four groups of tc tal and consecutive patients to the end of study operated on between 1976 and 1984 were Group ISM, 291 patients of MVR, ISA, 65 patients of AVR, and ISMA, 107 patients of MVR+AVR with the standard Ionescu-Shiley bovine pericardial valve, and H, 163 patients of valve replacement with the Hancock porcine aortic vlave. Operative mortality was 5.2%[ISM], 10.8%[ISA], 7.5%[ISMA] and 6.1%[H]. Early survivors were followed up for a total of 1148.3 patient-years[pt-yrs] [ISM], 271.2 pt-yrs [ISA], 488.1 pt-yrs[ISMA] and 822.9 pt-yrs[H]. Linearized late mortality was 2.1% /pt-yr [ISM], 1.l%/pt-yr[ISA], 1.8%/pt-yr[ISMA] and 1.8% /pt-yr[H]. Thromboembolic complication was experienced at the linearized rate of 1.045% /pt-yr [ISM], 1.475%/pt-yr[ISA], 0.615%/pt-yr[ISMA] and 1.822%/pt-yr[H], and bleeding complication at the rate of 0.871% /pt-yr[ISM], 0.63% /pt-yr[ISA], 0.205% /pt-yr [ISMA] and 0.729%a /pt-yr[H], respectively. Prosthetic valve endocarditis occurred at the rate of 0.610% /pt-yr[ISM], 1.475% /pt-yr[ISA], 1.639% /pt-yr[ISMA] and 0.972% /pt-yr[H]. The linearized annual incidence of primary tissue failure was 1.655%/pt-yr[ISM], l. 475%/pt-yr[ISA], 1.639% /pt-yr[ISMA], 2.187% /pt-yr[H] and 1.785% /pt-yr[Group HM : MVR with Hancock valve]. The incidence of tissue failure was significantly high in the patients younger than 30 years of age compared with the older patients. The actuarial survival was 87.7$\pm$2.5% at 10 years[ISM], 94.3$\pm$3.2% at 11 years[ISA], 89.6$\pm$3.4% at 10 years[ISMA] and 81.3$\pm$6.6% at 12 years[HM], The freedom from thromboembolism was 93.2$\pm$2.0% at 10 years[ISM], 90.6$\pm$4.6% at 11 years[ISA], 95.8$\pm$2.6% at 10 years[ISMA] and 80.9$\pm$11.1% at 12 years[HM], And, the freedom from primary tissue failure was 84.2$\pm$3.8% and 28.1$\pm$23.0% at 9 and 10 years[ISM], 60.4$\pm$16.9% at 11 years[ISA], 62.3$\pm$12.7 at 10 years[ISMA] and 65.6$\pm$9.8% at 12 years[HM]. In conclusion, the standard Ionescu-Shiley and the Hancock bioprosthetic valves are excellent in their antithrombogenicity and long-term survival. However, the features of the structural failure with the prolonged follow-up beyond 10 years appear to be guarding, and the clinical indications of these bioprostheses seem to be quite limited.

• Journal of Chest Surgery
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• v.30 no.9
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• pp.891-898
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• 1997

Between May 1984 and January 1996, 130 patients were replaced cardiac valve using 150 St. Jude Medical prosthetic valves(42 aortic, 68 mitral, 20 aortic and mitral valve replycements). Follow-up was 97.6% complete. The early mortality rate was 5.4%, and late mortality rate was 4.9%. The valve-related late mortality rate was 3.3%. Of late complications, there were 6 anticoagulant related hemorrhages, 4 thromboembolisms and 1 paravalvular leakage. Linearized rates of late complication and valve-related late mortality were as follows: total late complications, .1.68o per patient-year: anticoagulant related hemorrhages, 0.92% per patient-year: thromboembolism, 0.61% per patient-year: paravalvular leakage, 0.15% per patient-year: reoperation, 0.15% per patient-year: and valve-related late mortalities, 0.61% per patient-year. Actuar al event free rate at 10 years was 87.4 $\pm$ 3.2%. The overall actuarial survival rate was 90.4$\pm$2.7% at 5 years, 87.5$\pm$3.3% at 10 years. Ninety eight percent of the survivors were in the New York Heart Association functional class I or II at the end of follow-up. There was significant improvement of cardiothoracic ratio. In conclusion, this study suggests the excellent durability of the St. Jude Medical Heart valve and remarkable functional benefit for the majority of the patients. However, prosthesisrelated complications are still common. Outcome is strongly related to the patient's preoperative cardiac condition and to the adequacy of anticoagulation control.

• Journal of Chest Surgery
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• v.42 no.2
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• pp.193-200
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• 2009

Background: The long-term administration of oral anticoagulant to the patients with a mechanical heart valve prosthesis is mandatory. However, the appropriate intensity of oral anticoagulant therapy to prevent thromboembolic or hemorrhagic complications is still controversial. We tried to apply low intensity anticoagulant therapy for which the International Normalized Ratios ranged between 1.5 and 2.5, and we analyzed the anticoagulation-related long term outcomes. Material and Method: From January 1992 to December 2002, 144 patients who underwent a single cardiac valve replacement were included in the study, and their ages ranged from 15 to 72 years (mean age: $47.4{\pm}15.1$): there were 49 aortic valve replacements (AVR) and 95 mitral valve replacements (AVR). The patients were followed up monthly or bi-monthly at the outpatient clinic with clinical examinations and measuring the prothrombin time to adjust the International Normalized Ratios (INRs) within the low-intensity target range between 1.5 and 2.5. Result: The follow-up period was 835.3 patient-years (mean: $5.9{\pm}3.5$) and the INRs of 7,706 measurements were available for evaluation. The mean INRs of the aortic and the mitral valve replacement groups were significantly different (p<0.01). All the patients' INRs were within the target range in 61.9% of the measurements. The mean INRs $(2.16{\pm}0.23)$ of the patients with atrial fibrillation, which was found in 30.3% of the patients, were definitely higher than those $(2.03{\pm}0.27)$ measured in the patients with regular rhythm (p<0.01). Thromboembolic episodes occurred in 9 patients with an incidence of 1.08%/patient-year. Major bleeding occurred in 2 patients (MVR) with an incidence of 0.24%/patient-year. The patients who displayed better compliance showed a lower incidence of complications (p=0.000). Conclusion: The anticoagulation therapy with a low-intensity target range after MVR or AVR seems to be effective and feasible, and increasing the patients’ compliance should be done for achieving more effective anticoagulation therapy.

• Journal of Chest Surgery
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• v.31 no.12
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• pp.1172-1182
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• 1998

Background: Primary goal of anticoagulation treatment in patients with mechanical heart valve is the effective prevention of thromboembolism and safe avoidance of bleeding as well. Material and Method: Two-hundred and nine patients with the St. Jude Medical prosthesis operated on between 1984 and 1995, for mitral(MVR 122), aortic(AVR 39) and double mitral and aortic valve replacement(DVR 48) respectively, were studied on the practically achieved levels of anticoagulation and the clinical outcomes. Patients were on Coumadin and followed up by monthly visit to outpatient clinic for examination and prothrombin time measurement to adjust the International Normalized Ratios(INRs) within the low-intensity target range between 1.5 and 2.5. Result: A total anticoagulation follow-up period was 1082.0 patient- years(mean 62.1 months) and INRs of 10,205 measurements were available for evaluation. The accomplished INRs among the replacement groups were not significantly different and only 65% of INRs were within the target range. And, in individual patients, only 37% of patients had INRs included within the target range in more than 70% of tests during follow-up period. The levels of INRs in patients with atrial fibrillation, which was found in 57% of patients, were definitely higher than the ones measured in patients with regular rhythm(p<0.001). Thromboembolisms were experienced by 15 patients with the incidence of 1.265%/patient- year(MVR 1.412%, AVR 0.462% and DVR 1.531%/patient-year) and major bleeding by 4 patients with the incidence of 0.337%/patient-year(MVR 0.424%, AVR none and DVR 0.383%/patient-year). Frequent as well as prolonged missing of prothrombin time tests was the main risk factor strongly associated with the thromboembolic complications(odds ratio 1.99). The proportion of INRs within target range of less than 60% in individual patient was the highly significant risk factor of both thromboembolic and overall embolic and bleeding complications(p<0.004 and p<0.002 respectively). Conclusion: In conclusion, the low-intensity therapeutic target range of INRs was adequate in patients with AVR and in sinus rhythm. However, the patients with replacement of the mitral valve were more likely to require higher target range of INRs, especially in the presence of atrial fibrillation, to achieve the practical levels of anticoagulation enough to prevent thromboembolic complications effectively. For the higher therapeutic target range of INRs between 2.0∼3.0, further accumulation of clinical evidences are required. It is highly desirable to improve the patients' compliance under continuous instructions in visiting outpatient clinic and in taking daily Coumadin without omission and to keep INRs consistently within optimal range with tight control for minimization of chances and of periods of exposure to the risk of complications. And, particularly, patients with high risk of complications and with wide fluctuation of INRs should be better managed with frequent monitoring anticoagulation levels.

• Journal of Chest Surgery
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• v.32 no.4
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• pp.341-346
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• 1999

Background: Thirty children ranging from 3 to 15 years of age underwent cardiac valve replacement at Dongsan Medical Center from 1982 to 1997. Material and Method: There were 16 boys and 14 girls. The mean age was 12.1. The underlying pathological cause for valve replacement was congenital heart disease in 17 children and acquired heart disease in 13. The valve replaced was mitral in 15 children, aortic in 11, tricuspid in 3, and combined aortic and mitral in 1. Twenty-one mechanical and 10 tissue valves were placed: primary mechanical valve have been utilized since 1985. Eight of ten patients with tissue valves have had successful second valve replacements 4 to 11 years after the initial operation. Result: The operative mortality was 6.7%, but mortality was higher among patients less than 5 years of age and patients who had previous cardiac operations. Of the 28 operative survivors, 4 patients were lost to follow-up: the remaining patients were observed for a total of 2091 patient/months(mean 74.7 months, maximum 187 months). There was one late death from dilated cardiomyopathy after mitral valve replacement in 7 year-old patient with atrioventricular septal defect. After the operation, all patients with mechanical valves were placed on a strict anticoagulant regimen with Coumadin. The actuarial survival rate was 96% at the end of the follow-up. No instance of thromboembolism or major bleeding were observed in the survivors. Conclusion: These results indicate that valve replacement can be performed with low mortality in children, and with satisfactory long-term survival.

• Journal of Chest Surgery
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• v.30 no.2
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• pp.137-145
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• 1997

From July 1983 to December 1993, total 112 consecutive mitral valve replacements in 107 patients were performed in patient with mitral valvular abnormalities. To estimate the risk factor related to operative death, all patient's perioperative data were reviewed retrospectively. Except 20 patients received concomitant aortic valve replacement and 2 patients had incomplete data, 85 patients were included in this study. Mean age were $37.3\pm$ 13.1 years ranging from 13 to 72 years. Thirty-seven patients were male and fourty-eight patients were female. Mean follow-up durations were $51.1\pm33.8$ months ranging from 6 months t 11 years. Patients in this study showed improvement in mean NYHA functional clssification, from $3.02\pm0.73$ to 1 $78\pm0.55,$ and also in cardiothoracic ratio, from 0.61 $\pm0.09$ to $0.58\pm0.08$ at 6 months follow-up after operation. Operative complications were detected in 23 patients(27.1 %) and common postoperative complications were rhythm disturbance in 7 cases, pulmonary complications in 6 cases and low cardiac output syndrome in 6 cases. Early mortality was 10.6%(n=9) and the most common cause of death was a congestive heart failure due to low cardiac output syndrome. Main cause of our higher operative mortality than other study was that operative mortality in the initial period of our mitral surgery was high(5 operative deaths among 19 mitral valve replacement from July 1983 to December 1985). Actuarial survival was 80.8% at 5 years, 71.8% at 11 years including operative deaths. Actuarial freedom from anticoagulant-related bleeding was 85.3% at 5 years, 78.3% at 11 years. 95.1% at 5 years and 88.8% at 11 years among the patient in this study were free from thromboembolism, and 97.5% at 5 years and 75.1% at 11 years were free from reoperation. Preoperative cardiothoracic ratio and patient's age were statistically significant operative risk factors.

• Journal of Chest Surgery
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• v.39 no.12 s.269
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• pp.891-899
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• 2006

Background: This study is to evaluate the safety of ATS valve by examining the clinical results of ten-years experience. Material and Method: From July 1995 to March 2005, we reviewed 305 patients with ATS valve implantation. Mean age was $49.8{\pm}11.7$ years and 140(45.6%) males were included. Etiologies were rheumatic diseases in 207 cases(67.4%), degenerative changes in 57 cases(18.6%), valve dysfunction in 23 cases(7.5%) and infective endocarditis in 14 cases(4.6%). AVR was performed in 72 patients(23.5%), MVR in 156 patients (50.8%), DVR(AVR+MVR) in 63 patients(20.5%) and TVR in 16 patients(5.2%). Result: There were 9 operative mortalities(2.9%). Follow up period was $56.5{\pm}34.0(0{\sim}115)$ months and 96.4% patients were followed up with 9 late deaths. Five and ten years survival rates were $94.9{\pm}1.3%,\;91.2{\pm}2.3%$ using Kaplan-Meier's methods. Valve related event free survival rates in 5 and 10 years were $90.8{\pm}2.0%$ and $86.9{\pm}3.2%$. There were 16 anticoagulation-related hemorrhages, 6 thromboembolisms, 3 prosthetic valve endocarditis and 1 paravalvular leakage. NYHA class improved after operation(p<0.05). Postoperative echocardiography showed significant decrease in LA size, LVEDD and IVESD(p<0.01). Patients with 19 and 21 mm valve showed significantly higher transvalvular pressure gradient in aortic position(p<0.001, p<0.001). Conclusion: ATS valve showed good hemodynamic results with few valve related complications and thus can be used with acceptable risk.

• Journal of Chest Surgery
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• v.38 no.11 s.256
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• pp.761-772
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• 2005

Background: Following the implantation of heart valve prostheses, it is important to maintain therapeutic INR to reduce the risk of thromboembolism. The objective of this study was to suggest a practical dosing guideline for Korean outpatients with prosthetic heart valves managed by a pharmacist-run anticoagulation service (ACS). Material and Method: A retrospective chart review was completed for all patients enrolled in the ACS at Seoul National University Hospital from March, 1997 to September, 2000. Patients who were at least 6 months post-valve replacement and had nontherapeutic INR value (less than 2.0 or greater than 3.0) were included. The data on 688 patients (1,782 visits) requiring dosing adjustment without any known drug or food interaction with warfarin were analyzed. The amount of adjusted dose and INR changes based on the INR at the time of the event were calculated. Aortic valve replacements (AVR) patients and mitral or double valve replacement (MVR/DVR) patients were evaluated separately. Result: Two methods for the warfarin dosage adjustment were suggested: Guideline I (mg-based total weekly dose (TWD) adjustment), Guideline II (percentage-based TWD adjustment). The effectiveness of Guideline 1 was superior to Guideline II overall in patients with both AVR and MVR/DVR. Conclusion: The guideline suggested in this study could be useful when the dosage adjustment of wafarin is necessary in outpatients with mechanical heart valves.

• Journal of Chest Surgery
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• v.31 no.4
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• pp.346-352
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• 1998

Rheumatic valvulitis produces at least three distinct pathologic changes, the degree varying widely among the patients: fusion of the valve leaflets at the commissures; fusion and shortening of chordae tendinae: and fibrosis of the leaflets with subsequent stiffening, contraction and calcification. The most extensive changes usually are seen in patients with recurrent attacks of rheumatic fever. We studied on outcome of the surgical treatments of rheumatic valvular diseases that have been experienced for 12 years since 1982 at Pusan National University Hospital. The diagnoses were made by rheumatic fever history, echocardiographic findings, gross operative findings and microscopic findings. Total 502 patients were performed surgery for valvular heart diseases and 440 patients of rheumatic origin have bene analysed. There were more female than male patients as 1.3:1, and the mean age was 37.8 years old. 96.3% of them affected to the mitral valve, 19.8% to aortic valve, 16.3% affected to the tricuspid valve. Most of them underwent valve replacement, and valve repair was done in 3.9% of patients. There were 36 hospital deaths(8.2%) mainly from low cardiac output syndrome, and 15 late deaths equally due to embolism and hemorrhage. Follow up was 90.1% completed(2890 patient- year). Linealized rates of late complication events are follows : thromboembolism 1.3% per patient year; anticoagulant related hemorrhage 0.8% per patient year. Overall actuarial survival including hospital mortality was 92.7＋/-2.9% in 1 year, 88.0＋/-4.5% in 5 year, 82.3＋/-7.7% in 10 year. We conclude that the rheumatic disease is still the most frequent and the most important cause of heart valve disease. So more intensive study is needed in spite of the abrupt decreasing rate of rheumatic fever in U.S.A. and other industrial country.