• Proceedings of the KOSOMBE Conference
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• v.1989 no.05
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• pp.5-6
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• 1989

Polyurethane surface was chemically modified to have different hydrophilic polyethyleneoxide(PEO)/hydrophobic dodecanediol(DDO) groups and negatively charged sulfonate group to investigate the effect to the antithrombogenicity. The hydrophilicity of the surface was significantly increased after PEO grafting or sulfonation. Lowering in-vitro platelet adhesion led to a prologation in the ex-vivo occlusion time. Especially, the sulfonated PU-PEO surface showed most enhanced blood compatibility due to the synergistic effects of PEO and $SO_3$ groups.

• Journal of Chest Surgery
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• v.20 no.2
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• pp.289-299
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• 1987

A total of 1,239 patients had cardiac valve replacement using 1,514 substitute valves at Seoul National University Hospital from 1968 to 1986. Of the total substitute vales, 84.9% were the glutaraldehyde-treated xenograft valves. Six hundred ninety-four patients who had 820 bioprosthetic tissue valves were studied for their clinical characteristics. They were a total and consecutive cases to the end of the study. Four hundred sixty-four patients had the lonescu-Shiley pericardial valves: MVR 291, AVR 66 and MVR+AVR 107; 163 had the Hancock porcine valves; 46 had the Angell-Shiley porcine valves; and 21 had the Carpentier-Edwards porcine valves. Five hundred forty patients underwent single valve replacement: MVR 460, AVR 76 and TVR 4; 154 had multiple valve replacement: MVR+AVR 141, MVR+TVR 12 and one triple valve replacement. Additional surgery was necessary in 22.3% of the cases. Operative mortality rate within 30 days of surgery was 6.77% for the total patients: 5.2% and 4.2% with MVR, 13.6% and 12.5% with AVR, and 7.5% and 7.4% with MVR+AVR using the lonescu and the Hancock valves respectively. A linealized annual late mortality rate was 2.56%/patient-year. Six hundred forty-three operative survivors were followed up for a total of 1482.7 patient-years [a mean 27.7 months], and the follow-up rate was 67.7%. The Idealized complication rates were: 2.02% emboli/patient-year, 0.94% bleeding/patient-year, 1.21% endocarditis/patient-year, and 3.84% overall valve failure/patient-year. A linealized rate of primary tissue failure was 0.87%/patient-year. Actuarial survival rates including the operative mortality were: 87.8*2.6%, 82.3*4.9% and 82.2*4.7% with MVR, AVR and MVR+AVR using the lonescu valves at 4 years after surgery respectively; and they were 88.0*4.1% with MVR at 8 years, 82.3*4.9% with AVR at 4 years and 84.9*7.0% with MVR+AVR at 6 years after surgery using the Hancock valves respectively. Probabilities of freedom from thromboembolism were 89.8*6.3% with MVR using the lonescu valves at postoperative 5 years and 89.2*3.8% with MVR using the Hancock valves at postoperative 7 years, and 93.3*3.9% with AVR using the lonescu valves at postoperative 5 years. None had embolic complication after AVR using the Hancock valves. Probabilities of freedom from valve failure [according to the Stanford criteria] were 81.0*7.1% with MVR using the lonescu valves at postoperative 4 years and 57.4*12.5% with MVR using the Hancock valves at postoperative 9 years. These clinical results prove the excellent antithrombogenicity of the glutaraldehyde-treated xenograft substitute valves and confirm the previously speculated rate of tissue failure. At the present situation, it may be concluded that there is a room for the further development of more durable bioprosthetic valves.

• Journal of Chest Surgery
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• v.22 no.6
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• pp.980-989
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• 1989

The Hancock porcine xenograft valves had been used in Seoul National University Hospital, mainly because of their antithrombogenicity despite of the predicted failure, from March 1976 to April 1984, and a total and consecutive 163 patients were retrospectively studied for late results with the special stress on the structural failure. The hospital mortality rate [within 30 days] was 6.1 %, and the 153 early survivors were followed up for a total of 822.9 patient-years [p-y][Mean * SD 5.38 * 3.02 years]. The linealized late mortality was 1.823%/p-y. Four major complications related to the Hancock valve were: 1.822% thromboembolism/p-y; 0.729 % bleeding/p-y; 0.972% endocarditis/p-y; 3.646% overall valve failure/p-y and 2.187 % primary tissue failure [PTF]/p-y. The actuarial survival rates at 5 and 10 years were 94.90 * 1.89% and 80.58 * 5.21 %; and the probabilities of freedom from thromboembolism at 5 and 10 years were 90.93 * 2.63% and 83.35 * 7.64 9o respectively. The probabilities from PTF at 5, 10 and 12 years were 98.02 * 1.39%, 60.62 * 8.89% and 49.60 * 12.34 %. One hundred-eighteen patients [72.4%] had single MVR [age, 34.0 * 10.9 years] with the operative mortality rate of 4.2%; and 113 early survivors were followed up for a total 616.4 patient-years[5.46 * 2.96 years]. The late mortality rate was 1.460 %/p-y. The major complications were: 1.622 % thromboembolism /p-y; 0.487% bleeding/p-y; 0.649 % endocarditis/p-y; 2.920% primary valve failure/p y and 1.785% PTF/p-y. The actuarial survival rates were 97.08 * 1.67%[at 5 years] and 81.27 * 6.64%[at 10 years], and the probabilities of freedom from thromboembolism 92.44 * 2.76 %[at 5 years] and 80.89 * 11.08%[at 10 years]. The probabilities of freedom from PTF at 5 and 10 years were 98 70 * 1.29% and 65.59 * 9.78% respectively. The mean age of 11 patients of PTF was 25.7 * 8.8 years and the valve extraction period 7.16 * 1.45 years. Failure of bioprosthetic xenograft valves are reportedly known to occur earlier in young patients in an accelerated fashion. The study with two groups divided into the cumulative younger and the cumulative older patients according to the age limits of 5-year interval strongly suggested these tendency. Although PTF began to occur past postoperative 5 years and the probabilities of freedom from PTF increased as the age limits raised and the number of patients increased in the cumulative younger patients while they decreased as the age limits lowered and the number of patients increased in the cumulative older patients, the definite age limits from which the Hancock valve can be safely recommended could not be obtained. From the results, the Hancock valves are contraindicated in patients younger than 20 to 25 years and may be safely recommended in patients older than 45 years as a tentative conclusion. Further longitudinal study may define these age factors.

• 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.