• Journal of Chest Surgery
• /
• v.28 no.8
• /
• pp.731-741
• /
• 1995

Cardiac valve allografts have been used as replacements for diseased valves and right ventricular outflow tract reconstruction, the long term follow-up of which has been reported satisfactory. For a good long-term result, it is essential that the allograft be viable at implantation. In this study, we aimed at preparing the cardiac valve allografts aseptically, preserving them at cold- and cryo-conditions, and testing the viability of the allografts after preservation by four methods. We tested the viability of the cardiac valve allografts preserved in cold refrigerated state[4$^{\circ}$C in nutrient media & in liquid nitrogen tank[cryopreservation under -149$^{\circ}$C for pre-planned time periods. The testing methods were 1 glucose utility test 2 tissue culture 3 thymidine uptake test and 4 histologic evidence by light microscopy. We observed no differences in the viability between cold- & cryo-groups and similar results among the methods for testing the viability. In conclusion, there was no difference in the viability between cold- and cryopreserved-allografts at least for 14 days of preservation. And glucose utility test and thymidine uptake test were satisfactory in the evaluation of the allograft viability, since they were easy and rapid with relatively quantitative results.

• Journal of Chest Surgery
• /
• v.27 no.1
• /
• pp.1-8
• /
• 1994

Allograft cardiac valves have been used for over 30 years to replace diseased cardiac valves, reconstruct right or left ventricular outflow tract. With increasing its requirement, the establishment of a viable bank capable of maintaining the viability of graft over a prolonged period would be desirable. The method for determining the viability of allograft by metabolic assay technique using radiolabeled aminoacids has been used recently. An experimental study was done for evaluation of viability of cardiac allograft which was preserved for 14 days at 4oC in nutrient medium[fresh preservation] by metabolism assay technique using 3H-glycine. Also, the effectiveness of low concentration antibiotic solution[CLPV] for sterilization was evaluated. The effectiveness of CLPV solution for sterilization of allograft was perfect. Pre-treatment cultured organisms were not cultured after treatment at all in every cases. The viability of allograft after sterilization was reduced to 66.4%[aortic wall], 74.7%[pulmonary wall], 76.3%[aortic valve], 67.9%[aortic wall]. And after the fresh preservation for 14 days, the viability was reduced to 14.7%, 18.5%, 17.7%, 19.0%, respectively.In conclusion, viability of allograft was reduce to 71.3[66.4-76.3]% after sterilization and 17.5[14.7-19.0]% after fresh preservation. And sterilization effect of CLPV solution was satisfactory.

• Journal of Chest Surgery
• /
• v.30 no.6
• /
• pp.553-558
• /
• 1997

Arterial allografts have known advantages over prosthetic vascular conduit for treatment of heart valvular disease, congenital heart disease and aortic disease. Cell viability may play a role in determining the longterm outcome of allografts. Endothelial cell is one important part in determining the allograft viability. To evaluate the viability of endothelial cells using current allograft preservation technique, porcine heart valve leaflets and arterial wall were subjected to collagenase digestion. Single endothelial cell suspension was labeled with GSA-PITC(Griffonia simplicifolia agglutininfluorescein isothiocyan te), a vascular, endothelial cell specific marker. The cell suspension was washed and incubated with Pl(Propidium iodide), which does not bind with viable cells, Endothelial cell viability was evaluated by calculating the percentage of GSA-FITC(+) and Pl(-) group using flowcytometric analysis. Allografts were treated with $4^{\circ}C$ antibiotic solo!ion for 24 hours for sterilization. After this, half of allografts were stored in $4^{\circ}C$ RPMI 1640 with HEPES buffer culture medium with 10% fetal bovine serum for 1 to 14 days(Group I). Another half of allografts were cryopreserved with a currently used technique (Group II). During the procurement and sterilization of arterial allografts, 22.8% and 24.4% of endothelial cell viability declined, respectively. In Group I, 11.9% of endothelial cell viability declined further steadily during 14 days of storage. In Group II, 13.7% of endothelial cell viability declined. These results show that largest loss of endothelial cell viability occurs during the nitial process. After 14 days of arterial allograft storage under $4^{\circ}C$ nutrient medium or cryopreservation, about 40% of endothelial cell viability is maintained. There were no differences between the endothelial cell viability from aortic valve leaflet, pulmonic valve leaflets, aortic wall and pulmonic wall.

• Journal of Chest Surgery
• /
• v.30 no.8
• /
• pp.819-822
• /
• 1997

Aortic valve replacement with aortic allograft has been considered a treatment of choice for aortic valve disease secondary to bacterial endocarditis because of its good homodynamic performance and higher resistance to infection. The aortic root replacement technique might be superior to the subcoronary allograft implantation technique with regard to aortic regurgitation. A 46 yea,rs old male patient had acute aortic regurgitation with progressing heart failure secondary to acute bacterial endocarditis. The patient underwent emergent aortic root replacement using 20 mm aortic allograft. At operation, right coronary cusp perforation and heavy calcification of commissure between right and left coronary cusp were observed. The patient recovered well and postoperative echocardiography demonstrated no aortic regurgitation. Inflammatory signs were subsided after 8 weeks of antibiotics therapy. Medically uncontrolled acute bacterial endocarditis was treated successfully by aortic root replacement using aortic homograft.

• Journal of Chest Surgery
• /
• v.49 no.4
• /
• pp.258-263
• /
• 2016

Background: The advantages of using a homograft in valve replacement surgery are the excellent hemodynamic profile, low risk of thromboembolism, and low risk of prosthetic valve infection. The aim of this study was to evaluate the long-term outcomes of homograft implantation in the aortic valve position. Methods: This is a retrospective study of 33 patients (>20 years old) who underwent aortic valve replacement or root replacement with homografts between April 1995 and May 2015. Valves were collected within 24 hours from explanted hearts of heart transplant recipients (<60 years) and organ donors who were not suitable for heart transplantation. The median follow-up duration was 35.6 months (range, 0 to 168 months). Results: Aortic homografts were used in all patients. The 30-day mortality rate was 9.1%. The 1- and 5-year survival rates were $80.0%{\pm}7.3%$ and $60.8%{\pm}10.1%$, respectively. The 1-, 5-, and 10-year freedom from reoperation rates were $92.3%{\pm}5.2%$, $68.9%{\pm}10.2%$, and $50.3%{\pm}13.6%$, respectively. The 1-, 5-, and 10-year freedom from significant aortic dysfunction rates were $91.7%{\pm}8.0%$, $41.7%{\pm}14.2%$, and $25.0%{\pm}12.5%$, respectively. Conclusion: Homografts had the advantages of a good hemodynamic profile and low risk of thromboembolic events, and with good outcomes in cases of aortitis.

• Journal of Chest Surgery
• /
• v.30 no.8
• /
• pp.815-818
• /
• 1997

Prosthetic valve endocarditis(PVE), although uncommon, is associated with significant mortality if the infection spreads into the paravavular structures with later abscess formation. However, combined antibiotic and surgical treatment is often successful. Accurate diagnosis by on echocardiography, effective myocardial protection during operation and increased surgical experience have improved the short-term and long-term outcomes for patients with PVE. A 35-year-old male had a history of replacement of aortic and mitral valve, and tricuspid annuloplasty on August 1994, was admitted due to sudden onset of aphasia, leftward deviation of both eyeballs and spiking fever and diagnosed of having PVE by echocardiography. Reoperation was done after 6weeks of antibiotic treatment. On the operative field, we could notice circumferential vegetation along aortic valve annulus, paravalvular leakage and abscess pocket. The mitral valve amlulus was healthy. The patient underwent redo aortic valve replacement using cryopreserved aortic homograft after radical debridement of infected issue. During the follow up of 7 months period the homograft was well functioning without recurrence of symptoms.

• Journal of Chest Surgery
• /
• v.29 no.11
• /
• pp.1173-1181
• /
• 1996

The causes of degenerative changes in allograft cardiac valves are not well known to this day. Today's preserved allografts possess highly viable endothelial cells and degeneration of allografts can be facilitated by immune reaction which may be mediated by these viable cells. To test the antigenicity of endothelial cells, pieces from aortic wall were obtained from fresh and cryo-preserved rat allograft. Timings of sampling were prior to sterilization, after sterilization, after 1, 2, 7, 14 days of fresh preservation and cryopreservation. Endothelial cells were tested by immunohistochemical methods using monoclonal antibodies to MHC class I(MRC OX-18), class II(MRC OX-6) and ICAM-1 antigens. After transplantation of each group of aortic allograft at the subcutaneous layers of rats, population of CD4$^{+}$ T cell and CD8$^{+}$ T cell were analyzed with monoclonal antibodies after 1, 2, 3, 4, 6 and 8 weeks. MHC class I expression was 23.95% before preservation and increased to 35.53~48.08% after preservation(p=0.0183). MHC Class II expression was 9.72% before preservation and 10.13~13.39% after preservation(P=0.1599). ICAM-1 expression was 15.02% before preservation and increased to 19.85~35.33% after preservation(P=0.001). The proportion of CD4$^{+}$ T-cell was 42.13% before transplantation. And this was 49.23~36.8% after transplantation in No treat group (p=0.955), decreased to 29.56~32.80% in other group(p=0.0001~0.008). In all the groups, the proportion of CD8$^{+}$ T-cell increased from 25.57% before transplantation to 42.32~58.92% after transplantation(p=0.000l~0.0002). The CD4$^{+}$/CD8$^{+}$ ratio decreased from 1.22~2.28 at first week to 0.47~0.95 at eighth week(p=0.0001). The results revealed that the expression of MHC class I and ICAM-1 in aortic allograft endothelium were increased but that of MHC class II were not changed, despite the different method of preservation. During 8 weeks after transplantation of aortic allograft, the subpopulations of CD4$^{+}$ T cell were not changed or only slightly decreased but those of CD8$^{+}$ T cell were progressively increased.ely increased.

• Journal of Chest Surgery
• /
• v.30 no.3
• /
• pp.270-274
• /
• 1997

In recent years, the use of allograft conduits in repair of congenital cardiac disease is widely accepted. However, the supply of homograft. is currently limiting their increased clinical application, especially small cryopreserved homografts for use in neonates and inf'ants. We used a technique to surgically reduce the size of the more readily available large-diameter allografts, making them suitable for right ventricular outflow tract reconstruction in small infants and children. From December 1994 to March 1996, a total of 11 patients ranging in age from 10 months to 6 years (mean age, 27.3 months) and ranging in weight from 5.6 to 18.5 kg (mean 11.5 kg) underwent reconstruction of the right ventricular outflow tract using this surgical technique (pulmo ary atresia with ventricular septal defect, 9 cases ; tetralogy of Falloff, 2 cases). The diameter after downsizing ranged from 14 to 19 mm with a mean of 16.8 mm. There was one operative death due to rupture of the infected homograft. Evaluation of these patients between 2 and 15 months (mean 6.9 months) after homograft implantation reveals excellent clinical and echocardiographic results. There were no significant homograft insufficiency and RVOT obstructions. Although a longer follow-up is certainly required to evaluate the long term fate of the surgically modified bicuspid homografts, we believe that this technique may represent a valuable therapeutic alternative, at least in the short term, to the use of synthetic grafts when an appropriately sized homograft is not available.