The risk of transmission of the novel coronavirus (SARS-CoV-2) with human heart valve transplantation: evaluation of cardio-vascular tissues from two consecutive heart donors with asymptomatic COVID-19.

We report on two living donors of explanted hearts while receiving heart transplantation that tested positive for SARS-CoV-2 on the day of donation, although clinically asymptomatic. They underwent heart transplantation for ischaemic and hypertrophic obstructive cardiomyopathy, respectively. After evaluation of donor hearts, we cryopreserved and stored two pulmonary valves for clinical application and one aortic valve for research. Light microscopy of myocardium, mitral valve and aortic and pulmonary arterial wall and RT-PCR SARS-CoV-2 test of myocardium, mitral and tricuspid valve and aortic wall for detection of SARS-CoV-2 were performed. Presence of ACE2 in tissues was assessed with immunostaining. Light microscopy revealed a mild eosinophilic myocarditis in the ischemic cardiomyopathy heart, whereas enlarged cardiomyocytes with irregular nucleus and some with cytoplasmic vacuoles in the hypertrophic obstructive cardiomyopathy heart. Aortic and pulmonary wall were histologically normal. Immunostaining revealed diffuse presence of ACE2 in the myocardium of the heart with eosinophilic myocarditis, but only discrete presence in the hypertrophic cardiomyopathy heart. The RT-PCR SARS-CoV-2 test showed no presence of the virus in tested tissues. Despite eosinophilic myocarditis in the ischemic cardiomyopathy heart, no viral traces were found in the myocardium and valve tissues. However, ACE2 was present diffusely in the ischemic cardiomyopathy heart. SARS-CoV-2 could not be detected in the cardiac tissues of these COVID-19 asymptomatic heart donors. In our opinion, clinical application of the valves from these donors presents negligible risk for coronavirus transmission. Nonetheless, considering the uncertainty regarding the risk of virus transmission with the human tissue transplantation, we would not release in any case the pulmonary valve recovered from the eosinophilic myocarditis heart. In contrast, we may consider the release of the pulmonary valve from the dilated cardiomyopathy heart only for a life-threatening situation when no other similar allograft were available.

Determination of residual dimethylsulfoxide in cryopreserved cardiovascular allografts.

Dimethylsulfoxide (DMSO) is a solvent which protects the structure of allografts during the cryopreservation and thawing process. However, several toxic effects of DMSO in patients after transplantation of cryopreserved allografts have been described. The aim of this study is to determine the residual DMSO in the cardiovascular allografts after thawing and preparation of cryopreserved allografts for clinical application following guidelines of the European Pharmacopoeia for DMSO detection. Four types of EHB allografts (aortic valve-AV, pulmonary valve-PV, descending thoracic aorta-DA, and femoral artery-FA) are cryopreserved using as cryoprotecting solution a 10% of DMSO in medium 199. Sampling is carried out after thawing, after DMSO dilution and after delay of 30 min from final dilution (estimated delay until allograft implantation). After progressive thawing in sterile water bath at 37-42 °C (duration of about 20 min), DMSO dilution is carried out by adding consecutively 33, 66 and 200 mL of saline. Finally, tissues are transferred into 200 mL of a new physiologic solution. Allograft samples are analysed for determination of the residual DSMO concentration using a validated Gas Chromatography analysis. Femoral arteries showed the most important DMSO reduction after the estimated delay: 92.97% of decrease in the cryoprotectant final amount while a final reduction of 72.30, 72.04 and 76.29% in DMSO content for AV, PV and DA, was found, respectively. The residual DMSO in the allografts at the moment of implantation represents a final dose of 1.95, 1.06, 1.74 and 0.26 mg kg-1 in AV, PV, DA and FA, respectively, for men, and 2.43, 1.33, 2.17 and 0.33 mg kg-1 for same tissues for women (average weight of 75 kg in men, and 60 kg in women). These results are seriously below the maximum recommended dose of 1 g DMSO kg-1 (Regan et al. in Transfusion 50:2670-2675, 2010) of weight of the patient guaranteeing the safety and quality of allografts.

Evaluation of the composite milk somatic cell count as a predictor of intramammary infection in dairy cattle.

The objectives of this study were (1) to evaluate the test characteristics and predictive values of quarter-composite milk somatic cell count (quarter-cSCC) values based on either a single observation or the geometric mean of multiple recordings as a predictor of intramammary infection (IMI) in lactating dairy cows; and (2) to explore to what extent herd prevalence of IMI and cow factors such as parity and stage of lactation affect them. A total of 780 single-quarter milk samples were collected from 195 dairy cows for bacteriologic culture at a single cross-sectional herd screening performed at 21 different dairy herds as part of different research projects. Additionally, monthly quarter-cSCC milk samples at test day were available as part of the Dairy Herd Improvement program. Sensitivity (Se), specificity (Sp), positive predictive valu (PPV), and negative predictive value (NPV) were calculated to differentiate cows infected with any pathogen and cows infected with major pathogens from uninfected cows. Different threshold values for quarter-cSCC, ranging between 50,000 and 500,000 cells/mL, were evaluated for all animals in the study, as well as for high- and low-prevalence herds, heifers and multiparous cows, and cows in early, mid, and late lactation. The overall Se and Sp at a threshold of 200,000 cells/mL for a single quarter-cSCC observation obtained closest to the time of bacteriologic culture were 44.3 and 87.3%, respectively, for cows infected with any pathogen, and 65.1 and 73.0%, respectively, for cows infected with major pathogens. The overall PPV and NPV at a threshold of 200,000 cells/mL for a single quarter-cSCC observation obtained closest to the time of bacteriologic culture were 89.9 and 38.1%, respectively, for cows infected with any pathogen, and 40.6% and 88.1%, respectively, for cows infected with major pathogens. No major differences were observed between estimates of the test characteristics and predictive values of the quarter-cSCC criteria based on a single observation and the geometric mean of multiple observations. For IMI with any pathogen, the Se and PPV were higher in high-prevalence herds than in low-prevalence herds, particularly at thresholds of 50,000 and 100,000 cells/mL. For IMI with major pathogens, Sp was substantially higher in low-prevalence herds than in high-prevalence herds. Sensitivity was higher in multiparous cows than in heifers infected with any pathogen, more specifically at a threshold of 100,000 and 200,000 cells/mL. For cows in early and mid lactation infected with any pathogen, Sp was higher than for cows in late lactation using the single observation closest to the time of bacteriologic culture. The results suggest that the quarter-cSCC threshold value to select cows for bacteriologic culture to maximize the likelihood of finding the causative pathogen of IMI should depend on the group of pathogens one is interested in, the herd prevalence of subclinical mastitis, lactation stage, and the cow's parity.

Bacteriology testing of cardiovascular tissues: comparison of transport solution versus tissue testing.

Bacteriology testing is mandatory for quality control of recovered cardiovascular allografts (CVA). In this paper, two different bacteriology examinations (A tests) performed before tissue antibiotic decontamination were compared: transport solution filtration analysis (A1) and tissue fragment direct incubation (A2). For this purpose, 521 CVA (326 heart and 195 artery tissues) from 280 donors were collected and analyzed by the European Homograft Bank (EHB). Transport solution (A1) tested positive in 43.25 % of hearts and in 48.21 % of arteries, whereas the tissue samples (A2) tested positive in 38.34 % of hearts and 33.85 % of arteries. The main species identified in both A1 and A2 were Staphylococcus spp. in 55 and 26 % of cases, and Propionibacterium spp. in 8 and 19 %, respectively. Mismatches in bacteriology results between both initial tests A1 and A2 were found. 18.40 % of the heart valves were identified as positive by A1 whilst 13.50 % were considered positive by A2. For arteries, 20.51 % of cases were positive in A1 and negative in A2, and just 6.15 % of artery allografts presented contamination in the A2 test but were considered negative for the A1 test. Comparison between each A test with the B and C tests after antibiotic treatment of the allograft was also performed. A total decontamination rate of 70.8 % of initial positive A tests was obtained. Due to the described mismatches and different bacteria identification percentage, utilization of both A tests should be implemented in tissue banks in order to avoid false negatives.

Cleanrooms and tissue banking how happy I could be with either GMP or GTP?

The regulatory framework of tissue banking introduces a number of requirements for monitoring cleanrooms for processing tissue or cell grafts. Although a number of requirements were clearly defined, some requirements are open for interpretation. This study aims to contribute to the interpretation of GMP or GTP guidelines for tissue banking. Based on the experience of the participating centers, the results of the monitoring program were evaluated to determine the feasibility of a cleanroom in tissue banking and the monitoring program. Also the microbial efficacy of a laminar airflow cabinet and an incubator in a cleanroom environment was evaluated. This study indicated that a monitoring program of a cleanroom at rest in combination with (final) product testing is a feasible approach. Although no statistical significance (0.90 < p < 0.95) was found there is a strong indication that a Grade D environment is not the ideal background environment for a Grade A obtained through a laminar airflow cabinet. The microbial contamination of an incubator in a cleanroom is limited but requires closed containers for tissue and cell products.

Banking of cryopreserved arterial allografts in Europe: 20 years of operation in the European Homograft Bank (EHB) in Brussels.

Vascular allografts have been used for many years in patients with infection complications and when the patient lacks own autologous venous material. Cryopreservation has permitted the long term storage of these allografts, offering the optimal solution for particular clinical situations. For more than 20 years the European Homograft Bank has prepared, stored in the liquid nitrogen vapour below -130 °C and distributed various types of the quality controlled arterial allografts throughout the European centers and elsewhere. The tissues are prepared according to the existing European, Belgian, Swiss and other EU countries' regulations and standards. This paper gives an overview of this activity since 1991. During this period 1,428 batches of arteries were received from recovery centres within European Union and Switzerland and 3,941 arterial segments were evaluated. 1,250 (32 %) were discarded for morphological findings (58 %), bacteriology (31 %) and other reasons, while 2,685 or 68 % (ascending and descending aorta, arch, aortic bifurcation, iliac and femoral arteries and the non-valved pulmonary bifurcations) were cryopreserved and stored. 2,506 arteries were implanted in 1,600 patients in vascular and cardiac centers in European Union and elsewhere. The most important indications were infections (65 %), critical limb ischemia (15 %) and congenital cardiac malformations (15 %). Some allografts were used for the repair of arterial injury (2 %) or prosthetic graft thrombosis (1.5 %). 10 aortic allografts (0.4 %) were used for tracheal replacement in case of cancer. In 52 cases EHB did not fulfill the surgeon's requests due to shortage of arterial allografts. Collaboration with vascular surgeons in the tissue recovery might improve the number, diversity and quality of vascular allografts. A multicentric study is necessary to evaluate the long-term outcome of these allografts.

Belgian and European experience with the European Homograft Bank (EHB) cryopreserved allograft valves.--assessment of a 20 year activity.

European Homograft Bank (EHB) has been selecting, preparing, storing and distributing the cryopreserved allograft valves in Belgium and some other European Countries since 1989. It was established in 1988 by a pathologist and the cardiac and vascular surgeons from Belgian and other European centres as an inter-university, international nonprofit association. Due to its neutral behavior and very high quality criteria, European Homograft Bank became one of the prominent heart valve banks in Europe and wider. It collaborates with the transplant coordination in donor selection as well as with the huge network of the implanting surgeons in Belgium and other European Countries. The EHB responsible discusses with the implanting surgeon the allograft selection on basis of the indication and the patients state of emergency. A total of 8.911 donor heart valves have been evaluated in EHB during the last 20 years. After selection, 5.258 allograft valves (1.996 aortic, 3.189 pulmonary and 73 mitral) were cryopreserved and stored in vapors of liquid nitrogen between 6 weeks and 5 years. A total of 4.516 allograft valves (1.391 aortic, 2.620 pulmonary and 48 mitral) were implanted in the left or right ventricular outflow tract for replacement of the diseased aortic or pulmonary valve and for mitral or tricuspid valve replacement or repair. In 1.380 cases the allograft valves were used for right ventricular outflow tract reconstruction as part of the Ross- procedure, whereas in 668 cases the allograft valve served for replacement of the aortic valve for endocarditis. The most important indications for use of cryopreserved allograft valves were: important cardiac and valve malformation in children, female patients of child-bearing age with diseased cardiac valves, cases with contra-indication for anti-coagulation and the patients with severe endocarditis with septal or annular abscesses. Although the number of the donation increased by year, the available allograft valves in stock are still insufficient to respond to all the surgeons' request for different indications.

European homograft bank: twenty years of cardiovascular tissue banking and collaboration with transplant coordination in Europe.

Established in 1989 in Brussels as an international nonprofit association, the European Homograft Bank (EHB) has been collaborating closely with the transplant coordination of the different centers in Belgium and other European countries. Donor selection is made after discussion of exclusion criteria with the transplant coordinator of the procurement center. EHB collaborates with 15 Belgian, 11 German, 10 French, 10 Swiss, 3 Italian, 3 Dutch, and some other procurement and/or implantation centers. Donor ages range from newborn to 65 years. Tissue preparation, morphologic evaluation, and functional testing are performed under Class A laminar flow. After decontamination in a cocktail of 3 antibiotics (lincomycin, vancomycin, and polymixin B) during 20-48 hours, the tissues cryopreserved with liquid nitrogen to -100 degrees C are stored in vapors of liquid nitrogen below -150 degrees C for a maximum of 5 years. Systematic virologic examination of donor blood is performed for HIV, HTLV, hepatitis B/C, and syphilis, as well as for enteroviruses, Q fever, malaria, and West Nile virus by indication. Bacteriologic examination for anaerobic and aerobic contamination is performed at the different steps of processing. Histologic examination for malignant disease and infection is performed systematically. Indications for implantation are discussed with the requesting surgeon. Transport to the implantation center is carried out safely in a dry shipper at -150 degrees C or in dry ice at -76 degrees C. The EHB received 4,511 hearts and 1,169 batches of arteries from January 1989 to December 2008. The 5,133 heart valves (1,974 aortic, 3,106 pulmonary, and 53 mitral) and 2,066 arterial segments have been prepared and stored; 4,600 cryopreserved valvular (2,717 pulmonary, 1,835 aortic, and 48 mitral) and 1,937 arterial allografts have been distributed for implantation in various European Cardiovascular Centers. EHB is not always able to meet the increased demand for heart valves and arterial allografts. Collaboration between the EHB and the Transplant Coordination is satisfactory. Donor selection criteria are discussed with the transplant coordinator; whereas, implantation indication, with the implanting surgeon. Because the EHB is not always able to meet demands for the cryopreserved valves and arterial segments, there is a need to increase number of procurements. Cardiovascular surgeons need to play more active roles in the resolution of this problem.

Decontamination of heart valve and arterial allografts in the European Homograft Bank (EHB): comparison of two different antibiotic cocktails in low temperature conditions.

The aim of the study was to compare the efficiency of two different antibiotic cocktails in the cardiovascular allograft decontamination. Low temperature, low-concentration antibiotic cocktail with Cefoxitin, Lincomycin, Polymixin B and Vancomycin was decontamination protocol in EHB for many years. The modified cocktail doesn't contain Cefoxitin. The study had two steps. First step: cardiovascular allografts from 80 donors are incubated in classical (group 1) or modified cocktail (group 2). Second step: 184 and 182 allografts of group 1 and group 2 are incubated in the modified and classical antibiotic cocktail, respectively. The bacteriological examination is performed in three steps: A-transport solution, B-decontamination solution and C-cryopreservation solution. During the first step 23.75% of the tissues were initially contaminated mainly with Staphylococcus (78.95%). 93.75% of the allografts of group 1 and 100% of group 2 were sterile after incubation (p = 0.058). 25.54% and 30.77% of group 1 and 2, respectively were contaminated in A-examination during the second step. Staphylococci were isolated in 82.98% and 69.64% in group 1 and 2, respectively. About 4.35% of group 1 and 5.5% of group 2 were contaminated in A, B, and C whereas 5.4% of group 1 and 4.4% of group 2 were contaminated in B or C after being sterile in A. Finally 9.78% of the tissues were rejected and 90.22% cryopreserved in the modified, whereas 9.89% rejected and 90.11% accepted in the classical group (p = 0.1). The difference was non-significant in the level of decontamination between the two cocktails. Contamination of some tissues with low growing, low-pathogen germs that appeared in B or C examination, couldn't be explained. This issue needs complementary investigation.

Banking of the human heart valves and the arteries at the European homograft bank (EHB)--overview of a 14-year activity in this International Association in Brussels.

Processing of the human heart valves and arteries has been carried out at the European Homograft Bank (EHB) in Brussels since 1989 and 1991, respectively. Heart valve donors of 0-65 years were classified in (1) Beating heart donors (BHD), of which recipients of heart transplantation (RHT) and multiorgan donors (MOD) after brain death, and (2) non-beating heart donors (NBHD) with warm ischaemic time (WIT) of less then 6 h. Past history of the donors has been checked for malignant and chronic diseases, as well as biology for transmissible and infectious diseases. Perfect collaboration has been established with the transplant coordinators and transplant teams of the implanting centres. Dissection, decontamination, cryopreservation and storing in fluid nitrogen has been carried out in accordance with the Belgian and European Standards of cardiovascular allografts. During this period, a total of 2.828 hearts, 28 predissected valves and 616 batches of arteries arrived in the EHB. 3.537 valves and 1.137 different arteries were accepted for implantation. The main reasons for tissue rejection were morphology, contamination and cuts during the tissue retrieval or dissection. A huge network of different hospitals in Belgium and elsewhere in Europe and Switzerland were included in this process. Pulmonary allografts were not sent for implantation in the left ventricular outflow tract after 1998, since the early and mid-term results after 76 implantations were disappointing. The number of implanted aortic and pulmonary allografts remains stable from year to year, however the number of the allografts used for Ross operation is still increasing. Since the results of the follow up were disappointing, we still only require the implantation and immediate postoperative results, whereas the follow-up information only for specific study purposes.

Is ABO group incompatibility really the reason of accelerated failure of cryopreserved allografts in very young patients?--Echography assessment of the European Homograft Bank (EHB) cryopreserved allografts used for reconstruction of the right ventricular outflow tract.

Right ventricular outflow tract reconstruction (RVOTR) with cryopreserved allograft for Ross operation and other congenital or acquired cardiac malformation has become a routine and currently, the procedure of choice for children and young patients. A tendency of accelerated degeneration in the youngest recipients has been reported. Some authors advocate the ABO group incompatibility as the main reason for such failure. This retrospective monocentric study presents the long-term outcome of the European Homograft Bank (EHB) cryopreserved allografts, used for RVOTR in Ross operation (group one) and other congenital heart malformation-s (group two). The evaluation of the allograft performance was done by means of echography, considering the allografts with the transvalvular gradient of > or =40 mmHg and/or regurgitation of > or =3+ as failed. Fifty-one patients of group one and 123 of group two were analysed after completed follow-up information. About 25.5% of patients of group one and 30.8% of group two had a compatible, whereas 74.5% of group one and 68.92 of group two an incompatible ABO group with the donor. The mean follow up was 45.77 and 68.88 months, respectively. In second group 22.76% received the aortic, while 77.24% pulmonary allograft. Only three cases of group one (5.88%) failed: one with a compatible (7.69%) and two with an incompatible ABO group (5.26%) (p=0.1), whereas 39 patients (29.4%) of group two failed between 20.1 and 120.2 months (29.73% with and 29.07% without ABO compatibility, p=0.03). Contrary, the age showed more importance in the allograft failure: out of 41 failed allografts, 24 (58.54%) were implanted in patients of 0-5 years (9 or 37.5% with compatible and 15 or 62.5% with incompatible ABO group). Generally, analysing both groups together, there was no influence of ABO mismatching on the allograft failure (p=0.79). Contrary, there was a significant difference in survival between Ross and non-Ross group (p=0.00082).

Processing of cardiovascular allografts: effectiveness of European Homograft Bank (EHB) antimicrobial treatment (cool decontamination protocol with low concentration of antibiotics).

To assess the effectiveness of antimicrobial treatment by using cool decontamination protocol with low concentration of antibiotics during processing of cardiovascular allografts, 948 allografts processed during a 2-year period were analysed. Five hundred and fourty one donors aged <62 years were classified in: multiorgan donors (MOD) with non-transplantable hearts; recipients of cardiac transplantation (RHT); and non-beating heart cadavers with a warm ischemic time of less than 6 h (NBHD). During processing three samples for bacteriology testing were taken A (sampling before decontamination); B (sampling after decontamination); C (sampling on the final product). Samples A were positive in 348 cases (36.4%), respectively 36% for MOD, 21.6% for RHT and 78.1% for NBHD. All the allografts were immersed in a cocktail of four antibiotics at 4 degrees C. After exposure to antibiotics the rate of decontamination of those with A positive was 90.4, 92.5, 82.5% respectively for MOD, RHT, NBHD. At the end of processing, 57 allografts (6%) were positive in B and/or C, 15 allografts remained contaminated with the same bacteria as in A, 42 were contaminated during processing. The overall rate of sterility in the end of processing is 94% and for each group this is: 95.4% for MOD, 96.8% for RHT and 86.3% for NBHD. Analysis shows that there is no influence of time of exposure in AB in the rate of decontamination for MOD and RHT. The most predominant germ in contamination is Coagulase Negative Staphylococcus (CNS) (53.4% alone, 8.9% with other bacteria). 83.3% of MOD; 88.5% of RHT were contaminated with one germ, while 40.4% of NBHD were contaminated with more than one.

Calcification and degeneration characteristics of the Biocor no-react bovine internal mammary artery (BIMA) - in vivo evaluation in a sheep model.

OBJECTIVE: The No-React process for biomaterials was suggested to prevent calcification and degeneration. We examined in vivo in a chronic sheep model the performance of a Biocor bovine internal mammary artery (BIMA) graft after No-React processing. METHODS: 'No-React' processing consists of aldehyde cross-linkage following a detoxification process with multiple physical variables and incubation with surfactant. Biocor BIMA No-React treated grafts have been interposed in the carotid artery in seven sheep with a Dacron graft as control. Grafts were explanted after 3 or 6months and were grossly examined, by X-ray, histology, transmission and scanning electron microscopy, and atomic absorption spectrophotometry. RESULTS: In the BIMA, good healing was found with a smooth intimal surface, minimal inflammatory reaction, and a well preserved ultrastructure. Calcification increased progressively. In the Dacron grafts, a fibrous covering the inner surface and infiltration with fibroblasts, histiocytes and macrophages was noted. Calcium content was stable. CONCLUSION: Calcification increased progressively in Biocor BIMA No-React grafts. Minimal inflammatory changes, a smooth inner surface and well preserved ultrastructure were noted.

Ascending versus descending aortic balloon pumping: organ and myocardial perfusion during ischemia.

BACKGROUND: The ICS-Supracor (Abiomed, Danvers, MA) is a preshaped ascending aorta balloon pump. We compared the effects of this catheter with the classical descending intraaortic balloon pump (IABP). The study focused on hemodynamic effects, myocardial blood flow in normal and ischemic regions, cerebral perfusion, and peripheral organ perfusion. METHODS: We placed a stenosis on the lateral branch of the coronary artery to reduce flow 50% (sheep). Measurements included hemodynamic changes, myocardial blood flow, and organ flow (colored microspheres) at baseline, after stenosis, during IABP support, and during ICS support. RESULTS: Counterpulsation with the ICS led to a significantly higher peak diastolic aortic augmentation than with the IABP (IABP, 99 +/- 14 mm Hg; ICS, 140 +/- 29 mm Hg; p = 0.003). There was no significant change in cerebral perfusion or peripheral organ perfusion. Myocardial blood perfusion was significantly increased by the IABP as well as the ICS. This effect was seen in ischemic and nonischemic regions (subendocardial and subepicardial). The ICS improved myocardial blood flow significantly more than the IABP (IABP, 0.65 +/- 0.1 mL/min/g; ICS, 0.94 +/- 0.06 mL/min/g; p = 0.0005). CONCLUSIONS: The ICS increases myocardial blood flow in ischemic regions significantly more than the IABP, without impairment of cerebral flow. Assessment of vascular complications, peripherally and in the ascending aorta, has to await results of clinical trials.

Banking of cryopreserved heart valves in Europe: assessment of a 10-year operation in the European Homograft Bank (EHB).

BACKGROUND AND AIM OF THE STUDY: The preparation, banking and distribution of cryopreserved heart valves has been carried out at the European Homograft Bank (EHB) in Brussels without interruption since January 1989. We present an assessment of the Bank's activities during this 10-year period. METHODS: Heart valve donors aged <62 years form three categories: multiorgan donors with non-transplantable hearts; recipients of cardiac transplantation; and non-beating heart cadavers with a warm ischemia time of less than 6 h. Past history and biology are checked for transmissible diseases. Dissection, incubation in antibiotics and cryopreservation in 10% dimethylsulfoxide with storage in liquid nitrogen vapors (about -150 degrees C), and quality control are according to the standards of the Belgian Ministry of Health. Cryopreserved valves are shipped to the implantation centers in a dry shipper at about -150 degrees C. RESULTS: Between January 30th 1989 and December 31st 1998, 1,817 non-transplantable hearts and 12 excised semilunar valves were obtained. In total, 2,077 valves (1,032 pulmonary, 931 aortic and 13 mitral) were decontaminated, cryopreserved and stored in liquid nitrogen vapor (six more valves were refrigerated). In total, 1,515 valves were discarded at different stages of the protocol, the main causes of rejection being significant macroscopic lesions (68.2% aortic and 26.67% pulmonary). Inadequate excision at procurement (10.37% pulmonary), persistent contamination after antibiotics (5.6%) and positive serology for hepatitis B and C and Q fever (5.4%) were other frequent causes for rejection. Among the 2,117 accepted valves, 1,398 were graded first and 719 second choice, mainly on the basis of morphology. In total, 2,090 cryopreserved valves and one refrigerated valve were implanted in 39 institutions between May 1989 and December 1998. Of requests, 10.02% could not be satisfied. In total, 967 pulmonary valves were implanted in the right ventricular outflow tract (RVOT); 424 during a Ross procedure, and 76 in the left ventricular outflow tract (LVOT). Of the aortic valves, 732 were implanted in the LVOT and 266 in the RVOT. Mitral homografts were used for tricuspid valve replacement in two cases, and in the mitral position in seven. Complications at distribution and thawing included 10 bag ruptures and 16 transversal conduit wall fractures. Of the valves shipped, 317 (13.16%) were not used and were returned safely in the dry shipper. Comparison of distribution rates in the first 5.5 and last 4.5 years of EHB activity shows: (i) a significant increase in pulmonary valve implantations in the RVOT (from 71.95% to 81.95%); and (ii) a marked increase (265%) in pulmonary homograft implantations as part of a Ross operation, and a significant decrease (28%) in aortic homograft implantation in the LVOT. CONCLUSION: While macroscopic lesions of procured aortic valves remain the most frequent and unavoidable cause of homograft rejection during quality control, the high percentage of inadequate surgical heart valve excision should be corrected. The rates of bacterial contamination and positive serology seem acceptable. Storage and shipping of cryopreserved homografts in liquid nitrogen vapor permits them to be spared very efficiently. The increasing use of pulmonary valves for RVOT reconstruction either in congenital heart disease or as part of the Ross procedure compensates for the limited availability of good quality aortic valves.

Are pulmonary homografts which were subjected to pulmonary hypertension more appropriate for aortic valve replacement than normal pulmonary homografts? A long-term multicentric echography study.

OBJECTIVE: To compare long-term results of the European Homograft Bank (LHB) cryopreserved pulmonary homograft in left ventricular outflow tract (LVOT) subjected to pulmonary hypertension with those subjected to normal pulmonary pressure. The mid-term study of this material published in 1997 showed different results. METHODS: Statistical analysis is calculated by the Kaplan-Meier survival curves, while differences in prevalence by the Log-Rank test. RESULTS: Follow-up (FU) was available in 69 cases (76.7%): 46 in group 1 and 23 in group 2. Five patients have been excluded from the study because of early homograft explantation (technical problems or early valve incompetence). Fourteen out of 43 cases of group 1 (32. 6%) and seven out of 21 cases of group 2 (33.3%) have been explanted after 2.5-88 months and 7-88 months, respectively. Significant echography changes have been found in 19 of 43 (44.18%) of group 1 and 11 of 21 cases (52.38%) of group 2 during the follow-up. Histology showed essentially wear and tear induced lesions. Mean FU was 36.9 (range, 6-88) and 41.3 months (range, 4-88) for group 1 and 2, respectively. No significant difference in the long-term outcome have been found between the two groups (P=0.38). CONCLUSION: Contrary to our previous echocardiography study of mid-term implants the long-term follow up of the PHGs implanted in the LVOT did not show better function of the pulmonary homografts subjected to pulmonary hypertension than those with normal pulmonary pressure. The high failure rate of the PHGs should discourage their use for LVOT reconstruction. Further echocardiography studies of remaining PHGs implanted in the LVOT, and gross and microscopic explant studies are required to judge on the definitive outcome of these grafts.

Homograft valve insertion for pulmonary regurgitation late after valveless repair of right ventricular outflow tract obstruction.

OBJECTIVE: Pulmonary regurgitation after valveless repair of right ventricular outflow tract obstruction (RVOTO) results in progressive right ventricular (RV) dilatation and dysfunction in an increasing number of patients. Since 1989, we have exclusively used cryopreserved homografts to restore pulmonary valve competence in these patients. Our 9-year-experience with pulmonary valve insertion (PVI) in such cases has been reviewed to evaluate the indications for this procedure and its benefits. METHODS: From 1989 to 1998, 49 patients (original diagnosis: tetralogy of Fallot in 42 patients and pulmonary stenosis in seven) aged from 3 to 42 years (mean 18 +/- 9 years) underwent PVI with homografts late (mean 13 +/- 7 years) after valveless repair of RVOTO (transannular patch, n = 38; pulmonary valvulotomy therefore tau chi infundibular patch, n = 11). Preoperatively, all patients had severe pulmonary regurgitation, cardiomegaly, significant to severe RV dilatation and dysfunction, fatigue, reduced exercise tolerance, and were in NYHA class II (n = 43) or III (n = 6). Ten patients had ventricular arrhythmia. RESULTS: There was one early death, due to air embolism, and one late death, due to ventricular arrhythmia. All survivors but one, who subsequently underwent heart transplant, had symptomatic improvement after homograft insertion. The mean RV end-diastolic diameter decreased from 38 +/- 9 to 26 +/- 8 mm (P < 0.01), and cardiothoracic ratio decreased from 0.62 +/- 0.07 to 0.54 +/- 0.04 (P < 0.01). Good late homograft function was the rule, with all the survivors being free of reoperation for valve failure. At a mean follow-up of 42 +/- 28 months, 41 patients (87% of the survivors) were in New York Heart Association (NYHA) class I and six in class II. Within this group three patients are still in treatment for RV failure and five for ventricular arrhythmias. In these patients, the average interval between RVOTO repair and PVI was significantly longer than in the others (18 +/- 7 vs. 12 +/- 6 years, P < 0.01). CONCLUSION: Homograft PVI is safe and provides clinical improvement with a significant reduction in RV volume overload and excellent mid-term results in most patients with severe PR late after RVOTO repair. This procedure should be undertaken early in symptomatic patients, before severe RV failure and ventricular arrhythmias ensue.

The No-React anticalcification treatment: a comparison of Biocor No-React II and Toronto SPV stentless bioprostheses implanted in sheep.

Calcification of stentless aortic heterografts still limits the use of these bioprostheses in young patients despite their superior hemodynamic profile. The No-React treatment is described as an anticalcification treatment for biomaterials. We compared the Biocor No-React treated stentless bioprosthesis with the routine glutaraldehyde-fixed Toronto SPV bioprosthesis in a juvenile sheep model. Toronto SPV or Biocor No-React valves were implanted in pulmonary position in juvenile sheep (n = 6). The valves were explanted after 3 months and analyzed by gross inspection, x-ray studies, histological examination, and transmission electron microscopy. The Toronto SPV valve showed calcification of the aortic wall portion at both the inflow and outflow sides of the valve. No significant calcification of the cusps was found by gross inspection or by radiographic or histological examinations. Calcification was visible with electron microscopy in cell remnants and between collagen fibers in the cusps. The Biocor No-React valve showed extensive calcification of the residual aortic wall portion that is contained in the valve. With x-ray and histological examinations, clear calcification of the pericardial wrap, largely replacing the aortic wall tissue, was seen. Calcification scattered throughout the cusp was seen by electron microscopy. We conclude that the Biocor No-React process did not prevent calcification of glutaraldehyde-fixed stentless bioprostheses in a juvenile sheep experimental model. Furthermore, replacement of a large part of the aortic wall by a pericardial wrap did not prevent calcification of the stentless valve "wall."

First cardiological or cardiosurgical reintervention for ischemic heart disease after primary coronary artery bypass grafting.

OBJECTIVE: To study the first reintervention for ischemic heart disease anytime after coronary artery bypass grafting (CABG) and the variables that drive its need or bias its occurrence. Reintervention is defined as an isolated or combined repeat surgical or cardiological procedure for ischemic heart disease. METHODS: A consecutive series of 9600 CABG patients (1971-1992) were followed for up to 20 years (99.9% complete). A multivariable time-related analysis was performed. RESULTS: The 1-, 10- and 15-year freedom from reintervention was 99, 89 and 72% respectively. A three-phase hazard function was identified. Patient variables influencing early freedom included anginal instability, completeness of revascularization and institutional variables. Late freedom was influenced importantly by demographic variables, cardiac and non-cardiac comorbidity and extensive arterial grafting. The 1-month and 10-year survival after reintervention was 95 and 73%. The 1- and 10-year freedom from angina after reintervention was 74 and 32%. CONCLUSION: Reinterventions for ischemic heart disease by interventional cardiology or surgery are rather infrequent in the first decade after CABG but nearly half the patients surviving their second decade undergo one. The increased reintervention rate, apparent after 1985 did not go parallel with improved late post-CABG survival. Older age and the presence of multiple arterial grafts seem to reduce but also to bias the event. The very good survival, only when return of angina is present, suggests a more restrictive differential therapy approach, certainly in the presence of a well functioning arterial graft to the antero-septal region and where the co-morbidity might induce a high reinterventional survival cost.

Organ perfusion with Hemopump device assistance with and without intraaortic balloon pumping.

OBJECTIVE: Our objective was to analyze the potential advantage of combining an intraaortic balloon pump with a transthoracic Hemopump device (Medtronic, Inc., Minneapolis, Minn.) (Nimbus Medical, Inc., Rancho Cordova, Calif.). METHODS: Twelve sheep underwent implantation of a transthoracic Hemopump device and an intraaortic balloon pump. In the first series (n = 6), we analyzed the influence of the counterpulsation on the performance of the Hemopump device. In the second group (n = 6), hemodynamic changes, myocardial wall thickening, organ perfusion, and myocardial perfusion (determined with colored microspheres) were analyzed under the following conditions: (1) control situation, (2) during application of coronary stenosis, (3) during support with the Hemopump device, and (4) during support with the Hemopump device combined with intraaortic balloon pump support. RESULTS: In the first series, we found that addition of counterpulsation reduced output with the Hemopump device by 11.1% +/- 6%. In the second series, it was shown that coronary stenosis significantly reduced contractility (rate of pressure change and wall thickening) but did not cause hemodynamic collapse. Myocardial blood flow was significantly reduced in the poststenotic subendocardial regions (mean subendocardial blood flow dropped from 78 +/- 33 to 24 +/- 17 ml/min/100 gm; p = 0.0486). Support with the Hemopump device alone improved the ratio of subendocardial to subepicardial blood flow, but endocardial underperfusion remained (analysis of variance, p < 0.001). The Hemopump device with an intraaortic balloon pump completely restored perfusion in poststenotic regions. Peripheral organ perfusion did not change during ischemia or mechanical support. CONCLUSIONS: The association of balloon counterpulsation with the Hemopump device reduces the Hemopump output by 11% and increases myocardial blood flow to ischemic regions. Perfusion to peripheral organs remains unaltered. The transthoracic Hemopump device combined with an intraaortic balloon pump is an ideal support system for the ischemic, failing heart.