Control of early Aspergillus mortality after lung transplantation: outcome and risk factors.

Historic treatment strategies in our institute had resulted in 10% Aspergillus mortality within the first posttransplant year. Despite nebulized amphotericin B (nAmB) prophylaxis, a significant incidence of Aspergillus infection, usually with poor outcome, is still reported. The aim of this single-center retrospective study was to evaluate the outcomes of patients receiving either standard nAmB or additional systemic caspofungin prophylaxis for selected high-risk patients. We also tried to define independent risk factors for either fungal infection or death. We followed 76 consecutive lung transplant patients performed at our center between 2002 and 2010 from the day of transplantation. The median follow-up duration was 953 days (2.6 years; range, 16-2,751 days). The endpoints were postoperative Aspergillus colonization or disease or death due to any cause. All patients received either nAmB deoxycholate (nAmBd, 15 patients) or nAmB lipid complex (nAmBLC, 61 patients). In addition, 33 patients also received short-term caspofungin prophylaxis. The overall cumulative mortality during the entire follow up was 14.5%. No clinically confirmed invasive Aspergillus infections (IPA) occurred during the first 2 postoperative years; however, there was 1 possible and 1 probable IPA. One patient died of bronchiolitis obliterans and IPA at 2 years 3 months. Twelve patients showed transient Aspergillus colonization. The antifungal prophylactic regimens were well tolerated. The risk factors for death were age >55 years and postoperative Aspergillus detection (P = .011 and P = .015, respectively). Preoperative Aspergillus colonization/disease was not a risk factor for death (P = 1.000). The strongest predictor of death was age >55 years, due to the elder probably being more susceptible to the adverse effects of immunosuppressants. Postoperative detection of Aspergillus still seems to be an indicator of a poorer outcome. Preoperative Aspergillus colonization is not necessarily a threat with prompt institution of antifungal prophylaxis.

Collagens I and III in a porcine bronchial model of obliterative bronchiolitis.

The main extracellular matrix components of the lung, type I and III collagens, were studied in chronic allograft rejection developing in a porcine heterotopic bronchial transplantation model. Specific porcine complementary DNA probes were constructed for detection of the expression of type I and III procollagen messenger RNAs in the bronchial wall structures and in the obliterative plug by in situ hybridization. In autografts, and in allografts immunosuppressed with 40-O-(2-hydroxyethyl)-rapamycin, cyclosporine A, and methylprednisolone, no histological changes of obliterative bronchiolitis (OB) developed, and the number of fibroblast-like cells expressing type I and III procollagen mRNA remained low. In nontreated allografts obliterating within 21 d, a preponderance of fibroblast-like cells showing positivity for type III procollagen mRNA existed in the obliterative plug and bronchial wall. This study shows for the first time the temporal and spatial activation of type I and III procollagen genes during the course of obliterative bronchiolitis. The number of cells expressing procollagen III mRNA increased parallel to developing obliteration and fibrosis in nontreated allografts, whereas autografts and immunosuppressed allografts exhibited no such trend. This finding suggests a positive association between type III collagen mRNA expression in fibroblast-like cells and development of obliterative bronchiolitis.

Immune cells and immunosuppression in a porcine bronchial model of obliterative bronchiolitis.

BACKGROUND: To study obliterative bronchiolitis (OB), we have developed a porcine heterotopic bronchial model. Allografts obliterate within 3 weeks, the immunosuppression cyclosporine (CsA)-azathioprine (AZA)-methylprednisolone (MP) delays OB, but OB is prevented when AZA is switched to 40-0-(2-hydroxyethyl)-rapamycin (RAD). To characterize our model, we studied immune cells under various immunosuppressive conditions. METHODS: The groups studied were autografts (U), allografts (A), and allografts given either CsA-RAD-MP (R), or CsA-AZA-MP (C). The implants were harvested at 3, 7, 10, 14, 21, 30, 60, and 90 days after transplantation. Epithelial damage and obliteration were graded histologically, and the number of CD4, CD8, MHC class II expressing cells, macrophages, and B lymphocytes were counted (mean+SEM)/high-power visual field. RESULTS: In group U, normal epithelium was regained with no obliteration and only few immune cells. In group A, consistent with initially acute ejection, an influx of CD4 (105+23), CD8 (166+23), and class II (92+20) cells was seen up to day 21, when total obliteration preceded by epithelial destruction had already developed. Some macrophages were seen and B cells were scarce. In group R, epithelial damage and obliteration were insignificant, but moderate numbers of CD4, CD8, and class II cells were seen. In group C, epithelial damage and obliteration were only delayed, but the immune cell response was clearly blunted. CONCLUSIONS: In our model, rejection with significant immune cell influx was still active when obliteration was total in nontreated allografts. In immunosuppressed allografts, decrease in the number of immune cells alone did prevent OB. These results support OB being T-cell mediated. RAD may have additional important effects on growth factors and proliferation in prevention of OB.

Biodegradation of the copolymeric polylactide stent. Long-term follow-up in a rabbit aorta model.

The behavior of biodegradable polylactide as a stent material has not yet been fully established in small vessels such as arteries with a diameter <3 mm. The aim of this study was to investigate the long-term effect of a copolymeric polylactide (PLA96) stent. Appropriately sized spiral PLA96 stents were implanted into the infrarenal aortas of 20 rabbits. Intraoperative systemic heparinization (150 IU/kg), perioperative subcutaneous enoxaheparin sodium (10 mg), ticlopidine (250 mg/day) for 1 month, and acetosalicylic acid (12.5 mg/day) were continuously administered. Animals were euthanized according to a fixed timetable for up to 34 months for histologic and scanning-electron-microscopic assessment. Endothelialization was complete within 1 month. In 2 of the 3 aortas sampled 3 months after implantation, a mild inflammatory reaction was visible, with no sign of granulomatous or foreign-body reaction in the vessel wall. Instead, in 1 sample examined at the same time point, neointimal chondroid metaplasia was detected. After 6 months, inflammatory reaction declined in the vessel wall. Hydrolyzation of the stent was histologically evident at 12 months, with mild foreign-body reaction detectable in 2 of 5 aortas sampled at this time point. The stent disintegrated without fragmentation by 24 months, as it was gradually replaced by fibrosis. The vessel lumen remained patent at all time points. We conclude that the PLA96 stent degraded with minimal tissue response within 24 months. PLA96 may thus be a promising stent core material for small vessels in the future, although further investigation is needed to establish its final biocompatibility.

Healing of bronchial allografts in pigs.

Our purpose was to investigate the healing of bronchial grafts in a porcine experimental model. Via left thoracotomy, a 2.5 cm long bronchial stump was anastomosed back to the same animal (autograft) or to another pig (allograft). Autotransplanted bronchi (six pigs) healed very well without infection. Allotransplantation without immunosuppression (eight pigs) was followed in all cases by rejection with formation of major bronchopleural fistula. After allotransplantation with triple-drug immunosuppressive medication (seven pigs), three pigs showed infection-free healing, but the anastomoses were slightly stenosed at the time of sacrifice (mean 30 d), while four had bronchopleural fistula. The study thus showed the healing ability of totally avascular bronchial graft in pigs to be very good when it is autotransplanted, but poor when allotransplanted without immunosuppressive treatment.

Obliterative airway disease in a porcine heterotopic bronchial allograft model.

Representative animal models are needed for the study of posttransplant obliterative bronchiolitis (OB). Because human OB originates in terminal bronchi, the validity of tracheal models can be questioned. Using our hetrotopic model, we implanted pieces of a lobar bronchus subcutaneously into domestic pigs. Five groups were included: autograft implants, allograft implants, allograft implants with 2 regimens of cyclosporine (CsA)azathioprine (AZA)-methylprednisolone (MP), and allograft implants with CsA-SDZ RAD-MP. Samples were harvested at 2 weeks and at 1, 2, and 3 months. The histological findings were graded from 0 to 3. Following initial ischemic epithelial damage, autograft implants recovered, but untreated allografts and those treated with CsA-AZA-MP were totally and permanently damaged within one month. In the group treated with CsA-SDZ RAD-MP, a maximal grade 1.5 +/- 0.5 epithelial injury was seen at one month. Epithelial damage preceded and correlated with luminal obliteration. The obliterative lesions histologically resembled human OB. Differences from our previous findings with terminal bronchioles were minor. This study supports the use of larger-size airways in the study of OB.

Obliterative lesions in a heterotopic bronchial xenograft model--a preliminary study.

BACKGROUND: We further developed our heterotopic pig model of obliterative bronchiolitis to study airway obliteration in xenografts. METHODS: Four domestic piglets each received 40 bronchial xenografts s.c. from a donor lamb. Piglet X was not immunosuppressed. The other animals received daily oral cyclosporine, 15 mg/kg (XC), or SDZ RAD, 1.5 mg/kg (XR), or both (XCR). Five implants at a time were serially removed from each animal during 17 days for histological assessment. RESULTS: In contrast to the grafts of the others, the xenografts of XCR recovered after initial ischemic damage. No epithelial damage (P<0.01) or mural necrosis occurred on day 7. Airway obliteration developed in all, but was significantly delayed in XCR. CONCLUSIONS: Invariably developing airway obliteration in nontreated xenografts was delayed by immunosuppression, making the model useful, especially in testing the efficacy of immunosuppressive drugs in a xenogeneic system.

Coronary surgery in Europe: comparison of the national subsets of the European system for cardiac operative risk evaluation database.

OBJECTIVE: To compare the national samples of patients who underwent isolated coronary artery bypass grafting (CABG) during the European System for Cardiac Operative Risk Evaluation (EuroSCORE) trial in order to evaluate national differences in epidemiology, patient risk profile and surgical methods. METHODS: From September to November 1995, 11731 patients had CABG in the six largest contributing nations to the EuroSCORE project: Germany, UK, Spain, Finland, France and Italy. The Chi-square and Kruskal-Wallis tests were applied to obtain an international comparison of patient general status, including pre-operative risk factors, cardiac status, critical pre-operative states, rare conditions, urgency of surgery, angina status, coronary lesions, procedures and EuroSCORE risk assessment. RESULTS: Large national samples (from 984 patients in Finland to 3138 in Germany) identified significant differences in epidemiology, risk profile and surgical practice. Regarding epidemiology, CABG accounted for 62.8% of adult cardiac surgery, with a range of 46.2 in Spain to 77.7% in Finland (P<0.001). The mean age was 62.9 years (61.4 in Britain to 64.4 in France, P<0.001). The mean body mass index was 26.8 (26 in France to 27.5 in Finland, P<0.001). With regard to risk profile, diabetes was present in 20.3% of patients (11.8% in Britain to 27.7% in Spain, P<0.001). Chronic renal failure was present in 8.3% (6.8% in Germany to 10.6% in Spain, P<0.001). Chronic airway disease affected 3.8% (1.9% in Italy to 5. 1% in Germany, P<0.001). The mean ejection fraction was 0.56 (0.48 in Britain to 0.58 in Finland, P<0.001). The mean predicted mortality (according to EuroSCORE) was 3.3% (2.8% in Finland to 3.6% in France, P<0.001). The prevalence of chronic congestive heart failure, unstable angina and recent myocardial infarction also showed statistically significant differences. No differences were found for some critical preoperative states (such as immediate preoperative cardiac massage and pre-operative intubation), or for surgery for catheter laboratory complication. Regarding surgical practice, major differences were noted in preoperative intra-aortic balloon use (mean 1%, Finland 0%, Spain 2.3%, P<0.001), the number of mammary artery conduits used (mean 0.9, Spain 0.7, France 1.1, P=0.0001) and the number of distal anastomoses (mean 3, France 2.7, Finland 3.8, P=0.001). CONCLUSION: There are important epidemiological differences in the national cohorts of CABG patients in the EuroSCORE database. Any international comparison of European surgical results must therefore take into account the risk profile of patients by using a compatible risk stratification system.

Prevention of small airway obliteration in a swine heterotopic lung allograft model.

BACKGROUND: In our swine model of obliterative bronchiolitis preventing obliteration by the standard immunosuppression with cyclosporine, methylprednisolone, and azathioprine was not successful. The purpose of this study was to test the ability of a new immunosuppressive regimen to prevent alloimmune reaction and obliteration of the allografts. This regimen includes the novel macrolide SDZ RAD, i.e., 40-O-(2hydroxyethyl)-rapamycin. METHODS: Donor lung allografts of 1 cm3 were implanted sub-cutaneously into 11 random-bred non-related domestic pigs receiving daily oral cyclosporine (10 mg/kg) and methylprednisolone (20 mg). In addition, the animals received either oral azathioprine (2 mg/kg) (Group 1) or oral SDZ RAD (1.5 mg/kg) (Group 2). Histologic alterations were graded from 0 to 3 based on repeatedly removed implants during a follow-up period of 3 months. RESULTS: Total epithelial destruction and permanent luminal obliteration occurred within 37 days in Group 1. After an initial grade of 2.3+/-0.3 destruction, epithelial recovery was evident in Group 2 (P < 0.01), and the bronchi stayed patent. Cartilaginous destruction was milder in Group 2 (P < 0.05) than in Group 1, but chondrocytic proliferation was more intense (P < 0.05). Alveolar tissue and native structures of the bronchial wall were destroyed in Group 1, but preserved in Group 2 with total recovery after a mild-grade initial necrosis. CONCLUSIONS: Unlike the standard triple therapy, SDZ RAD combined with cyclosporine and methylprednisolone preserves the pulmonary allografts and prevents epithelial destruction and subsequent luminal obliteration. This suggests that this regimen might efficiently suppress obliterative bronchiolitis and improve long-term results in lung transplant recipients.

Alloimmune injury preceding airway obliteration in porcine heterotopic lung implants: a histologic and immunohistologic study.

BACKGROUND: Obliterative bronchiolitis (OB), the major long-term complication of lung transplantation, has thus far lacked a good large-animal model. Our goal was to develop such a model on the basis of previous rodent models with tracheal implants. METHODS: Fragments of pulmonary tissue with structures of terminal bronchi were subcutaneously transplanted to four random-bred domestic piglets. Each animal received 10 autograft and 10 allograft implants. The histologic findings were graded from 0 to 3 for implants harvested repeatedly over 2 months. RESULTS: In autografts, partial destruction of the respiratory epithelium and gradual luminal obliteration as well as mild damage to the cartilage and the bronchial wall underwent rapid reversal after initial ischemic injury. In the allografts, epithelial destruction and gradual obliteration were total within 14 days, the difference being statistically significant (P<0.05) in both. The histologic features of the obliterative plug were similar to those of human OB. In the allografts, cartilaginous destruction and pericartilaginous inflammation increased gradually to severe levels, significantly worse than in the autografts (P<0.05). Necrosis and inflammation of the bronchial wall were also more severe in the allografts (P<0.05). CONCLUSIONS: At the end of follow-up, all autografts were vital, whereas the allografts were almost totally rejected and were without native structures. All bronchi in the allografts exhibited accelerated obliteration with histologic features characteristic of human OB, thus providing a model for research into OB and its prevention.

Ceftriaxone versus vancomycin prophylaxis in cardiovascular surgery.

The efficacy of antibiotic prophylaxis in cardiac surgery was compared between 97 patients receiving a single 2 g dosage of ceftriaxone and 103 receiving 500 mg of vancomycin i.v. every 6 h for 48 h. The overall infection rate was 13.4% in the ceftriaxone and 10.7% in the vancomycin group. Four (4%) wound infections, including one mediastinitis, occurred in the ceftriaxone group and five (5%) in the vancomycin group, with no statistically significant difference. The findings of this study support the adequacy of a simple single dose of ceftriaxone prophylaxis in cardiac surgery, at least in hospitals with low incidence of vancomycin-resistant staphylococcal infections.

Risk factors and outcome in European cardiac surgery: analysis of the EuroSCORE multinational database of 19030 patients.

OBJECTIVE: To assess risk factors for mortality in cardiac surgical adult patients as part of a study to develop a European System for Cardiac Operative Risk Evaluation (EuroSCORE). METHODS: From September to November 1995, information on risk factors and mortality was collected for 19030 consecutive adult patients undergoing cardiac surgery under cardiopulmonary bypass in 128 surgical centres in eight European states. Data were collected for 68 preoperative and 29 operative risk factors proven or believed to influence hospital mortality. The relationship between risk factors and outcome was assessed by univariate and logistic regression analysis. RESULTS: Mean age (+/- standard deviation) was 62.5+/-10.7 (range 17-94 years) and 28% were female. Mean body mass index was 26.3+/-3.9. The incidence of common risk factors was as follows: hypertension 43.6%, diabetes 16.7%, extracardiac arteriopathy 2.9%, chronic renal failure 3.5%, chronic pulmonary disease 3.9%, previous cardiac surgery 7.3% and impaired left ventricular function 31.4%. Isolated coronary surgery accounted for 63.6% of all procedures, and 29.8% of patients had valve operations. Overall hospital mortality was 4.8%. Coronary surgery mortality was 3.4% In the absence of any identifiable risk factors, mortality was 0.4% for coronary surgery, 1% for mitral valve surgery, 1.1% for aortic valve surgery and 0% for atrial septal defect repair. The following risk factors were associated with increased mortality: age (P = 0.001), female gender (P = 0.001), serum creatinine (P = 0.001), extracardiac arteriopathy (P = 0.001), chronic airway disease (P = 0.006), severe neurological dysfunction (P = 0.001), previous cardiac surgery (P = 0.001), recent myocardial infarction (P = 0.001), left ventricular ejection fraction (P = 0.001), chronic congestive cardiac failure (P = 0.001), pulmonary hypertension (P = 0.001), active endocarditis (P = 0.001), unstable angina (P = 0.001), procedure urgency (P = 0.001), critical preoperative condition (P = 0.001) ventricular septal rupture (P = 0.002), noncoronary surgery (P = 0.001), thoracic aortic surgery (P = 0.001). CONCLUSION: A number of risk factors contribute to cardiac surgical mortality in Europe. This information can be used to develop a risk stratification system for the prediction of hospital mortality and the assessment of quality of care.

Bioabsorbable self-reinforced poly-L-lactide, metallic, and silicone stents in the management of experimental tracheal stenosis.

The aim of the present study was to compare, in rabbits, the biocompatibility and suitability of a bioabsorbable spiral stent made of self-reinforced poly-L-lactide (SR-PLLA) in the management of experimental tracheal stenosis with stents made of metal and silicone. Tracheobronchial stenosis, and its management, is still problematic because stenoses are not always amenable to surgical resection and reconstruction, especially concerning anastomotic problems and stenosis after lung transplantation. Stenosis can be handled with stenting, although the ideal stent has yet to be developed; all the stents available have their disadvantages. Because stenting of the airways can be only temporary, stents made of bioabsorbable materials, theoretically, offer benefits. Tracheal stenosis was created in rabbits by the extramucosal resection of cartilaginous arches of the cervical trachea. After a few weeks, the animals were operated on again, and those stenoses that had developed were dilated with a balloon. Stents then were implanted in the area of stenosis to keep the dilated trachea open. All the animals in the group with silicone stents had to be killed because of respiratory difficulties: their stents had a tendency to occlude because of internal encrustation, and they developed a hyperplastic polyp at the ends of the stents. The SR-PLLA and metallic stents were tolerated well, and after follow-up ended the animals were put to death. This experimental study showed that silicone stents had a tendency to occlude and that stents made of metal and of SR-PLLA were well tolerated and can be used in the management of airway stenosis.

Raised endothelin content in bronchoalveolar lavage fluid during lung allograft rejection in pigs.

Various pathophysiologic mechanisms are implicated in the rejection of transplanted lungs, for example production of vasoactive substances such as endothelin. In this study the measured endothelin content of bronchoalveolar lavage (BAL) fluid was correlated to the grade of lung allograft rejection. Left lung allotransplantation was performed in seven piglets (weight 16-24 kg). Triple-drug immunosuppression (cyclosporin, azathioprine, methylprednisolone) was given, and episodes of acute rejection were induced by withdrawing the medication. The development of acute rejection was monitored with computed tomography and bronchoscopy with BAL and transbronchial biopsy. In 46 BAL samples the endothelin content was radioimmunologically assayed. Transbronchial biopsies taken simultaneously showed grade 0 rejection in 17 tissue samples, grade 1 in 21 and grade 2 in eight. The endothelin content of BAL (pg/ml) increased from 34.3 +/- 6.1 in grade 0 rejection to 54.6 +/- 6.8 in grade 1 and to 98.5 +/- 35.6 in grade 2. The increase from grade 0 was statistically significant to grade 1 (p < 0.05) and to grade 2 (p < 0.02). The increased endothelin content of BAL may have harmful effects on the lung, as endothelin is a potent vaso- and bronchoconstrictive peptide with mitogenic properties.

Small airway obliteration in a new swine heterotopic lung and bronchial allograft model.

BACKGROUND: We studied a heterotopic large-animal model with obliterative airway lesions caused by allograft rejection. METHODS: Lung fragments (1 cm3) with airways (LB), and 1 to 2 mm diameter bronchi alone (B) were implanted subcutaneously in 11 domestic piglets weighing 20 kg. Six animals each received 40 implants from nonrelated donors without immunosuppression (group A). Another 5 animals had autograft implants (group U). The implants were harvested consecutively for histologic analysis over 3 months in group A and 6 months in group U. RESULTS: In group U, the initial ischemia caused mild to moderate epithelial damage with moderate metaplasia but with a return to normal ciliary epithelium within 1 month. Transient mild luminal obliteration with granulation tissue and mononuclear cells was observed during the first weeks, but after 4 weeks the lumen was patent and filled with mucus. In the bronchial wall, moderate fibrosis developed in LB implants, whereas mild fibrosis was seen in B implants. In group A, the epithelium was totally absent by 2 weeks, and mild inflammation, fibrosis, and destruction of the cartilage with pericartilaginous mononuclear accumulation were observed in the bronchial wall. Small airways were gradually obliterated between days 7 and 21, initially by granulation tissue and mononuclear cells and later by progressive fibrosis. CONCLUSIONS: In this model, autografted airway implants stayed patent for at least 6 months, whereas total luminal obliteration histologically resembling obliterative bronchiolitis developed in allografts within 21 days. Because small airways, including bronchioli, can be transplanted with the use of this model, it may be useful for research into the causes of airway obliteration, which may be relevant to the pathogenesis of obliterative bronchiolitis in lung recipients.