Activity of disinfectants against Gram-negative bacilli isolated from patients undergoing lung transplantation for cystic fibrosis

Lung transplant recipients with cystic fibrosis are frequently colonized with antibiotic-resistant bacteria. We evaluated the in vitro activity of 5 disinfectants frequently used in cardiac surgery against strains of Burkholderia cepacia and Pseudomonas aeruginosa isolated from patients undergoing sequential single lung transplantation. Our results suggest that the activity of Taurolin and Noxyflex is superior to conventional disinfectants.

Non-immune acute graft injury after lung transplantation and the risk of subsequent bronchiolitis obliterans syndrome (BOS)

BACKGROUND

Primary graft dysfunction remains a major cause of early morbidity and mortality after lung transplantation. Evidence from animal models shows acute non-immune lung injury increases organ immunogenicity by enhancing MHC Class II expression. We hypothesized that acute non-immune injury in the lung allograft may impact, not only on early survival, but also on longer term survival by increasing the incidence of bronchiolitis obliterans syndrome (BOS).

METHODS

A single-center, retrospective, observational study in a population of over 320 lung transplant recipients was undertaken. The histologic diagnosis of diffuse alveolar damage (DAD) in an early graft biopsy was used to define those recipients at risk. Serial measurements of forced expiratory volume in 1 second (FEV(1)) in long-term follow-up defined the incidence of BOS.

RESULTS

Early graft biopsy was available in 291 of the recipients following transplantation. DAD was confirmed in 55 (19%); their 30-day survival (62.5%) was significantly worse than in recipients without DAD (87.5%; p < 0.0001, chi-square test). When 30-day deaths were excluded, however, there was no difference in survival between recipients with and without DAD (hazards ratio 0.69 [0.37 to 1.3]; p = 0.25, Wilcoxon's survival analysis). The incidence of subsequent BOS over the follow-up period was not significantly different in those with and without DAD on early biopsy at 46% and 59%, respectively (hazards ratio 0.88 [0.48 to 1.62]; p = 0.22, chi-square test). BOS did not occur any earlier in the DAD group (median 953 days, range 152 to 1,393) days compared with the non-DAD group (median 665 days, range 52 to 4,299) (p = 0.48, Fisher's exact test).

CONCLUSIONS

The development of severe non-immune acute graft injury after lung transplantation has a poor early prognosis. However, recipients with non-immune acute graft injury who survive >30 days show no significant difference in long-term survival or BOS-free time compared with recipients without early injury.

Concurrent coronary grafting of the donor heart with left internal mammary artery: 10-year experience

We report 4 donor hearts with palpable atherosclerosis on the surface of the left anterior descending coronary artery (LAD), which was thought to be significant. The heart ordinarily would have been rejected in the absence of availability of donor coronary angiography or bench angiography. Instead, we accepted the organ and bypassed the atherosclerotic lesion with a left internal mammary artery. Long-term outcome and follow-up are reported.

Improving the quality of kidneys from non-heart-beating donors, using streptokinase: an animal model

BACKGROUND

Non-heart-beating donors (NHBD) offer a promising potential to increase the cadaveric organ donor pool, especially for kidneys. However, almost half of NHBD kidneys are discarded after viability assessment. This wastage is costly in both human and monetary terms. Intravascular thrombosis at the time of donor death is an event leading to failure in the viability assessment. We have developed an animal model to investigate the effects of the addition of streptokinase to the in situ flush medium before transplant in an attempt to redress the situation.

METHODS

Two groups of eight healthy young Landrace Yorkshire white pigs were entered into the study. Both groups were subjected to approximately 70 min warm ischemia. Both groups received an intravascular flush with 4 L of Marshall's solution with heparin (1000 IU/L); one group of pigs also had streptokinase (1.5 MIU/L) added. After donor nephrectomy, all kidneys were machine perfused for 4 hr. Data on perfusion characteristics were taken and samples of kidney effluent were assayed for tissue damage biomarkers, glutathione S-transferase (GST) and alanine aminopeptidase (Ala-AP). Wedge sections of porcine kidneys were taken at the end of perfusion, for histological analysis.

RESULTS

Data on machine perfusion parameters (temperature, mean pressure index, resistance) indicate better cooling, lower resistance, and lower mean pressure index in the streptokinase-treated group of pigs. GST and Ala-AP levels were increased in the nonstreptokinase group perfusates. Histopathological analysis of porcine kidneys indicated more ischemic injury and tissue damage in the nonstreptokinase group.

CONCLUSION

The use of streptokinase in this porcine NHBD model conferred benefits to donor kidneys when assessed by machine perfusion. Markers of biochemical injury indicated that less renal tissue damage occurred with the incorporation of streptokinase in the in situ flush medium.

Expression of chemokine receptors CXCR1 and CXCR2 during cardiopulmonary bypass

OBJECTIVE

This study investigated the effects of cardiopulmonary bypass on neutrophil expression of chemokine receptors, CXCR1 and CXCR2, and the beta2 integrin CD11b.

METHODS

Ten patients undergoing coronary artery grafting with cardiopulmonary bypass were studied. Blood samples were collected preoperatively, before bypass, at termination of bypass, and 12 to 18 hours postoperatively. In vitro studies were performed on control subjects to determine changes in the surface expression of CXCR1, CXCR2, and CD11b on stimulation with interleukin 8. Receptor expression was measured by flow cytometry. Plasma levels of interleukin 8 from the patients were determined by enzyme-linked immunoassay.

RESULTS

After bypass, CXCR2 expression fell by 66% (P <.0001) and remained low postoperatively (P <.0001). CXCR1 expression persisted at preoperative levels. CD11b expression increased significantly after bypass (P <.0001), returning to prebypass levels postoperatively. In vitro studies showed a dose-related fall of both CXCR1 (P <.0001) and CXCR2 expression (P <.0001) and a significant rise in CD11b expression (P <.0001). Plasma interleukin 8 increased significantly after bypass (P <.0001), remaining elevated 12 to 18 hours postoperatively (P =.02). Correlations between interleukin 8 levels and CXCR2 expression (P <.0001) and CD11b expression (P <.03) were demonstrated.

CONCLUSIONS

CXCR2 expression is significantly down-regulated after bypass; in contrast, CXCR1 expression remains unchanged. In addition, whereas interleukin 8 is an important determinant of both CXCR1 and CXCR2 expression in vitro, it only correlates with CXCR2 and CD11b expression in vivo. This has implications in the search for antagonists against CXC chemokines and their receptors.

Burkholderia cepacia complex genomovars and pulmonary transplantation outcomes in patients with cystic fibrosis

Burkholderia cepacia is a group of organisms that comprises seven genotypically distinct species (B cepacia genomovars I-VII), which are collectively known as the B cepacia complex. Preoperative infection with B cepacia is associated with a poor prognosis in lung transplant recipients with cystic fibrosis. Many centres do not, therefore, offer transplants to these individuals. Our aim was to ascertain whether or not post-transplant mortality is affected by pretransplant genomovar status. We studied archived isolates with PCR-based methods, and recorded excessive mortality in patients infected with B cepacia genomovar III, but not in those infected with other genomovars.

Donor-acquired small cell lung cancer following pulmonary transplantation

We describe a case of donor-acquired small cell lung cancer after pulmonary transplantation for cystic fibrosis. The recipient was an ex-smoker with minimal smoking history and had been abstinent for 20 years. At the time of death, the donor chest radiographic finding was normal. The recipient had multiple posttransplant bronchoscopies and a normal CT scan result at 4 months after transplantation. The recipient presented 13 months after transplantation with metastatic disease. He did not respond to chemotherapy and died shortly thereafter. Molecular genetic techniques revealed that the primary tumor and metastases were different to recipient tissues, confirming the donor origin.

Functional assessment of non-heart-beating donor lungs: prediction of post-transplant function

OBJECTIVES

To enable an increase in the numbers of donor lungs using organs from non-heart-beating donors (NHBD). To develop an isolated ventilation and perfusion technique to assess the degree of warm ischaemic organ injury suffered prior to retrieval, thereby enabling identification of lungs with predictably good post-transplant function.

METHODS

Lungs from Landrace-Yorkshire White cross pigs were retrieved after 1 (NHBD(1)), 2 (NHBD(2)) or 4 h (NHBD(4)) post-hypoxic death induced by cessation of ventilation. Control organs were retrieved using standard techniques for each group from matched animals immediately following aortic cross-clamping (Control(1) and combined Control(2,4)). Modified Euro-Collins pulmoplegia was used in all groups, prior to ventilating a single lung with 100% oxygen and perfusion with neutrophil-depleted and deoxygenated blood. For all of the lungs in the NHBD(2) and combined Control(2,4) groups, and one of the successfully perfused NHBD(4), the contralateral lung was then transplanted with post-transplant function assessed for 12 h. All animals were anaesthetized throughout and euthanased without regaining consciousness.

RESULTS

On assessment, oxygenation after 5 min of perfusion did not differ between NHBD(1) (n=4) vs. Control(1) (n=5; analysis of variance (ANOVA), P=0.152). However, oxygenation had deteriorated significantly in the NHBD(2) group (n=6) vs. Control(2,4) (n=8; ANOVA, P<0.0005) and was significantly poorer than initial values after 8 min (unpaired t-test with Bonferroni correction, P<0.03). In NHBD(4) (n=6), four lungs failed assessment due to the development of gross pulmonary oedema, although the remaining pair functioned as well as Control(2,4). Post-transplantation, NHBD(2) (n=6) contralateral lungs showed significantly poorer overall oxygenation, (mean+/-SD, 46+/-22 kPa) when compared with Control(2,4) (n=6; 59+/-16 kPa; ANOVA, P=0.001), although oxygenation was satisfactory. The contralateral organ from one successfully perfused NHBD(4) lung functioned well post-transplantation.

CONCLUSIONS

The significant deterioration in oxygenating performance seen during assessment after 2 h warm ischaemia and the idiosyncratic function after 4 h warm ischaemia indicates the importance of functional testing of NHBD lungs. The similar deterioration in oxygenating performance seen post-transplantation in the contralateral lungs suggests that this method detects functional warm ischaemic lung injury.

Renal function after pediatric cardiac transplantation: the effect of early cyclosporin dosage

BACKGROUND

There is little data on renal function in pediatric heart transplant recipients. Early rejection is a major concern and most units run high cyclosporin A (CyA) levels during the 2 to 3 months after transplantation. We sought to document long-term renal function after transplantation and to assess influence of early CyA levels.

METHODS

We reviewed all of our pediatric transplants between June 1985 and August 1998 who survived longer than 6 months (n = 54). Glomerular filtration rate (GFR) was estimated at 1, 2, 4, and 8 years posttransplantation using the Schwartz formula: GFR (mL/min/1.73m(2)) = [Ht(cm)/creatinine(micromol/L)] x X We also analyzed whether change in renal function correlated with trough CyA levels.

RESULTS

Median age at transplant was 4 years and median follow-up was 5 years. Survival rates were 87% at 1 year and 80% at 5 years. Mean GFR pretransplant was 79 +/- 19 mL/min/1.73 m(2), reflecting prerenal impairment. One year later, mean GFR was 72 mL/min/1.73 m(2); after 2 years it was 65 mL/min/1.73 m(2), after 4 years (n = 35) it was 60 mL/min/1.73 m(2), and after 8 years (n = 14) it was 57 mL/min/1.73 m(2). CyA levels during the first 2 months correlated with the change in GFR during the first year (r(2) = 0.21).

CONCLUSIONS

This study demonstrates for the first time that decline in renal function after heart transplantation correlates with early CyA exposure; this dysfunction persists even when CyA doses are subsequently reduced.

The value of flow cytometric crossmatch in cardiac transplantation

One of the major clinical problems in cardiac transplantation is that of moderate rejection of the graft, and over the past few years there is increasing evidence that humoral antibody may be important in graft prognosis. The sensitivity of the conventional cytotoxic crossmatch has been questioned, and an increased significance of there of the flow cytometric crossmatch (FCXM) to detect the presence of antibodies before transplantation has been reported. In this study we have examined the sera of 138 cardiac transplants (1988-1992) for the presence of donor-directed IgG and IgM antibodies using FCXM. Sera were collected immediately before transplantation and before the institution of immunosuppressive therapy. All pretransplant cytotoxic crossmatches were negative. After a minimum follow-up period of 3 months, the performance of the transplants was graded by endomyocardial biopsy: 1, no or mild evidence of rejection; 2, patients showing moderate rejection requiring increased immunosuppression. Of the 138 patients studied, 10 patients were excluded as they died within the first week of transplantation. Eight children were excluded since they were given prophylactic ATG (Merieux). A positive FCXM result was defined as showing values in excess of that found for the AB control sera. A significant association was found between the presence of both IgG to T and B cells and IgM to T cells and graft performance (P = 0.02 and 0.93, respectively). Indeed, IgM-directed T-cell antibodies were only found in patients with moderate rejecton. These two groups were mutually exclusive, so that the FCXM was able to identify the presence of moderate rejection in 55% of the patients. In conclusion, results show that pretransplant FCXM in cardiac transplantation provides a more sensitive assay of antibody status in recipients and has proved to be of prognostic value.

Elevated levels of interleukin-8 in donor lungs is associated with early graft failure after lung transplantation

Increased levels of the neutrophil chemokine interleukin (IL)-8 in the lungs of severe trauma patients can predict subsequent development of acute respiratory distress syndrome. Because the lungs of brain-dead organ donors can contain high levels of IL-8, we hypothesized that this may predispose to early graft failure in the recipient after lung transplantation. Twenty-six organ donors prospectively satisfying clinical criteria for lung donation underwent bronchoalveolar lavage and lung biopsy to determine the effect of neutrophil infiltration and IL-8 expression in the donor lung on graft function and survival in 26 respective recipients after lung transplantation. Nine recipients developed severe graft dysfunction, of whom six subsequently died (median survival: 24 d [range: 5 to 39 d]); all others survived beyond 6 mo. The IL-8 signal in the donor lung correlated with the percent neutrophils in bronchoalveolar lavage fluid (BALF) before implantation (42.4 +/- 7.24 [mean +/- SE]%, p = 0.03) and with the degree of impairment in graft oxygenation after implantation (p = 0.01). An increased level of IL-8 in the donor BALF was associated with the development of severe early graft dysfunction (p = 0.027) and with early recipient mortality (p = 0.0034). Use of donor lungs with high IL-8 levels is associated with a poor prognosis after lung transplantation. Attenuating the donor's inflammatory response before organ retrieval may improve early outcome after lung transplantation, and help maximize lung use from the existing donor pool.

Orthotopic heart transplantation with concurrent aortic valve replacement and coronary artery bypass grafting

We report a case of successful orthotopic heart transplantation of a donor heart with normal ventricular function, 2-vessel coronary artery disease, and a bicuspid aortic valve, which required concurrent aortic valve replacement and coronary artery bypass grafting. In confronting the disparities in demand and supply, we must consider the so-called marginally acceptable heart for either critically ill recipients or those who may be disadvantaged on the waiting list.

Long-term follow-up of pediatric cardiac transplant recipients on a steroid-free regime: the role of endomyocardial biopsy

BACKGROUND

Endomyocardial biopsy is used in long-term follow-up of cardiac transplant recipients to detect sub-clinical rejection. The value of this for adults and children on triple-drug immunosuppression has been disputed. We investigated its value in children maintained on a steroid-free regime.

METHODS

We used a retrospective review of annual surveillance biopsy results from children younger than 13 years at the time of cardiac transplant.

RESULTS

In a series of 40 children older than 10 years, we found no evidence of rejection in 88/130 (67.7%) biopsies; 41/130 (31.5%) showed grade 1A rejection, and 1/130 (0.8%) showed grade 1B rejection. No grade 2, 3, or 4 biopsies were found. Nine patients with 1A rejection had subsequent grade 0 biopsies, without any adjustment in treatment. Seven children had treatment changes and repeat biopsies because of grade 1A biopsies.

CONCLUSION

Significant late rejection is rare even in children on steroid-free maintenance. It is unlikely to be detected unexpectedly, and the practice of indefinite routine biopsy in children who are well is not justified. Future use should focus on individuals at higher risk of rejection.

Tests of airway function in detecting and monitoring treatment of obliterative bronchiolitis after lung transplantation

BACKGROUND

This study evaluated different tests of airway function in detection of obliterative bronchiolitis. It included analysis of spirogram within the time domain in patients with and without obliterative bronchiolitis (OB) after heart lung and lung transplantation. The purpose of this analysis is to evaluate which tests are of greatest value for early recognition of OB.

METHODS

The coefficient of variation of different airway function tests was calculated in 13 patients who had no evidence of OB and 12 patients who developed OB post-transplantation. In the patients with OB the effect of treatment with total lymphoid irradiation (TLI) was investigated by comparing the rate of change of lung function before and after TLI. Several lung function tests were used.

RESULTS

The measurements that showed the least variation were FEV(1), FVC, PEF, FEV(1)/FVC ratio and the Moment Ratio, while those which became abnormal earlier were FEV(1), FEV(1)/FVC, MEF(50), and the first moment. Additionally, the tests that became abnormal in a higher proportion of patients were MMEF, MEF(50), MEF(75), and the first moment.

CONCLUSIONS

The results o thi support the use of simple spirometric indices for the detection of OB. In the patients with OB the rates of decline of lung function were significantly attenuated by treatment with TLI as determined by several different tests.

KEYWORDS

obliterative bronchiolitis, lung transplantation, moments analysis, airway function tests, total lymphoid irradiation

Changing cyclosporin A formulation: an analysis in paediatric cardiac transplant recipients

Cyclosporin A is the primary immunosuppressive agent used in cardiac transplantation to maintain chronic immunosuppression. Absorption may be erratic and major side-effects include nephrotoxicity. A recently introduced formulation (Neoral) improves absorption in cystic fibrosis heart-lung transplant recipients, but episodes of rejection have been reported on conversion from the oil-based formulation. A retrospective analysis of 21 paediatric cardiac transplant recipients who had been converted from the oil-based formulation to the micro-emulsified formulation was performed. No clinical rejection episodes occurred following conversion. There was a significant reduction in dose following conversion (p < 0.001). The mean trough level was less on the new formulation (p = 0.04), but there was no difference in coefficient of variation or standard deviation. Mean glomerular filtration rate (GFR) was significantly less, but there was no difference in the rate of change of GFR on the new formulation. Erratic absorption and deteriorating renal function remain as significant problems in paediatric cardiac transplant recipients despite conversion to the new formulation.

Electrophysiological properties of the recipient atrial remnant after human orthotopic cardiac transplantation

AIMS

The recipient atrial remnant has been used as a control in studies ofchronotropic response following orthotopic cardiac transplantation and as a trigger for the donor heart. It is not known, however, whether its function is normal. We investigated the electrophysiological properties of the recipient atrial remnant.

METHODS AND RESULTS

Fifty patients were studied, mean age 49 years (range 20-63) and mean time post-orthotopic cardiac transplantation of 31 months (range 1-107). Recipient atrial rhythm, spontaneous cycle length and sinus node function were determined. Atrial fibrillation/flutter was identified in 10/50 (20%). Of those in sinus rhythm, significant bradycardia was present in 12/40 (30%). The mean spontaneous cycle length was 929+/-188 ms. Three patients demonstrated variable atrial electrocardiogram morphology and a further three patients had marked variations in resting cycle length. The sinus node function was abnormal in 2/34 (6%).

CONCLUSIONS

Only 56% recipient atria had normal sinus rhythm, with 21% of these demonstrating features consistent with a wandering atrial pacemaker. The recipient atrial remnant is not normal in the majority of transplant recipients and should be used with caution in studies involving its use as a control or as a trigger for the donor heart.

Significance of Epstein-Barr virus status and post-transplant lymphoproliferative disease in pediatric thoracic transplantation

Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disease (PTLD) is a serious complication of organ and bone marrow transplantation. The importance of EBV matching between recipient and donor remains unclear. Between October 1987 and December 1997, 64 pediatric cardio-pulmonary transplants were performed at this center (58 hearts, two heart/lungs, four sequential single lungs). The EBV viral capsid antigen (VCA) immunoglobulin G (IgG) status of both donor and recipient was determined at the time of transplant. Of 56 patients from whom paired sera was available for analysis, 27 (50%) were recipient and donor EBV IgG positive, four (7%) were recipient EBV IgG positive and donor EBV IgG negative, and 12 (20%) were recipient EBV IgG negative and donor EBV IgG negative. The remaining 13 (23%) patients were EBV IgG negative but received organs from EBV IgG-positive donors. The EBV immunoglobulin M (IgM) status was determined from 6 weeks post-transplant in the 11 mismatches who survived for longer than 28 d. Seven became EBV IgM positive, two remained EBV IgM negative; the status of the remaining two remains unknown. The EBV IgM status was also determined retrospectively in patients who were EBV IgG negative pretransplant and received organs from EBV IgG-negative donors. Nine became EBV IgM positive; the rest remained negative. PTLD was diagnosed in two of 56 patients from whom paired sera was available; one was donor and recipient EBV IgG negative; the other was donor and recipient EBV IgG positive. No cases of PTLD were diagnosed in the remaining eight patients from whom paired sera was not available. Our experience suggests that PTLD does not occur with any greater frequency in the 'mismatch' group, and does not justify EBV matching in pediatric thoracic transplantation where there is a higher proportion of EBV-negative recipients than in adults.

A new porcine model of reperfusion injury after lung transplantation

Rodent models have been described to investigate lung preservation and reperfusion injury but have significant disadvantages. In large animals single lung transplant studies are probably optimal but problems remain over the ability to rigorously separate the lungs for assessment while promoting medium to long-term animal survival for meaningful investigation. Our aim was to develop a novel and refined large animal model to assess reperfusion injury in the transplanted lung, overcoming the difficulties associated with existing models. Specifically, small animal models of lung transplantation usually have short perfusion times (often one hour) and include extracorporeal circuits while larger animal models often require the contralateral lung to be excluded after transplantation-an unphysiological situation under which to evaluate the graft. A porcine model of left lung allotransplantation was developed in which native and donor lungs are individually ventilated. Sampling catheters placed within the graft lung allowed specimen withdrawal without mixing of blood from the contralateral lung after reimplantation. The model permits a variety of clinical scenarios to be simulated with the native lung supporting the animal irrespective of function in the graft. This model has been used in over 60 transplant procedures with a postoperative survival time of 12 h being readily achieved. The mean operating time was 2.6 h. The mortality rate is 4% in our series. We have found the model to be reliable, reproducible and flexible. We propose this model as an adaptable investigation for evaluating lung reperfusion injury and preservation.