Lung transplantation, gastroesophageal reflux, and fundoplication

Lung transplantation is an accepted treatment strategy for end-stage lung disease; however, bronchiolitis obliterans syndrome is a major cause of morbidity and mortality. This review explores the role of gastroesophageal reflux disease in bronchiolitis obliterans syndrome and the evidence suggesting the benefits of anti-reflux surgery in improving lung function and survival. There is a high prevalence of gastroesophageal reflux in patients post lung transplantation. This may be due to a high preoperative incidence, vagal damage and immunosuppression. Reflux in these patients is associated with a worse outcome, which may be due to micro-aspiration. Anti-reflux surgery is safe in selected lung transplant recipients; however there has been one report of a postoperative mortality. Evidence is conflicting but may suggest a benefit for patients undergoing anti-reflux surgery in terms of lung function and survival; there are no controlled studies. The precise indications, timing, and choice of fundoplication are yet to be defined, and further studies are required.

Targeting allograft injury and inflammation in the management of post-lung transplant bronchiolitis obliterans syndrome

Chronic allograft dysfunction, manifesting as bronchiolitis obliterans syndrome (BOS), is the major cause of morbidity and mortality in human lung transplant recipients. While alloimmunity has a definite role, there is increasing interest in overall allograft injury and subsequent inflammation and remodeling. This review deals with nonalloimmune factors that may potentiate alloimmune injury. We discuss infection and reflux/aspiration as examples of allograft injury, which may lead to chronic loss of graft function and BOS. Surgical and nonsurgical treatments aimed at preventing these insults and improving survival are considered. The need for further evidence, including randomized-controlled trials, to evaluate the role of medical and surgical therapies is emphasized by the current literature.

Norepinephrine and arginine vasopressin increase hepatic but not renal inflammatory activation during hemodynamic resuscitation in a rodent model of brain-dead donors

OBJECTIVES

Hypotension that occurs after brain death causes a deterioration in organ function, which in turn restricts the number of organs that can be retrieved and leads to graft dysfunction. The correction of hypotension by the administration of norepinephrine increases the number of organs suitable for retrieval but is associated with cardiac allograft failure. Arginine vasopressin is relatively less cardiotoxic; however, the effect of that drug on intra-abdominal organs is unknown. We used a rodent model and real-time reverse transcription polymerase chain reaction to assess changes in the expression of inflammatory mediators in livers and kidneys that occurred in response to resuscitation with those drugs.

MATERIALS AND METHODS

Fifty outbred male Wistar rats were anesthetized, and an intracranial balloon was inserted. In 35 rats, the balloon was inflated to induce brain death and subsequent hypotension. In 20 of those rats, hypotension was corrected with either norepinephrine (n = 10) or vasopressin (n = 10), while the remaining 15 rats received no resuscitation. Brain death was not induced in 15 rats that did not become hypotensive or receive resuscitation. Organs were retrieved 30 minutes, 2 hours, and 5 hours after balloon insertion, and inflammatory activation was assessed via real-time reverse transcription polymerase chain reaction.

RESULTS

Significant time-dependent up-regulation of CXC motif chemokine ligand 1, interleukin-1beta, and heme oxygenase 1 occurred after brain death. Significantly greater up-regulation of CXC motif chemokine ligand and interleukin-1beta occurred in the livers of rats that received norepinephrine and vasopressin than in those that received no resuscitation. No increase in the expression of those mediators was noted in the kidneys.

CONCLUSIONS

This study showed that both norepinephrine and vasopressin amplified the inflammatory response that followed brain death in the livers, but not the kidneys, of rats in this model.

Targeting allograft injury and inflammation in the management of post-lung transplant bronchiolitis obliterans syndrome

Chronic allograft dysfunction, manifesting as bronchiolitis obliterans syndrome (BOS), is the major cause of morbidity and mortality in human lung transplant recipients. While alloimmunity has a definite role, there is increasing interest in overall allograft injury and subsequent inflammation and remodeling. This review deals with nonalloimmune factors that may potentiate alloimmune injury. We discuss infection and reflux/aspiration as examples of allograft injury, which may lead to chronic loss of graft function and BOS. Surgical and nonsurgical treatments aimed at preventing these insults and improving survival are considered. The need for further evidence, including randomized-controlled trials, to evaluate the role of medical and surgical therapies is emphasized by the current literature.

Acute hemodynamic effects of intravenous sildenafil citrate in congestive heart failure: comparison of phosphodiesterase type-3 and -5 inhibition

BACKGROUND

The reversibility of elevated pulmonary vascular resistance in heart failure bears an important relation to outcome after cardiac transplantation. The phosphodiesterase 3 (PDE3) and PDE5 inhibitors both increase levels of cyclic nucleotides in the vascular smooth muscle, causing vasodilatation. PDE3 inhibitors also have direct inotropic effects. We contrasted the acute hemodynamic responses to intravenous PDE3 and PDE5 inhibitors in patients with congestive cardiac failure to assess their relative suitability for reversibility testing in this setting.

METHODS

Thirty patients undergoing assessment for cardiac transplantation underwent right heart catheterization. Patients were randomized to receive an intravenous bolus of milrinone (0.05 mg/kg) or sildenafil citrate at a high (0.43 mg/kg) or low dose (0.05 mg/kg).

RESULTS

Differences between low- and high-dose sildenafil were not significant. Both agents caused similar reductions in systemic and pulmonary vascular resistance. Milrinone caused significantly greater reductions in pulmonary artery wedge and mean pulmonary artery pressure, and increases in heart rate. In all study groups, greater increases in cardiac index (>25%) were seen in patients with a higher pulmonary artery wedge pressure at baseline (29 +/- 1 vs 20 +/- 2 mm Hg; p < 0.001).

CONCLUSIONS

In end-stage congestive cardiac failure, intravenous milrinone and sildenafil both cause similar reductions in systemic and pulmonary vascular resistance; however, milrinone has more cardiac selective effects on left ventricular filling and heart rate. Both agents appear to have a suitable hemodynamic profile for testing of reversibility of secondary pulmonary hypertension in congestive cardiac failure. Larger studies are needed to confirm these results.

Pseudomembranous colitis in four patients with cystic fibrosis following lung transplantation

In the present study, 4 patients with cystic fibrosis undergoing lung transplantation (from a total of 137) who developed fulminant pseudomembranous colitis are described. Initial presentation was variable and the mortality rate was 50% despite urgent colectomy. In one case the presenting abdominal distension was thought to be due to meconium ileus equivalent. It is concluded that Clostridium difficile colitis may be a difficult diagnosis in patients with cystic fibrosis and follows a fulminant course after lung transplantation.

Circulating endothelial progenitor cell numbers are not associated with donor organ age or allograft vasculopathy in cardiac transplant recipients

INTRODUCTION

Increasing age is associated with reduced numbers of circulating endothelial progenitor cells (EPCs). It is unclear whether this relates to depletion or impairment of bone marrow progenitors, or to deficient mobilization signals from aging tissues. In cardiac transplant patients, one previous study has reported an association between circulating EPCs and the risk of cardiac allograft vasculopathy (CAV). We investigated whether increased donor heart age, a strong risk factor for CAV, was associated with reduced circulating EPC numbers in a group of cardiac transplant recipients matched for factors which influence EPC numbers, but with maximally discordant donor heart ages.

METHODS

We identified 32 patient pairs, matched for factors known to influence EPC numbers, but who had discordant donor heart ages by at least 20 years. EPCs were quantified using flow cytometry for absolute counts of cells expressing all the combinations of CD45, CD34, CD133 and the kinase domain receptor (KDR).

RESULTS

There were no significant differences in the numbers of circulating EPCs between patients with old or young donor heart age. There was no association between the presence of CAV and circulating EPC numbers.

CONCLUSIONS

We suggest that the increased susceptibility to CAV of older donor hearts is not mediated via circulating EPCs. Our results are consistent with the theory that the normal age-related decline in EPC numbers relates to bone marrow aging rather than failure of target tissues to induce EPC mobilization.

Smoking after cardiac transplantation

Although smoking cessation is a prerequisite prior to listing for cardiac transplantation, some patients return to smoking after recovery. We have covertly assessed the smoking habits of our cardiac transplant recipients (with ethical approval) since 1993 by measuring urinary cotinine: a level of >500 ng/mL signifying continued tobacco use. We retrospectively analyzed survival, causes of death and the development of graft coronary artery disease (GCAD) with respect to the number of positive and negative cotinine levels. One hundred four of 380 (27.4%) patients tested positive for active smoking at some point posttransplant, and 57 (15.0%) tested positive repeatedly. Smokers suffered significantly more deaths due to GCAD (21.2% vs. 12.3%, p < 0.05), and due to malignancy (16.3% vs. 5.8%, p < 0.001). In univariate analysis, smoking after heart transplantation shortened median survival from 16.28 years to 11.89 years. After correcting for the effects of pretransplant smoking in time-dependent multivariate analysis, posttransplant smoking remained the most significant determinant of overall mortality (p < 0.00001). We conclude that tobacco smoking after cardiac transplantation significantly impacts survival by accelerating the development of graft vasculopathy and malignancy. We hope that this information will deter cardiac transplant recipients from relapsing, and intensify efforts in improving cessation rates.

Histology of the explanted hearts of children transplanted for dilated cardiomyopathy

There is little information as to the histology of the explanted hearts of children transplanted for presumed dilated cardiomyopathy. We therefore aimed to describe the histology of these explants. Thirty-six children [mean age 7.4 years (range 0.1-17)] transplanted for dilated cardiomyopathy were identified. Based on histological examination of the explanted hearts patients were classified into three groups: severe inflammation, mild to moderate inflammation, and minimal or no inflammation. Cell death/damage and fibrosis were also scored. Duration of symptoms and degree of support at transplant were ascertained from the case notes. Two patients had severe confluent inflammation, nine mild or moderate focal inflammation, and 25 minimal or no inflammation. The degree of inflammation and fibrosis did not correlate with the interval between presentation and transplant (p = 0.37 and p = 0.78). Patients requiring inotropes or ventricular assist had a shorter time interval between presentation and transplant (p = 0.017) although these levels of support were not associated with the degree of inflammation or fibrosis (p = 0.90 and 0.5). We conclude that the explanted hearts of one-third of children transplanted for presumed cardiomyopathy have some degree of inflammation. Histological findings are not associated with symptom duration or support required.

Aortic valve replacement in octogenarians

Background and Aims

As our population ages and life expectancy increases the number of people aged over 80 and more referred for cardiac surgery is growing. This study sought to identify the outcome of aortic valve replacement (AVR) in octogenarians.

Methods

68 patients aged 80 years or more underwent AVR at the Freeman Hospital, between April 2001 and April 2004. A retrospective review of the notes and outcomes from the patients' GP and the NHS strategic tracking service was performed. 54% (37) underwent isolated AVR whilst 46% (31) underwent combined AVR and CABG.

Results

Follow up was 100% complete. The mean age was 83.1 ± s.d. 2.9 years, a mean gradient of 83 ± s.d. 31 mmHg and mean AVA of 0.56 cm². The mean additive EuroSCORE was 8.6 ± s.d. 1.2, the logistic EuroSCORE mean 12.0 ± s.d. 5.9. In hospital 30 day mortality was 13 %. Survival was 80% at 1 year and 78% at 2 years. Median follow up was for 712 days. Stepwise logistic regression identified chronic obstructive airways disease as an independent predictor of mortality (p < 0.05). Survival was not adversely affected by the addition of coronary artery bypass grafts to aortic valve replacement, the presence of peripheral vascular disease, hypertension or diabetes. In this study duration of cross clamp or bypass time were not found to reach significance as independent predictors of mortality.

Conclusion

Our study demonstrates that the operative mortality for AVR in the over eighties is good, whilst the mid to long term outcome is excellent There is a very low attrition rate with those undergoing the procedure living as long than their age matched population. This study confirms AVR is a safe, acceptable treatment for octogenarians with excellent mid term outcomes.

Pepsin, a biomarker of gastric aspiration in lung allografts: a putative association with rejection

RATIONALE

Human lung transplantation is a therapeutic option for selected patients with advanced cardiopulmonary disease, but long-term survival is limited by chronic rejection. Persistent acute rejection and gastric aspiration have been implicated as risk factors but there is little or no evidence to date that they are associated.

OBJECTIVES

We have tested the hypothesis that pepsin, a marker of gastric aspiration, is present in lung transplant recipients, and that high levels are associated with biopsy-diagnosed acute rejection and/or bronchiolitis obliterans syndrome.

METHODS

Levels of bronchoalveolar lavage (BAL) pepsin were measured by ELISA in 36 lung transplant recipients, 4 normal volunteers, and 17 subjects with unexplained chronic cough.

MEASUREMENTS AND MAIN RESULTS

Our primary finding was that, compared with control subjects, BAL pepsin levels were elevated in stable lung transplant recipients, subjects with acute rejection, and subjects with bronchiolitis obliterans syndrome. Our secondary finding was that the highest levels were found in recipients with acute vascular rejection grade > or = A2 (median, 11.2; range, 5.4 - 51.7 ng/ml; normal median, 1.1; range, 0-2.3 ng/ml; p = 0.004).

CONCLUSIONS

We have shown that elevated levels of pepsin, a biomarker of gastric aspiration, are consistently identified in the BAL of lung allografts. The highest levels were seen in patients with > or = grade A2 acute rejection. This provides further evidence supporting the possible role of aspiration in the development of overall allograft injury.

Early hemodynamic injury during donor brain death determines the severity of primary graft dysfunction after lung transplantation

Sympathetic discharge and hypertensive crisis often accompany brain death, causing neurogenic pulmonary edema. Progressive systemic inflammatory response develops, which can injure the lung further. We investigated whether (a) early hemodynamic injury during donor brain death increases reperfusion injury after lung transplantation and (b) delaying lung recovery would augment reperfusion injury further, because of the progressive systemic inflammatory response in the donor. Brain death was induced by intracranial balloon inflation in rats, with or without alpha-adrenergic blockade pretreatment to prevent the hypertensive crisis. Another group of rats had a sham procedure. Lungs were retrieved 15 min after brain death or sham procedure and reperfused using recipient rats. In a fourth group, brain death was induced and the lungs were retrieved 5 h after brain death and reperfused. Postreperfusion, lungs retrieved early from untreated brain-dead donors developed more severe reperfusion injury, as assessed by functional parameters and inflammatory markers, than those from sham or alpha-blockade-treated donors. Lungs retrieved late from brain-dead donors had similar inflammatory markers after reperfusion to those retrieved early, but significantly lower pulmonary vascular resistance. Early hemodynamic damage during donor brain death increases reperfusion injury after lung transplantation. Delaying retrieval may allow the lung to recover from the hemodynamic injury.

Differential Pulmonary Vein Gases Predict Primary Graft Dysfunction

BACKGROUND

Donor arterial blood gas measurements correlate poorly with lung allograft function in the recipient. We assessed the utility of reduced pulmonary vein gas (PVG) partial pressure of oxygen (PO2) in predicting the incidence of primary graft dysfunction.

METHODS

While the donor was ventilated with 100% oxygen, superior and inferior pulmonary veins were directly aspirated bilaterally and pulmonary venous PO2 measured. A PO2 of less than 300 mm Hg was considered subnormal. These values were assessed for predictive value in terms of primary graft dysfunction in univariate and multivariate analysis.

RESULTS

In 112 of the 201 lung and heart-lung transplants performed during the period January 2000 to December 2004, full PVGs were available for analysis. The number of pulmonary veins with sub-normal PVG correlated significantly with the incidence of severe primary graft dysfunction posttransplant in univariate (p = 0.01) and multivariate analysis (hazard ratio 2.35, p = 0.016). When analyzed separately, this correlation remained significant for recipients of single or bilateral transplants alone. No correlation existed between arterial PO2 at donor referral and incidence of primary graft dysfunction. Median duration of ventilation, intensive care unit stay, and 30-day and 90-day mortality were not significantly different for those with any subnormal PVG compared with those with all values in the normal range.

CONCLUSIONS

Differential PVGs are a useful tool in the assessment of donor lung function before procurement. It is a helpful indicator of whether preischemic dysfunction is localized or diffuse, and can be used to predict the extent to which ischemia and reperfusion will exacerbate any existing abnormality.

Marginal Lung Donors: A Diminishing Margin of Safety?

Lung donor shortages have resulted in the critical appraisal of cadaveric donor acceptability criteria and the gradual relaxation of once strict guidelines. Many centers have reported their results with these "extended criteria" donors and an increasing number of multicenter registry studies have also been published. The results have been contradictory and leave many questions unanswered. Important new data has however come to light since the last review of the subject by the International Society for Heart and Lung Transplantation Pulmonary Council. We review the current literature focusing on recent developments in the pursuit of an expanded lung donor pool with acceptable outcomes.

Extended donor criteria in lung transplantation: Impact on organ allocation

OBJECTIVE

Some reports have documented a higher early mortality with the use of extended criteria donors in lung transplantation. None have evaluated how outcomes compare with the use of these organs for single and bilateral transplantation or whether this practice results in a higher incidence of early bronchiolitis obliterans syndrome.

METHODS

We performed a retrospective review of case notes, intensive therapy unit database, and donor details. Between January 1, 2000, and December 31, 2004, 201 patients underwent lung or heart-lung transplantation.

RESULTS

Eighty-three (41.3%) patients received organs deemed marginal on the basis of at least one of the following criteria: donor age greater than 55 years, duration of ventilation greater than 5 days, purulent secretions or inflammation at bronchoscopy, smoking of 20 or more cigarettes per day, abnormality on chest roentgenogram, or PO2/fraction of inspired oxygen ratio of less than 300 mm Hg immediately before donor organ procurement. Recipients of marginal lungs had a higher incidence of severe (grade 3) primary graft dysfunction (43.9% vs 27.4%, P = .015) and 90-day organ-specific mortality (15.7% vs 5.1%, P = .012). Bilateral transplantation carried a significantly higher 30-day mortality if performed with marginal organs (17.0% vs 2.7% with standard donor organs, P = .005). Thirty-day mortality was not significantly different for the transplantation of single marginal or standard donor lungs. Cumulative survival and survival free of bronchiolitis obliterans syndrome was not affected by marginal donor status.

CONCLUSION

Transplantation of extended criteria donor lungs leads to a higher incidence of primary graft dysfunction. Bilateral transplantation with these organs seems to confer less reserve, resulting in a higher early mortality rate. Medium-term functional outcome is, however, not adversely affected by the relaxation of donor criteria.

Pseudomembranous colitis in four patients with cystic fibrosis following lung transplantation

Pseudomembranous colitis is an uncommon complication in patients with cystic fibrosis, despite the use of multiple high-dose antibiotic regimens and the frequency of hospital admissions. Four patients from a total of 137 patients with cystic fibrosis undergoing lung transplantation are described who developed fulminant pseudomembranous colitis. Initial presentation was variable and the mortality rate was 50% despite urgent colectomy. In one case the presenting abdominal distension was thought to be due to meconium ileus equivalent. It is concluded that Clostridium difficile colitis may be a difficult diagnosis in patients with cystic fibrosis and follows a fulminant course after lung transplantation.