High Donor Age, Low Donor Oxygenation, and High Recipient Inotrope Requirements Predict Early Graft Dysfunction in Lung Transplant Recipients

Primary graft dysfunction: what we know

Many advances in lung transplant have occurred over the last few decades in the understanding of primary graft dysfunction (PGD) though effective prevention and treatment remain elusive. This review will cover prior understanding of PGD, recent findings, and directions for future research. A consensus statement updating the definition of PGD in 2016 highlights the growing complexity of lung transplant perioperative care taking into account the increasing use of high flow oxygen delivery and pulmonary vasodilators in the current era. PGD, particularly more severe grades, is associated with worse short- and long-term outcomes after transplant such as chronic lung allograft dysfunction. Growing experience have helped identify recipient, donor, and intraoperative risk factors for PGD. Understanding the pathophysiology of PGD has advanced with increasing knowledge of the role of innate immune response, humoral cell immunity, and epithelial cell injury. Supportive care post-transplant with technological advances in extracorporeal membranous oxygenation (ECMO) remain the mainstay of treatment for severe PGD. Future directions include the evolving utility of ex vivo lung perfusion (EVLP) both in PGD research and potential pre-transplant treatment applications. PGD remains an important outcome in lung transplant and the future holds a lot of potential for improvement in understanding its pathophysiology as well as development of preventative therapies and treatment.

Risk Factor Analysis for Intraoperative Extracorporeal Membrane Oxygenation Weaning Failure After Lung Transplantation

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has been widely used for hemodynamic support during lung transplantation (LTx). We evaluated the risk factors associated with failure of weaning from ECMO in the operating room during LTx.

METHODS

We retrospectively reviewed 74 consecutive patients who had undergone LTx from March 2013 to February 2016. Patients who underwent single LTx, multiorgan transplantation, and LTx for pulmonary hypertension were excluded. All operations were performed under ECMO support. Clinical data of donor, recipient, and intraoperative parameters were reviewed.

RESULTS

Younger donors (40 ± 11 versus 45 ± 10 years, p = 0.047), donors with shorter mechanical ventilation (125 ± 74 versus 160 ± 80 minutes, p = 0.066) and donors with higher Pao₂ at 100% oxygen (455 ± 87 mm Hg versus 399 ± 88 mm Hg, p = 0.008) were significantly different in the ECMO weaning group than in the weaning failure group. Of the recipients, the number of patients who had preoperative ECMO support were significantly fewer in the successful weaning group than in the weaning failure group (11.9% versus 34.4%, p = 0.061). The operation time was significantly shorter in the weaning group than in the weaning failure group (392 ± 66 versus 435 ± 82 minutes, p = 0.014). In multivariate logistic regression analysis, the independent risk factors for ECMO weaning were donor age (odds ratio 1.101, 95% confidence interval: 1.030 to 1.177, p = 0.005), donor Pao₂ (odds ratio 0.992, 95% confidence interval: 0.984 to 0.999, p = 0.034), and operation time (odds ratio 1.010, 95% confidence interval: 1.000 to 1.019, p = 0.043).

CONCLUSIONS

Our results showed that younger donor age, high Pao₂, and shorter operation time were factors related to successful ECMO weaning in the operating room after LTx.

The association of donor age and survival is independent of ischemic time following deceased donor lung transplantation

PURPOSE

Early research suggests prolonged ischemic time in older donor lungs is associated with decreased survival following lung transplantation. The purpose of this study was to determine whether this association holds in the post-lung allocation score era.

METHODS

We analyzed the United Network for Organ Sharing database 2005-2013 for adult recipients of cadaveric lung transplants. Cox proportional hazards modeling was utilized to determine the association of donor age, ischemic time, and the interaction of donor age and ischemic time with transplant-free survival.

RESULTS

Eleven thousand eight hundred thirty-five patients met criteria. Median donor age was 32 years, and median ischemic time was 4.9 hours. Cox modeling demonstrated that donor age 50-60 (adjusted hazard ratio (HR): 1.11) and ≥60 (adjusted HR: 1.42) were associated with reduced overall survival. Neither ischemic time nor interaction of ischemic time and donor age were significantly associated with overall survival. Subanalysis demonstrated that this finding held true for patients undergoing either single or bilateral lung transplantation.

CONCLUSIONS

Prolonged ischemic time is not associated with decreased overall survival in patients undergoing lung transplantation regardless of the donor's age. However, donor age >50 is independently associated with decreased survival. The lack of an association between ischemic time and survival should encourage broader geographic allocation of pulmonary allografts.

Donor lung assessment using selective pulmonary vein gases

OBJECTIVES

Standard donor lung assessment relies on imaging, challenge gases and subjective interpretation of bronchoscopic findings, palpation and visual assessment. Central gases may not accurately represent true quality of the lungs. We report our experience using selective pulmonary vein gases to corroborate the subjective judgement.

METHODS

Starting, January 2012, donor lungs have been assessed by intraoperative bronchoscopy, palpation and visual judgement of lung collapse upon temporary disconnection from ventilator, central gases from the aorta and selective pulmonary vein gases. Partial pressure of oxygen (pO₂) <300 mmHg on FiO₂ of 1.0 was considered low. The results of the chest X-ray and last pO₂ in the intensive care unit were also collected. Post-transplant primary graft dysfunction and survival were monitored.

RESULTS

To date, 259 consecutive brain-dead donors have been assessed and 157 transplants performed. Last pO₂ in the intensive care unit was poorly correlated with intraoperative central pO₂ (Spearman's rank correlation r_s = 0.29). Right inferior pulmonary vein pO₂ was associated (Mann-Whitney, P < 0.001) with findings at bronchoscopy [clean: median pO₂ 443 mmHg (25th-75th percentile range 349-512) and purulent: 264 mmHg (178-408)]; palpation [good: 463 mmHg (401-517) and poor: 264 mmHg (158-434)] and visual assessment of lung collapse [good lung collapse: 429 mmHg (320-501) and poor lung collapse: 205 mmHg (118-348)]. Left inferior pulmonary pO₂ was associated (P < 0.001) with findings at bronchoscopy [clean: 419 mmHg (371-504) and purulent: 254 mmHg (206-367)]; palpation [good: 444 mmHg (400-517) and poor 282 mmHg (211-419)] and visual assessment of lung collapse [good: 420 mmHg (349-496) and poor: 246 mmHg (129-330)]. At 72 h, pulmonary graft dysfunction 2 was in 21/157 (13%) and pulmonary graft dysfunction 3 in 17/157 (11%). Ninety-day and 1-year mortalities were 6/157 (4%) and 13/157 (8%), respectively.

CONCLUSIONS

Selective pulmonary vein gases provide corroborative objective support to the findings at bronchoscopy, palpation and visual assessment. Central gases do not always reflect true function of the lungs, having high false-positive rate towards the individual lower lobe gas exchange. Objective measures of donor lung function may optimize donor surgeon assessment, allowing for low pulmonary graft dysfunction rates and low 90-day and 1-year mortality.

Inhaled nitric oxide for the brain dead donor with neurogenic pulmonary edema during anesthesia for organ donation: a case report

Neurogenic pulmonary edema (NPE) in brain dead organ donors occurring after an acute central nervous system insult threatens organ preservation of potential organ donors and the outcome of organ donation. Hence the active and immediate management of NPE is critical. In this case, a 50-year-old male was admitted to the intensive care unit (ICU) for organ donation. He was hypoxic due to NPE induced by spontaneous intracerebral hemorrhage and intraventricular hemorrhage. Protective ventilatory management, intermittent recruitment maneuvers, and supportive treatment were maintained in the ICU and the operating room (OR). Despite this management, the hypoxemia worsened after the OR admission. So inhaled nitric oxide (NO) therapy was performed during the operation, and the hypoxic phenomena showed remarkable improvement. The organ retrieval was successfully completed. Therefore, NO inhalation can be helpful in the improvement of hypoxemia caused by NPE in brain dead organ donors during anesthesia for the organ donation.

Donor age and early graft failure after lung transplantation: a cohort study

Lungs from older adult organ donors are often unused because of concerns for increased mortality. We examined associations between donor age and transplant outcomes among 8860 adult lung transplant recipients using Organ Procurement and Transplantation Network and Lung Transplant Outcomes Group data. We used stratified Cox proportional hazard models and generalized linear mixed models to examine associations between donor age and both 1-year graft failure and primary graft dysfunction (PGD). The rate of 1-year graft failure was similar among recipients of lungs from donors age 18-64 years, but severely ill recipients (Lung Allocation Score [LAS] >47.7 or use of mechanical ventilation) of lungs from donors age 56-64 years had increased rates of 1-year graft failure (p-values for interaction = 0.04 and 0.02, respectively). Recipients of lungs from donors <18 and ≥65 years had increased rates of 1-year graft failure (adjusted hazard ratio [HR] 1.23, 95% CI 1.01-1.50 and adjusted HR 2.15, 95% CI 1.47-3.15, respectively). Donor age was not associated with the risk of PGD. In summary, the use of lungs from donors age 56 to 64 years may be safe for adult candidates without a high LAS and the use of lungs from pediatric donors is associated with a small increase in early graft failure.

Postoperative complications in the intensive care unit following lung transplantation in adults: results in University Hospital Reina Sofia

The postoperative period following lung transplantation remains critical because of several complications. Infection, primary graft failure, acute rejection, and surgical complications are risk factors for mortality and morbidity. The recognition and early treatment of these complications is important to optimize outcomes. This article provides an overview of postoperative complications observed in our center during the last year. We were particularly interested in the influence of variables, such as inotrope usage and Acute Physiology and Chronic Health Evaluation (APACHE II) score, a well-known, and validated mortality prediction model for general intensive care unit (ICU) patients only infrequently reported in the transplantation literature. High APACHE II scores were significantly associated with prolonged mechanical ventilation (P = 0.041) and a tracheostomy requirement (P = .035). The factors significantly associated with an early postoperative death were older donor age (P = .005), prolonged donor ICU period (P = .004), need for cardiopulmonary bypass (CB; P = .005), and high inotrope requirements in the ICU (P = .034). CB data were biased because we selected the worst case patients. Donor age and high inotrope requirements in the ICU have been reported previously to be prognostic factors for poor graft function. We believe that control of these variables may improve outcomes.

Normothermic perfusion of donor lungs for preservation and assessment with the Organ Care System Lung before bilateral transplantation: a pilot study of 12 patients

BACKGROUND

Cold flush and static cold storage is the standard preservation technique for donor lungs before transplantations. Several research groups have assessed normothermic perfusion of donor lungs but all devices investigated were non-portable. We report first-in-man experience of the portable Organ Care System (OCS) Lung device for concomitant preservation, assessment, and transport of donor lungs.

METHODS

Between Feb 18, and July 1, 2011, 12 patients were transplanted at two academic lung transplantation centres in Hanover, Germany and Madrid, Spain. Lungs were perfused with low-potassium dextran solution, explanted, immediately connected to the OCS Lung, perfused with Steen's solution supplemented with two red-cell concentrates. We assessed donor and recipient characteristics and monitored extended criteria donor lung scores; primary graft dysfunction scores at 0, 24, 48, and 72 h; time on mechanical ventilation after surgery; length of stays in hospital and the intensive-care unit after surgery; blood gases; and survival of grafts and patients.

FINDINGS

Eight donors were female and four were male (mean age 44·5 years, range 14-72). Seven recipients were female and five were male (mean age 50·0 years, range 31-59). The preharvest donor ratio of partial pressure of oxyen (PaO(2)) to fractional concentration of oxygen in inspired air (F(I)O(2)) was 463·9 (SD 91·4). The final ratio of PaO(2) to F(I)O(2) measured with the OCS Lung was 471·58 (127·9). The difference between these ratios was not significant (p=0·72). All grafts and patients survived to 30 days; all recipients recovered and were discharged from hospital.

INTERPRETATION

Lungs can be safely preserved with the OCS Lung, resulting in complete organ use and successful transplantation in our series of high-risk recipients. In November, 2011, we began recruitment for a prospective, randomised, multicentre trial (INSPIRE) to compare preservation with OCS Lung with standard cold storage.

FUNDING

TransMedics and German Federal Ministry of Education and Research.

Selecting lung transplant candidates: where do current guidelines fall short?

In 2010, 1770 lung transplant procedures were performed in the USA, yet 2469 new candidates were added to the waiting list the same year. The shortage of suitable donor lungs requires that transplant professionals select patients for lung transplantation only if they are likely to sustain a survival benefit from the procedure. However, 20% of lung transplant recipients die within the first year of transplantation, suggesting that we are failing to identify those at high risk for severe early complications. In this perspective, we review the current guidelines for the selection of lung transplant candidates, which are based largely on expert opinion and small case series. We also propose the study of new extrapulmonary factors, such as frailty and sarcopenia, that might help improve the prediction of complications and early death after lung transplantation, leading to an improved candidate selection process.

Recommendations for the use of extended criteria donors in lung transplantation

Selection criteria for lung donation were based on initial experiences with lung transplantation without further studies to improve them, thereby guaranteeing the best use of donated organs. A definition of an extended criteria donor is therefore required to obtain more lungs to meet the demands of patients awaiting transplantation. Studies have been reviewed for the impact on survival and morbidity of age ranges, oxygen fraction, cause of death, smoking habits, x-ray findings, infection, hepatitis serology and non-heart-beating status, seeking to support physicians to make decisions regarding the use of marginal organs.

Recommendations for the assessment and reporting of multivariable logistic regression in transplantation literature

Multivariable logistic regression is an important method to evaluate risk factors and prognosis in solid organ transplant literature. We aimed to assess the quality of this method in six major transplantation journals. Eleven analytical criteria and four documentation criteria were analyzed for each selected article that used logistic regression. A total of 106 studies (6%) out of 1,701 original articles used logistic regression analyses from January 1, 2005 to January 1, 2006. The analytical criteria and their respective reporting percentage among the six journals were: Linearity (25%); Beta coefficient (48%); Interaction tests (19%); Main estimates (98%); Ovefitting prevention (84%); Goodness-of-fit (3.8%); Multicolinearity (4.7%); Internal validation (3.8%); External validation (8.5%). The documentation criteria were reported as follows: Selection of independent variables (73%); Coding of variables (9%); Fitting procedures (49%); Statistical program (65%). No significant differences were found among different journals or between general versus subspecialty journals with respect to reporting quality. We found that the report of logistic regression is unsatisfactory in transplantation journals. Because our findings may have major consequences for the care of transplant patients and for the design of transplant clinical trials, we recommend a practical solution for the use and reporting of logistic regression in transplantation journals.

Age and sex predict PaO2/FiO2 ratio in brain-dead donor lungs

OBJECTIVES

To define the prevalence of various ranges of the ratio of partial arterial oxygen tension to fraction of inspired oxygen (Pao(2)/Fio(2)) and to determine correlative and predictive variables of donor lung Pao(2)/Fio(2).

MATERIAL AND METHODS

From the brain death database of Masih Daneshvari Hospital Organ Procurement Center, we extracted demographic data, cause of injury, patient clinical condition, and laboratory findings as independent data. Donor lung suitability was determined with an oxygen challenge test, with results of 400 mm Hg considered ideal; 300 to 399 mm Hg, good; 200 to 299 mm Hg, borderline; and less than 200 mm Hg, not acceptable.

RESULTS

Using the Pao(2)/Fio(2) cutoff points, 6.7% of donor lungs were considered ideal; 26.7%, good; 40%, borderline; and 26.7%, unacceptable. Mean (SD; range) Pao(2)/Fio(2) was 266.6 (85.6; 110-460). The Pao(2)/Fio(2) was significantly correlated with age (r = -0.35; P = .02). After entering the study variables into a linear regression model, age (-2.3; P = .008) and sex (51.5; P = .04) were significant predictors of donor lung suitability (R(2) = 0.95; P < .001).

CONCLUSION

Results of oxygen challenge tests demonstrated better suitability of lungs from male and younger brain-dead donors. This finding is independent of other variables including cause of brain death and clinical and paraclinical data.

Extended donor criteria in lung transplantation

PURPOSE OF REVIEW

Despite improvements in respiratory care and lung transplant organ allocation algorithms, waiting lists continue to grow worldwide. Attempts at improving organ donation rates have generally had little impact on the increase in the number of transplants performed. Improved use of the available pool of cadaveric organ donors, therefore, represents one of few immediately available strategies to alleviate organ shortages.

RECENT FINDINGS

The once-strict lung donor selection criteria have, of necessity, been relaxed and, in many instances, this situation has been to no apparent detrimental effect on posttransplant outcome. There is, however, some evidence that extension of donor acceptability in some respects leads to poorer early outcomes, mainly by increasing the rate of early graft dysfunction. The extension of selection criteria to allow the maximum number of safe lung transplants, coupled with aggressive and appropriate donor management is, therefore, of particular current relevance to the lung transplantation community.

SUMMARY

Although the available evidence for and against the commonly used lung donor selection criteria leaves many questions unanswered, it can help decrease the large number of uncertainties that be falls the practice of lung donor selection and recipient matching.

Impact of human donor lung gene expression profiles on survival after lung transplantation: a case-control study

Primary graft dysfunction (PGD) continues to be a major cause of early death after lung transplantation. Moreover, there remains a lack of accurate pretransplant molecular markers for predicting PGD. To identify distinctive donor lung gene expression signatures associated with PGD, we profiled human donor lungs using microarray technology prior to implantation. The genomic profiles of 10 donor lung samples from patients who subsequently developed clinically defined severe PGD were compared with 16 case-matched donor lung samples from those who had a favorable outcome without PGD (development set, n = 26). Selected PCR validated predictive genes were tested by quantitative reverse transcription-polymerase chain reaction in an independent test set (n = 81). Our microarray analyses of the development set identified four significantly upregulated genes (ATP11B, FGFR2, EGLN1 and MCPH1) in the PGD samples. These genes were also significantly upregulated in donor samples of the test set of patients with poor outcomes when compared to those of patients with good outcomes after lung transplantation. This type of biological donor lung assessment shows significant promise for development of a more accurate diagnostic strategy to assess donor lungs prior to implantation.

Predictors of independent lung ventilation: an analysis of 170 single-lung transplantations

OBJECTIVE

Single-lung transplantation for chronic obstructive pulmonary disease can cause unique postoperative problems that might require independent lung ventilation. We evaluated preoperative and immediate postoperative factors to predict the need for independent lung ventilation.

METHODS

We retrospectively studied 170 patients who received a single-lung transplant over a 15-year period, 20 (12%) of whom required independent lung ventilation.

RESULTS

Patients requiring independent lung ventilation were similar in age, sex, ischemic time, and donor characteristics to those who required conventional ventilation. Patients receiving independent lung ventilation had a greater degree of preoperative airflow limitation, more hyperinflation, lower postoperative PaO2/fraction of inspired oxygen ratios, more radiologic mediastinal shift, and more transplant lung infiltrate on the postoperative chest radiograph. Multivariate logistic regression analysis showed that independent lung ventilation was associated with increasing levels of recipient hyperinflation (percentage total lung capacity compared with predicted value; odds ratio, 1.04; 95% confidence interval, 1.01-1.07; P = .032) and reduced early postoperative PaO2/fraction of inspired oxygen ratio (odds ratio, 0.97; 95% confidence interval, 0.95-0.99; P = .005). Length of ventilation and intensive care unit stay and mortality were higher in the independent lung ventilation group. Among patients who survived to hospital discharge, there were no differences in long-term mortality between the 2 groups.

CONCLUSIONS

The need for independent lung ventilation in patients undergoing single-lung transplantation for obstructive lung disease is predicted by the combination of increased hyperinflation measured on recipients' preoperative lung function tests and a low PaO2/fraction of inspired oxygen ratio, indicating graft dysfunction in the immediate postoperative period.

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.