Impact of Bacterial and Fungal Donor Organ Contamination in Lung, Heart–Lung, Heart and Liver Transplantation

Expanding Donor Options for Lung Transplant: Extended Criteria, Donation After Circulatory Death, ABO Incompatibility, and Evolution of Ex Vivo Lung Perfusion

Only using brain-dead donors with standard criteria, the existing donor shortage has never improved in lung transplantation. Currently, clinical efforts have sought the means to use cohorts of untapped donors, such as extended criteria donors, donation after circulatory death, and donors that are ABO blood group incompatible, and establish the evidence for their potential contribution to the lung transplant needs. Also, technical maturation for using those lungs may eliminate immediate concerns about the early posttransplant course, such as primary graft dysfunction or hyperacute rejection. In addition, recent clinical and preclinical advances in ex vivo lung perfusion techniques have allowed the safer use of lungs from high-risk donors and graft modification to match grafts to recipients and may improve posttransplant outcomes. This review summarizes recent trends and accomplishments and future applications for expanding the donor pool in lung transplantation.

Impact of Culture-Positive Preservation Fluid on Early Morbidity and Mortality After Lung Transplantation

The prevalence, risk factors and outcomes associated with culture-positive preservation fluid (PF) after lung transplantation (LT) are unknown. From January 2015 to December 2020, the microbiologic analyses of PF used to store the cold ischaemia-placed lung graft(s) of 271 lung transplant patients were retrospectively studied. Culture-positive PF was defined as the growth of any microorganism. Eighty-three (30.6%) patients were transplanted with lung grafts stored in a culture-positive PF. One-third of culture-positive PF were polymicrobial. Staphylococcus aureus and Escherichia coli were the most frequently isolated microorganisms. No risk factors for culture-positive PF based on donor characteristics were identified. Forty (40/83; 48.2%) patients had postoperative pneumonia on Day 0 and 2 (2/83; 2.4%) patients had pleural empyema with at least one identical bacteria isolated in culture-positive PF. The 30-day survival rate was lower for patients with culture-positive PF compared with patients with culture-negative PF (85.5% vs. 94.7%, p = 0.01). Culture-positive PF has a high prevalence and may decrease lung transplant recipient survival. Further studies are required to confirm these results and improve understanding of the pathogenesis of culture-positive PF and their management.

Bacterial infections in lung transplantation

Lung transplantation has lower survival rates compared to other than other solid organ transplants (SOT) due to higher rates of infection and rejection-related complications, and bacterial infections (BI) are the most frequent infectious complications. Excess morbidity and mortality are not only a direct consequence of these BI, but so are subsequent loss of allograft tolerance, rejection, and chronic lung allograft dysfunction due to bronchiolitis obliterans syndrome (BOS). A wide variety of pathogens can cause infections in lung transplant recipients (LTRs), including a number of nosocomial pathogens and other multidrug-resistant (MDR) pathogens. Although pneumonia and intrathoracic infections predominate, LTRs are at risk of a number of types of infections. Risk factors include altered anatomy and function of airways, impaired immunity, the microbial flora of the donor and recipient, underlying medical conditions, and genetic factors. Further work on immune monitoring has the potential to improve outcomes. The infecting agents can be derived from the donor lung, pre-existing recipient flora, or acquired from the environment over time. Certain infections may preclude lung transplantation, but this varies from center to center, and more recent studies suggest fewer patients should be disqualified. New molecular methods allow microbiome studies of the lung, gut, and other sites that may further our knowledge of how airway colonization can result in infection and allograft loss. Surveillance, early diagnosis, and aggressive antimicrobial therapy of BI is critical in LTRs. Antibiotic resistance is a major barrier to successful management of these infections. The availability of new agents for MDR Gram-negatives may improve outcomes. Other new therapies, such as bacteriophage therapy, show promise for the future. Finally, it is important to prevent infections through peri-transplant prophylaxis, vaccination, and infection control measures.

Donor lung management: Changing perspectives

Worldwide, lung transplantation has been a therapeutic option for select end-stage lung disease patients who are on optimized medical regimens, but the underlying clinical condition continues to progress. For any successful lung transplantation program, it is important to have a robust donor lung management program. Lungs are commonly affected by the various factors related to trauma or neurogenic in brain stem death donors. This article would focus on the basic protocols to optimize donor lungs which would help in increasing donor pool. It would also elaborate COVID-specific points for donor lung evaluation. This article would also describe the criteria for ideal as well as marginal donor lungs. A comprehensive literature search was performed using PubMed to review various articles related to donor lung management.

Heart Infection Prognosis Analysis by Two-dimensional Spot Tracking Imaging

Cardiovascular death is one of the leading causes worldwide; an accurate identification followed by diagnosing the cardiovascular disease increases the chance of a better recovery. Among different demonstrated strategies, imaging on cardiac infections yields a visible result and highly reliable compared to other analytical methods. Two-dimensional spot tracking imaging is the emerging new technology that has been used to study the function and structure of the heart and test the deformation and movement of the myocardium. Particularly, it helps to capture the images of each segment in different directions of myocardial strain values, such as valves of radial strain, longitudinal strain, and circumferential strain. In this overview, we discussed the imaging of infections in the heart by using the two-dimensional spot tracking.

Review of donor and recipient surgical procedures in lung transplantation

Lung transplant remains the only durable treatment of end stage lung disease. Efficient surgical technique and preservation strategy are of critical importance in avoiding ischemia reperfusion injury and primary graft dysfunction (PGD), both associated with poorer outcomes. We present our surgical and preservation strategy for both donor and recipient procedures, including endobronchial and intracorporeal lung assessment, mediastinal dissection, lung preservation, donor pneumonectomy, back bench preparation, recipient approach, pneumonectomy, along with the bronchial, pulmonary artery, and pulmonary venous anastomoses.

Underutilization of potential donors for lung transplantation at a tertiary care center in North India

Objective:

Lung transplantation is infrequently performed in India due to several constraints, and whether the poor lung transplantation rates in India are due to a lack of eligible lung donors is unclear. In this study, we explored the availability of donors for lung transplantation.

Materials and Methods:

This was a retrospective analysis of all brain-dead participants who underwent assessment of eligibility for lung donation between August 2015 and June 2018. All participants underwent a detailed clinical evaluation that included history, physical examination, arterial blood gas analysis, chest radiograph, and bronchoscopy. The final eligibility for lung donation was assessed using the existing “ideal” criteria and the less stringent “extended” criteria.

Results:

A total of 55 brain-dead participants (41 [74.5%] males) were assessed for eligibility for lung donation. The mean (standard deviation [SD]) age of the participants was 38.4 (17.2) years. The mean (SD) duration of prior invasive mechanical ventilation at the time of assessment was 4 (3.1) days, with a mean (SD) partial pressure of arterial oxygen: inspired oxygen fraction ratio (PaO₂:FiO₂) of 326.6 (153.5). The proportion of participants who were found suitable for lung donation was 16 (29.1%) and 35 (63.6%) on employing the ideal and the extended criteria, respectively. Inadequate oxygenation status, abnormal chest radiograph, and sepsis were the most common reasons for excluding participants using either criteria. Despite the availability of adequate lung donors, only one lung transplantation could be performed.

Conclusion:

Even with the most stringent criteria for lung assessment, nearly one-third of the brain-dead participants had lungs suitable for lung transplantation. Lack of eligible lung donors is not a reason for the poor lung transplantation rates in India.

Reasons for Donor Lungs Unsuitability After Radiographic Selection

OBJECTIVES

Deceased lung donation requires optimum donor care, with lung viability greatly affected by the progress of the disease leading to brain death. In this study, we searched for causes of lung unsuitability for transplant in both primary and secondary evaluations.

MATERIALS AND METHODS

Primary lung evaluations included chest radiography, oxygen challenge test, and donor clinical and history examination. Secondary evaluations for lungs that passed the first step included fiberoptic bronchoscopy and donor-recipient matching.

RESULTS

From 2012 to 2017, there were 1020 potential deceased organ donors in our center. Primary evaluations showed that the most prominent reason for lung donation unsuitability was low oxygen challenge result (n = 433, 42.5%). Other reasons were abnormal chest radiograph (n = 378, 38%), history of heavy smoking and inhaled drugs addiction (n = 112, 11%), prolonged intubation (n = 28, 2.7%), and lung disease history (n = 69, 6.7%). There were 104 (10.1%) potential donors to undergo fiberoptic bronchoscopy for further lung evaluation, with 47 (45.2%) selected for final lung donation. Five lungs (4.8%) with bronchoscopic confirmation for suitability were not retrieved due to lack of instruments and resources. Among the 57 (54.8%) rejected potential lung donations, the greatest factor impacting suitability was observation of purulent secretions in bronchoscopy (n = 24, 23%), evidence of aspiration (n = 10, 9.6%), infiltration (n = 7, 6.7%), and tracheitis.

CONCLUSIONS

The most common cause of lung rejection after primary evaluation is observation of purulent secretions in tracheobronchial tree. Therefore, implementation of appropriate strategies to prevent respiratory infection in the intensive care unit is needed to expand the lung donor pool.

Experience of the first lung transplantation performed in public sector in India

Lung transplantation is the only modality that offers a long-term solution for end-stage lung diseases. Few centers in India have an active lung transplant program. Preoperative and postoperative considerations in lung transplantation may be different in the developing countries when compared to the developed world. In the early posttransplant period, infection could be the major consideration in developing countries, unlike graft rejection, that is usually the primary concern in the developed world. Herein, we report the first lung transplantation from a public sector hospital in India. The patient was a 33-year-old female, who underwent bilateral lung transplantation at our center, but succumbed to surgical and infectious complications in the early posttransplant period.

Lung donor selection criteria

The criteria that define acceptable physiologic and social parameters for lung donation have remained constant since their empiric determination in the 1980s. These criteria include a donor age between 25-40, a arterial partial pressure of oxygen (PaO2)/FiO2 ratio greater than 350, no smoking history, a clear chest X-ray, clean bronchoscopy, and a minimal ischemic time. Due to the paucity of organ donors, and the increasing number of patients requiring lung transplant, finding a donor that meets all of these criteria is quite rare. As such, many transplants have been performed where the donor does not meet these stringent criteria. Over the last decade, numerous reports have been published examining the effects of individual acceptance criteria on lung transplant survival and graft function. These studies suggest that there is little impact of the historical criteria on either short or long term outcomes. For age, donors should be within 18 to 64 years old. Gender may relay benefit to all female recipients especially in male to female transplants, although results are mixed in these studies. Race matched donor/recipients have improved outcomes and African American donors convey worse prognosis. Smoking donors may decrease recipient survival post transplant, but provide a life saving opportunity for recipients that may otherwise remain on the transplant waiting list. No specific gram stain or bronchoscopic findings are reflected in recipient outcomes. Chest radiographs are a poor indicator of lung donor function and should not adversely affect organ usage aside for concerns over malignancy. Ischemic time greater than six hours has no documented adverse effects on recipient mortality and should not limit donor retrieval distances. Brain dead donors and deceased donors have equivalent prognosis. Initial PaO2/FiO2 ratios less than 300 should not dissuade donor organ usage, although recruitment techniques should be implemented with intent to transplant.

The Physiology of Brain Death and Organ Donor Management

Brain death is associated with complex physiologic changes that may impact the management of the potential organ donor. Medical management is critical to actualizing the individual or family’s intent to donate and maximizing the benefit of that intent. This interval of care in the PICU begins with brain death and consent to donation and culminates with surgical organ procurement. During this phase, risks for hemodynamic instability and compromise of end organ function are high. The brain dead organ donor is in a distinct and challenging pathophysiologic condition that culminates in multifactorial shock. The potential benefits of aggressive medical management of the organ donor may include increased number of donors providing transplantable organs and increased number of organs transplanted per donor. This may improve graft function, graft survival, and patient survival in those transplanted. In this chapter, pathophysiologic changes occurring after brain death are reviewed. General and organ specific donor management strategies and logistic considerations are discussed. There is a significant opportunity for enhancing donor multi-organ function and improving organ utilization with appropriate PICU management.

Current practice of heart donor evaluation in Germany: multivariable risk factor analysis confirms practicability of guidelines

Background. Organ shortage has liberalised the acceptance criteria of grafts for heart transplantation, but which donor characteristics ultimately influence the decision to perform transplantation? For the first time this was evaluated using real-time donor data from the German organ procurement organization (DSO). Observed associations are discussed with regard to international recommendations and guidelines. Methods. 5291 German donors (2006–2010) were formally eligible for heart donation. In logistic regression models 160 donor parameters were evaluated to assess their influence on using grafts for transplantation (random split of cases: 2/3 study sample, 1/3 validation sample). Results. Successful procurement was determined by low donor age (OR 0.87 per year; 95% CI [0.85–0.89], P < 0.0001), large donor height (OR 1.04 per cm; 95% CI [1.02–1.06], P < 0.0001), exclusion of impaired left ventricular function or wall motion (OR 0.01; 95% CI [0.002–0.036], P < 0.0001), arrhythmia (OR 0.05; 95% CI [0.009–0.260], P = 0.0004), and of severe coronary artery disease (OR 0.003; 95% CI [<0.001–0.01], P < 0.0001). Donor characteristics differed between cases where the procedure was aborted without and with allocation initiated via Eurotransplant.

Extended criteria donor lungs and clinical outcome: results of an alternative allocation algorithm

BACKGROUND

Despite the scarcity of donor lungs, most potential donor organs are not offered by organ procurement organizations or are turned down by transplant centers because no suitable recipient is found according to regular allocation. Although extended criteria donors (ECDs) have recently been considered by many programs, the lung utilization rate remains < 30% in most countries. The allocation policy of Eurotransplant for donor lungs that have been turned down for donor-related medical reasons by 3 centers is to attempt a rescue offer, for which centers choose the recipients themselves. At Hannover Medical School we systematically divert these organs to more stable recipients to avoid adverse transplant outcomes. We follow up on these transplants and compare them with those following regular allocation.

METHODS

This study is an analysis of all organ offers and corresponding recipients at our center during the period from January 2010 to August 2011.

RESULTS

A total of 183 lung transplantations were performed, 111 regular donor lung offers were accepted for their intended recipient, whereas a total of 72 rescue lung offers, including all extended criteria donors, were accepted for recipients selected by our center. Donor characteristics differed between the 2 groups accordingly. Median age of ECD organ donors was significantly higher than that of regular donors (46.0 [IQR 21] vs 40.0 [IQR 22] years, p = 0.02). Donor mechanical ventilation time did not differ (3.5 ± 4.8 vs 3.0 ± 4.0 days, p = 0.33, not statistically significant [NS]). Donor oxygenation ratio (PaO2:FIO2) at time of organ offer was significantly lower (398.3 ± 110.3 vs 423.0 ± 97.6 mm Hg, p = 0.02). Recipients of rescue allocation organs were older than regularly selected recipients (53.7 ± 11.7 vs 46.7 ± 15.4 years, p = 0.0003), needed a shorter time for mechanical ventilation post-operatively (19.5 ± 306.6 vs 68.5 ± 718.8 hours, p = 0.02), and had shorter hospital stays (24.0 ± 23.4 vs 47.0 ± 43.4 days, p > 0.0001). Intensive care stay length did not differ significantly (2.0 ± 14.5 vs 5.0 ± 23.7 days, p = 0.21 [NS]). Post-operative survival up to 27 months after transplantation was not worse in recipients receiving rescue allocation when compared with standard allocation lung offers (81.62% vs 80.76%, p = 0.89 [NS]). The pre-operative status of the 2 recipient cohorts differed considerably, as indicated by the standard allocation group consisting of 65.8% "high-urgency" (HU)-listed patients, whereas the rescue offers were used for only 11.1% of HU-listed recipients, reflecting our center's policy.

CONCLUSIONS

Rescue allocation donor lungs can be used safely for transplantation and therefore salvaged for the donor pool. The data support our policy of accepting marginal donor lungs for stable recipients. This practice leads to very good overall survival.

Hand hygiene compliance in transplant and other special patient groups: an observational study

BACKGROUND

This study evaluates hand hygiene behavior of health care workers in a German university hospital stratified for treatment of special patient groups (eg, transplant patients).

METHODS

From 2008 to 2010, comprehensive education and training of all health care workers was implemented to improve hand hygiene compliance. Consumption rates of alcohol-based hand rub and gloves were collected and evaluated.

RESULTS

Of the 5,647 opportunities of hand disinfection evaluated, 1,607 occurred during care for transplant patients. To our knowledge, this is the largest survey of hand hygiene compliance in special patient groups on intensive care units in a university hospital in Germany. Health care workers on surgical intensive care units showed lower hand hygiene compliance compared with health care workers on other types of intensive care units. Compliance toward hand hygiene was significantly higher on hemato-oncologic and pediatric wards. In general, hand disinfection was performed significantly more frequently after an intervention than before (P < .05, 95% confidence interval: 1.24-1.84). Overall, there was no significant difference in hand hygiene compliance when caring for transplant patients or other patients (odds ratio, 1.16; 95% confidence interval: 0.95-1.42). Nurse's and physician's hand hygiene compliance improved because of education.

CONCLUSION

Hand hygiene compliance is not increased in the care for transplant patients (despite their predisposition for nosocomial infections) compared with other patients. Additional studies will be necessary to further investigate these findings.

High-resolution CT findings of pulmonary infections after orthotopic liver transplantation in 453 patients

OBJECTIVES

The objective of this study was to review the high-resolution CT (HRCT) findings in patients with pulmonary infection after orthotopic liver transplantation (OLT) and to determine distinguishing findings among the various types of infection.

METHODS

This study included 453 consecutive liver transplant recipients with pulmonary infection, on whom HRCT of the chest was performed within 24 h of the beginning of symptoms and for whom proven diagnosis had taken place within 1 week of the onset of symptoms. Two radiologists analysed the CT images; final decisions regarding the findings were reached by consensus.

RESULTS

Bacterial and viral pneumonia made up the bulk of infections (63.4% and 29.4%, respectively), followed by fungal infiltrates (24.5%). Large nodules were most common in patients with fungal pneumonia, having been seen in 38 (54%) of the 70 patients with fungal pneumonia, 22 (10%) of 220 with bacterial pneumonia (p=0.0059) and 6 (8%) of 78 with viral pneumonia (p=0.0011). The halo sign was also more frequent in patients with fungal pneumonia, having been seen in 38 (54%) of the 70 patients with fungal pneumonia, 17 (8%) of 220 with bacterial pneumonia (p=0.0026) and 7 (9%) of 78 with viral pneumonia (p=0.0015). There was no statistically significant difference in the prevalence of the other HRCT patterns including air-space consolidation, ground-glass attenuation and small nodules among bacterial, viral and fungal infections (all p>0.05).

CONCLUSION

The presence of large nodules with the halo sign is most suggestive of fungal infection after OLT. Other HRCT patterns are not helpful in distinguishing among the various types of infection seen in liver transplant recipients.

Hepatocyte transplantation for inherited metabolic diseases of the liver

Inherited metabolic diseases of the liver are characterized by deficiency of a hepatic enzyme or protein often resulting in life-threatening disease. The remaining liver function is usually normal. For most patients, treatment consists of supportive therapy, and the only curative option is liver transplantation. Hepatocyte transplantation is a promising therapy for patients with inherited metabolic liver diseases, which offers a less invasive and fully reversible approach. Procedure-related complications are rare. Here, we review the experience of hepatocyte transplantation for metabolic liver diseases and discuss the major obstacles that need to be overcome to establish hepatocyte transplantation as a reliable treatment option in the clinic.

Invasive fungal infections in solid organ transplant recipients

Invasive fungal infections are a major problem in solid organ transplant (SOT) recipients. Overall, the most common fungal infection in SOT is candidiasis, followed by aspergillosis and cryptococcosis, except in lung transplant recipients, where aspergillosis is most common. Development of invasive disease hinges on the interplay between host factors (e.g., integrity of anatomical barriers, innate and acquired immunity) and fungal factors (e.g., exposure, virulence and resistance to prophylaxis). In this article, we describe the epidemiology and clinical features of the most common fungal infections in organ transplantation. Within this context, we review recent advances in diagnostic modalities and antifungal chemotherapy, and their impact on evolving prophylaxis and treatment paradigms.

Immunocompromised Patients

The ominous prognosis of cancer patients with or without neutropenia in need of critical care has led to reservations with regard to admission of cancer patients to the ICU. However, significant improvements in ICU and in-hospital survival of cancer patients in ICU have been demonstrated in studies in recent years [1–4]. Risk factors for mortality have shifted from those related to the underlying condition to those related to the severity of acute illness similar to other critically-ill patients. Neutropenia per se and the underlying malignancy (solid and hematological) do not have an impact on the outcome of patients in ICU. Recent chemotherapy is associated rather with improved survival [3, 5–7], while organ dysfunction, severity of disease scores, need for vasopressor treatment, need for mechanical ventilation immediately or after noninvasive ventilation, no definite diagnosis and a non-infectious diagnosis are associated with mortality [1–3, 8]. Invasive aspergillosis is also associated with very high mortality rates in ICU (see below). In several studies, admission to ICU in the early stages of sepsis or other acute event was associated with better survival than admission later, after development of organ dysfunction. Performance status is perhaps the most important and only variable relating to the underlying condition that is correlated with ICU death. The prognosis remains guarded for certain cancer patients, including patients after allogeneic hematopoietic stem cell transplantation (HSCT) with active uncontrolled graft versus host disease, those with relapse of the primary disease after allogeneic HSCT and special cases of solid cancer including pulmonary carcinomatous lymphangitis and carcinomatous meningitis with coma [9].

Donor infection and transmission to the recipient of a solid allograft

Transmission of infection from donor to recipient is a potential complication of transplantation. More data on this issue are needed to expand the insufficient donor pool. This study evaluates the incidence of donor nonviral infection, transmission from infected donors and the effect of donor infection on 30-day recipient survival. Data from 211 infected donors contributing to 292 (8.8%) of 3322 consecutive transplant procedures within RESITRA (Spanish Research Network for the Study of Infection in Transplantation) were prospectively compiled and analyzed. Lung was the most likely transplanted organ carried out with an infected donor and Staphylococcus aureus was the most commonly isolated microorganism. In more than a half of donors, the lung was the site of infection. Donor-to-host transmission was documented in 5 patients out of 292 (1.71%), 2 of whom died of the acquired infection (40%). Nonetheless, there was no difference in 30-day patient survival when comparing transplant procedures performed with organs from infected or uninfected donors. In conclusion, donor infection is not an infrequent event, but transmission to the recipient is quite low. Hence, with careful microbiological surveillance and treatment, the number of organs available for transplantation may be increased.