Cardiac transplant rejection assessment with 18F-FDG PET-CT: initial single-centre experience for diagnosis and management.

BACKGROUND: Rejection is a major cause of mortality and morbidity in heart transplant (HTx) recipients. Current methods for diagnosing rejection have limitations. Imaging methods to map the entire left ventricle and reliably identify potential sites of rejection is lacking. Animal studies suggest FDG PET-CT (FDG PET) could have potential application in human HTx recipients. METHODS: Between December 2020 and February 2022, all HTx recipients at Harefield Hospital, London, with definite or suspected rejection underwent FDG PET in addition to routine work-up. RESULTS: Thirty HTx recipients (12 with definite and 18 with suspected rejection) underwent FDG PET scans. Overall, 12 of the 30 patients had FDG PET with increased myocardial avidity, of whom 2 died (17%). Eighteen patients of the 30 patients had FDG PET with no myocardial avidity and all are alive (100%, p = 0.15). All patients with definite rejection, scanned within 2 weeks of starting anti-rejection treatment, showed increased myocardial avidity. In 5 cases, FDG PET showed myocardial avidity beyond 6 weeks despite pulsed steroid treatment, suggesting unresolved myocardial rejection. CONCLUSION: Preliminary findings suggest FDG PET may have a role in diagnosing cardiac transplant rejection. Future blinded studies are needed to help further validate this.

Critical care pharmacy service provision and workforce in adult extracorporeal membrane oxygenation centres: a multicentre cross-sectional survey.

BACKGROUND: There is good evidence describing pharmacy workforce and service provision in general critical care units. However, no data exist from adult extracorporeal membrane oxygenation (ECMO) centres. AIM: To describe workforce characteristics, pharmacy service provision, and pharmaceutical care activities in critical care units (CCUs) providing an adult ECMO service in the United Kingdom (UK) and compare to national staffing standards for CCUs. METHOD: We conducted a multicentre, cross-sectional electronic survey inviting one pharmacy professional response per UK ECMO centre. We collated information on workforce, service provision, and pharmaceutical care activities provided by pharmacy teams in adult CCUs with an ECMO service. RESULTS: The survey response rate was 90.9%: representatives of 10/11 tertiary hospitals providing ECMO services responded. Median critical care pharmacist to critical care bed was 1:12.1 (IQR: 1:9.4-1:14.9). Most centres (90.0%) did not meet national standards for pharmacy professionals to critical care bed staffing ratios for weekday services. Total critical care beds covered by the critical care pharmacy team varied across the UK: median (IQR) - 45 (37-80) beds. Two centres funded pharmacist time for ECMO activity, and one centre funded a pharmacy technician post. Median peak ECMO activity was 4 ECMO patients in a single day (IQR: 3-5). Most respondents reported reduced pharmacy service at weekends compared to weekday, with limited on-site support. CONCLUSION: Most responding ECMO centres in the UK reported pharmacy staffing ratios below nationally agreed critical care standards. There was high variability in clinical pharmacy services to ECMO patients over 7 days.

Antifungal Dosing in Critically Ill Patients on Extracorporeal Membrane Oxygenation.

Extracorporeal membrane oxygenation (ECMO) is an established advanced life support system, providing temporary cardiac and/or respiratory support in critically ill patients. Fungal infections are associated with increased mortality in patients on ECMO. Antifungal drug dosing for critically ill patients is highly challenging because of altered pharmacokinetics (PK). PK changes during critical illness; in particular, the drug volume of distribution (Vd) and clearance can be exacerbated by ECMO. This article discusses the available literature to inform adequate dosing of antifungals in this patient population. The number of antifungal PK studies in critically ill patients on ECMO is growing; currently available literature consists of case reports and studies with small sample sizes providing inconsistent findings, with scant or no data for some antifungals. Current data are insufficient to provide definitive empirical drug dosing guidance and use of dosing strategies derived from critically patients not on ECMO is reasonable. However, due to high PK variability, therapeutic drug monitoring should be considered where available in critically ill patients receiving ECMO to prevent subtherapeutic or toxic antifungal exposures.

Conventional and Novel Approaches to Immunosuppression in Lung Transplantation.

Most therapeutic advances in immunosuppression have occurred over the past few decades. Although modern strategies have been effective in reducing acute cellular rejection, excess immunosuppression comes at the price of toxicity, opportunistic infection, and malignancy. As our understanding of the immune system and allograft rejection becomes more nuanced, there is an opportunity to evolve immunosuppression protocols to optimize longer term outcomes while mitigating the deleterious effects of traditional protocols.

Variable Sequestration of Antifungals in an Extracorporeal Membrane Oxygenation Circuit.

Fungal infections are common and frequently associated with clinical failure in patients receiving extracorporeal membrane oxygenation (ECMO). Antifungal drugs have physicochemical characteristics associated with a higher likelihood of sequestration onto ECMO circuitry potentially leading to a subtherapeutic drug concentration. The percentage of sequestration of the antifungal drugs-caspofungin, posaconazole, and voriconazole-was determined using an ex vivo ECMO model. The circuits were primed with whole human blood, sodium chloride 0.9%, and human albumin solution. Serial 2 ml samples were taken at baseline, 0.5, 1, 2, 6, 12, and 24 hours after drug addition, paired with non-ECMO controls stored in a water bath at 37°C. Mean loss from the blood-primed ECMO circuits and controls at 24 hours relative to baseline were 80% and 61% for caspofungin ( p = ns), 64% and 11% for posaconazole ( p < 0.005), and 27% and 19% for voriconazole ( p < 0.05). Calculated AUC 0-24 showed a 44% for caspofungin ( p = ns), 30.6% posaconazole ( p < 0.005), and 9% loss for voriconazole ( p = 0.003) compared with the controls, suggesting therapeutic concentrations of these antifungal agents cannot be guaranteed with standard dosing in patients on ECMO. Posaconazole exhibited the greatest loss to the ECMO circuit correlating with both high lipophilicity and protein binding of the drug.

Antifungal stewardship in solid-organ transplantation: What is needed?

BACKGROUND: Antifungal stewardship (AFS) lags behind antimicrobial stewardship (AMS) in terms of implementation, evidence base, and workforce experience. Solid-organ transplantation (SOT) carries a significant risk of invasive fungal infection, with high associated mortality, and is therefore associated with significant opportunities to optimize antifungal use. METHODS: A literature search for the terms "antifungal stewardship" and "solid-organ transplant" revealed a small evidence base to support AFS programs in this patient group. RESULTS: There is significant overlap in the methodology used in AMS and AFS programs, with notable differences in diagnostics, which are discussed in detail. The primary AFS interventions tested in SOT recipients are implementation of clinical guidelines and care bundles, digital enablers of AFS, and post-prescription review/audit and feedback. CONCLUSION: There is an urgent need for further research to support effective AFS strategies in this highly susceptible population.

Machines that help machines to help patients: optimising antimicrobial dosing in patients receiving extracorporeal membrane oxygenation and renal replacement therapy using dosing software.

Intensive care unit (ICU) patients with end-organ failure will require specialised machines or extracorporeal therapies to support the failing organs that would otherwise lead to death. ICU patients with severe acute kidney injury may require renal replacement therapy (RRT) to remove fluid and wastes from the body, and patients with severe cardiorespiratory failure will require extracorporeal membrane oxygenation (ECMO) to maintain adequate oxygen delivery whilst the underlying pathology is evaluated and managed. The presence of ECMO and RRT machines can further augment the existing pharmacokinetic (PK) alterations during critical illness. Significant changes in the apparent volume of distribution (Vd) and drug clearance (CL) for many important drugs have been reported during ECMO and RRT. Conventional antimicrobial dosing regimens rarely consider the impact of these changes and consequently, are unlikely to achieve effective antimicrobial exposures in critically ill patients receiving ECMO and/or RRT. Therefore, an in-depth understanding on potential PK changes during ECMO and/or RRT is required to inform antimicrobial dosing strategies in patients receiving ECMO and/or RRT. In this narrative review, we aim to discuss the potential impact of ECMO and RRT on the PK of antimicrobials and antimicrobial dosing requirements whilst receiving these extracorporeal therapies. The potential benefits of therapeutic drug monitoring (TDM) and dosing software to facilitate antimicrobial therapy for critically ill patients receiving ECMO and/or RRT are also reviewed and highlighted.

Oral milrinone for management of refractory right ventricular failure in patients with left ventricular assist devices.

AIMS: We present a single-centre retrospective experience using oral milrinone in patients with a left ventricular assist device (LVAD) and concurrent refractory right ventricular failure. METHODS AND RESULTS: All patients implanted with LVAD between January 2013 and July 2021 from a high-volume advanced heart failure service were reviewed. Eight patients were initiated on oral milrinone during this period. Oral milrinone was started 1.5 [inter-quartile range (IQR) 1-2.3] years after LVAD implantation and continued for 1.2 (IQR 0.5-2.8) years. Therapeutic milrinone levels were achieved (232.2 ± 153.4 ng/mL) with 62.4 ± 18% of time within the therapeutic range. Two patients had adverse events (non-sustained ventricular tachycardia and ventricular fibrillation effectively treated by internal cardioverter defibrillator) but did not require milrinone discontinuation. Four deaths occurred, one after transplant and three from disease progression determined to be unrelated to oral milrinone use. Three patients continue oral milrinone therapy in the community. There was no significant difference found after the initiation of oral milrinone on any of the physiological measures; however, there were trends in reduction of New York Heart Association class from 3.4 ± 0.5 to 3.0 ± 0.8 (P = 0.08), reduction of right atrial/wedge pressure from 0.9 ± 0.3 to 0.5 ± 0.2 (P = 0.08), and improvement of right ventricular stroke work index from 3.8 ± 2 to 5.8 ± 2.7 (P = 0.16). CONCLUSIONS: Oral milrinone appears safe for long-term use in the outpatient setting when combined with therapeutic monitoring in this complex medical cohort with limited management options. Further study is needed to ascertain whether this treatment is effective in reducing heart failure symptoms and admissions.

A Large Retrospective Assessment of Voriconazole Exposure in Patients Treated with Extracorporeal Membrane Oxygenation.

BACKGROUND: Voriconazole is one of the first-line therapies for invasive pulmonary aspergillosis. Drug concentrations might be significantly influenced by the use of extracorporeal membrane oxygenation (ECMO). We aimed to assess the effect of ECMO on voriconazole exposure in a large patient population. METHODS: Critically ill patients from eight centers in four countries treated with voriconazole during ECMO support were included in this retrospective study. Voriconazole concentrations were collected in a period on ECMO and before/after ECMO treatment. Multivariate analyses were performed to evaluate the effect of ECMO on voriconazole exposure and to assess the impact of possible saturation of the circuit's binding sites over time. RESULTS: Sixty-nine patients and 337 samples (190 during and 147 before/after ECMO) were analyzed. Subtherapeutic concentrations (<2 mg/L) were observed in 56% of the samples during ECMO and 39% without ECMO (p = 0.80). The median trough concentration, for a similar daily dose, was 2.4 (1.2-4.7) mg/L under ECMO and 2.5 (1.4-3.9) mg/L without ECMO (p = 0.58). Extensive inter-and intrasubject variability were observed. Neither ECMO nor squared day of ECMO (saturation) were retained as significant covariates on voriconazole exposure. CONCLUSIONS: No significant ECMO-effect was observed on voriconazole exposure. A large proportion of patients had voriconazole subtherapeutic concentrations.

Report from the 2018 consensus conference on immunomodulating agents in thoracic transplantation: Access, formulations, generics, therapeutic drug monitoring, and special populations.

In 2009, the International Society for Heart and Lung Transplantation recognized the importance and challenges surrounding generic drug immunosuppression. As experience with generics has expanded and comfort has increased, substantial issues have arisen since that time with other aspects of immunomodulation that have not been addressed, such as access to medicines, alternative immunosuppression formulations, additional generics, implications on therapeutic drug monitoring, and implications for special populations such as pediatrics and older adults. The aim of this consensus document is to address critically each of these concerns, expand on the challenges and barriers, and provide therapeutic considerations for practitioners who manage patients who need to undergo or have undergone cardiothoracic transplantation.

Donor heart and lung procurement: A consensus statement.

Heart and lung procurements are multiphased processes often accompanied by an array of complex logistics. Approaches to donor evaluation and management, organ procurement, and organ preservation vary among individual procurement teams. Because early graft failure remains a major cause of mortality in contemporary thoracic organ transplant recipients, we sought to establish some standardization in the procurement process. This paper, in this vein, represents an international consensus statement on donor heart and lung procurement and is designed to serve as a guide for physicians, surgeons, and other providers who manage donors to best optimize the clinical status for the procurement of both heart and lungs for transplantation. Donation after brain death (DBD) and donation after circulatory determination death (referred to as donation after circulatory death [DCD] for the remainder of the paper) for both heart and lung transplantation will be discussed in this paper. Although the data available on DCD heart donation are limited, information regarding the surgical technique for procurement is included within this consensus statement. Furthermore, this paper will focus on adult DBD and DCD heart and lung procurement. Currently, no certification, which is either recognized and/or endorsed by the transplant community at large, exists for the training of a cardiothoracic procurement surgeon. Nevertheless, establishing a training curriculum and credentialing requirements are beyond the scope of this paper.

Challenging immunosuppression treatment in lung transplant recipients with kidney failure.

Kidney failure after lung transplantation is a risk factor for chronic kidney disease. Calcineurin inhibitors are immunosuppressants which play a major role in terms of postoperative kidney failure after lung transplantation. We report our preliminary experience with the anti-interleukin-2 monoclonal antibody Basiliximab utilized as a "calcineurin inhibitor-free window" in the setting of early postoperative kidney failure after lung transplantation. Between 2012 and 2015 nine lung transplant patients who developed kidney failure for more than 14 days were included. Basiliximab was administrated in three doses (Day 0, 4, and 20) whilst Tacrolimus was discontinued or reduced to maintain a serum level between 2 and 4 ng/mL. Baseline glomerular filtration rate pre transplant was normal for all patients. Seven patients completely recovered from kidney failure (67%, mean eGFR pre and post Basiliximab: 42.3 mL/min/1.73 m(2) and 69 mL/min/1.73 m(2)) and were switched back on Tacrolimus. Only one of these patients still needs ongoing renal replacement therapy. Two patients showed no recovery from kidney failure and did not survive. Basiliximab might be a safe and feasible therapeutical option in patients which are affected by calcineurin inhibitor-related kidney failure in the early post lung transplant period. Further studies are necessary to confirm our preliminary results.

Assessing Anticoagulation Practice Patterns in Patients on Durable Mechanical Circulatory Support Devices: An International Survey.

Anticoagulation in mechanical circulatory support (MCS) patients dictated by local practice, and therefore uniform standards for management are lacking. To characterize the worldwide variance in anticoagulation and antiplatelet therapy in patients with MCS devices, a 42 item survey was created and distributed electronically in August 2014. The survey assessed the center-perceived thromboembolic risk (minimal, low, moderate, or high) and characterized the antiplatelet and anticoagulant strategies for the Thoratec HeartMate II (HMII) and HeartWare HVAD (HVAD). A total of 83/214 centers (39%) responded: North America (60/152), Europe (18/50), Australia (2/4), and Asia (3/8). Although the most common target international normalized ratio (INR) was 2-3 for both devices, significant variability exists. Anticoagulation intensity tended to be lower with the HMII, with more centers targeting INR values of less than 2.5. Aspirin monotherapy was the most common antiplatelet regimen; however, the HVAD patients were more likely to be on daily aspirin doses over 100 mg. In addition, parenteral bridging was more frequent with the HVAD device. While 43.8% of respondents indicated an increase in the perceived risk of HMII device thrombosis in 2014, intensification of anticoagulation (22%) or antiplatelet (11%) therapy was infrequent. Our findings verify the wide variety of anticoagulation practice patterns between MCS centers.

Usefulness of Rabbit Anti-thymocyte Globulin in Patients With Giant Cell Myocarditis.

Giant cell myocarditis (GCM) is an aggressive inflammatory myocardial disease. Immunosuppression is an effective treatment for some cases. However, the duration of action of agents such as muromonab CD3 is short and others such as the calcineurin inhibitors may lead to renal failure. Here we describe the outcome of a novel approach to treatment using rabbit anti-thymocyte globulin (RATG). A retrospective analysis of 6 patients treated with RATG for GCM was performed. Diagnosis was confirmed by endomyocardial biopsy, and RATG was administered with a high dose of corticosteroids. None of the patients had cytokine release syndrome or leukopenia, and 5 had thrombocytopenia (2 of them severe). Only 1 had a serious bleeding event that occurred after implantation of mechanical circulatory support. None developed impaired renal function after the treatment. Five were successfully discharged home with an increase in global left ventricular ejection fraction of 29%. Four are currently alive without recurrent disease, 1 of them after heart transplantation, with a mean follow-up of 970 days (423 to 1,875 days), left ventricular ejection fraction of 53%, and all in current New York Heart Association Classification class ≤II. Only 1 case had GCM recurrence. There were 2 deaths: one because of intracranial bleeding after mechanical circulatory support implantation and the other caused by primary graft dysfunction. In conclusion, patients with GCM can be successfully immunosuppressed with RATG and corticosteroids, thereby avoiding renal impairment. Early thrombocytopenia is the main adverse event. Larger cohorts of patients are necessary to compare the different immunosuppressant strategies available for GCM in a randomized fashion.

Fungal infection in cardiothoracic transplant recipients: outcome without systemic amphotericin therapy.

Transplant recipients require immunosuppression to prevent allograft rejection, placing them at risk of opportunistic infections including fungal infection. Difficulties in managing fungal infections include: establishing diagnosis, poor treatment response, drug interactions and toxicity. We report our single centre experience of treating fungal infections using systemic non-Amphotericin current generation antifungals. Patients receiving inpatient antifungal therapy from September 2005 to December 2010 were identified from pharmacy records. Fungal infections were retrospectively classified according to European Organization for Research and Treatment of Cancer (EORTC) criteria. Treatment outcomes were classified in a manner similar to those used in clinical trials. Two hundred and forty-nine recipients received antifungal treatment, 204 lungs and 45 hearts. One hundred and one patients received Voriconazole, 82 Caspofungin and 65 received both agents. One patient was unsuccessfully treated with additional Amphotericin. Treatment duration varied from 1.5 to 12 weeks. One hundred and sixty-five patients had a complete response, 24 had a partial response and in 60 patients treatment was unsuccessful. The response to systemic non-Amphotericin based antifungal therapy was high. We propose that diagnostic criteria without positive identification of a fungus allow treatment to be started early with few clinically relevant side effects.

Late antibody-mediated rejection after heart transplantation following the development of de novo donor-specific human leukocyte antigen antibody.

BACKGROUND: Antibody-mediated rejection (AMR) is an important problem after heart transplantation. Most cases seem to occur in sensitized recipients with preformed donor-specific human leukocyte antigen antibody (DSA) early after transplantation. Few data exist on AMR in patients who form de novo DSA. We describe the clinical features and treatment outcome for late AMR secondary to de novo DSA. METHODS: This was a retrospective, observational cohort study. All heart transplant patients treated for symptomatic AMR secondary to de novo DSA between November 2005 and August 2011. RESULTS: Fifteen patients were treated for AMR giving an incidence of 3.1 cases per 1000 person years and a prevalence of 1.4%. All had evidence of heart failure on presentation and de novo DSA at diagnosis. There was a spectrum of histologic and immunohistochemical findings. Despite treatment with immunepheresis, intravenous immunoglobulin, and rituximab, and in some cases total lymph node irradiation (n=3) and bortezomib (n=2), clinical outcomes were poor. DSA antibody levels, measured using Labscreen single antigen kits, were reduced by a mean of 76% with a median of 77% and a range of 35% to 99%, but were not eliminated. Forty-six percent had persistent cardiac allograft dysfunction. Mean and median survival was 1.3 and 0.8 years after diagnosis of AMR. Only 40% were alive at the end of the study period. CONCLUSION: Late cardiac AMR caused by de novo DSA was an uncommon but serious problem. Despite treatment consistent with current best practice, 46% of patients developed persistent cardiac dysfunction and their medium-term survival was poor.

ATP-binding cassette subfamily B member 1 polymorphisms do not determine cyclosporin exposure, acute rejection or nephrotoxicity after heart transplantation.

BACKGROUND: We hypothesized that genetic variation of ATP-binding cassette subfamily B member 1 (ABCB1) that encodes P-glycoprotein (involved in the uptake of cyclosporin A [CsA]) contributes to trough drug concentrations and thereby to CsA's immunosuppressive and toxic effects. METHODS: Three hundred thirty-seven adult heart transplant recipients were studied retrospectively. White recipients receiving CsA at month 3 and years 1 to 5 after transplantation (n=192, 168, 156, 130, 95, and 74, respectively) were then studied with respect to ABCB1 genotype or haplotype and CsA disposition. Genotyping was performed using a gel-based polymerase chain reaction method. Dose- and weight-adjusted CsA trough concentrations ([microg/L]/[mg/kg]), time to first endomyocardial biopsy-proven acute rejection episode (grade>or=3A), weaning from steroids at 1 year, and renal function at 1 year posttransplant were measured. RESULTS: An association between dose- and weight-adjusted CsA trough concentrations and ABCB1 haplotypes was found, with 12/1236, 21/2677, 26/3435 CC/GG/CC individuals having significantly higher concentrations than TT/TT/TT individuals at years 1 and 5 (68.9+/-26.9 vs. 54.9+/-19.5 and 70.6+/-35 vs. 50.0+/-12.2 [microg/L]/[mg/kg] P<0.05, respectively) There was no difference in the incidence of acute rejection, steroid weaning, or renal impairment between the genotype or haplotype groups. CONCLUSIONS: The association of ABCB1 12/1236, 21/2677, and 26/3435 CC/GG/CC haplotype with increased CsA dose- and weight-adjusted CsA trough concentrations in this group of adult white heart transplant recipients was not consistent over time and had no effect on the incidence of acute rejection or on the development of renal impairment.

Transfer from ciclosporin to mycophenolate-sirolimus immunosuppression for chronic renal disease after heart transplantation: safety and efficacy of two regimens.

BACKGROUND: Chronic kidney disease is common after heart transplantation, and is related to ciclosporin (CsA) therapy. We compared the safety and efficacy of two ciclosporin withdrawal regimens. METHODS: CsA was stopped and sirolimus (SRL) commenced immediately and the transfer was covered with prednisolone. Those on azathioprine (AZA) were transferred to MMF. In protocol A, the SRL target concentration was 16 (12-20) ng/ml; in protocol B, the target concentration was 7(5-10) ng/ml, but mycophenolate (MMF) and steroids were commenced prior to the transfer. RESULTS: Baseline characteristics were similar in both groups except that group B were switched later after transplantation. Renal function improved significantly in both groups; this was maintained up to 1 year. Two patients in group A experienced acute rejection (ISHLT grade 3A or 2R); none was seen in group B. Six patients (46%) remained on protocol A and 22 (85%) remained on protocol B at 1 year. CONCLUSIONS: MMF-SRL substitution resulted in a rapid but partial improvement in renal function; the lower dose SRL regimen was better tolerated.