Invasive fungal infection after heart transplantation: A 7-year, single-center experience

Risk Factors and Outcomes of Invasive Candida Infections in Heart Transplant Recipients: A Case-Control Study

BACKGROUND

Invasive Candida infections (ICI) are the most common invasive fungal infections in solid organ transplant recipients. There are limited contemporary data on the risk factors for infection in heart transplant (HT) recipients especially since the expansion of temporary mechanical circulatory support (MCS) use.

METHODS

This was a case-control study conducted at a tertiary care academic hospital of HT recipients from January 2022 to January 2024. All patients who developed ICI by the detection of Candida species from a normally sterile site were included as cases. Four controls who underwent HT, two before the case and two after the case, were selected. ​Fisher's exact or Mann-U-Whitney tests were used for the analysis.

RESULTS

There were 12 cases and 48 controls out of a total of 117 transplants during the study period​. The proportion of ICI was 10.6%. The median time to ICI from transplant was 16 days (IQR 10, 83). The most common organisms isolated were Candida parapsilosis and Candida albicans. The majority of infections were mediastinitis. Risk factors for ICI included receipt of antibiotics for more than 7 days within 1 month prior to transplant (58.3% vs. 22.9%, p = 0.03), tracheostomy (41.7% vs. 10.4%, p = 0.02), prolonged chest tube placement (13 vs. 9 days, p = 0.02), and temporary MCS (p = 0.042). Patients who developed ICI had increased 90-day all-cause mortality compared to controls (33.3% vs. 4.2%, p = 0.01).

CONCLUSION

This study identified several risk factors for ICI following HT. Further research is essential to develop interventions that mitigate these risk factors in this patient population.

Epidemiology and pathogen characteristics of infections following solid organ transplantation

Solid organ transplantation (SOT) recipients have a heightened risk for infection due to prolonged immunosuppressive drug use following transplant procedures. The occurrence of post-transplant infections is influenced not only by the transplanted organ type but also by varied factors. The kidney is the most common organ in SOT, followed by the liver, heart, and lung. This review aims to provide a comprehensive overview of the current epidemiological characteristics of infections after kidney, liver, heart, and lung transplantation, focusing on bacterial, fungal, and viral infections. The incidence and infection types demonstrated significant variability across different SOTs. Furthermore, this review attempts to elucidate the clinical characteristics of infections across patients following different SOTs and contribute to the development of individualized prevention strategies according to infection incidence, ultimately enhancing the quality of life of transplant recipients.

Risk Factors for Early Fungal Disease in Solid Organ Transplant Recipients: A Systematic Review and Meta-analysis

BACKGROUND

Invasive fungal infections are associated with high morbidity in solid organ transplant recipients. Risk factor modification may help with preventative efforts. The objective of this study was to identify risk factors for the development of fungal infections within the first year following solid organ transplant.

METHODS

We searched for eligible articles through February 3, 2023. Studies published after January 1, 2001, that pertained to risk factors for development of invasive fungal infections in solid organ transplant were reviewed for inclusion. Of 3087 articles screened, 58 were included. Meta-analysis was conducted using a random-effects model to evaluate individual risk factors for the primary outcome of any invasive fungal infections and invasive candidiasis or invasive aspergillosis (when possible) within 1 y posttransplant.

RESULTS

We found 3 variables with a high certainty of evidence and strong associations (relative effect estimate ≥ 2) to any early invasive fungal infections across all solid organ transplant groups: reoperation (odds ratio [OR], 2.92; confidence interval [CI], 1.79-4.75), posttransplant renal replacement therapy (OR, 2.91; CI, 1.87-4.51), and cytomegalovirus disease (OR, 2.97; CI, 1.78-4.94). Both posttransplant renal replacement therapy (OR, 3.36; CI, 1.78-6.34) and posttransplant cytomegalovirus disease (OR, 2.81; CI, 1.47-5.36) increased the odds of early posttransplant invasive aspergillosis. No individual variables could be pooled across groups for invasive candidiasis.

CONCLUSIONS

Several common risk factors exist for the development of any invasive fungal infections in solid organ transplant recipients. Additional risk factors for invasive candidiasis and aspergillosis may be unique to the pathogen, transplanted organ, or both.

Population Pharmacokinetics of Caspofungin and Dose Simulations in Heart Transplant Recipients

The effect of heart transplantation (HTx) on the pharmacokinetics (PK) of caspofungin is not well-characterized. The aim of this study was to investigate the population PK of caspofungin in HTx and non-HTx patients and to identify covariates that may affect the PK of caspofungin. Seven successive blood samples were collected before administration and at 1, 2, 6, 10, 16, and 24 h after the administration of caspofungin for at least 3 days. This study recruited 27 HTx recipients and 31 non-HTx patients with 414 plasma concentrations in total. A nonlinear mixed-effects model was used to describe the population PK of caspofungin. The PK of caspofungin was best described by a two-compartment model. The clearance (CL) and volume of the central compartment (V_c) of caspofungin were 0.385 liter/h and 4.27 liters, respectively. The intercompartmental clearance (Q) and the volume of the peripheral compartment (V_p) were 2.85 liters/h and 6.01 liters, respectively. In the final model, we found that albumin (ALB) affected the CL of caspofungin with an adjustment factor of -1.01, and no other covariates were identified. In this study, HTx was not found to affect the PK of caspofungin. Based on the simulations, the dose of caspofungin should be proportionately increased in patients with decreased ALB levels.

Weekly high-dose liposomal amphotericin B prevents invasive aspergillosis after heart transplantation

BACKGROUND

Preventive strategies for invasive aspergillosis (IA) have still not been determined in heart transplant recipients whereas IA leads to a high mortality rate at 12 months posttransplantation. The use of voriconazole or echinocandins was proposed but can favor emergence of Aspergillus or Candida sp. resistant strains or promote neurological and liver disorders in some patients.

OBJECTIVES

To assess whether universal prophylaxis with weekly high-dose of liposomal amphotericin-B (L-AmB) can safely prevent IA in heart transplant recipients.

PATIENTS/METHODS

Retrospective before/after study that included 142 patients who received heart transplantation between 2010 and 2019 at the University Hospital of Toulouse (France). Weekly high dose of L-AmB (7.5 mg/kg/week) was used as universal prophylaxis from 2016 because of high environmental exposure to Aspergillus sp. and high incidence of IA.

RESULTS

Cumulative 1-year incidence of IA decreased from 23% to 5% after introduction of L-Amb prophylaxis. Multivariate analysis (Cox model) identified L-AmB prophylaxis as a protective factor against IA (hazard ratio [HR] 0.21 [95% confidence interval 0; 0.92], p = .04), whereas postoperative renal replacement therapy was associated with IA (HR 3.6 [95% confidence interval 1.38; 9.3], p = .001), after correction for confounding effects (induction regimen, methylprednisolone pulses and history of hematological malignancy). The incidence of acute kidney injury requiring renal replacement therapy was similar in the two groups, suggesting a low risk of kidney toxicity when L-AmB is used weekly. No patient developed severe kidney electrolyte loss nor L-AmB-related anaphylaxis.

CONCLUSIONS

Once-weekly high-dose L-AmB is safe and may prevent the development of IA after heart transplantation.

Risk factors of invasive fungal infections in lung transplant recipients: A systematic review and meta-analysis

BACKGROUND

Invasive fungal infection (IFI) remains a common complication after lung transplantation, causing significant morbidity and mortality. We have attempted to quantify systematically risk factors of IFI in lung transplant recipients.

METHODS

Studies were retrieved from Ovid MEDLINE, Ovid Embase, Cochrane database of systematic reviews and Cochrane central register of controlled trials. All case-control and cohort studies evaluating the risk factors of IFI in adult lung transplant recipients were screened. Two researchers reviewed and assessed all studies independently. We pooled the estimated effect of each factor associated with IFI by using a random effect model.

RESULTS

Eight studies were included in the systematic review and 5 studies were eligible for the meta-analysis. Rates of IFI range from 8% to 33% in lung transplant recipients. Independent risk factors for invasive aspergillosis (IA) in lung transplantation include previous fungal colonization (odds ratio [OR] 2.44; 95% confidence interval [CI] 0.08-0.47), cytomegalovirus infection (OR 1.96; 95% CI 1.08-3.56), and single lung transplantation (OR 1.77; 95% CI 1.08-2.91). Pre-emptive antifungal therapy is a protective factor for IA in lung transplant (OR 0.2; 95% CI 0.08-0.47).

CONCLUSION

Cytomegalovirus infection, previous fungal colonization and single lung transplantation independently increase the risk of IA in lung transplant recipients. Pre-emptive antifungal therapy is a protective factor for IA in the lung transplant population.

Epidemiology, risk factors, and association of antifungal prophylaxis on early invasive fungal infection in heart transplant recipients

BACKGROUND

Invasive fungal infection (IFI) in heart transplant recipients is associated with poor outcomes. Estimated risk of 1-year IFI in heart transplant recipients is 3.4-8.6% with risk factors inconsistently identified in previous studies. The role of antifungal prophylaxis is unclear. The transplant program at Mayo Clinic provides 6 months of universal azole prophylaxis for those heart transplant recipients in Arizona. We sought to define risk factors for 1-year IFI and determine the effect of antifungal prophylaxis.

METHODS

We conducted a retrospective cohort study of patients undergoing heart transplantation at Mayo Clinic from January 2000 to March 2019. We analyzed demographics, details of transplant hospitalization, antifungal prophylaxis, and fungal infection. Multivariable Cox analyses were performed to identify risk factors of 1-year IFI and impact of IFI on posttransplant mortality.

RESULTS

A total of 966 heart transplant recipients were identified with a median age of 56 years (IQR 47, 62). A total of 444 patients received antifungal prophylaxis. Over 1-year follow-up, 62 patients developed IFI with a cumulative incidence of 6.4%. In multivariable analysis, factors associated with IFI were renal replacement therapy (RRT) (HR 3.24, 95% CI 1.65-6.39), allograft rejection (HR 2.33, 95% CI 1.25-4.34), and antifungal prophylaxis (HR 0.32, 95% CI 0.11-0.96). RRT was also associated with invasive mold infection (HR 3.00, 95% CI 1.29-6.97).

CONCLUSIONS

RRT and allograft rejection after transplantation are associated with 1-year IFI, and RRT is also associated with invasive mold infection. Antifungal prophylaxis appears to be protective and further study is needed in the heart transplant population.

FDG PET/CT for Detection of Infectious Complications Following Solid Organ Transplantation

Infectious complications after solid organ transplantation (SOT) are often more severe and remain a diagnostic challenge due to vague and atypical clinical presentations. Diagnostic performance of conventional diagnostic tools is frequently inadequate which may lead to delayed diagnosis with the risk of poorer outcomes. This literature review aimed to investigate the current evidence on the use of ¹⁸F-fluoro-deoxy-glucose (FDG) Positron Emission Tomography (PET)/computer tomography (CT) in infectious complications after SOT. Based on search in PubMed, Medline, and Cochrane databases, 13 articles and 46 case reports were included. For inclusion, articles were to include data on patients with infectious complications after SOT, and where FDG PET/CT was part of the work-up. Final searches were conducted on 02 September 2020. Overall, in the absence of initial diagnostic clues, FDG PET/CT should be considered as the imaging technique of choice as it may guide further investigations and eventually reveal the diagnosis in most of the patients. However, the available literature of the role of FDG PET/CT in SOT recipients with infectious complications is scarce and well-designed prospective studies including control groups are warranted to establish the role of FDG PET/C/ in SOT recipients. The main drawback of FDG PET/CT is the lack of ability to differentiate between cancer and infectious diseases which are both highly prevalent in this patient group. Accordingly, the main reasons for "false" results of FDG PET/CT is the misdiagnosis of cancer in benign inflammatory or infectious processes, information which nonetheless can be useful.

Needles in a haystack: Extremely rare invasive fungal infections reported in FungiScopeⓇ-Global Registry for Emerging Fungal Infections

OBJECTIVES

Emerging invasive fungal infections (IFI) have become a notable challenge. Apart from the more frequently described fusariosis, lomentosporiosis, mucormycosis, scedosporiosis, and certain dematiaceae or yeasts, little is known about extremely rare IFI.

METHODS

Extremely rare IFI collected in the FungiScope^Ⓡ registry were grouped as Dematiaceae, Hypocreales, Saccharomycetales, Eurotiales, Dermatomycetes, Agaricales, and Mucorales.

RESULTS

Between 2003 and June 2019, 186 extremely rare IFI were documented in FungiScope^Ⓡ. Dematiaceae (35.5%), Hypocreales (23.1%), Mucorales (11.8%), and Saccharomycetales (11.3%) caused most IFI. Most patients had an underlying malignancy (38.7%) with acute leukemia accounting for 50% of cancers. Dissemination was observed in 26.9% of the patients. Complete or partial clinical response rate was 68.3%, being highest in Eurotiales (82.4%) and in Agaricales (80.0%). Overall mortality rate was 29.3%, ranging from 11.8% in Eurotiales to 50.0% in Mucorales.

CONCLUSIONS

Physicians are confronted with a complex variety of fungal pathogens, for which treatment recommendations are lacking and successful outcome might be incidental. Through an international consortium of physicians and scientists, these cases of extremely rare IFI can be collected to further investigate their epidemiology and eventually identify effective treatment regimens.

Incidence and outcomes of invasive fungal infection among solid organ transplant recipients: A population-based cohort study

BACKGROUND

Invasive fungal infection (IFI) in solid organ transplant (SOT) recipients is associated with significant morbidity and mortality. The long-term probability of post-transplant IFI is poorly understood.

METHODS

We conducted a population-based cohort study using linked administrative healthcare databases from Ontario, Canada, to determine the incidence rate; 1-, 5-, and 10-year cumulative probabilities of IFI; and post-IFI all-cause mortality in SOT recipients from 2002 to 2016. We also determined post-IFI, death-censored renal allograft failure.

RESULTS

We included 9326 SOT recipients (median follow-up: 5.35 years). Overall, the incidence of IFI was 8.3 per 1000 person-years. The 1-year cumulative probability of IFI was 7.4% for lung, 5.4% for heart, 1.8% for liver, 1.2% for kidney-pancreas, and 1.1% for kidney-only allograft recipients. Lung transplant recipients had the highest incidence rate and 10-year probability of IFI: 43.0 per 1000 person-years and 26.4%, respectively. The 1-year all-cause mortality rate after IFI was 34.3%. IFI significantly increased the risk of mortality in SOT recipients over the entire follow-up period (hazard ratio: 6.50, 95% CI: 5.69-7.42). The 1-year probability of death-censored renal allograft failure after IFI was 9.8%.

CONCLUSION

Long-term cumulative probability of IFI varies widely among SOT recipients. Lung transplantation was associated with the highest incidence of IFI with considerable 1-year all-cause mortality.

Yeast Infections in Solid Organ Transplantation

Invasive candidiasis (IC) remains the most common invasive fungal infection following solid-organ transplant (SOT), but risk factors are evolving. Current challenges include infection due to drug resistant non-albicans and emerging novel species such as Candida auris. Preventive antifungal use in SOT needs to be re-examined in light of these current challenges. Cryptococcosis is the second most common IFI following SOT. Cryptococcus gattii is an emerging pathogen that can have reduced in-vitro susceptibility to antifungal agents. Cryptococcus associated IRIS in SOT is a clinical entity that warrants heightened awareness for timely recognition and management.