Antifungal prophylaxis in lung transplantation

Antifungal Prophylaxis After Lung Transplantation: Where Are We Now?

BACKGROUND

Lung transplantation is an important treatment option for various end-stage lung diseases. However, survival remains limited due to graft rejection and infections. Despite that fungal infections are frequent and carry a bad prognosis, there is currently no consensus on efficacy, optimal drug, route, or duration of antifungal prophylaxis. This narrative review summarizes current strategies for antifungal prophylaxis after lung transplantation.

METHODS

English language articles in Embase, Pubmed, UptoDate, and bibliographies were used to assess the efficacy and safety of available antifungal agents for prophylaxis in adult lung transplant recipients.

RESULTS

Overall, there are limited high-quality data. Universal prophylaxis is more widely used and may be preferable over targeted prophylaxis. Both formulations of inhaled amphotericin B and systemic azoles are effective at reducing fungal infection rates, yet with their own specific advantages and disadvantages. The benefit of combination regimens has yet to be proven. Considering the post-transplant timing of the onset of fungal infections, postoperative prophylaxis during the first postoperative months seems indicated for most patients.

CONCLUSIONS

Based on existing literature, universal antifungal prophylaxis with inhaled amphotericin B and systemic voriconazole for at least 3-6 mo after lung transplantation may be advisable, with a slight preference for amphotericin B because of its better safety profile.

Risk factors of breakthrough aspergillosis in lung transplant recipients receiving itraconazole prophylaxis

INTRODUCTION

Invasive Aspergillus infection (IA) in lung transplantation can result in poor outcomes. Itraconazole has been shown to be effective for fungal prophylaxis in lung transplant recipients. However, IA remains a major cause of death after lung transplantation. Therefore, we aimed to clarify the risk factors for IA on itraconazole prophylaxis.

METHODS

We examined 120 recipients to uncover their IA epidemiology, clinical characteristics, and outcomes. In addition, a case-control study was performed to identify risk factors of IA.

RESULTS

Of the 120 patients, 12 developed IA under itraconazole prophylaxis. The patient demographics and clinical characteristics were compared among the following two groups: IA group, 12 patients, and control group, 108 patients. Significant differences were observed in age (p = 0.004), history of interstitial pneumonia (p = 0.032), and CMV infection (p < 0.001) between the groups. Before the onset of IA, 92% (11/12) of the patients received itraconazole with trough concentrations above the therapeutic range. IA developed at 272.9 ± 114.1 days after lung transplantation. Of the 12 patients who developed IA, 66.7% (8/12) had early cessation of cytomegalovirus (CMV) prophylaxis due to toxicity of valganciclovir, as follows: leukocytopenia in 4 patients, and renal dysfunction in 4 patients. Of the 8 patients who stopped valganciclovir, 75% (6/8) developed CMV infection subsequently.

CONCLUSION

This study suggests that older age, history of interstitial pneumonia, and CMV infection may be important risk factors for IA on itraconazole prophylaxis. These results may help clinicians optimize prophylactic strategies for IA.

Invasive Fungal Infection After Lung Transplantation: Epidemiology in the Setting of Antifungal Prophylaxis

BACKGROUND

Lung transplant recipients commonly develop invasive fungal infections (IFIs), but the most effective strategies to prevent IFIs following lung transplantation are not known.

METHODS

We prospectively collected clinical data on all patients who underwent lung transplantation at a tertiary care academic hospital from January 2007-October 2014. Standard antifungal prophylaxis consisted of aerosolized amphotericin B lipid complex during the transplant hospitalization. For the first 180 days after transplant, we analyzed prevalence rates and timing of IFIs, risk factors for IFIs, and data from IFIs that broke through prophylaxis.

RESULTS

In total, 156 of 815 lung transplant recipients developed IFIs (prevalence rate, 19.1 IFIs per 100 surgeries, 95% confidence interval [CI] 16.4-21.8%). The prevalence rate of invasive candidiasis (IC) was 11.4% (95% CI 9.2-13.6%), and the rate of non-Candida IFIs was 8.8% (95% CI 6.9-10.8%). First episodes of IC occurred a median of 31 days (interquartile range [IQR] 16-56 days) after transplant, while non-Candida IFIs occurred later, at a median of 86 days (IQR 40-121 days) after transplant. Of 169 IFI episodes, 121 (72%) occurred in the absence of recent antifungal prophylaxis; however, IC and non-Candida breakthrough IFIs were observed, most often representing failures of micafungin (n = 16) and aerosolized amphotericin B (n = 24) prophylaxis, respectively.

CONCLUSIONS

Lung transplant recipients at our hospital had high rates of IFIs, despite receiving prophylaxis with aerosolized amphotericin B lipid complex during the transplant hospitalization. These data suggest benefit in providing systemic antifungal prophylaxis targeting Candida for up to 90 days after transplant and extending mold-active prophylaxis for up to 180 days after surgery.

Scedosporium apiospermum and Lomentospora prolificans in lung transplant patients - A single center experience over 24 years

INTRODUCTION

Scedosporium apiospermum and Lomentospora prolificans (Scedosporium/Lomentospora) species are emerging, multi-resistant pathogens that cause life-threatening illnesses among lung transplant (LTx) recipients. The current epidemiology and management in LTx are unknown.

METHODS

We performed a retrospective single center audit of all sputum/bronchoscopy samples for Scedosporium/Lomentospora species in LTx patients over a 24-year period (1995-2019). Patients were diagnosed as colonized or with invasive fungal disease.

RESULTS

From a cohort of 962 LTx recipients, 30 patients (3.1%) cultured Scedosporium/Lomentospora (1.2%, 1.9%, respectively). There were no isolates from 1995 to 2013, with multiple yearly isolates thereafter. Nineteen (63%) cases were classified as IFD, and 11 (37%) as colonization. The median time to first culture from transplantation was 929 days (Interquartile-range [IQR] 263-2960). Most patients (63%) had received antifungals prior to the first positive culture of Scedosporium/Lomentospora for other fungal infection. The most common antifungal used for treatment of Scedosporium/Lomentospora was posaconazole (n = 16; 53%). Median duration of therapy was 364 days (IQR 164-616). Treatment was associated with improved lung function over 6 months (median FEV1 increased from 1.3L[IQR 0.9-1.8L] to 1.8L[IQR 1.1-2.3] P = .05). Six patients cultured Scedosporium/Lomentospora prior to transplantation, and no survival disadvantage was seen as compared to our whole LTx cohort (P = .8).

CONCLUSION

Our single center 24-year experience suggests that the incidence of Scedosporium/Lomentospora is increasing. Scedosporium/Lomentospora is typically isolated several years after LTx, and requires prolonged anti-fungal treatment that is usually associated with improved in lung function. Culture of Scedosporium/Lomentospora prior to LTx did not pose a survival disadvantage. Further surveillance is required to fully characterize implications of these organisms for LTx recipients.

Postoperative management of lung transplant recipients

Despite advances in surgical technique, lung transplantation is associated with worse survival when compared with other solid organ transplantations. Graft dysfunction and infection are the leading causes of mortality in the first 30 days following transplantation. Primary graft dysfunction (PGD) is a form of reperfusion injury that occurs early after transplantation. Management of PGD is mainly supportive with use of lung protective ventilation. Inhaled nitric oxide (iNO) and extracorporeal membrane oxygenation may be used in severe cases. Bacterial pneumonias are the most common infectious complication in the immediate post transplant period, but invasive fungal infections may also occur. Other potential complications in the postoperative period include atrial arrhythmias and neurologic complications such as stroke. There is a lack of multicenter, randomized trials to guide ventilation strategies, infection prophylaxis, and treatment of atrial arrhythmias, therefore prevention and management of post-transplant complications vary by transplant center.

Pulmonary rehabilitation improves survival in patients with idiopathic pulmonary fibrosis undergoing lung transplantation

This study was conducted to evaluate whether a pulmonary rehabilitation program (PRP) is independently associated with survival in patients with idiopathic pulmonary fibrosis (IPF) undergoing lung transplant (LTx). This quasi-experimental study included 89 patients who underwent LTx due to IPF. Thirty-two completed all 36 sessions in a PRP while on the waiting list for LTx (PRP group), and 53 completed fewer than 36 sessions (controls). Survival after LTx was the main outcome; invasive mechanical ventilation (IMV), length of stay (LOS) in intensive care unit (ICU) and in hospital were secondary outcomes. Kaplan-Meier curves and Cox regression models were used in survival analyses. Cox regression models showed that the PRP group had a reduced 54.0% (hazard ratio = 0.464, 95% confidence interval 0.222–0.970, p = 0.041) risk of death. A lower number of patients in the PRP group required IMV for more than 24 hours after LTx (9.0% vs. 41.6% p = 0.001). This group also spent a mean of 5 days less in the ICU (p = 0.004) and 5 days less in hospital (p = 0.046). In conclusion, PRP PRP completion halved the risk of cumulative mortality in patients with IPF undergoing unilateral LTx

Common Infections Following Lung Transplantation

The lungs are the only transplanted organ in direct contact with the ‘outside world’. Infection is a significant cause of morbidity and mortality in lung transplantation. Early accurate diagnosis and optimal management is essential to prevent short and long term complications. Bacteria, including Mycobacteria and Nocardia, viruses and fungi are common pathogens. Organisms may be present in the recipient prior to transplantation, transmitted with the donor lungs or acquired after transplantation. The degree of immunosuppression and the routine use of antimicrobial prophylaxis alters the pattern of post-transplant infections.

Fungal infections in solid organ transplantation: An update on diagnosis and treatment

Invasive fungal infections constitute an important cause of morbidity and mortality in solid organ transplantation recipients. Since solid organ transplantation is an effective therapy for many patients with end-stage organ failure, prevention and treatment of fungal infections are of vital importance. Diagnosis and management of these infections, however, remain difficult due to the variety of clinical symptoms in addition to the lack of accurate diagnostic methods. The use of fungal biomarkers can lead to an increased diagnostic accuracy, resulting in improved clinical outcomes. The evidence for optimal prophylactic approaches remains inconclusive, which results in considerable variation in the administration of prophylaxis. The implementation of a standard protocol for prophylaxis remains difficult as previous treatment regimens, which can alter the distribution of different pathogens, affect the outcome of antifungal susceptibility testing. Furthermore, the increasing use of antifungals also contributes to incremental costs and the risk of development of drug resistance. This review will highlight risk factors, clinical manifestations and timing of fungal infections and will focus predominately on the current evidence for diagnosis and management of fungal infections.

Low dose posaconazole delayed release tablets for fungal prophylaxis in lung transplant recipients

In November 2013, posaconazole delayed release (DR) tablets were approved by the FDA with the labeled dose of 300 mg daily for fungal prophylaxis. There are no studies demonstrating the appropriate dose in lung transplant recipients (LTR). We performed a 2-center retrospective cohort study of LTR taking posaconazole DR tablets for prophylaxis between January 2014 and January 2017. Mean serum trough concentrations and percentage of measurements ≥0.7 mcg/mL were compared by daily dose. Forty-nine subjects with 156 steady state serum posaconazole concentrations were included. There was a significant difference in percentage of first measured concentration ≥0.7 mcg/mL by initial daily dose (P = .04). The mean serum posaconazole concentration by dose was 0.9 (±0.42) mcg/mL for 100 mg daily, 1.66 (±0.91) mcg/mL for 200 mg daily, 2.39 (±1.49) mcg/mL for 300 mg daily, and 1.75 (±0.21) mcg/mL for 400 mg daily (P < .001). Mean concentrations were at goal in 63.3%, 96.9%, 94.9%, and 100% of subjects taking 100 mg, 200 mg, 300 mg, and 400 mg daily respectively (P = .04). Our results suggest that doses less than 300 mg daily of posaconazole DR tablets may be adequate to achieve target serum concentrations in LTR. Larger studies are needed to confirm these findings.