Changing trends in infectious disease in heart transplantation

Infections in the first year after heart transplantation in a Latin American country

BACKGROUND

Heart transplantation is the therapy of choice in patients with advanced heart failure refractory to other medical or surgical management. However, heart transplants are associated with complications that increase posttransplant morbidity and mortality. Infections are one of the most important complications after this procedure. Therefore, infections in the first year after heart transplantation were evaluated.

METHODS

A retrospective cohort study of infections after heart transplants was conducted in a teaching hospital in Colombia between 2011 and 2019. Patients registered in the institutional heart transplant database (RETRAC) were included in the study. Microbiological isolates and infectious serological data were matched with the identities of heart transplant recipients and data from clinical records of individuals registered in the RETRAC were analyzed. The cumulative incidences of events according to the type of microorganism isolated were estimated using Kaplan-Meier survival analyses.

RESULTS

Seventy-nine patients were included in the study. Median age was 49 years (37.4-56.3), and 26.58% of patients were women. Eighty-seven infections were documented, of which 55.17% (48) were bacterial, 22.99% (20) were viral, and 12.64% (11) were fungal. Bacterial infections predominated in the first month. In the first year, infections caused 38.96% of hospital admissions and were the second cause of death after heart transplants (25.0%).

CONCLUSION

Posttransplant infections in the first year of follow-up were frequent. Bacterial infections predominated in the early posttransplant period. Infections, mainly bacterial, were the second most common cause of death and the most common cause of hospitalization in the first year after heart transplantation.

Cardiac transplantation in adult congenital heart disease with prior sternotomy

BACKGROUND

Adult congenital heart disease (ACHD) patients who require orthotopic heart transplantation are surgically complex due to anatomical abnormalities and multiple prior surgeries. In this study, we investigated these patients' outcomes using our institutional database.

METHODS

ACHD patients who had prior intracardiac repair and subsequent heart transplant were included (2008-2018). Adult patients without ACHD were extracted as a control. A comparison of patients with functional single ventricular (SV) and biventricular (BV) hearts was performed.

RESULTS

There were 9 SV and 24 BV patients. The SV group had higher central venous pressure/pulmonary capillary wedge pressure (P = .028), hemoglobin concentration (P = .010), alkaline phosphatase (P = .022), and were more likely to have liver congestion (P = .006). Major complications included infection in 16 (48.5%), temporary dialysis in 12 (36.4%), and graft dysfunction requiring perioperative mechanical support in 7 (21.2%). Overall in-hospital mortality was 15.2%. Kaplan-Meier analysis showed a higher, but not statistically significant, survival after 10 years between the ACHD and control groups (ACHD 84.9% vs. control 67.5%, P = .429). There was no significant difference in 10-year survival between SV and BV groups (78% vs. 88%, P = .467).

CONCLUSIONS

Complex ACHD cardiac transplant recipients have a high incidence of early morbidities after transplantation. However, long-term outcomes were acceptable.

Recent Trends of Infectious Complications Following Heart Transplantation

BACKGROUND

Heart transplantation is a life-saving procedure that has seen improvements in transplant and patient outcomes due to advances in immunosuppression and prevention of posttransplantation infectious episodes (IEps). This study systematically evaluates IEps in the modern era of heart transplantation at Stanford University Medical Center.

METHODS

This is a single-center retrospective review that includes 279 consecutive adult heart transplantation recipients from January 2008 to September 2017. Baseline demographic, clinical, serological, and outcomes information were collected. Kaplan-Meier estimator was used to assess survival stratified by IEp occurrence within the first year.

RESULTS

A total of 600 IEps occurred in 279 patients (2.15 IEps per patient) during a median follow-up period of 3 years. Overall survival was 83.3% (95% confidence interval [CI], 76.2-88.4) at 1 year posttransplantation for those with any IEp compared with 93.0% (95% CI, 87.2-96.4) in those without IEp (P = 0.07). Bacterial IEps were the most common (n = 375; 62.5%), followed by viral (n = 180; 30.0%), fungal (n = 40; 6.7%), and parasitic (n = 5; 0.8%). IEps by Gram-negative bacteria (n = 210) outnumbered those by Gram-positive bacteria (n = 142). Compared with prior studies from our center, there was a decreased proportion of viral (including cytomegalovirus), fungal (including Aspergillus spp. and non-Aspergillus spp. molds), and Nocardia infections. There were no IEps due to Mycobacterium tuberculosis, Pneumocystis jirovecii, or Toxoplasma gondii.

CONCLUSIONS

A significant reduction in viral, fungal, and Nocardia IEps after heart transplantation was observed, most likely due to advancements in immunosuppression and preventive strategies, including pretransplant infectious diseases screening and antimicrobial prophylaxis.

Infectious complications after heart transplantation in patients screened with gene expression profiling

BACKGROUND

The risk of infection after heart transplantation is highest within the first year and represents the leading cause of early mortality. In this cohort of patients enrolled in the Outcomes AlloMap Registry (OAR), we sought to describe infection episodes (IEp) resulting in hospitalization, in the early (<1 year) and late (≥1 year) post-transplant period and determine the impact of immunosuppression on incidence of infection.

METHODS

The primary aim was to assess the incidence and nature of IEp. The secondary aim was to evaluate the effect of potential risk factors, such as recipient age; sex; body mass index; panel-reactive antibodies; cytomegalovirus (CMV) primary mismatch; prednisone, tacrolimus, and sirolimus levels; and gene expression profile (GEP) score, in the development of IEp.

RESULTS

The OAR comprises 1,504 patients, of whom 220 patients (14.6%) had an IEp during a median follow-up period of 382 days (interquartile range [IQR] 230 to 579 days). The cause-specific 5-year hazard ratio for any infection was 2.029 (p = 0.12). The pattern of early infection was consistent with nosocomial and opportunistic causes, whereas later infection was consistent with late-onset opportunistic and community-acquired etiologies. Sixty-two percent of the infections occurred early. In the time-dependent analysis, higher prednisone dose (log prednisone, hazard ratio [HR] 1.30, p = 0.022) was the most significant risk factor for all IEp.

CONCLUSIONS

In the OAR cohort, the majority of infections occurred within 1 year after transplantation. Clinicians may consider more aggressive prednisone withdrawal in low-risk patients to reduce IEp.

Infections in Heart, Lung, and Heart-Lung Transplantation

Half a century has passed since the first orthotopic heart transplant took place. Surgical innovations allowed for heart, lung, and heart-lung transplantation to save lives of patients with incurable chronic cardiopulmonary conditions. The complexity of the surgical interventions, chronic host health conditions, and antirejection immunosuppressive medications makes infectious complications common. Infections have remained one of the main barriers for successful transplantation and a source of significant morbidity and mortality. Recognition of infections and its management in this setting require outstanding clinical skills since transplant recipients may not exhibit classic signs or symptoms of disease, and laboratory work has some pitfalls. The prevention, identification, and management of infectious diseases complications in this population are a priority to undertake to improve the medical outcomes of transplantation. Herein, we reviewed the historical aspects, epidemiology, and prophylaxis of infections in heart, lung, and heart-lung transplantation. We also discuss the most prevalent organisms affecting the host and the organ systems involved.

Outcomes and Predictors of Early Infection after Heart Transplantation

BACKGROUND

Limited data exist on the incidence and outcome of early infection after orthotopic heart transplantation (OHT). The purpose of this study was to describe characteristics and outcomes of OHT recipients with an early infection and to identify predictors of such infections.

METHODS

This retrospective, single-center study included patients greater than 18 years of age who underwent OHT from February 2009 to May 2014 and had an infection within 30 days of transplantation. Patient demographics, clinical variables, and outcomes were collected. Multivariable logistic regression was performed to identify independent predictors of infection.

RESULTS

Of the 172 eligible OHT recipients, 51 (29.7%) had an early infection. The median time to diagnosis was five days, with gram-negative organisms being slightly more common (58.2%). No differences in mortality rate, rejection, or re-admission were found between the groups. Longer durations of mechanical ventilation and lengths of stay were found in the infection group (p < 0.001). Patients with an early infection also had a higher incidence of mechanical circulatory support, history of drive-line infection, longer duration of mechanical ventilation, continuous renal replacement therapy (CRRT), and delayed chest closure (p < 0.05 for all). Pre-OHT left-ventricular assist device (adjusted odds ratio [AOR] 2.53; 95% confidence interval [CI] 1.015-6.286; p < 0.046), pre-OHT extracorporeal membrane oxygenation (AOR 14.10; 95% CI 1.38-150.5; p = 0.026) and post-OHT CRRT (AOR 3.98; 95% CI 1.67-9.52; p = 0.002) were found to be independent risk factors for an early infection. A total of 90% of the available susceptibility panels for the gram-negative isolates (26/29) were resistant to the standard peri-operative cephalosporin given.

CONCLUSIONS

Prior mechanical circulatory support and the acute need for CRRT may predispose OHT patients to an infection early in the post-operative period. Evaluation of peri-operative antimicrobial prophylaxis, based on an individual center's resistance panels, may be warranted.

Nocardia infections in the transplanted host

BACKGROUND

Nocardia are uncommon pathogens that disproportionately afflict the immunocompromised host. Epidemiology and outcome data of Nocardia infections in transplant recipients are limited.

METHODS

We performed a retrospective chart review of all patients at Duke University Hospital with a history of solid organ transplant (SOT) or hematopoietic cell transplant (HCT) and at least one positive culture for Nocardia between 1996 and 2013. Our aim was to describe the epidemiology and outcomes of Nocardia infections in the transplanted host.

RESULTS

During the 18-year study period, 51 patients (14 HCT and 37 SOT recipients) had Nocardia infection. Nocardia incidence was stable during the study period in all populations except heart transplants, whose incidence declined. Infection occurred earlier in the HCT group than the SOT group (median time to diagnosis of 153 and 370 days, respectively). In both groups, the most common site involved was the lung. Outcomes were overall poor, especially in the HCT group with a cure rate of 29%. Heart transplant recipients had significantly better overall survival (P < .05) than other patients. Trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis did not provide complete protection from Nocardia infections, nor did it appear to select for resistant Nocardia isolates.

CONCLUSIONS

Infections with Nocardia are typically a late post-transplant complication. The use of TMP-SMX prophylaxis was not associated with TMP-SMX-resistant Nocardia. Overall outcomes remain poor.

Honoring 50 Years of Clinical Heart Transplantation in Circulation

Heart transplantation has become a standard therapy option for advanced heart failure. The translation of heart transplantation from innovative experiments to long-term clinical success has married prescient insights with discipline and organization in the domains of surgical techniques, organ preservation, immunosuppression, organ donation and transplantation logistics, infection control, and long-term graft surveillance. This review explores the key milestones of the past 50 years of heart transplantation and discusses current challenges and promising innovations on the clinical horizon.

A case of central nervous system nocardiosis in a patient with lupus treated with belimumab

Belimumab was approved by the United States Food and Drug Administration in March 2011 as the first biological agent for treating active systemic lupus erythematosus (SLE). To the best of our knowledge, this is the first case report regarding a patient with SLE treated with belimumab who was diagnosed with central nervous system nocardiosis.

Pentamidine in Pneumocystis jirovecii prophylaxis in heart transplant recipients

Despite advances in transplantation techniques and the quality of post-transplantation care, opportunistic infections remain an important cause of complications. Pneumocystis jirovecii (P. jirovecii) is an opportunistic organism, represents an important cause of infections in heart transplantation patients. Almost 2% to 10% of patients undergoing cardiac transplantation have Pneumocystis pneumonia. Prophylaxis is essential after surgery. Various prophylaxis regimes had been defined in past and have different advantages. Trimethoprim/sulfamethoxazole (TMP/SMX) has a key role in prophylaxis against P. jirovecii. Generally, although TMP/SMX is well tolerated, serious side effects have also been reported during its use. Pentamidine is an alternative prophylaxis agent when TMP/SMX cannot be tolerated by the patient. Structurally, pentamidine is an aromatic diamidine compound with antiprotozoal activity. Since it is not effectively absorbed from the gastrointestinal tract, it is frequently administered via the intravenous route. Pentamidine can alternatively be administered through inhalation at a monthly dose in heart transplant recipients. Although, the efficiency and safety of this drug is well studied in other types of solid organ transplantations, there are only few data about pentamidine usage in heart transplantation. We sought to evaluate evidence-based assessment of the use of pentamidine against P. jirovecii after heart transplantation.

Fatal Case of Probable Invasive Aspergillosis after Five Years of Heart Transplant: A Case Report and Review of the Literature

Invasive fungal infections are very common in solid organ transplants and occur most frequently in the first three months after transplant. A 49-year-old female with a history of two remote heart transplants with the most recent one occurring 5 years ago was admitted for increasing shortness of breath, cough, and fever. Computerized tomography (CT) scan of the chest showed left lower lung ground-glass and tree-in-bud opacities. She was started on broad spectrum antibiotics along with ganciclovir and micafungin. Ganciclovir was added due to the patient's past history of CMV infection and empiric fungal coverage with micafungin. Bronchoalveolar lavage (BAL) was performed as her respiratory status worsened and voriconazole was added for possible aspergillosis in combination therapy with micafungin. BAL galactomannan returned positive which was suggestive of aspergillosis. Patient worsened clinically and subsequently succumbed to cardiorespiratory arrest despite our best efforts. It is important to have a high degree of clinical suspicion for invasive aspergillosis in transplant patients even many years after transplant and initiate aggressive therapy due to poor outcomes.

Use of a multiplex polymerase chain reaction system for enhanced bloodstream pathogen detection in thoracic transplantation

BACKGROUND

Bloodstream infections (BSIs) constitute a frequent post-transplant complication in thoracic allograft recipients, especially during the early post-surgical period when patients are under intense immunosuppression. Thus, early and accurate identification of the responsible pathogens is of critical importance for patient survival. In this study we investigated the potential clinical utility of a multiplex real-time polymerase chain reaction (PCR) technology (SeptiFast; Roche Diagnostics) for the detection of BSIs in a cohort of thoracic allograft recipients.

METHODS

Our observational study included analysis of 130 blood samples from 30 thoracic allograft recipients (23 heart and 7 lung) using SeptiFast in parallel with blood culture. Samples were drawn when there were clinical and laboratory signs of BSI. The applied molecular assay has been designed to allow direct detection of a wide panel of Gram-positive and Gram-negative bacteria and fungi in blood samples.

RESULTS

Real-time PCR yielded concurrent negative and positive results with blood culture methodology in 113 (86.9%) and 5 (3.9%) samples, respectively, with 100% concordance in species identification. SeptiFast identified microorganisms in 9 (6.9%) additional samples that were negative by blood culture. The combined use of SeptiFast and blood culture during the early post-transplant period (<2 months) significantly increased the number of positive samples detected to 17.9% (14 of 78) from 7.7% (6 of 78) detected by blood culture alone (p < 0.05). SeptiFast results were available, on average, within 6 hours from sample collection.

CONCLUSIONS

The PCR-based SeptiFast test is a valuable addition to the traditional blood culture method for rapid etiologic diagnosis of BSIs in thoracic transplant recipients, especially during the early post-transplant period.

Staphylococcus aureus bacteremia in solid organ transplant recipients: evidence for improved survival when compared with nontransplant patients

BACKGROUND

Staphylococcus aureus bacteremia (SAB) is an important cause of morbidity and mortality. Herein, we describe the incidence, clinical characteristics, and outcomes of SAB after solid organ transplantation (SOT) and compare these features with non-SOT controls.

METHODS

In a single-center retrospective study, blood cultures positive for S. aureus were obtained from January 1, 2000, to December 31, 2008. Chart review was performed on all SOT recipients with SAB. The social security death index was used to determine all-cause mortality.

RESULTS

Seventy of 2959 patients with SAB were SOT recipients (26 lung, 19 liver, 18 kidney, and seven heart). The overall attack rate of SAB in SOT was 22.9/1000 transplant patients. Early-onset SAB (≤ 90 days) was more frequent in liver recipients (79%), when compared with kidney recipients (17%). All-cause 30-day and 1-year mortality rates were 6% and 28% in SOT, respectively. Pneumonia as a source was associated with an increased 30-day mortality (18% vs. 2%, P = 0.04). Comparing SOT versus non-SOT controls, methicillin resistance was more frequent (86% vs. 52%, P < 0.0001), and duration of bacteremia was longer (mean 3.8 vs. 1.6 days, P < 0.01). SOT status was independently associated with lower risk of 30-day mortality (risk ratio [RR]: 0.37, P = 0.02).

CONCLUSIONS

In our cohort of SOT recipients, SAB was less common than previously reported and surprisingly had lower 30-day mortality, when compared with non-SOT. In SOT recipients, pneumonia as a source of SAB in SOT is associated with an increased 30-day mortality.

[Prophylaxis of cytomegalovirus infection in heart transplantation]

Cytomegalovirus (CMV) is a common complication after heart transplantation, affecting almost half of all recipients. The clinical spectrum of this infection includes, in order of greater to lesser severity, latent infection, asymptomatic viremia, CMV syndrome and CMV disease. CMV is associated with rejection and vascular graft disease and is a major cause of morbidity and mortality. The factors most frequently involved in susceptibility to this infection and its severity are donor and recipient CMV serological status, the intensity of immunosuppression and the type of immunosuppressive agents used. The management strategies of this infection include universal or targeted prophylaxis, preemptive therapy and treatment of established disease. The use of preventive measures significantly reduces the incidence of symtomatic infection or CMV disease, which has been reported to be less than 3% in some recent series.

Outcomes of Pneumocystis jiroveci pneumonia infections in pediatric heart transplant recipients

PJP is known to cause significant morbidity and rarely death in immunosuppressed patients. The prevalence and outcomes of PJP in pediatric solid-organ transplant patients are not well established. This study utilizes data from the PHTS to establish the prevalence and outcome of PJP in pediatric heart transplant recipients. We conducted a retrospective cohort study using data from the PHTS, including data from 24 institutions between January 1, 1993, and December 31, 2004. Infections that occur in PHTS subjects are recorded in a standardized data collection form. The prevalence and outcomes of PJP in pediatric heart transplant recipients were determined. There were a total of 18 patients (1%) with PJP out of the 1854 pediatric heart transplant recipients in the PHTS database. A majority of PJP occurred two months to two yr post-transplant, and patients with PJP had a significantly decreased mortality compared with other fungal infections. PJP is an infrequent complication experienced by pediatric heart transplant recipients. Patients that have experienced PJP have an increased survival compared to patients with other fungal infections, and most PJP occurred within two yr of transplant.

Immunological risk factors for infection after immunosuppressive and biologic therapies

Immunosuppressive and biologic therapies are costly and can involve a considerable risk of infection. Noninvasive diagnostic tools for early prediction of infection before and after administration of these therapies are of major interest. Serial longitudinal immune monitoring would provide data on immunocompetence and complement clinical follow-up protocols. Biomarkers of immune response may be useful to identify patients at risk of developing infection and who could be candidates for immunosuppressant dose reduction. This article focuses on the potential use of biomarkers of immune response to predict development of infection after immunosuppressive and biologic therapies in selected settings of autoimmune disease (rituximab for treatment of rheumatoid arthritis) and solid organ transplantation.

Late presentation of Pneumocystis jiroveci pneumonia after cardiac transplantation

We report the case of a 64-year-old man who had received a heart transplant 9 years previously and was on long-term immunosuppression. He was referred to the intensive care unit of our district general hospital with acute respiratory distress and was diagnosed with community-acquired pneumonia. He was treated with antimicrobials, whose spectrum was extended empirically to cover Pneumocystis jiroveci, and respiratory support was provided with continuous positive airway pressure (CPAP). PCR analysis subsequently confirmed a diagnosis of pneumocystis pneumonia (PCP). Despite appropriate therapy the patient unfortunately died 8 days after admission to the unit. To the author's knowledge, this is the first report in the literature of such a late presentation of PCP after cardiac transplantation. We discuss current diagnostic and treatment strategies for PCP.

Impact of different long-term maintenance immunosuppressive therapy strategies on patients' outcome after heart transplantation

The introduction of cyclosporine in the early 1980s meant a decisive improvement in post-transplant outcomes for all solid-organ transplants and, in particular, it allowed heart transplantation to emerge as a viable therapeutic option for patients with end-stage cardiac failure. Many factors, including recipient and donor selection, organ preservation and the technical aspects of the transplant itself, influence post-operative outcomes following heart transplantation but the continued need to treat the recipient's immune response plays a key role in determining long-term outcomes. Thereby interactions between immunosuppressive drugs used in different combinations play an important role in patients' outcome. After more than two decades, significant controversy still exists as to the best immunosuppressive regimen for long-term maintenance. During the 1990s and 2000s, newer immunosuppressive medications, specifically, tacrolimus, mycophenolate mofetil, sirolimus, everolimus and the IL-2 receptor blockers (daclizumab and basiliximab), were introduced that allow the clinician several options to try to minimize side effects and maximize the desired therapeutic effects. The side effects involve direct organ toxicity (e.g. renal and hepatic dysfunction), metabolic disturbances, (e.g. diabetes, hyperlipidemia and hypertension), neurotoxicity, and several other significant adverse events, such as cholestasis and myelosuppression. Newer immunosuppressive drugs can impair wound healing, induce lung toxicity and produce various cytopenic states. Steroids continue to plague patients with their well-known side effects. This article reviews the current data on the benefits and risks of the various therapeutic regimens available, which are analyzed under three main themes: calcineurin inhibitor based therapies, calcineurin minimization protocols and calcineurin free regimens.