Ventricular assist devices as bridge to heart transplantation: impact on post-transplant infections

Interventional Radiological Treatment of Orthotopic Heart Transplant Complications

Orthotopic heart transplantation is a life-saving procedure that has substantially improved the lives of countless patients since its inception. However, there are several procedure-related complications that require prompt management. Interventional radiology, with its ever expanding toolkit, is a cornerstone of the multidisciplinary team following post-cardiac transplant patients. Percutaneous, endovascular therapy provides minimally invasive, safe, and effective treatments for immediate and delayed cardiac transplant complications and this paper serves to highlight the various management options interventional radiology can provide for orthotopic heart transplantation complications.

IgM-enriched immunoglobulin as adjuvant therapy for heart transplant after infection of left ventricular assist devices

Patients undergoing heart transplantation (HTx) with active infection of left ventricular assist devices (LVAD) are at high risk for postoperative infections. Between 2021 and 2022, five (P1-P5) of a total of n = 44 patients underwent HTx in our department while suffering from LVAD infection. Postoperatively, patients received adjuvant IgM-enriched human intravenous immunoglobulin (IGM-IVIG), consisting of 76% IgG, 12% IgM, and 12% IgA as a novel approach to prevent infective complications. While in P1, P2, and P4, LVAD driveline infection was known before HTx; in P3 and P5, abscess of device pocket was found incidentally during HTx. After a single dose of IGM-IVIG, all patients showed adequate rise in serum immunoglobulins. In the postoperative course, no patient developed infective complications. All patients were successfully discharged and in good condition at the last follow-up. Therefore, IGM-IVIG seems to be an effective adjuvant treatment for patients undergoing HTx with LVAD infections.

Impact of Ventricular Assist Device-Specific Infections on Post-Heart Transplant Infections: A Retrospective Single-Center Study

BACKGROUND

Patients with a ventricular assist device (VAD) who are awaiting heart transplant (HTx) are susceptible to infections. Such infections, especially at the site of the VAD, may increase the risk of severe post-transplant infections and mortality. Information on the characteristics of VAD-specific infections and outcomes in HTx recipients after prolonged periods of LVAD therapy is scarce.

PURPOSE

We aimed to assess the impact of active VAD-specific infections on the incidence of early post-transplant infections and patient survival.

METHODS

We conducted a retrospective review of adult HTx cases at our center between April 2011 and October 2020. Informed consent was waived due to study design. A total of 86 patients were included in this study, among whom 94.2% (n = 81) were bridged with a VAD, and the median VAD support period was 1089 days.

RESULTS

Patients with active VAD-specific infections were significantly more likely to develop severe acute mediastinitis [odds ratio (OR) 14.8, 95% confidence interval (CI) 4.83-45.4, P < .01]. Active VAD infections were significantly related to increased length of intensive care unit stay (22.1 days vs 13.0 days, P = .016) and longer mechanical ventilation periods (324.7 hours vs 113.2 hours, P = .03). The 30-day survival rates for patients with and without post-transplant infections were 100% and 97.1%, respectively.

CONCLUSION

Compared to other risk factors, the presence of active VAD-specific infections increases the risk of early post-heart transplant infections and morbidity, without affecting mortality.

Association between continuous-flow left ventricular assist device infections requiring long-term antibiotic use and post-heart transplant morbidity and mortality

BACKGROUND AND AIM OF STUDY

There exists controversy regarding the impact of infection in patients with a left ventricular assist device (LVAD) on post-heart transplant outcomes. This study evaluated the association between infections during LVAD support and the risk of early and late post-heart transplant infection, rejection, and mortality in transplant recipients bridged with an LVAD.

METHODS

This is a single-center retrospective observational cohort study of consecutive adults supported with a continuous flow LVAD undergoing heart transplant between 2006 and 2019 at the Toronto General Hospital. The grade of LVAD infection was classified as per International Society of Heart and Lung Transplantation guidelines. Patients were divided into three groups: (1) patients with LVAD-specific infection confirmed with positive cultures requiring long-term antibiotic use until the time of transplant; (2) patients with any type of infection in whom antibiotics were stopped at least 1 month before transplant; (3) patients without any infections between LVAD implant and transplant. Logistic regression and Cox proportional hazard models were used to evaluate early- and late-post transplant outcomes, respectively.

RESULTS

We included 75 LVAD recipients: 16 (21%) patients had a chronic LVAD-related infection on suppressive antibiotics, 30 (40%) had a resolved infection, and 29 (39%) had no infections. During a median post-transplant follow-up time of 4 (2 to 7) years, 65 (87%) patients developed infections, 43 (64%) rejections, and 17 (23%) deaths. Both short- and long-term risks of infection, rejection, and mortality did not differ significantly among the groups.

CONCLUSION

LVAD patients with infections did not have a significantly higher risk of infection, rejection, or mortality at any time point after transplant.

Ventricular Assist Device-Specific Infections

Ventricular assist device (VAD)-specific infections, in particular, driveline infections, are a concerning complication of VAD implantation that often results in significant morbidity and even mortality. The presence of a percutaneous driveline at the skin exit-site and in the subcutaneous tunnel allows biofilm formation and migration by many bacterial and fungal pathogens. Biofilm formation is an important microbial strategy, providing a shield against antimicrobial treatment and human immune responses; biofilm migration facilitates the extension of infection to deeper tissues such as the pump pocket and the bloodstream. Despite the introduction of multiple preventative strategies, driveline infections still occur with a high prevalence of ~10-20% per year and their treatment outcomes are frequently unsatisfactory. Clinical diagnosis, prevention and management of driveline infections are being targeted to specific microbial pathogens grown as biofilms at the driveline exit-site or in the driveline tunnel. The purpose of this review is to improve the understanding of VAD-specific infections, from basic "bench" knowledge to clinical "bedside" experience, with a specific focus on the role of biofilms in driveline infections.

Impact of Induction Immunosuppression on Post-Transplant Outcomes of Patients Bridged with Contemporary Left Ventricular Assist Devices

For patients bridged to transplant (BTT) with left ventricular assist devices (LVAD), data regarding the use of induction immunosuppressive therapy remain limited. The objectives of the current study were to describe the current trends and clinical consequences of IT in patients BTT with LVAD. The United Network of Organ Sharing database was queried to identify adult, single-organ heart transplant recipients who were BTT with LVAD between 2008 and 2018. Propensity score matching was then used to balance clinical covariates between those patient who did and did not receive IT. The primary outcomes of interest were graft survival, hospitalization for rejection and infection, and freedom from transplant coronary artery disease (TCAD). In the overall cohort, 49.1% (n = 3,978) received IT, with basiliximab being the most commonly used agent followed by antithymocyte globulin. After propensity score matching, 4,388 patients (2,194 without induction and 2,194 with induction) were identified. Between those who did and did not receive IT, there was no significant difference in graft survival, freedom from hospitalization for rejection, and freedom from hospitalization for infection. Patients who received IT experienced increased freedom from TCAD (p = 0.004) with unadjusted hazard ratio of 0.81 (95% Cardiac Index: 0.70-0.93). For freedom from TCAD, antithymocyte globulin was associated with better outcomes than basiliximab (80.2% vs. 73.1% at 5 years, log rank p value = 0.004). In a sensitivity analysis, there was no significant increase in hospitalization for infection in those patients with an infected LVAD before transplant. Use of induction therapy in patients BTT with LVAD appears to be safe and feasible, without a significant increase in the risk of infection or rejection, even in those patients with pretransplant device-related infections. IT, particularly antithymocyte globulin, was associated with increased time to development of TCAD. Routine use of IT in patients BTT with LVAD may be considered, and further randomized control trials are warranted to further support these data.

Outcomes of patients with infection related to a ventricular assist device after heart transplantation

BACKGROUND

Despite significant advances in durable mechanical support survival, infectious complications remain the most common adverse event after ventricular assist device (VAD) implantation and the leading cause of early death after transplantation. In this study, we aim to describe our local infectious epidemiology and review short-term survival and infectious incidence rates in the post-transplantation period and assess risk factors for infectious episodes after transplantation.

METHODS

Retrospective single-center study of all consecutive adult heart transplant patients from 2008 to 2017. Survival data were estimated and summarized using the Kaplan-Meier method. We quantified and evaluated the difference in the incidence rate between patients with and without infection using a Fine-Gray model. The outcome of interest is the time to first infection diagnosis with post-transplant death as the competing event.

RESULTS

Among 278 heart transplant patients, 74 (26.5%) underwent LVAD implantation. Twenty-one patients (28.3%) developed an infection while supported by an LVAD. When compared to patients supported by an LVAD without a preceding infection, BMI was significantly greater (31.2 vs 27.8 kg/m² , P = .03). Median follow-up post-transplantation was 3.01 years. Significant risk factors for the competing risk regression for infection after heart transplantation include LVAD infection (HR 1.94, [95% CI] 1.11-3.39, P = .020) and recipient COPD (HR 2.14, [95% CI] 1.39-3.32, P = .001) when adjusted for recipient age, gender, hypertension, diabetes mellitus, and body mass index.

CONCLUSIONS

Patients with LVAD-related infection had a significantly increased risk of infectious complications after heart transplantation. Further research on the avoidance of induction agents and reduced maintenance immunosuppression in this patient population is warranted.

VAD infection during bridge-to-transplant, unique aspects of treatment and prevention

PURPOSE OF REVIEW

VAD infections remain a frequent complication of VAD care and can markedly affect patient management before and after transplantation. This review highlights the standard-of-care approaches offered by recent guidelines as well as published data that may improve the care for patients with these challenging and often persistent infections.

RECENT FINDINGS

Prevention and management of VAD infections has become more standardized with updated consensus guidelines published in 2017. Unfortunately, advanced devices have not markedly affected the incidence of VAD infection. Efforts to improve, yet streamline, the prevention of VAD-specific infections are ongoing. However, the data provided in the best of recent publications are rarely effectively comparative. Granular data on management strategies are limited to a few studies. Nevertheless, several publications provide more detailed posttransplant outcomes for patients with pretransplant VAD infections and demonstrate overall excellent posttransplant survival.

SUMMARY

Prevention and management of VAD-specific and VAD-related infections are the ongoing work of all VAD programs. Consensus guidelines are a marker of progress for this field. Despite very good posttransplant outcomes for these patients, more granular data are required to understand how such patients arrive successfully to transplantation and how their posttransplant course is affected.

Ventricular assist device-related infections and solid organ transplantation-Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

The Infectious Diseases Community of Practice of the American Society of Transplantation has published evidenced-based guidelines on the prevention and management of infectious complications in SOT recipients since 2004. This updated guideline reviews the epidemiology of ventricular assist device (VAD) infections and provides recommendations for the management and prevention of these infections. Almost one half of those awaiting heart transplantation are supported with VADs. Despite advances in device technologies, VAD infections commonly complicate mechanical circulatory support and remain typified by common components and anatomic locations. These infections have important implications for transplant candidates, most notably increased wait-list mortality. Strategic management of these infections is crucial for successful transplantation. Coincidentally, explantation of all VAD components at the time of transplantation is often the definitive cure for the device-associated infection. Highlighted in this updated guideline is the reported success of transplantation in patients with a variety of pre-existing VAD infections and guidance on post-transplant management strategies.

Infectious complications following heart transplantation in the era of high-priority allocation and extracorporeal membrane oxygenation

Background

Infectious complications are a major cause of morbidity and mortality after heart transplantation (HT). However, the epidemiology and outcomes of these infections in the recent population of adult heart transplant recipients have not been investigated.

Methods

We conducted a single-center retrospective study on infectious complications occurring within 180 days following HT on consecutive heart transplant recipients, from January 2011 to June 2015 at Bichat University Hospital in Paris, France. Risk factors for non-viral infections occurring within 8, 30 and 180 days after HT were investigated using competing risk analysis.

Results

Overall, 113 patients were included. Fifty-eight (51%) HTs were high-priority allocations. Twenty-eight (25%) patients had an extracorporeal membrane oxygenation (ECMO) support at the time of transplantation. Ninety-two (81%) patients developed at least one infection within 180 days after HT. Bacterial and fungal infections (n = 181 episodes) occurred in 80 (71%) patients. The most common bacterial and fungal infections were pneumonia (n = 95/181 episodes, 52%), followed by skin and soft tissue infections (n = 26/181, 14%). Multi-drug-resistant bacteria were responsible for infections in 21 (19%) patients. Viral infections were diagnosed in 44 (34%) patients, mostly Cytomegalovirus infection (n = 39, 34%). In multivariate subdistribution hazard model, prior cardiac surgery (subdistribution hazard ratio sHR = 2.7 [95% CI 1.5–4.6] p < 0.01) and epinephrine or norepinephrine at the time of HT (sHR = 2.3 [95% CI 1.1–5.2] p  = 0.04) were significantly associated with non-viral infections within 8 days after HT. Prior cardiac surgery (sHR = 2.5 [95% CI 1.4–4.4] p < 0.01), recipient age over 60 years (sHR = 2.0 [95% CI 1.2–3.3] p < 0.01) and ECMO following HT (sHR = 1.7 [95% CI 1.0–2.8] p = 0.04) were significantly associated with non-viral infection within 30 days after HT, as well as within 180 days after HT.

Conclusion

This study confirmed the high rate of infections following HT. Recipient age, prior cardiac surgery and ECMO following HT were independent risk factors for early and late bacterial and fungal infections.

Electronic supplementary material

The online version of this article (10.1186/s13613-019-0490-2) contains supplementary material, which is available to authorized users.

The impact of infection among left ventricular assist device recipients on post-transplantation outcomes: A retrospective review

INTRODUCTION

Left ventricular assist device (LVAD) infections are common, and the consequences of LVAD infections on orthotopic heart transplantation (OHT) outcomes are not well described.

AIMS

The aim of this study was to describe clinical characteristics and evaluate risk factors for developing LVAD infections, and examine outcomes of LVAD-specific infections (VSI) after OHT.

METHODS

We retrospectively investigated the records of 74 consecutive patients at two institutions who had undergone LVAD placement and subsequent OHT between January 2007 and December 2012.

RESULTS

Forty-six of 74 (62%) LVAD recipients who underwent OHT had pre-transplant infections, and 18 (24%) had LVAD-specific infection (VSI), of which 71% were caused by gram-negative organisms. Of pre-transplant non-LVAD infections, Clostridium difficile infection (CDI) was the most common (26%) followed by urinary tract infection (UTI, 16%) and pneumonia (PNA 15%). Univariate analysis comparing subjects with VSI to those without VSI showed a significant association with time spent outside the hospital prior to transplantation (median 231.8 days vs 142.2 days, P < 0.03) and total time between VAD placement and OHT (244.0 days and 150.5 days, P < 0.002). Logistic regression was performed and significant predictors for VAD-related infection were age and the presence of diabetes, with type of device as an effect modifier. Six months post-OHT survival was not significantly affected by the presence of VSI prior to transplant. There was a trend toward an association between the presence of any infection and post-transplant rejection (P < 0.09). There were 10 post-transplant deaths by 6 months. Of these deaths, 4/10 (40%) were cardiopulmonary and 6/10 (60%) were related to infections.

CONCLUSIONS

Advanced age and presence of diabetes were predictors of VSI, as well as type of VAD device, although device choice is likely affected by many clinical factors including age and comorbidities, as well as institution-specific preferences. VSI was not associated with a decrease in 6-month post-OHT survival. However, infections remain the major causes of death by 6 months post-transplant. Certain infections are associated with an increased risk of rejection, which merits further investigation.