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

Impact of type of mechanical circulatory support before transplant on postorthotopic heart transplantation infections

BACKGROUND

Infections after orthotopic heart transplantation (OHT) cause significant morbidity and mortality. Concurrent with increased pre-OHT temporary mechanical circulatory support (MCS), there have been recent concerns of a perceived increase in infections post-OHT. We examined the association between pre-OHT temporary versus durable MCS and post-OHT infection.

METHODS

We performed a single-center retrospective review of patients who received OHT at Tufts Medical Center between January 2014 and April 2022. Our composite outcome was the occurrence of bacteremia, invasive fungal infections, opportunistic infections, or skin/soft tissue infections of device sites within 1-year post-OHT. We used Cox proportional hazards models to assess the relationship between the type of pre-OHT MCS and time to the first infection, treating death from other causes as a competing risk. We addressed confounding with 2 statistical methods: propensity score (PS) with inverse probability weighting (IPW) and an instrumental variable (IV) analysis.

RESULTS

Of the 320 OHT recipients, 268 required MCS before OHT; 192 were managed with durable MCS and 76 with temporary MCS. Patients receiving pre-OHT temporary MCS had no difference in time to first infection (unadjusted hazard ratio [HR] 0.77, 95% CI 0.41-1.44) compared to durable MCS. Results were similar in the model employing PS with IPW (HR 0.61, 95% CI 0.29-1.27) and the IV analysis (HR 0.28, 95% CI 0.26-2.36).

CONCLUSIONS

Pre-OHT temporary MCS was not associated with the composite outcome of bacteremia, invasive fungal infections, opportunistic infections, or skin/device site infections post-OHT compared to durable MCS in this single-center cohort.

Risk factors, diagnostic methods and treatment of infection in adult patients undergoing left ventricular assist device implantation: A scoping review

BACKGROUND

Evidence on infection risk factors is scarce, and precise localization of the site of infection and its treatment remain clinically challenging.

OBJECTIVES

This study aimed to map the recommendations for adult patients undergoing left ventricular assist device implantation.

DESIGN

This is a scoping review, registered in the Open Science Framework under DOI10.17605/OSF.IO/Q76B3(https://osf.io/q76b3/).

METHOD

This is a scoping review limited to the period between 2015 and 2022.The results of this scoping review are discussed and presented separately in 3 articles. This second paper synthesizes research evidence on the risk factors, diagnostic methods and treatment of infection in adult patients undergoing left ventricular assist device implantation.

RESULTS

The initial searches identified 771 studies. Sixty-nine patients met the eligibility criteria and were included in the scoping review. Forty-three articles addressing the risk factors, diagnosis and treatment of infection were included to answer the questions of this review.

CONCLUSION

Obesity has been shown to be the most common risk factor for the described process of infection by left ventricular assist devices.18F-fluorodeoxyglucose positron emission tomography showed high sensitivity in detecting cardiac device infection, and labeled leukocyte or gallium citrate-67 scintigraphy showed high specificity for left ventricular assist device infections; therefore, it can help differentiate infection from inflammation, particularly in patients with equivocal fluorodeoxyglucose positron emission tomography. Also, this review brings and discusses the limitations and strengths of diagnostic tests, the knowledge regarding the risk factors for left ventricular assist device infection, the therapeutic heterogeneity, the methodological issues of the studies, and the vast opportunity for future research on left ventricular assist device.

IMPLICATIONS FOR CLINICAL PRACTICE

Ventricular assist device professionals should evaluate risk factors prior to device implantation and periodically.18F-fluorodeoxyglucose positron emission tomography should be considered as diagnostic tool in detecting superficial and deep driveline infections. Early treatment, including chronic suppressive therapy and serial surgical debridement, combined with driveline exteriorization and delayed driveline relocation may constitute a potential therapeutic strategy for deep driveline infections.

Pneumonia After Cardiovascular Surgery: Incidence, Risk Factors and Interventions

Postoperative pneumonia (POP) is prevalent in patients undergoing cardiovascular surgery, associated with poor clinical outcomes, prolonged hospital stay and increased medical costs. This article aims to clarify the incidence, risk factors, and interventions for POP after cardiovascular surgery. A comprehensive literature search was performed to identify previous reports involving POP after cardiovascular surgery. Current situation, predictors and preventive measures on the development of POP were collected and summarized. Many studies showed that POP was prevalent in various cardiovascular surgical types, and predictors varied in different studies, including advanced age, smoking, chronic lung disease, chronic kidney disease, cardiac surgery history, cardiac function, anemia, body mass index, diabetes mellitus, surgical types, cardiopulmonary bypass time, blood transfusion, duration of mechanical ventilation, repeated endotracheal intubation, and some other risk factors. At the same time, several targeted interventions have been widely reported to be effective to reduce the risk of POP and improve prognosis, including preoperative respiratory physiotherapy, oral care and subglottic secretion drainage. Through the review of the current status, risk factors and intervention measures, this article may play an important role in clinical prevention and treatment of POP after cardiovascular surgery.

Prevention of infection and optimizing vaccination in the solid organ transplant candidate and recipient

PURPOSE OF REVIEW

Infections can result in serious complications in solid organ transplant (SOT) patients. The need to remain up to date on recommendations on screening, vaccinations, and chemoprophylaxis is paramount in the management of SOT patients. The goal of this review is to provide an overview of current recommendations for the prevention of infections and optimization of vaccinations from the pretransplant through posttransplant periods.

RECENT FINDINGS

There is an emphasis on thorough pretransplant evaluation to guide clinicians and pretransplant testing based on epidemiological and endemic risk factors. Additionally, recent studies on vaccine safety and efficacy of newer vaccine formulations in SOT recipients are addressed.

SUMMARY

This review provides insight on updated recommendations for pretransplant screening, new data on vaccine optimization in SOT recipients and posttransplant prophylaxis. Further research is needed in order to improve preventive measures including screening tests, vaccines, and chemoprophylaxis.

Contemporary Management Strategies in VAD Infection

PURPOSE OF REVIEW

The use of durable ventricular assist devices (VAD) to manage end-stage heart failure is increasing, but infection remains a leading cause of morbidity and mortality among patients with VAD. In this review, we synthesize recent data pertaining to the epidemiology, diagnosis, management, and prevention of VAD infections, discuss transplant considerations in patients with VAD infections, and highlight remaining knowledge gaps. We also present a conceptual framework for treating clinicians to approach these infections that draws on the same principles that guide the treatment of analogous infections that occur in patients without VAD.

RECENT FINDINGS

Despite advances in device design, surgical techniques, and preventative interventions, more than a third of VAD recipients still experience infection as an adverse outcome. Positron emission tomography has emerged as a promising modality for identifying and characterizing VAD infections. High-quality data to support many of the routine therapeutic strategies currently used for VAD infections-including suppressive antibiotic therapy, surgical debridement/device exchange, and novel antimicrobials for emerging multidrug-resistant organisms-remain limited. Although pre-transplant VAD infection may impact some early transplant outcomes, transplantation remains a viable option for patients with most types of VAD infection. Standardized definitions of VAD infection applied to large registry datasets have yielded key insights into the epidemiology of infectious complications among VAD recipients, but more prospective studies are needed to evaluate the effectiveness of existing and novel diagnostic and therapeutic strategies.

Dynamic Forecasts of Survival for Patients Living With Destination Left Ventricular Assist Devices: Insights From INTERMACS

Background Left ventricular assist devices (LVADs) improve outcomes in patients with end-stage heart failure and are increasingly implanted for destination therapy. We describe dynamic estimates of event-free survival with conditional survival probabilities in a destination therapy LVAD population. Methods and Results We studied 8245 adult patients in INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) implanted with a continuous-flow destination therapy LVAD. The composite primary end point was death, device exchange or removal, or heart transplantation. Conditional survival probabilities were calculated and stratified by implantation characteristics and nonfatal adverse events experienced within the first year after implant. Probabilities of surviving an additional 1 to 3 years were numerically higher after longer prior event-free survival. INTERMACS profile 1, extracorporeal membrane oxygenation support, prior or concomitant surgery, and dialysis within 48 hours of implantation were associated with significantly lower event-free survival in the first year but did not impact event-free survival beyond then. For patients who experienced a nonfatal adverse event within the first year, subsequent 1-year conditional survival was lower than in the absence of that event for stroke (65% [95% CI, 57%-73%] versus 75% [95% CI, 73%-77%]; P<0.001), device-related infection (64% [95% CI 57%-71%] versus 76% [95% CI, 74%-78%]; P<0.001), and pump thrombosis or malfunction (64% [95% CI, 57%-70%] versus 76% [95% CI, 74%-78%]; P<0.001). Conclusions Conditional survival in patients with destination therapy LVADs improves over time, even for patients with unfavorable implantation characteristics. However, LVAD-related complications including stroke, device-related infection, and pump thrombosis or malfunction have an enduring negative influence on dynamic estimates of long-term prognosis.

Screening of donors and recipients for infections prior to solid organ transplantation

PURPOSE OF REVIEW

This review is a brief overview of current guidelines on screening donors and candidates for bacterial, fungal, parasitic and viral infections prior to solid organ transplantation. The pretransplant period is an important time to evaluate infection exposure risk based on social history as well as to offer vaccinations.

RECENT FINDINGS

One of the major changes in the past few years has been increased utilization of increased Public Health Service risk, HIV positive, and hepatitis C-positive donors. There has also been increased attention to donor and recipient risks for geographically associated infections, such as endemic fungal infections and flaviviruses.

SUMMARY

Screening for donors and candidates prior to organ transplantation can identify and address infection risks. Diagnosing infections in a timely manner can help guide treatment and additional testing. Use of necessary prophylactic treatment in organ recipients can prevent reactivation of latent infections and improve posttransplant outcomes.

Heart Transplantation After Ventricular Assist Device Therapy: Benefits, Risks, and Outcomes

Heart transplantation is an established treatment for end-stage heart failure. Due to the increase in demand and persistent scarcity of organ, mechanical circulatory devices have played a major role in therapy for advanced heart failure. Usage of left ventricular assist device (LVAD) has gone up from 6% in 2006 to 43% in 2013 as per the United Network of Organ Sharing database. Majority of patients presenting for a heart transplantation are often bridged with an assist device prior for management of heart failure while on wait-list. On one hand, it is well established that LVADs improve survival on wait-list; on the other hand, the effect of LVAD on morbidity and survival after a heart transplantation is still unclear. In this article, we review the available literature and attempt to infer the outcomes given the risks and benefits of heart transplantation with prior LVAD patients.

Racial Disparities and Outcomes After Left Ventricular Assist Device Implantation as Bridge to Transplantation or Destination Therapy

OBJECTIVE

We sought to investigate outcomes after left ventricular assist device (LVAD) implantation in advanced heart failure patients stratified by race.

METHODS

Patients who had LVADs inserted at a single center as a bridge to transplant (BTT) or destination therapy (DT) were divided into 3 groups based on race: Caucasian, African American (AA), and Hispanic. Postoperative outcomes including complications, discharge disposition, and survival at defined time points were compared. Cox proportional hazards were used to identify factors associated with 1-year all-cause survival.

RESULTS

A total of 158 patients who had LVADs as BTT (n = 63) and DT (n = 95) were studied. Of these, 56% (n = 89) were Caucasians, 35% (n = 55) were AA, and 9% (n = 14) were Hispanics. AA patients had higher BMI and lower socioeconomic status and educational level, and were more likely to be single or divorced. Operative outcomes were similar among all 3 groups. Unadjusted 30-day, 6-month, 1-year, and 2-year survival rates for Caucasians versus AA versus Hispanics were 82% versus 89% versus 93%, P = 0.339; 74% versus 80% versus 71%, P = 0.596; 67% versus 76% versus 71%, P = 0.511; and 56% versus 62% versus 68%, P = 0.797. On multivariate analysis, device-related infection, malfunction, and abnormal rhythm were factors associated with overall all-cause mortality.

CONCLUSION

AA patients who undergo LVAD implantation as BTT or DT have lower socioeconomic status and educational level compared to their Caucasian or Hispanic counterparts. These differences, however, do not translate into postimplant survival outcomes.