Complications of left ventricular assist devices causing high urgency status on waiting list: impact on outcome after heart transplantation

The Predictive Role of Metabolic Volume Segmentation Compared to Semiquantitative PET Parameters in Diagnosis of LVAD Infection using [18F]FDG Imaging

PURPOSE

Left ventricular assisting device (LVAD) is a vital mechanical circulatory assist device for patients with end-stage heart disease, serving as either a bridge to transplantation or palliative destination therapy. Yet device infection represents a major lethal complication, warranting a multi-step, complex therapy approach including an urgent device exchange or heart transplantation. Still, timely diagnosis of site and extent of VAD-specific infection for a proper therapy planning poses challenges in regular clinical care. This single-center, retrospective study aimed to evaluate the impact of volumetric PET parameters with different thresholding compared to semiquantitative PET parameters for accurate diagnosis of VAD-specific infection.

PROCEDURES

Seventeen patients (1 female, 16 males; mean age 57 ± 11 years) underwent [18F]FDG imaging for suspected VAD-specific infection between April 2013 and October 2023. Various metabolic and volumetric PET parameters with different thresholding were collected for specific LVAD components including driveline entry point, subcutaneous driveline, pump pocket, inner cannula and outflow tract. Microbiology and clinical follow-up were used as the final diagnosis standard.

RESULTS

Nine of eleven patients with VAD-specific infection underwent urgent heart transplantation, and one had a surgical revision of LVAD. Two patients had non-VAD specific infections, and two had non-VAD related infections. Metabolic burden determination using a fixed absolute threshold provided the best outcome compared to relative thresholding or other metabolic SUV parameters. The total metabolic tumor volume (MTV) cutoff value was 9.3 cm3, and the corresponding sensitivity, specificity, accuracy, and AUC were 90.0%, 71.43%, 82.5%, and 0.814 (95% CI 0.555-0.958), respectively. The total lesion glycolysis (TLG) was 30.6, and the corresponding sensitivity, specificity, accuracy, and AUC were 90.0%, 71.4%, 82.5%, and 0.829 (95% CI 0.571-0.964), respectively.

CONCLUSIONS

Volumetric PET parameters with fixed absolute thresholding appear to be a valuable auxiliary tool in the evaluation of [18F]FDG imaging to enhance the diagnostic accuracy of VAD-specific infection.

Durable left ventricular assist devices as a bridge to transplantation: what to expect along the way?

INTRODUCTION

The scarcity of donors coupled with the improvements in left ventricular assist devices (LVAD) technology has led to the use of LVAD as a bridge to transplantation (BTT).

AREAS COVERED

The authors provide an overview of the current status of LVAD BTT implantation with special focus ranging from patient selection and pre-implantation optimization to post-transplant outcomes.

EXPERT OPINION

The United Network for Organ Sharing 2018 policy amendment resulted in a significant reduction in the number of LVADs used for BTT in the US. To overcome this issue, modifications in the US allocation policy to consider factors such as days on device support, age, and type of complications may be necessary to potentially increase implantation rates.

LVAD as a Bridge to Transplantation-Current Status and Future Perspectives

Heart failure (HF) is a common disease associated with high morbidity and mortality rates despite advanced pharmacological therapies. Heart transplantation remains the gold standard therapy for end-stage heart failure; however, its application is curtailed by the persistent shortage of donor organs. Over the past two decades, mechanical circulatory support, notably Left Ventricular Assist Devices (LVADs), have been established as an option for patients waiting for a donor organ. This comprehensive review focuses on elucidating the benefits and barriers associated with this application. We provide an overview of landmark clinical trials that have evaluated the use of LVADs as a bridge to transplantation therapy, with a particular focus on post-transplant outcomes. We discuss the benefits of stabilizing patients with these systems, weighing associated complications and limitations. Further technical advancements and research on optimal implantation timing are critical to ultimately improve outcomes and securing quality of life. In a world where the availability of donor organs remains constrained, LVADs are an increasingly important piece of patient care, bridging the critical gap to transplantation in advanced heart failure management.

Advanced Heart Failure: Therapeutic Options and Challenges in the Evolving Field of Left Ventricular Assist Devices

Heart Failure is a chronic and progressively deteriorating syndrome that has reached epidemic proportions worldwide. Improved outcomes have been achieved with novel drugs and devices. However, the number of patients refractory to conventional medical therapy is growing. These advanced heart failure patients suffer from severe symptoms and frequent hospitalizations and have a dismal prognosis, with a significant socioeconomic burden in health care systems. Patients in this group may be eligible for advanced heart failure therapies, including heart transplantation and chronic mechanical circulatory support with left ventricular assist devices (LVADs). Heart transplantation remains the treatment of choice for eligible candidates, but the number of transplants worldwide has reached a plateau and is limited by the shortage of donor organs and prolonged wait times. Therefore, LVADs have emerged as an effective and durable form of therapy, and they are currently being used as a bridge to heart transplant, destination lifetime therapy, and cardiac recovery in selected patients. Although this field is evolving rapidly, LVADs are not free of complications, making appropriate patient selection and management by experienced centers imperative for successful therapy. Here, we review current LVAD technology, indications for durable MCS therapy, and strategies for timely referral to advanced heart failure centers before irreversible end-organ abnormalities.

Evolution of Mechanical Circulatory Support for advanced heart failure

This comprehensive review highlights the significant advancements in Left Ventricular Assist Device (LVAD) therapy, emphasizing its evolution from the early pulsatile flow systems to the cutting-edge continuous-flow devices, particularly the HeartMate 3 (HM3) LVAD. These advancements have notably improved survival rates, reduced complications, and enhanced the quality of life (QoL) for patients with advanced heart failure. The dual role of LVADs, as a bridge-to-transplantation and destination therapy is discussed, highlighting the changing trends and policies in their application. The marked reduction in hemocompatibility-related adverse events (HRAE) with the HM3 LVAD, compared to previous models signifies ongoing progress in the field. Challenges such as managing major infections are discussed, including innovative solutions like energy transfer systems aimed at eliminating external drivelines. It explores various LVAD-associated complications, including HRAE, infections, hemodynamic-related adverse events, and cardiac arrhythmias, and underscores emerging strategies for predicting post-implantation outcomes, fostering a more individualized patient care approach. Tools such as the HM3 risk score are introduced for predicting survival based on pre-implant factors, along with advanced imaging techniques for improved complication prediction. Additionally, the review highlights potential new technologies and therapies in LVAD management, such as hemodynamic ramp tests for optimal speed adjustment and advanced remote monitoring systems. The goal is to automate LVAD speed adjustments based on real-time hemodynamic measurements, indicating a shift towards more effective, patient-centered therapy. The review concludes optimistically that ongoing research and potential future innovations hold the promise of revolutionizing heart failure management, paving the way for more effective and personalized treatment modalities.

Post-transplant survival with pre-transplant durable continuous-flow mechanical circulatory support in a Swiss cohort of heart transplant recipients

BACKGROUND

Worldwide, almost half of all heart transplantation candidates arrive today at their transplant operation with durable continuous-flow mechanical circulatory support (CF-MCS). This evolution is due to a progressive increase of waiting list time and hence an increased risk of haemodynamic worsening. Longer duration of CF-MCS is associated with a higher risk of device-related complications with potential adverse impact on post-transplant outcome as suggested by recent results from the United Network of Organ Sharing of the United States.

METHODS

A 2-centre Swiss heart transplantation programme conducted a retrospective observational study of consecutive patients of theirs who underwent a transplant in the period 2008-2020. The primary aim was to determine whether post-transplant all-cause mortality is different between heart transplant recipients without or with pre-transplant CF-MCS. The secondary outcome was the acute cellular rejection score within the first year post-transplant.

RESULTS

The study participants had a median age of 54 years; 38/158 (24%) were females. 53/158 study participants (34%) had pre-transplant CF-MCS with a median treatment duration of 280 days. In heart transplant recipients with pre-transplant CF-MCS, the prevalence of ischaemic cardiomyopathy was higher (51 vs 32%; p = 0.013), the left ventricular ejection fraction was lower (20 vs 25; p = 0.047) and pulmonary vascular resistance was higher (2.3 vs 2.1 Wood Units; p = 0.047). Over the study period, the proportion of heart transplant recipients with pre-transplant CF-MCS and the duration of pre-transplant CF-MCS treatment increased (2008-2014 vs 2015-2020: 22% vs 45%, p = 0.009; increase of treatment days per year: 34.4 ± 11.2 days, p = 0.003; respectively). The primary and secondary outcomes were not different between heart transplant recipients with pre-transplant CF-MCS or direct heart transplantation (log-rank p = 0.515; 0.16 vs 0.14, respectively; p = 0.81).

CONCLUSION

This data indicates that the strategy of pre-transplant CF-MCS with subsequent orthotopic heart transplantation provides post-transplant outcomes not different to direct heart transplantation despite the fact that the duration of pre-transplant assist device treatment has progressively increased.

Increased severe primary graft dysfunction in left ventricular assist device patients following united network for organ sharing allocation changes

INTRODUCTION

In 2018, the United Network for Organ Sharing (UNOS) implemented a new heart allocation system which prioritized patients on temporary support devices and left-ventricular assist device (LVAD) patients with complications. These changes have the potential to impact outcomes for patients bridged to transplant with an LVAD.

METHODS

We performed a retrospective study of 168 adult heart transplant recipients at our center between 2016 and 2020 evaluating post-transplant outcomes before and after UNOS allocation changes. Donor and recipient data were retrieved from chart review and national databases. The primary outcome of this study was severe primary graft dysfunction (PGD) with secondary outcomes of 30-day readmission, 30-day mortality, and 1-year mortality.

RESULTS

Incidence of severe PGD was similar in the overall cohort before and after the changes (10% vs. 15%, respectively, p = .3) and increased in the LVAD-bridged cohort (12% vs. 40%, respectively, p < .01). Secondary outcomes of readmission and survival were similar between all groups. Blood transfusion was predictive of severe PGD in multivariable modeling (OR 1.3 [1.11-1.59], p < .01).

Surgical Interventions for Late Aortic Valve Regurgitation Associated with Continuous Flow-Left Ventricular Assist Device Therapy: Experience Gained and Lessons Learned

This study aimed to investigate the outcomes of surgical interventions for symptomatic moderate-to-severe aortic regurgitation (AR), including aortic valve replacement (AVR) and repair (AVP), in 184 patients who underwent continuous flow-left ventricular assist device (Cf-LVAD) implantation as a bridge-to-transplant (BTT) between November 2007 and April 2020. Ten patients (median age, 34 (25-41) years; 60% men) underwent surgical interventions (AVR, n = 6; AVP, n = 4) late after cf-LVAD implantation. The median duration after the device implantation was 34 (24-44) months. Three patients required additional tricuspid valve repair. Aortic valve suturing resulted in severe recurrent AR 6 months postoperatively, due to leaflet cutting in one patient. Seven patients with AVR survived without regurgitation during the study period, except for one non-survivor complicated by liver failure due to postoperative right heart failure. Therefore, six patients after AVP (n = 4) and AVR (n = 2) underwent successful heart transplantation 7 (4-13) months after aortic intervention. Kaplan-Meier analysis showed no significant difference in overall survival through 5 years after cf-LVAD implantation, regardless of the surgical AV intervention chosen (log-rank test, p = 0.86). In conclusion, surgical interventions (AVR or AVP) for patients with an ongoing cf-LVAD are safe, effective, and viable options.

Impact of Left Ventricular Assist Devices on Days Alive and Out of Hospital in Hemodynamically Stable Patients with End-Stage Heart Failure: A Propensity Score Matched Study

The two main surgical options to treat end-stage heart failure are heart transplantation (HTx) or left ventricular assist device (LVAD) implantation. In hemodynamically stable patients, the decision for HTx listing with or without LVADs is challenging. We analyzed the impact of both options on days alive and out of hospital (DAOH) and survival. This retrospective study screened all patients with HTx or LVAD implantation between 2010 and 2020. The main inclusion criterion was hemodynamic stability defined as independence of intravenous inotropic/vasoactive support at decision. Propensity score matching (PSM) was performed. The primary endpoint was DAOH within one year after the decision. Secondary endpoints included survival, duration until HTx, and hospitalizations. In total, 187 patients received HTx and 227 patients underwent LVAD implantation. There were 21 bridge-to-transplant (BTT)-LVAD patients (implantation less than a month after HTx listing or listing after implantation) and 44 HTx-waiting patients included. PSM identified 17 matched pairs. Median DAOH at one year was not significantly different between the groups (BTT-LVAD: median 281, IQR 89; HTx waiting: median 329, IQR 74; p = 0.448). Secondary endpoints did not differ significantly. Our data suggest that BTT-LVAD implantation may not be favorable in terms of DAOH within one year for hemodynamically stable patients compared to waiting for HTx. Further investigations on quality of life and long-term outcomes are warranted.

Durable mechanical circulatory support as bridge to heart transplantation

PURPOSE OF REVIEW

Durable mechanical circulatory support (MCS) technology has changed over time as devices have evolved from pulsatile to continuous flow support. In this review, we discuss recent data and substantial changes to current practice as it pertains to the subject of current era durable left ventricular assist devices (LVADs) as a bridge to heart transplantation.

RECENT FINDINGS

The results of heart transplantation in patients bridged with durable LVAD support are satisfactory even after prolonged duration of support. Reports of recent experience with LVAD related infection suggest that this complication has limited impact on post-transplant outcomes. Important sex-related disparities continue to exist following durable LVAD implantation. Recent changes in the United Network for Organ Sharing donor heart allocation policy have resulted in a drastic decline in the use of durable LVAD support for Bridge to Transplant in the United States.

SUMMARY

Durable MCS in the form of LVAD as a BTT strategy continues to evolve over time. Optimization of its role in the treatment of end-stage heart failure, particularly in females will need to be the focus of future research.

Days alive and out of hospital after left ventricular assist device implantation

AIMS

Implantation of left ventricular assist devices (LVADs) as a bridge to transplant or as destination therapy is increasing. The selection of suitable patients and outcome assessment belong to the key challenges. Mortality has traditionally been a focus of research in this field, but literature on quality of life is very limited. This study aimed to identify perioperative factors influencing patients' life as measured by days alive and out of hospital (DAOH) in the first year after LVAD implantation.

METHODS AND RESULTS

This retrospective single-centre cohort study screened 227 patients who underwent LVAD implantation at the University Hospital Duesseldorf, Germany, between 2010 and 2020. First, the influence of 10 prespecified variables on DAOH was investigated by univariate analysis. Second, multivariate quantile regression was conducted including all factors with significant influence on DAOH in the univariate model. Additionally, the impact of all variables on 1 year mortality was investigated using Kaplan-Meier curves to oppose DAOH and mortality. In total, 221 patients were included into analysis. As pre-operative factors, chronic kidney disease (CKD), pre-operative mechanical circulatory support (pMCS), and Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) stadium < 3 were associated with lower DAOH at 1 year [CKD: 280 (155-322) vs. 230 (0-219), P = 0.0286; pMCS: 294 (155-325) vs. 243 (0-293), P = 0.0004; INTERMACS 1: 218 (0-293) vs. INTERMACS 2: 264 (6-320) vs. INTERMACS 3: 299 (228-325) vs. INTERMACS 4: 313 (247-332), P ≤ 0.0001]. Intra-operative additional implantation of a right ventricular assist device (RVAD) was also associated with lower DAOH [RVAD: 290 (160-325) vs. 174 (0-277), P ≤ 0.0001]. As post-operative values that were associated with lower DAOH, dialysis and tracheotomy could be identified [dialysis: 300 (252-326) vs. 186 (0-300), P ≤ 0.0001; tracheotomy: 292 (139-325) vs. 168 (0-269), P ≤ 0.0001]. Multivariate analysis revealed that all of these factors besides pMCS were independently associated with DAOH. According to Kaplan-Meier analysis, only post-operative dialysis was significantly associated with increased mortality at 1 year (survival: no dialysis 89.4% vs. dialysis 70.1%, hazard ratio: 0.56, 95% confidence interval: 0.33-0.94; P = 0.031).

CONCLUSIONS

The results of this study indicate that there can be a clear discrepancy between hard endpoints such as mortality and more patient-centred outcomes reflecting life impact. DAOH may relevantly contribute to a more comprehensive selection process and outcome assessment in LVAD patients.

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 Cardiopulmonary Resuscitation of Donors on Days Alive and Out of Hospital after Orthotopic Heart Transplantation

Background: The number of patients waiting for heart transplantation (HTX) is increasing. Optimizing the use of all available donor hearts is crucial. While mortality seems not to be affected by donor cardiopulmonary resuscitation (CPR), the impact of donor CPR on days alive and out of hospital (DAOH) is unclear. Methods: This retrospective study included adults who underwent HTX at the University Hospital Duesseldorf, Germany from 2010–2020. Main exposure was donor-CPR. Secondary exposure was the length of CPR. The primary endpoint was DAOH at one year. Results: A total of 187 patients were screened and 171 patients remained for statistical analysis. One-year mortality was 18.7%. The median DAOH at one year was 295 days (interquartile range 206–322 days). Forty-two patients (24.6%) received donor-CPR hearts. The median length of CPR was 15 (9–21) minutes. There was no significant difference in DAOH between patients with donor-CPR hearts versus patients with no-CPR hearts (CPR: 291 days (211–318 days) vs. no-CPR: 295 days (215–324 days); p = 0.619). Multivariate linear regression revealed that there was no association between length of CPR and DAOH (unstandardized coefficients B: −0.06, standard error: 0.81, 95% CI −1.65–1.53, p = 0.943). Conclusions: Donor CPR status and length of CPR are not associated with reduced DAOH at one year after HTX.

Improved survival of left ventricular assist device carriers in Europe according to implantation eras - results from the PCHF-VAD registry

BACKGROUND AND AIM

Temporal changes in patient selection and major technological developments in have occurred in the field of LVADs, yet analyses depicting this trend are lacking for Europe. We describe the advances of European LVAD programmes from the PCHF-VAD registry across device implantation eras.

METHODS

Of 583 patients from 13 European centres in the registry, 556 patients (mean age 53 ± 12 years, 82% male) were eligible for this analysis. Patients were divided to eras (E) by date of LVAD implantation: E1 from December 2006 to and including December 2012 (6 years), E2 from January 2013 to January 2020 (7 years).

RESULTS

Patients implanted more recently were older with more comorbidities, but less acutely ill. Receiving an LVAD in E2 was associated with improved 1-year survival in adjusted analysis (HR 0.58 [0.35-0.98] p = 0.043). LVAD implantation in E2 was associated with a significantly lower chance of heart transplantation (adjusted HR 0.40 [0.23-0.67], p = 0.001), and lower risk of LVAD-related infections (adjusted HR 0.64, [0.43-0.95], p = 0.027), both in unadjusted and adjusted analyses. The adjusted risk of haemocompatibility-related events decreased (HR 0.60 [0.39-0.91], p = 0.016), while the heart failure-related events increased in E2 (HR 1.67 [1.02-2.75], p = 0.043).

CONCLUSION

In an analysis depicting the evolving landscape of cf-LVAD carriers in Europe over 13 years, a trend towards better survival is seen in the recent years, despite older recipients with more comorbidities, potentially attributable to increasing expertise of LVAD centres, improved patient selection and pump technology. However, a smaller chance of undergoing heart transplantation was noted in the second era, underscoring the relevance of improved outcomes on LVAD support.

Trends and Outcomes of Left Ventricular Assist Device Therapy: JACC Focus Seminar

As the prevalence of advanced heart failure continues to rise, treatment strategies for select patients include heart transplantation or durable left ventricular assist device (LVAD) support, both of which improve quality of life and extend survival. Recently, the HeartMate 3 has been incorporated into clinical practice, the United Network for Organ Sharing donor heart allocation system was revised, and the management of LVAD-related complications has evolved. Contemporary LVAD recipients have greater preoperative illness severity, but survival is higher and adverse event rates are lower compared with prior eras. This is driven by advances in device design, patient selection, surgical techniques, and long-term management. However, bleeding, infection, neurologic events, and right ventricular failure continue to limit broader implementation of LVAD support. Ongoing efforts to optimize management of patients implanted with current devices and parallel development of next-generation devices are likely to further improve outcomes for patients with advanced heart failure.

Impact of pretransplant left ventricular assist device support duration on outcome after heart transplantation

 

OBJECTIVES

Heart transplantation after left ventricular assist device (LVAD) implantation remains challenging. It is still unclear whether its support duration impacts the outcome after transplantation.

METHODS

All patients undergoing heart transplantation between 2010 and 2021 at a single department after previous left ventricular assistance were retrospectively reviewed and divided into 4 different study groups with regard to the duration of LVAD support to examine the impact on the postoperative morbidity and mortality.

RESULTS

A total of n = 198 patients were included and assigned to the 4 study groups (group 1: <90 days, n = 14; group 2: 90 days to 1 year, n = 31; group 3: 1–2 years, n = 29; group 4: >2 years, n = 24). Although there were no differences between the 4 groups concerning relevant mismatch between the recipients and donors, the incidence of primary graft dysfunction was numerically increased in patients with the shortest support duration, and also those patients with >1 year of support (group 1: 35.7%, group 2: 25.8%, group 3: 41.4%, group 4: 37.5%, P = 0.63). The incidence of acute graft rejection was by trend increased in patients of group 1 (group 1: 28.6%, group 2: 3.3%, group 3: 7.1%, group 4: 12.5%, P = 0.06). Duration of LVAD support did not impact on perioperative adverse events (infections, P = 0.79; acute kidney injury, P = 0.85; neurological events, P = 0.74; thoracic bleeding, P = 0.61), neither on postoperative survival (1-year survival: group 1: 78.6%, group 2: 66.7%, group 3: 80.0%, group 4: 72.7%, P = 0.74).

CONCLUSION

We cannot identify a significant impact of the duration of pretransplant LVAD support on postoperative outcome; therefore, we cannot recommend a certain timeframe for transplantation of LVAD patients.

Complications of left ventricular assist devices causing high urgency status on waiting list: impact on outcome after heart transplantation

Aims

Heart transplantation (HTx) represents optimal care for advanced heart failure. Left ventricular assist devices (LVADs) are often needed as a bridge‐to‐transplant (BTT) therapy to support patients during the wait for a donor organ. Prolonged support increases the risk for LVAD complications that may affect the outcome after HTx.

Methods and results

A total of 342 patients undergoing HTx after LVAD as BTT in a 10‐year period in two German high‐volume HTx centres were retrospectively analysed. While 73 patients were transplanted without LVAD complications and with regular waiting list status (T, n = 73), the remaining 269 patients were transplanted with high urgency status (HU) and further divided with regard to the observed leading LVAD complications (infection: HU1, n = 91; thrombosis: HU2, n = 32; stroke: HU3, n = 38; right heart failure: HU4, n = 41; arrhythmia: HU5, n = 23; bleeding: HU6, n = 18; device malfunction: HU7, n = 26). Postoperative hospitalization was prolonged in patients with LVAD complications. Analyses of perioperative morbidity revealed no differences regarding primary graft dysfunction, renal failure, and neurological events except postoperative infections. Short‐term survival, as well as Kaplan–Meier survival analysis, indicated comparable results between the different study groups without disadvantages for patients with LVAD complications.

Conclusions

Left ventricular assist device therapy can impair the outcome after HTx. However, the occurrence of LVAD complications may not impact on outcome after HTx. Thus, we cannot support the prioritization or discrimination of HTx candidates according to distinct mechanical circulatory support‐associated complications. Future allocation strategies have to respect that device‐related complications may define urgency but do not impact on the outcome after HTx.