Decreased frequency of transplantation and lower post-transplant survival free of re-transplantation in LVAD patients with the new heart transplant allocation system

Escalating Surgical Treatment for Left Ventricular Assist Device Infection and Expected Mortality: Clinical Risk Prediction Score

BACKGROUND

Left ventricular assist devices (LVAD) improve survival for patients with cardiac failure, but LVAD-specific infection (VSI) remains a challenge with poorly understood predictive risk factors. The indications and use of escalating medical treatment to surgical debridement and potential flap reconstruction are not well characterized.

STUDY DESIGN

A retrospective review of consecutive patients undergoing primary LVAD implantation at a tertiary academic center was performed. The primary outcome measures were 90-day and overall mortality after VSI. Cox proportional hazards regression was used to generate a risk prediction score for mortality.

RESULTS

Of the 760 patients undergoing primary LVAD implantation, 255 (34%) developed VSI; of these patients, 91 (36%) were managed medically, 134 (52%) with surgical debridement, and 30 (12%) with surgical debridement and flap reconstruction. One-year survival after infection was 85% with median survival of 2.40 years. Factors independently associated with increased mortality were diabetes (hazard ratio [HR] 1.44, p = 0.04), MRSA infection (HR 1.64, p = 0.03), deep space (pump pocket or outflow cannula) involvement (HR 2.26, p < 0.001), and extracorporeal membrane oxygenation after LVAD (HR 2.52, p < 0.01). Factors independently associated with decreased mortality were flap reconstruction (HR 0.49, p = 0.02) and methicillin-sensitive Staphylococcus aureus infection (HR 0.63, p = 0.03). A clinical risk prediction score was developed using these factors and showed significant differences in median survival, which was 5.67 years for low-risk (score 0 to 1), 3.62 years for intermediate-risk (score 2), and 1.48 years for high-risk (score ≥3; p < 0.001) patients.

CONCLUSIONS

We developed a clinical risk prediction score to stratify patients with VSI. In selected cases, escalating surgical treatment was associated with increased survival. Future work is needed to determine whether early surgical debridement and flap reconstruction can alter outcomes in select cases of VSI.

"Durable left ventricular assist devices as a bridge to transplantation in The Old and The New World"

Heart transplantation remains the gold standard treatment for end-stage heart failure patients without contraindications. However, limited donor availability and long wait times have created a need for left ventricular assist devices (LVAD) to be used as a bridge to transplantation in appropriately selected patients. Improvements in LVAD technology have resulted in improved short- and long-term outcomes, further supporting the use of these devices for a bridge-to-transplant (BTT) indication. LVAD utilization as BTT exhibits notable disparities worldwide, mainly due to variations in organ availability, allocation policies, and financial constraints. Although Europe has experienced a consistent increase in the use of LVAD for this purpose, 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.The authors provide an overview comparing the current state of heart transplantation in the US and Europe, with a particular focus on how distinct allocation policies and organ availability impact medical practices. Additionally, the review will examine critical aspects ranging from patient selection and pre-implantation optimization to post-transplant outcomes.

The impact of the OPTN policy change on patients with a durable left ventricular assist device and chronic kidney disease: Analysis of the UNOS database

BACKGROUND

The Organ Procurement and Transplantation Network (OPTN) implemented modifications in 2018 to the adult heart transplant allocation system to better stratify the most medically urgent transplant candidates. We evaluated the impact of these changes on patients supported by a durable left ventricular assist device (LVAD) with chronic kidney disease (CKD).

OBJECTIVE

To evaluate the impact of the OPTN policy change on patients supported by durable left ventricular assist devices (LVAD) with chronic kidney disease (CKD).

METHODS

We performed an analysis of patients from the United Network of Organ Sharing Database supported by durable LVAD listed for a heart transplant (HT) between October 17, 2016 and September 30, 2021. Patients were divided into two groups: pre- and postpolicy, depending on whether they were listed on or prior to October 17, 2018. Patients who were on dialysis prior to surgery or discharge were excluded from the analysis. Patients with simultaneous heart and kidney transplants were excluded. Patients who were listed for transplant prepolicy change but transplanted postpolicy change were excluded. This cohort was then subdivided into degrees of CKD based on estimated glomerular filtration rate (eGFR), which resulted in 678 patients (23.7%) in Stage 1 (GFR ≥89.499) (Prepolicy: 345, Postpolicy: 333), 1233 (43.1%) in Stage 2 (89.499 > GFR ≥ 59.499) (Prepolicy: 618, Postpolicy: 615), 613 (21.4%) in Stage 3a (59.499 > GFR ≥ 44.499) (Prepolicy: 291, Postpolicy: 322), 294 (10.3%) in Stage 3b (44.499 > GFR ≥ 29.499) (Prepolicy: 143, Postpolicy: 151), 36 (1.3%) in Stage 4 (29.499 > GFR ≥ 15) (Prepolicy: 21, Postpolicy: 15), and 9 (0.3%) in Stage 5 (15 > GFR) (Prepolicy: 4, Postpolicy: 5). The primary outcome was 1-year and 2-year post-HT survival.

RESULTS

There were 2863 patients who met the study criteria (1422 prepolicy, 1441 postpolicy). Overall survival, regardless of CKD stage, was lower following the policy change (p < 0.01). There was a similar risk of primary graft failure (PGF) in the pre- and postpolicy period (1.8% vs. 1.2%, p = 0.26). 1-year overall survival was 93% (91, 94) and 89% (87, 91) in the pre- and postpolicy periods, respectively. 2-year overall survival was 89% (88, 91) and 85% (82, 87) in the pre- and postpolicy periods, respectively. For CKD Stages 1, 2, 3a, 3b, 4, and 5, 1 -year survival was 93% (91, 95), 92% (90,93), 89% (86, 91), 89% (86, 93), 80% (68, 94), and 100% (100, 100), respectively. For CKD Stages 1, 2, 3a, 3b, 4, and 5, 2-year survival was 91% (88, 93), 88% (86, 90), 84% (81, 88), 84% (80, 89), 73% (59, 90), and 100% (100, 100), respectively. Patients with CKD 1 and 2 had better survival compared to those with CKD 3 (p < 0.01) and CKD 4 and 5 (p = 0.03) in the pre- and postpolicy periods. Patients with CKD 3 did not have a survival advantage over those with CKD 4 and 5 (p = 0.25). On cox regression analysis, advancing degrees of CKD were associated with an increased risk of mortality.

CONCLUSIONS

Patients with LVAD support had decreased overall survival after the OPTN policy change. Patients with more advanced CKD had lower survival than patients without advanced CKD, though they were not impacted by the OPTN policy change.

Early Outcomes in Patients With LVAD Undergoing Heart Transplant via Use of the SherpaPak Cardiac Transport System

BACKGROUND

Heart transplant (HT) in recipients with left ventricular assist devices (LVADs) is associated with poor early post-HT outcomes, including primary graft dysfunction (PGD). As complicated heart explants in recipients with LVADs may produce longer ischemic times, innovations in donor heart preservation may yield improved post-HT outcomes. The SherpaPak Cardiac Transport System is an organ preservation technology that maintains donor heart temperatures between 4 °C and 8 °C, which may minimize ischemic and cold-induced graft injuries. This analysis sought to identify whether the use of SherpaPak versus traditional cold storage was associated with differential outcomes among patients with durable LVAD undergoing HT.

METHODS

Global Utilization and Registry Database for Improved Heart Preservation-Heart (NCT04141605) is a multicenter registry assessing post-HT outcomes comparing 2 methods of donor heart preservation: SherpaPak versus traditional cold storage. A retrospective review of all patients with durable LVAD who underwent HT was performed. Outcomes assessed included rates of PGD, post-HT mechanical circulatory support use, and 30-day and 1-year survival.

RESULTS

SherpaPak (n=149) and traditional cold storage (n=178) patients had similar baseline characteristics. SherpaPak use was associated with reduced PGD (adjusted odds ratio, 0.56 [95% CI, 0.32-0.99]; P=0.045) and severe PGD (adjusted odds ratio, 0.31 [95% CI, 0.13-0.75]; P=0.009), despite an increased total ischemic time in the SherpaPak group. Propensity matched analysis also noted a trend toward reduced intensive care unit (SherpaPak 7.5±6.4 days versus traditional cold storage 11.3±18.8 days; P=0.09) and hospital (SherpaPak 20.5±11.9 days versus traditional cold storage 28.7±37.0 days; P=0.06) lengths of stay. The 30-day and 1-year survival was similar between groups.

CONCLUSIONS

SherpaPak use was associated with improved early post-HT outcomes among patients with LVAD undergoing HT. This innovation in preservation technology may be an option for HT candidates at increased risk for PGD.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04141605.

Predictors of Survival After Heart Transplant in the New Allocation System: A UNOS Database Analysis

Clinical predictors of posttransplant graft loss since the United Network for Organ Sharing (UNOS) heart allocation system change have not been well characterized. Single organ adult heart transplants from the UNOS database were identified (n = 10,252) and divided into a test cohort (n = 6,869, 67%) and validation cohort (n = 3,383, 33%). A Cox regression analysis was performed on the test cohort to identify recipient and donor risk factors for posttransplant graft loss. Based on the risk factors, a score (max 16) was developed to classify patients in the validation cohort into risk groups of low (≤1), mid (2-3), high (≥4) risk. Recipient factors of advanced age, Black race, recipient blood group O, diabetes, etiology of heart failure, renal dysfunction, elevated bilirubin, redo-transplantation, elevated pulmonary artery pressure, transplant with a durable ventricular assist device, or transplant on extracorporeal membrane oxygenation (ECMO) or ventilator were associated with more posttransplant graft loss. Donor factors of ischemic time and donor age were also associated with outcomes. One year graft survival for the low-, mid-, high-risk groups was 94%, 91%, and 85%, respectively. In conclusion, easily obtainable clinical characteristics at time of heart transplant can predict posttransplant outcomes in the current era.

Heart Transplantation

Heart transplantation (HTx) remains the last therapeutic resort for patients with advanced heart failure. The present work is a clinically focused review discussing current issues in heart transplantation. Several factors have been associated with the outcome of HTx, such as ABO and HLA compatibility, graft size, ischemic time, age, infections, and the cause of death, as well as imaging and laboratory tests. In 2018, UNOS changed the organ allocation policy for HTx. The aim of this change was to prioritize patients with a more severe clinical condition resulting in a reduction in mortality of people on the waiting list. Advanced heart failure and resistant angina are among the main indications of HTx, whereas active infection, peripheral vascular disease, malignancies, and increased body mass index (BMI) are important contraindications. The main complications of HTx include graft rejection, graft angiopathy, primary graft failure, infection, neoplasms, and retransplantation. Recent advances in the field of HTx include the first two porcine-to-human xenotransplantations, the inclusion of hepatitis C donors, donation after circulatory death, novel monitoring for acute cellular rejection and antibody-mediated rejection, and advances in donor heart preservation and transportation. Lastly, novel immunosuppression therapies such as daratumumab, belatacept, IL 6 directed therapy, and IgG endopeptidase have shown promising results.

Durable Mechanical Circulatory Support: JACC Scientific Statement

Despite advances in medical therapy for patients with stage C heart failure (HF), survival for patients with advanced HF is <20% at 5 years. Durable left ventricular assist device (dLVAD) support is an important treatment option for patients with advanced HF. Innovations in dLVAD technology have reduced the risk of several adverse events, including pump thrombosis, stroke, and bleeding. Average patient survival is now similar to that of heart transplantation at 2 years, with 5-year dLVAD survival now approaching 60%. Unfortunately, greater adoption of dLVAD therapy has not been realized due to delayed referral of patients to advanced HF centers, insufficient clinician knowledge of contemporary dLVAD outcomes (including gains in quality of life), and deprioritization of patients with dLVAD support waiting for heart transplantation. Despite these challenges, novel devices are on the horizon of clinical investigation, offering smaller size, permitting less invasive surgical implantation, and eliminating the percutaneous lead for power supply.

Impact of the 2018 UNOS Heart Transplant Policy Changes on Patient Outcomes

In 2018, the United Network for Organ Sharing implemented a 6-tier allocation policy to replace the prior 3-tier system. Given increasing listings of critically ill candidates for heart transplantation and lengthening waitlist times, the new policy aimed to better stratify candidates by waitlist mortality, shorten waiting times for high priority candidates, add objective criteria for common cardiac conditions, and further broaden sharing of donor hearts. There have been significant shifts in cardiac transplantation practices and patient outcomes following the implementation of the new policy, including changes in listing practices, waitlist time and mortality, transplant donor characteristics, post-transplantation outcomes, and mechanical circulatory support use. This review aims to highlight emerging trends in United States heart transplantation practice and outcomes following the implementation of the 2018 United Network for Organ Sharing heart allocation policy and to address areas for future modification.

Donor Utilization in the Recent Era: Effect of Sex, Drugs, and Increased Risk

Background:

Heart transplantation volumes have increased in recent years, yet less than a third of donors are typically accepted for transplantation. Whether donor sex, donor drug use, or perception of increased risk affects utilization for transplantation is unclear.

Methods:

The United Network for Organ Sharing database was queried for donors from January 1, 2007, to December 31, 2017. Donor toxicology was collected when available. Multivariate analysis was conducted to examine correlations with donor utilization.

Results:

Between January 1, 2007, and December 31, 2017, there were 87 816 heart donors aged ≥15 years. The mean age was 42.7±15.8 years, and 24 831 donors (28.3%) were utilized for heart transplantation. Subsequent analyses focused on donors between 15 and 39 years old.

The strongest associations with donor acceptance were for male donor sex, blood type, hepatitis C antibody, donor age, left ventricular hypertrophy, and history of donor drug use. After removing hepatitis C, Public Health Service Increased Risk was identified as a strong negative predictor. Most positive drug toxicology results were associated with donor nonuse except for donors between 15 and 19 years of age. Exceptions included alcohol, marijuana, and cocaine. Opiates were associated with less utilization at all donor ages. The Public Health Service Increased Risk status was associated with significantly less utilization in all age groups except 15- to 19-year-old donors.

Conclusions:

While male donors were preferentially utilized, donors with drug use or those deemed Public Health Service Increased Risk were significantly less utilized for heart transplantation. Further consideration of such donors would be appropriate particularly as the demand for transplantation continues to increase.