Early Outcomes With Marginal Donor Hearts Compared With Left Ventricular Assist Device Support in Patients With Advanced Heart Failure

Extended criteria donor organ use for heart-lung transplantation in the modern era

BACKGROUND

Demand for donor hearts and lungs exceeds their supply. Extended Criteria Donor (ECD) organs are used to help meet this demand, but their impact on heart-lung transplantation outcomes is poorly characterized.

METHODS AND RESULTS

The United Network for Organ Sharing was queried for data on adult heart-lung transplantation recipients (n = 447) from 2005‒2021. Recipients were stratified based on whether they received ECD hearts and/or lungs. Morbidity was analyzed using Kruskal-Wallis, chi-square, and Fisher's exact tests. Mortality was analyzed using Kaplan-Meier estimation, log-rank tests and Cox regression. Sixty-five (14.5%) patients received two ECD organs, 134 (30.0%) received only an ECD lung, and 65 (14.5%) only an ECD heart. Recipients of two ECD organs were older, more likely to have diabetes, and more likely transplanted from 2015‒2021 (p < 0.05). Groups did not differ by pre-transplant diagnosis, intensive care unit disposition, life support use, or hemodynamics. Group five-year survival rates ranged from 54.5% to 63.2% (p = 0.428). Groups did not differ by 30-day mortality, strokes, graft rejection, or hospital length of stay.

CONCLUSIONS

Using ECD hearts and/or lungs for heart-lung transplantation is not associated with increased mortality and is a safe strategy for increasing donor organ supply in this complex patient population.

Predictors of one-year outcome after cardiac re-transplantation: Machine learning analysis

BACKGROUND

As cardiac re-transplantation is associated with inferior outcomes compared with primary transplantation, allocating scarce resources to appropriate re-transplant candidates is important. The aim of this study is to elucidate the factors associated with 1-year mortality in cardiac re-transplantation using the random forests algorithm for survival analysis.

METHODS

We retrospectively reviewed the United Network for Organ Sharing registry and identified all adult (>17 years old) recipients who underwent cardiac re-transplantation between January 2000 and March 2020. The random forest algorithm on Cox modeling was used to calculate the variable importance (VIMP) of independent variables for contributing to one-year mortality.

RESULTS

A total of 1294 patients underwent cardiac re-transplantation. Of these, 137 patients were re-transplanted within one year of their first transplant, while 1157 patients were re-transplanted more than one year after their first transplant. One-year mortality was significantly higher for patients receiving early transplantation compared with those receiving late transplantation (Early 40.6% vs. Late 13.6%, log-rank P<0.001). Machine learning analysis showed that total bilirubin (>2 mg/dl) (VIMP, 2.99%) was an independent predictor of one-year mortality after early re-transplant. High BMI (>30.0 kg/m2) (VIMP, 1.43%) and ventilator dependence (VIMP, 1.47%) were independent predictors of one-year mortality for the late re-transplantation group.

CONCLUSION

Machine learning showed that optimal one-year survival following cardiac re-transplantation was significantly related to liver function in early re-transplantation, and to obesity and preoperative ventilator dependence in late re-transplantation. This article is protected by copyright. All rights reserved.

Impact of using higher-risk donor hearts for candidates with pre-transplant mechanical circulatory support

BACKGROUND

We evaluated post-heart transplant (HTx) outcomes after use of higher-risk donor hearts for candidates supported with pre-HTx mechanical circulatory support (MCS).

METHODS

In this retrospective analysis of the national United Network for Organ Sharing registry, a total of 9,915 adult candidates on MCS underwent HTx from January 1, 2010 to March 31, 2019. Multi-organ, re-transplant, and congenital heart disease patients were excluded. Higher-risk donor organs met at least one of the following criteria: left ventricular ejection fraction <50%, donor to recipient predicted heart mass ratio <0.86, donor age >55 years, or ischemic time >4 hours. Primary outcome was 1 year post-transplant survival.

RESULTS

Among HTx recipients, 3688 (37.2%) received higher-risk donor hearts. Candidates supported with pre-HTx extracorporeal membrane oxygenation or biventricular assist device (n = 374, 3.8%) who received higher-risk donor hearts had comparable 1 year survival (HR: 1.14, 95% CI: [0.67-1.93], p = 0.64) to recipients of standard-risk donor hearts, when adjusted for recipient age and sex. In candidates supported with intra-aortic balloon pump (n = 1391, 14.6%), transplantation of higher-risk donor hearts did not adversely affect 1 year survival (HR: 0.80, 95% CI: [0.52-1.22], p = 0.30). Patients on durable left ventricular assist devices (LVAD) who received higher-risk donor hearts had comparable 1 year survival to continued LVAD support on the waitlist, but mortality was increased compared to those who received standard-risk donor hearts (HR: 1.37, 95% CI: [1.11-1.70], p = 0.004).

CONCLUSIONS

Patients requiring pre-HTx temporary MCS who received higher-risk donor hearts had comparable 1 year post-transplant survival to those who received standard-risk donor hearts. Stable patients on durable LVADs may benefit from waiting for standard-risk donor hearts.

Impact of Reported Donor Ejection Fraction on Outcome after Heart Transplantation

OBJECTIVES

 The global shortage of donor organs has urged transplanting units to extend donor selection criteria, for example, impaired left ventricular function (LVF), leading to the use of marginal donor hearts. We retrospectively analyzed our patients after orthotopic heart transplantation (oHTX) with a focus on the clinical outcome depending on donor LVF.

METHODS

 Donor reports, intraoperative, echocardiographic, and clinical follow-up data of patients undergoing oHTX at a single-center between September 2010 and June 2020 were retrospectively analyzed. Recipients were divided into two groups based on donor left ventricular ejection fraction (dLVEF): impaired dLVEF (group I; dLVEF ≤ 50%; n = 23) and normal dLVEF group (group N; dLVEF > 50%; n = 137).

RESULTS

 There was no difference in 30-day, 90-day, and 1-year survival. However, the duration of in-hospital stay was statistically longer in group I than in group N (N: 40.9 ± 28.3 days vs. I: 55.9 ± 39.4 days, p < 0.05). Furthermore, postoperative infection events were significantly more frequent in group I (p = 0.03), which was also supported by multivariate analysis (p = 0.03; odds ratio: 2.96; confidence interval: 1.12-7.83). Upon correlation analysis, dLVEF and recipient LVEF prove as statistically independent (r = 0.12, p = 0.17).

CONCLUSIONS

 Impaired dLVEF is associated with prolonged posttransplant recovery and slightly increased morbidity but has no significant impact on survival up to 1 year posttransplant.

Continuous-flow left ventricular assist device versus orthotopic heart transplantation in adults with heart failure: a systematic review and meta-analysis

Background

Due to the lack of donor hearts, many studies have assessed the prognosis of heart failure (HF) patients treated with a continuous-flow left ventricular assist device (CF-LVAD). However, previous results have not been consistent and minimal data is available regarding long-term outcomes. There is no consensus on whether CF-LVAD as a bridge or destination therapy (DT) can equal orthotopic heart transplantation (HTx). The purpose of our study is to compare clinical outcomes between CF-LVAD and HTx in adults.

Methods

We searched controlled trials from PubMed, Cochrane Library, and Embase databases until July 1, 2020. The mortality at different time points and adverse events were analyzed among 12 included studies.

Results

No significant differences were found in mortality at one-year [odds ratio (OR) =1.08; 95% CI: 0.97-1.21], two-year (OR =1.01; 95% CI: 0.91-1.12), three-year (OR =1.02; 95% CI: 0.69-1.51), and five-year (OR =1.02; 95% CI: 0.93-1.11), as well as the comparison of stroke, bleeding, and infection between CF-LVAD as a bridge versus HTx. The pooled analysis of one-year mortality (OR =2.76; 95% CI: 0.38-20.18) and two-year mortality (OR =1.64; 95% CI: 0.22-12.23) revealed no significant difference between CF-LVAD DT and HTx. Comparisons of adverse events showed no differences in bleeding or infection, but a higher risk of stroke (OR =5.09; 95% CI: 1.74-14.84) for patients treated with CF-LVAD DT than with HTx.

Conclusions

CF-LVAD as a bridge results in similar outcomes as HTx within five years. CF-LVAD as a DT is associated with similar one-year and two-year mortality, but carries a higher risk of stroke, as compared with HTx.

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.

Heart transplantation versus left ventricular assist devices as destination therapy or bridge to transplantation for 1-year mortality: a systematic review and meta-analysis

Background

The optimal treatment for advanced heart failure (HF) patients with regards to mortality remains unknown. Heart transplantation (HTx) and left ventricular assist devices (LVAD) used either as a bridge to transplant (BTT) or destination therapy (DT) have been compared in a number of studies, without definite conclusions with regards to mortality benefit. We sought to systematically review the pertinent literature and perform a meta-analysis of all the available studies presenting head-to-head comparisons between HTx and LVAD BTT or LVAD DT for late (>6 months) all-cause mortality.

Methods

We performed a systematic search of Medline and Cochrane Central databases in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We conducted a meta-analysis of late mortality comparing HTx vs. BTT LVAD and HTx vs. DT LVAD using a random effects model.

Results

Eight studies were included in our meta-analysis, reporting data on 7,957 patients in total. Although the available studies are of high quality [8 stars in Newcastle-Ottawa Scale (NOS) on average], there is paucity of mortality data. Specifically, seven studies compared HTx with BTT and five studies compared HTx with DT for 1-year mortality. Our pooled estimates showed that there was no difference in late mortality among these strategies.

Conclusions

Our meta-analysis highlights the small number and the heterogeneity of available studies referring to the optimal invasive management of advanced HF, and shows that there are no differences between HTx and LVAD for these patients with regards to late mortality.

Heart Transplant Survival Based on Recipient and Donor Risk Scoring: A UNOS Database Analysis

Unlike the lung allocation score, currently, there is no quantitative scoring system available for patients on heart transplant waiting list. By using United Network for Organ Sharing (UNOS) data, we aim to generate a scoring system based on the recipient and donor risk factors to predict posttransplant survival. Available UNOS data were queried between 2005 and 2013 for heart transplant recipients aged ≥18 years to create separate cox-proportional hazard models for recipient and donor risk scoring. On the basis of risk scores, recipients were divided into five groups and donors into three groups. Kaplan-Meier curves were used for survival. Total 17,131 patients had heart transplant within specified time period. Major factors within high-risk groups were body mass index > 30 kg/m (46%), mean pulmonary artery pressure >30 mmHg (65%), creatinine > 1.5 mg% (63%), bilirubin > 1.5 mg% (54%), noncontinuous-flow left ventricular assist devices (45%) for recipients and gender mismatch (81%) and ischemia time >4 hours (88%) for donors. Survival in recipient groups 1, 2, 3, 4, and 5 at 5 years was 81, 80, 77, 74, and 62%, respectively, and in donor groups 1, 2, and 3 at 5 years was 79, 77, and 70%, respectively (p < 0.001). Combining donor and recipient groups based on scoring showed acceptable survival in low-risk recipients with high-risk donor (75% at 5 years). A higher recipient and donor risk score are associated with worse long-term survival. A low-risk recipient transplanted with high-risk donor has acceptable survival at 5 years, but high-risk recipient combined with a high-risk donor has marginal results. Using an objective scoring system could help get the best results when utilizing high-risk donors.

Minimally invasive left ventricular assist device placement

BACKGROUND

The use of left ventricular assist device (LVAD) as bridge-to-transplant and destination therapy has increased significantly in the recent years along with the rapidly increasing heart failure patient population worldwide. It is crucial to be familiar with the standard surgical technique of LVAD implantation, but also to further advance the technique to optimize patient outcomes. Numerous studies have shown minimally invasive cardiac surgeries, including cardiac valves procedures can improve patient outcomes with decrease post-operative bleeding, reduced blood transfusion requirement, shorter hospital stay, faster recovery rate and lower hospital cost. With the advancement of mechanical circulatory support, the smaller and current generation of centrifugal continuous-flow LVADs has made minimally invasive LVAD implantation feasible. In this review, we described our surgical technique of minimally invasive LVAD placement.

METHODS

In addition to the standard pre-LVAD implantation evaluation, multiple studies, including chest radiography, chest computed tomography and echocardiography are further examined for patient selection and planning of the operation. Instead of a full standard sternotomy, a lateral mini-thoracotomy and hemi-sternotomy or second intercostal space anterior mini-thoracotomy are utilized. Special techniques are also applied to allow easy access for future re-entry, e.g., heart transplantation and to improve post-operative outcomes. Off-pump approach is our prefer approach for the minimally invasive procedure.

RESULTS

With minimally invasive approach, avoiding a full sternotomy, can reduce surgical trauma and post-operative bleeding, and can make subsequent LVAD explantation and heart transplantation less technically challenging and will allow patients to have a faster post-operative recovery rate. With the intact pericardium, the right ventricle can be protected from acute unrestricted dilation and further right heart failure after LVAD placement. The use of off-pump approach allows the avoidance of cardiopulmonary bypass and will decrease the incidence of post-operative vasoplegia and coagulopathy.

CONCLUSIONS

With the current generation of LVADs, minimally invasive surgical approach is very feasible and may improve patient outcomes. Further large prospective randomized studies will help to further demonstrate the potential advantages and disadvantage of minimally invasive LVAD placement. The upcoming generations of LVADs and minimally invasive instrumentations are currently being evaluate and will further advance the success of LVAD therapy.

Left ventricular assist devices: current controversies and future directions

Advanced heart failure is a growing epidemic that leads to significant suffering and economic losses. The development of left ventricular assist devices (LVADs) has led to improved quality of life and long-term survival for patients diagnosed with this devastating condition. This review briefly summarizes the short history and clinical outcomes of LVADs and focuses on the current controversies and issues facing LVAD therapy. Finally, the future directions for the role of LVADs in the treatment of end-stage heart failure are discussed.