Differences in Status 1A Heart Transplantation Survival in the Continuous Flow Left Ventricular Assist Device Era

Seasonal trends in donor heart availability: an analysis of the UNOS database

Despite the widespread belief that donor organ availability varies around holidays and seasons, there is little empirical data supporting this long-held belief. Variations in donor heart availability may be of interest to patients and clinicians. The UNOS/OPTN registry was queried for all heart donations from October 1987 through March 2017. Daily heart donation rates were modeled nationally using Poisson regression including splines for year and day of the year. Seasonality was assessed using a likelihood ratio test for the spine terms for day of the year. The holiday effect was assessed using conditional logistic regression. Seasonal plots suggest a significant, although modest, increase in organ availability during the summer months, except for region 1. The regions with the highest amplitude were region 7 (peak: June 21, amplitude: 16.63%) and region 6 (peak: July 5, amplitude: 11.29%). There was no significant difference in the odds of heart donation when comparing holidays vs. non-holidays using national data (odds ratio [95% CI]: 1.01 [0.98, 1.03], P = 0.560) or any regional subsets. There was no observable correlation between donor heart availability and holidays. However, a significant seasonality effect was observed with higher donation rates occurring during warmer months.

Progression to Transplant under New Heart Allocation System: The Society of Thoracic Surgeons Intermacs Database

BACKGROUND

Under the new heart allocation policy, durable left ventricular assist devices receive lower priority on the transplant list. We sought to identify predictors of successful heart transplant after durable device implant as a means to inform patient care in the current era.

METHODS

All patients (n=25,164) undergoing primary durable left ventricular device implant in the Society of Thoracic Surgeons Intermacs database (2010-2019) were evaluated. Patients identified as bridge to transplant (BTT, n=5242) or bridge to candidacy (BTC, n=6248) were analyzed with the endpoint of transplant before (n=10,588) and after (n=902) the change in the heart allocation system on October 18, 2018. Multivariable hazard modeling was used to assess risk-adjusted time to event associations.

RESULTS

Of 11,490 patients, 45.5% progressed to transplant, (BTT 53.0%, BTC 36.6%), most by 14 months post LVAD. Under the new allocation system, progression to transplant was significantly lower at 14 months (18.6% vs. 34.8%, p<0.001). Factors associated with successful bridge to transplant before the allocation change included BTT status, white race and married. Under the new allocation system, BTT status (HR 1.79 95% CI 1.19-2.69, p<0.0054) remained a positive predictor, while blood type O (HR 0.43, 95% CI 0.28-0.65, p<0.0001) remained a negative predictor.

CONCLUSIONS

Despite having priority in the previous allocation system, less than half of BTT/BTC patients progressed to transplant. Under the current system, these numbers are further reduced. Heart teams should consider the implications of longer wait times with a durable left ventricular assist device when determining the optimal bridging strategy.

Heart transplant waiting list implications of increased ventricular assist device use as a bridge strategy: A national analysis

The use of ventricular assist devices (VADs) as a bridge to heart transplant (HT) is increasing, while HT volume remains stagnant. This may portend longer waiting times and an otherwise more competitive environment for all patients on the HT waiting list. A retrospective analysis of patients who were listed for HT in the United Network for Organ Sharing (UNOS) database from 2000 to 2015 was conducted. Mean waiting time, proportion of HT reception (%HT), proportion of death (%death), and proportion of waiting list removal (%removal) were calculated across three eras: Era 1 (2000-2007), Era 2 (2008-2011), and Era 3 (2012-2015). During the study period, 29 728 patients successfully underwent HT. 19 127 (64.3%) were directly transplanted (direct HT); 4491 (15.1%) received VADs prior to listing as a bridge to decision (BTD); and 4593 (15.5%) received VADs after listing as a bridge to transplant (BTT). Across the three eras, the average number of registrants per year grew. Among all groups, waiting time increased across the eras. %HT generally decreased in the BTD and BTT groups but remained constant in the direct HT group. %removal increased, while %death decreased in all group across the eras. Waiting time for HT increased from 2000 to 2015. Patients with VADs as a bridge strategy experienced decreasing %HT and increasing %removal but stable survival. Improvements in VAD safety and durability will ensure their success as part of a bridge strategy to HT under the new UNOS allocation policy.

Temporary left ventricular assist devices as a bridge to heart transplantation

BACKGROUND

To create equitable access to donor organs for the highest mortality patients, the cardiac transplant allocation system now prioritizes patients with surgically implanted temporary left ventricular assist devices (T-LVADs). The outcomes following a direct bridge from a T-LVAD to orthotopic heart transplant (OHT) are not well delineated.

AIM

This study investigates the T-LVAD waitlist outcomes and compares the posttransplant outcomes in patients bridged to OHT with surgically implanted T-LVADs to patients bridged with durable continuous-flow left ventricular assist devices (CF-LVADs).

METHODS

Adults recorded in the United Network for Organ Sharing registry bridged to OHT with a durable CF-LVAD and T-LVADs, with or without temporary right ventricular assist devices (T-RVADs), between 2010 and 2018 were included. Propensity matching and multivariable Cox regression were utilized to compare outcomes.

RESULTS

Of 504 patients waitlisted with T-LVADs, the majority were transplanted (50%), bridged to CF-LVAD (17%), or recovered (9%). A total of 9047 recipients were bridged to OHT during the study period with 8875 CF-LVADs and 172 T-LVADs. Early survival in propensity-matched T-LVAD ± T-RVAD patients was similar to CF-LVAD ± T-RVAD patients but reduced at a 1-year follow-up. This difference in survival at 1-year follow-up was attributable to significantly reduced survival in patients with combined T-LVAD + T-RVAD support when compared with CF-LVAD, isolated T-LVAD and combined CF-LVAD + T-RVAD support (80% vs 90% vs 90% vs 91%; P = .005).

CONCLUSIONS

This study demonstrates that most patients waitlisted with a T-LVAD are successfully bridged to durable therapy or recover, and those bridged to OHT have acceptable posttransplant outcomes, particularly when T-RVADs are not required.

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.