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Published on: January 12, 2019
Understanding preservation time thresholds in the modern era of heart transplantation
Chen Chia Wang1, Jessica B Briscoe2, Corbin E Goerlich2
1Vanderbilt University School of Medicine, Nashville, MD, USA.
Insights
The traditional 4-hour heart preservation limit is less critical in modern heart transplants. Extended preservation times (5-8 hours) did not increase mortality in the modern era, suggesting the threshold may be too restrictive.
Area of Science:
- Cardiovascular Surgery
- Transplantation Medicine
- Medical Technology
Background:
- The standard for cardiac allograft preservation is 4 hours.
- Prolonged storage is associated with increased morbidity.
- Novel technologies aim to improve allograft viability during preservation.
Purpose of the Study:
- To evaluate the impact of cardiac allograft preservation time on one-year mortality.
- To compare outcomes between early (2000-2015) and modern (2020-2023) heart transplant eras.
- To assess the influence of machine perfusion on transplant outcomes.
Main Methods:
- Retrospective analysis of adult heart transplant recipients in the United States.
- Stratification into early and modern eras, and standard (≤4h) vs. prolonged (≥5h) preservation groups.
- Statistical analysis including hazard ratios, confidence intervals, and spline analysis.
Main Results:
- In the early era, prolonged preservation significantly increased one-year mortality (HR 1.60).
- This association was not significant in the modern era (HR 1.14).
- Preservation times of 5-8 hours did not increase one-year mortality in the modern era (HR 1.09).
- Machine perfusion was not associated with one-year mortality (HR 1.15).
Conclusions:
- The link between cardiac allograft preservation duration and patient mortality has weakened in the modern era.
- The current 4-hour preservation threshold may be overly restrictive for contemporary heart transplantation.
- Advancements in preservation techniques and recipient care have potentially mitigated risks of longer ischemic times.
Abstract:
A 4-h preservation time threshold for cardiac allografts is the current standard in heart transplantation, but novel technologies are proposed to decrease the morbidity associated with prolonged allograft storage. This study examined adult heart transplant recipients from 2000-2015 and 2020-2023 in the United States, stratified into an early (2000-2015) and modern era (2020-2023), then into standard (≤ 4 h) and prolonged (≥ 5 h) preservation time groups within each era. This study reinforced the 4-h threshold in the early era, where prolonged preservation significantly increased one-year mortality (HR 1.60, 95% CI 1.36-1.90). However, this association was no longer significant in the modern era (HR 1.14, 95% CI 0.85-1.50). A sub-analysis showed that using machine perfusion devices for allograft storage was not associated with one-year mortality (HR 1.15, 95% CI 0.79-1.70). Spline analysis demonstrated possible inflection points between 4 and 5 h and 8-9 h in the modern era, and further analysis found that 5-8 h of preservation did not increase one-year mortality (HR 1.09, 95% CI 0.80-1.47) relative to the ≤ 4 h group. In conclusion, the association between cardiac allograft preservation duration and morbidity has decreased in the modern era. Today, a 4-h preservation duration threshold may be too restrictive.
