MedicalResearch.com: What did your study evaluate and why is this important?
Answer: We performed a rigorous, retrospective review of the Scientific Registry of Transplant Recipients (SRTR) data base to evaluate donor, recipient, and technical characteristics associated with graft survival in patients undergoing mechanical circulatory support (MCS) device explantation at the time of heart transplantation surgery.
Donor and recipient characteristics has been well described in the medical literature for routine heart transplantation, however these characteristics in patients who were supported with a long term MCS device at the time of heart transplant was not known. Additionally, due to chronic donor heart shortages, an increasing number of patients with advanced heart failure are being bridged with MSC devices until a suitable donor heart can be obtained.
MedicalResearch.com: What are the main findings of the study?
Answer: First, we found that the specific Left Ventricular Assist Device (LVAD) type (HeartMate-II, HeartWare, or HeartMate XVE) explanted at the time of transplantation did not influence graft survival, however, when compared to the LVAD group, removal of the total artificial heart (TAH) device at the time of transplantation was associated with decreased graft survival.
Second, donor and recipient characteristics that were independently associated with worse graft survival after heart transplantation at the time of MSC device explant were: high PVR, longer ischemic time, a donor to recipient gender mismatch, increased donor age, and a lower donor to recipient body mass index (BMI) ratio.
MedicalResearch.com: Were any of the findings unexpected?
Answer: Interestingly, LVAD type (including continuous flow vs. pulsatile types) was not associated with reduced graft survival; however the total artificial heart, which is effectively a Biventricular assist device (BIVAD), was associated with reduced graft survival. This is likely a reflection of the overall increased severity of illness in a patient population who requires biventricular (ie: TAH) versus left ventricular only bridging until a suitable donor organ is identified. Additionally, I believe explanting a TAH at the time of transplantation is a more technically demanding surgery than LVAD only device explantation.
MedicalResearch.com What should clinicians and patients take away from your report?
Answer: Commonly used LVAD types were not associated with reduced graft survival, however, when the TAH device was explanted at time of transplantation, there was a significant association with reduced graft survival.
This study confirms the importance of previously identified donor and recipient characteristics that independently influence graft survival in a heart transplant only population, and expands the importance of these characteristics to a patient population bridged to transplantation with MCS devices. Specifically, we observed that a donor-to-recipient body mass index (BMI) ratio < 0.8 compared with a BMI ratio of 1.2 was associated with decreased graft survival.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Answer: This study answered important questions as to whether certain donor and recipient characteristics influence graft survival at the time heart transplantation and MCS device explantation. However, several specific donor and recipient characteristics were not available in the clinical registry we accessed.
Therefore, in future studies, it would be interesting to assess
1) If duration of LVAD implant prior to heart transplantation is associated with graft survival outcomes
2) if there are specific LVAD complications prior to transplantation that influence graft survival outcomes and finally; 3
3) if transplant listing status (ie: 1A or 1B) at time of transplantation and MSC device explantation is associated with graft survival.
Mechanical Circulatory Support and Heart Transplantation: Donor and Recipient Factors Influencing Graft Survival
Simon Maltais, Nikhil P. Jaik, Irene D. Feurer, Mark A. Wigger, Thomas G. DiSalvo, Kelly H. Schlendorf, Rashid M. Ahmad, Daniel J. Lenihan, John M. Stulak, Mary E. Keebler
The Annals of Thoracic Surgery – 02 August 2013 (10.1016/j.athoracsur.2013.05.043)