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The "Art" of Donor Heart Selection


Kambiz Ghafourian, MD
Cedars-Sinai Heart Institute
Los Angeles, CA, USA

Jon Kobashigawa, MD
Cedars-Sinai Heart Institute
Los Angeles, CA, USA
kobashigawaj@cshs.org



Donor availability has always been a key limiting factor in heart transplantation. Since 2005, there has been an upward trend in the number of heart transplant candidates who are added each year to the waiting list [1]. Based on the OPTN data as of December 19, 2014, there were 4,016 heart transplant candidates on the waiting list in the United States. However, only 2,513 heart transplants were performed in 2013. Contributing to this negative balance in demand and supply is the fact that about 63% of the currently available donor hearts are discarded, in part due to the stringent selection criteria [3].

The challenge in donor heart selection is to maximize utilization while avoiding poor outcomes. There is significant variation among institutions and individuals with regard to the donor heart selection and the process is still deservedly referred to as the "art" of donor selection. Khush and colleagues sought to identify the current predictor of cardiac allograft nonuse [4]. They studied the association of 11 donor risk factors with allograft use in a cohort of 1,872 organs donors. In a multivariable model, the most important predictors of use were donor age, cause of death, LVEF, and history of hypertension. However, none of these four characteristics were associated with increased recipient morality at one year after transplant.

Our center's data [5], as well as observations from the ISHLT registry [2], suggest that increasing donor age is a risk factor for mortality after cardiac transplantation. However, a single center study from Portugal [6] showed similar incidence of PGD, acute rejection and 5-year mortality in heart transplant recipients from donors of at least 50 years of age (mean 52 years) compared to the recipients from donors younger than 40 years (mean 28 years). One important difference between the donor groups was statistically significantly shorter ischemic time in the older donor group. In fact, in 58% of the older donor group, the total ischemic time was < 60 minutes. A multicenter study from Spain came to a similar conclusion and showed no difference in the odds of acute rejection and overall mortality between recipients from donors > 50 years old and those from donors < 50 years after adjustment for confounding factors such as recipient age [7]. The age of the donor as a risk factor needs to be re-addressed, especially as the upper limit of donor age has been increasing over the past few years. According to the latest data, the median donor age for heart transplant has increased to 35 years in the U.S. [2] and 43 years in Europe (Eurotransplant annual report, 2013).

With regard to the donor/recipient gender mismatch, a UNOS registry study showed that male recipients of female donor hearts had the lowest 5-year actuarial survival, whereas 5-year actuarial survival in female recipients was not affected by donor sex [8]. Data from our center, reviewing the records of 857 heart transplant patients, were similar to these findings with an important difference-we found that not only do male recipients of female donors have poor long-term survival, but so do female recipients of male donors [9]. A recent experience in our center raised a unique challenge when a transgender donor heart was offered for a male recipient. This again highlighted the uncertainties about the importance of gender mismatch in heart transplantation.

There are several other donor characteristics that have been suggested to be associated with poor outcomes but a consensus is lacking among the experts about their significance in donor heart selection. Presence and severity of the left ventricular hypertrophy, presence and severity of coronary artery disease manifested on coronary angiogram, cardiac hemodynamics such as ideal right atrial pressure and lastly, elevation of cardiac biomarkers are among such characteristics.

Other than donor risk factors, several of the recipient characteristics should be considered in donor heart selection. For example, there has been a tendency in heart transplant community to favor oversized donor hearts for heart transplant candidates with mild to moderate degree of pulmonary hypertension. Review of data from our center showed similar 1- and 3-year survival between recipients with pre-operative systolic pulmonary artery pressure > 40 mmHg who received oversized versus undersized donor hearts [10]. In this study, the size matching between donors and recipients was based on weight. This raises a separate question about the best parameter for size matching, as some experts strongly prefer height, BMI or left ventricular mass index for this purpose.

Donor heart selection process and matching the donor heart with the right recipient involves meticulous review of several of the donor and recipient characteristics, as well as consideration of factors such as ischemic time and problems in special populations such as the risk of bleeding and prolonged operations in heart transplant candidates with durable mechanical circulatory support devices. Ideally, a scoring system that can incorporate all these multitude of factors can maximize donor heart utilization without jeopardizing the outcomes. Although valuable steps have been taken in developing a donor heart scoring system [11], implementing a reliable scoring system is far from completion and requires concerted effort and multi-center clinical trials to provide accurate and reliable data. In the meantime, there is need for a consensus among the experts to establish a standardized approach for donor heart selection and to develop a platform for future research. ■

Disclosure Statement: The author has no conflicts of interest to disclose


References:
1. Stevenson LW. The urgent priority for transplantation is to trim the waiting list. J Heart Lung Transplant. 2013 Sep;32(9):861-7.

2. Lund LH, Edwards LB, Kucheryavaya AY, et al. The registry of the International Society for Heart and Lung Transplantation: thirty-first official adult heart transplant report--2014. J Heart Lung Transplant. 2014 Oct;33(10):996-1008.

3. Israni AK, Zaun D, Rosendale JD. OPTN/SRTR 2012 annual data report: deceased organ donation. Am J Transplant. 2014 Jan;14 Suppl 1:167-83. 4. Khush KK, Menza R, Nguyen J, et al. Donor predictors of allograft use and recipient outcomes after heart transplantation. Circ Heart Fail. 2013 Mar;6(2):300-9.

5. Tehrani YS, Yu Z, Luu M, et al. The policy of placing older donors into older recipients: is it worth the risk? Clin Transplant. 2014 Jul;28(7):802-7.

6. Prieto D, Correia P, Baptista M, et al. Outcome after heart transplantation from older donor age: expanding the donor pool. Eur J Cardiothorac Surg. 2014 Jul 9. pii: ezu257.

7. Roig E, Almenar L, Crespo-Leiro M, et al. Heart transplantation using allografts from older donors: Multicenter study results. Article in press, published online: November 3, 2014.

8. Khush KK, Kubo JT, Desai M. Influence of donor and recipient sex mismatch on heart transplant outcomes: Analysis of the International Society for Heart and Lung Transplantation Registry. J Heart Lung Transplant. 2012 May;31(5):459-66.

9. Kittleson MM, Shemin R, Patel JK, et al. Donor-recipient sex mismatch portends poor 10-year outcomes in a single-center experience. J Heart Lung Transplant. 2011 Sep;30(9):1018-22.

10. Kwon MH, Wong S, Kittleson M, et al. Selecting oversized donor cardiac allografts for patients with pulmonary hypertension may be unnecessary. Transplant Proc. 2014 Jun;46(5):1497-501.

11. Smits JM, De Pauw M, de Vries E, et al. Donor scoring system for heart transplantation and the impact on patient survival. J Heart Lung Transplant. 2012 Apr;31(4):387-97.




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