Elevated troponin I should not rule out donor hearts

By Laura Cowen

Donor cardiac troponin I level is not associated with intermediate-term mortality, cardiac allograft vasculopathy or primary graft failure in patients receiving heart transplants, US researchers report.

"To date and to our knowledge, this is the largest analysis to show a lack of any prognostic value of donor troponin in post-transplant outcomes, and such findings suggest that elevated troponin levels in an otherwise suitable donor should not preclude acceptance of an organ for transplantation," Snehal Patel (Albert Einstein College of Medicine, New York) and colleagues remark.

The authors explain that, on average, "only 1 in 3 potential donor hearts is accepted for transplantation", and elevated donor troponin levels, even with preserved cardiac function, can be a reason for rejecting a donor organ.

"[H]owever, the data supporting this practice are limited", they add.

To address this, Patel and team analysed outcomes in relation to peak donor troponin I levels in 10,943 adult (≥18 years) recipients of organs with preserved left ventricular ejection fraction (≥50%), registered in the United Network of Organ Sharing (UNOS) database.

Kaplan-Meier survival estimates at 30 days, 1 year, 3 years and 5 years were 96.0%, 89.8%, 83.2% and 77.1%, respectively.

The researchers found no significant association between peak donor troponin I levels and recipient mortality up to 1 year when the level was analysed as a continuous variable, even after accounting for differences in donor characteristics, such as cardiopulmonary resuscitation, inotropic support and age.

Furthermore, when the cohort was divided according to donor troponin I values (<1 ng/mL, 1-10 ng/mL and >10 ng/mL) there was no significant difference in recipient mortality between the three groups at 30 days, 1 year, 3 years or 5 years in either unadjusted or adjusted analyses.

Similarly, transplant recipients in the elevated troponin groups were not at increased risk of cardiac allograft vasculopathy, which occurred in 29.8% at 5 years, when compared with those with a donor troponin level below 1 ng/mL. Nor did they have a higher rate of primary graft failure, which was 1.4% overall, at 30 days.

The median length of hospital stay post transplant was also similar across groups, at around 14 days.

Patel et al conclude in Circulation: Heart Failure that their findings "could help expand the donor pool."

But editorialists Shravani Pasupneti and Kiran Khush, both from Stanford University School of Medicine in California, USA, warn that study limitations, such as the use of a single troponin I measurement and the possibility of selection bias mean "there is still need for further investigation."

Nonetheless, the findings "should go a long way toward reassuring transplant centers when evaluating heart offers from donors with normal cardiac function in the setting of elevated troponin levels", they write.

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