Major Finding: Ten-year survival in gender-matched heart transplantation was 69%–71%, compared with 58%–59% in mismatched cases.
Data Source: A review of 857 heart transplant patients from between 1994 and 2008.
Disclosures: Dr. Kittleson reported that she had no relevant disclosures with regard to this presentation.
CHICAGO — Gender mismatch between heart donors and transplant recipients who were on triple-drug immunosuppression without induction therapy was associated with significantly lower 10-year survival, according to results of a study of 857 heart transplant cases.
The findings suggest that gender mismatch portends a poor prognosis in heart transplantation, Dr. Michelle Kittleson said at the meeting.
“The implications … are that maintaining sex matching in heart transplantation is beneficial, and these findings may impact donor selection and recipient wait time to transplant,” she said.
Previous studies showing decreased survival in gender mismatch heart transplant cases did not distinguish between immunosuppressive regimens or the use of induction therapy. So the current study was designed to evaluate the impact of gender mismatch in patients on standard triple-drug immunosuppression without induction therapy (tacrolimus, mycophenolate mofetil, and prednisone), explained Dr. Kittleson of the University of California, Los Angeles.
Dr. Kittleson and her colleagues assessed patients for 10-year actuarial survival and for freedom from allograft vasculopathy and nonfatal major adverse cardiac events, such as mycardial infarction, heart failure, percutaneous intervention, defibrillation, stroke, and new peripheral vascular disease.
Differences in survival between the gender-matched and gender-mismatched groups were statistically significant, but no significant differences were seen on the other outcome measures.
The investigators evaluated cases between 1994 and 2008 that included 506 with male-to-male (MM) donation, 132 with female-to-male (FM) donation, 113 with female-to-female (FF) donation, and 106 with male-to-female (MF) donation.
Ten-year survival rates in the four groups, respectively, were 69%, 58%, 71%, and 59%, Dr. Kittleson said.
Previous studies, such as one in which researchers used United Network for Organ Sharing data, have shown similar survival results with gender-mismatched transplantation with FM donation; most have suggested that female recipients are not affected by donor gender (Circ. Heart Failure 2009;2:401–8).
Although the mechanisms for this are unclear, several explanations have been suggested, such as immunologic effects and smaller heart size in FM donation, which provides inadequate functional reserve for males.
In the current study, however, both male and female recipient survival was affected by mismatched donor gender, which might be a factor of study design and follow-up, Dr. Kittleson noted.
For example, survival in FM donation decreased rapidly and remained lower throughout the 10-year period, compared with gender-matched donations, while survival in MF donation did not begin to diverge until after the 4th posttransplant year; some prior studies failed to extend follow-up long enough to identify this divergence.
Another study showing no survival differences in females enrolled patients over a longer time period, which could explain the difference.