SAN DIEGO – Cardiac transplant recipients who are given hearts from donors with left ventricular hypertrophy are not at increased risk of death, Dr. Omar Wever Pinzon reported at the annual meeting of the International Society for Heart and Lung Transplantation.
In a retrospective nationwide study of more than 2,500 adults who underwent cardiac transplantation during a recent 4-year period, nearly half of the donor hearts had LVH, although it was mild in most cases.
Dr. Omar Wever Pinzon
Recipients who had been given hearts with LVH did not have poorer survival overall than did their counterparts who had been given hearts without this high-risk characteristic. But getting a heart with LVH did reduce survival if, in addition, the donor was older than 55 years or the graft had a longer ischemic time.
"Overall survival of recipients of donor hearts with LVH is similar to those without LVH, which indicates that the current donor selection and allocation algorithms successfully mitigate the risk that donor LVH could pose to recipient survival," Dr. Pinzon said. However, "the combination of donor LVH with certain other high-risk characteristics can result in excess mortality."
Because few donor hearts had moderate or severe LVH, "I think we have to be very cautious" when using those hearts, he added. "But I would say [hearts having an interventricular septum and posterior wall thickness] up to 1.3 cm may be safe in the absence of other high-risk characteristics."
The scarcity of donor hearts – coupled with growing knowledge about the impact of various donor characteristics on recipient outcomes – has led to strategies to make more hearts available for transplantation, according to Dr. Pinzon.
"Thanks to these strategies, patients with left ventricular hypertrophy, considered a high-risk characteristic, are more likely now to become donors," he commented. However, some studies have raised concerns that such hearts are more susceptible to ischemic graft injury, which could translate into poorer outcomes for the recipients.
Using data from the United Network for Organ Sharing and the Organ Procurement and Transplantation Network, the investigators studied 2,626 adult patients who underwent a first, single-organ heart transplantation in 2006-2010.
On the basis of the thickness of the interventricular septum and posterior wall, donor hearts were classified as having no LVH (less than 1.1 cm) or LVH that was mild (1.1-1.3 cm), moderate (1.4-1.6 cm), or severe (1.7 cm or greater).
Study results showed that the transplant recipients were 52 years old on average, and 78% were men. The donors were 33 years old on average, and 72% were men.
Fully 44% of the donor hearts had some degree of LVH, reported Dr. Pinzon, who is a heart failure/transplant fellow with the UTAH (Utah Transplantation Affiliated Hospitals) Cardiac Transplant Program in Salt Lake City. The LVH was mild in most cases (38%) but occasionally moderate (5%) or severe (1%).
Relative to their peers who had been given donor hearts without LVH, recipients who had been given donor hearts with LVH had a higher body mass index and a higher ratio of donor-to-recipient BMI, had been on the waiting list for a shorter time, and were marginally more likely to have a graft ischemic time exceeding 4 hours.
During a follow-up period of 3.3 years post transplantation, 13% of the recipients died or – rarely – underwent retransplantation.
In univariate and multivariate analyses, neither recipients of donor hearts with mild LVH nor recipients of donor hearts with moderate or severe LVH were more likely to die than their counterparts whose donor hearts did not have any LVH, Dr. Pinzon reported.
However, recipients’ risk of death increased with the age of their donor (hazard ratio, 1.01) and with their own serum creatinine level (HR, 1.31) and mean pulmonary artery pressure (HR, 1.01).
Also, they were more likely to die if their donor had used tobacco (HR, 1.32), or if they themselves were older than 55 years of age (HR, 1.30) or had been on extracorporeal membrane oxygenation support (HR, 6.0).
Further analyses revealed an interaction between donor heart LVH and donor age. Among recipients whose donor was older than 55 years, those getting a heart with any LVH had roughly six times the risk of death (P = .01). But there was no such association among recipients whose donors were younger.
There was also an interaction between donor heart LVH and graft ischemic time. Among recipients whose graft had an ischemic time of 4 hours or longer, those receiving a heart with moderate or severe LVH had twice the risk of death (P = .04). There was no such association among recipients whose graft ischemic time was shorter.