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Jan 08, 2014

Size Matters for Patients Undergoing Heart Transplantation

Study finds that receiving an undersized heart increases risk of death in heart transplant patients.

Each year, more than 3,700 people undergo a heart transplant in hopes of replacing their damaged or diseased heart with a new, healthy donor heart. The problem, according to a recent study, is that many patients receive a heart that is too small, which can increase risk of death.

Published in the Journal of the American College of Cardiology, this study used a national registry called the United Network of Organ Sharing to identify more than 31,500 adults who received a heart transplant between 1989 and 2011 in the United States. Using a mathematic equation, researchers calculated the weight of patients’ faulty hearts along with the weight of their new, donor hearts to determine whether their new heart was the same, smaller or larger than their original heart. And after tapping into medical records, investigators were also able to see whether differences in the new heart size had any impact on risk of death after transplantation.

After analysis, researchers found that mismatches in size, particularly for patients who received a heart that was significantly smaller than their initial heart, had increased risk of mortality—a phenomenon that they refer to as the “Grinch effect.” Interestingly, however, receiving a larger donor heart had somewhat of a protective effect in patients.

But perhaps most important, researchers found that mismatching hearts by sex (for example, giving a male heart to a female or vice versa) accounted for much of the differences in weight. These findings could impact the way patients are matched with donor hearts and have the potential to improve outcomes for heart transplant patients.

Currently, doctors only take into account body weight when matching a patient with a donor heart because it’s believed that weight plays an important role in heart size. However, study investigators argue that taking into account factors like height, weight, age and sex is more accurate when it comes to matching patients with a proper donor heart. And it’s clear that matching patients with an appropriate-sized heart can help improve outcomes and increase survival rates.

Additional research is needed to perfect the recipient-donor matching process, but this study confirms the importance of size when it comes to heart transplants. Matching patients with an undersized heart can have a significant impact on outcomes and it’s possible that by taking into account factors like gender, patients can be more accurately matched with a proper heart.
Read the full study in the Journal of the American College of Cardiology

Questions for You to Consider

  • What is a heart transplant?
  • A heart transplant is surgery used to replace a damaged or diseased heart with a healthy donor heart. It may be performed in patients with severe chest pain (angina), heart failure, an abnormal heartbeat (arrhythmia) or severe heart defects.
  • How common is heart transplantation?
  • It’s estimated that there are more than 3,700 heart transplants performed worldwide each year. However, heart transplantation is only done as a life-saving measure for patients, especially those with severe heart failure, for whom no other treatments have worked. Donor hearts are in short supply so patients who need heart transplantation must go through a careful selection process to ensure that they truly need a new heart, yet are healthy enough to receive it.


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