Study suggests stem cell transplant survivors at increased risk of developing heart disease

New research appearing online today in Blood, the Journal of the American Society of Hematology (ASH), suggests that long-term survivors of hematopoietic cell transplants (HCT) are at an increased risk of developing heart disease risk factors such as high blood pressure, diabetes, and high cholesterol when compared to the general population. These risk factors, combined with exposure to pre-HCT therapy, contribute to a noticeably increased risk of heart disease over time.

HCT, the transplantation of blood-forming stem cells from the bone marrow, circulating blood, or umbilical cord blood, is the primary treatment option for many patients with blood disorders. The healthy transplanted stem cells replace patients' damaged cells that caused their illness. Advances in transplantation strategies have contributed to marked improvements in patient outcomes, resulting in a growing number of long-term transplant survivors, many of whom struggle with one or more chronic, post-transplant health conditions. Previous researchers have speculated that survivors' exposure to potentially heart damaging pre-transplant chemotherapy and radiation or treatment for a life-threatening transplant complication known as graft-versus-host-disease (GVHD) can increase their risk of developing heart disease and its associated risk factors. However, there have been limited data to validate the contribution of pre-conditioning chemotherapy or radiation and GVHD to the eventual development of heart disease in long-term HCT survivors.

"While we know that heart disease is a real concern for long-term HCT survivors, small sample sizes and a lack of long-term follow up in previous studies have only allowed us to look at a small piece of the puzzle of how this chronic condition develops in these patients," said Saro H. Armenian, DO, MPH, the study's first author, Assistant Professor in the Division of Outcomes Research, and Medical Director of the Pediatric Survivorship Clinic in the Childhood Cancer Survivorship Program at City of Hope in Duarte, CA. "Our study sought to better determine the specific factors before and after transplant that can lead to heart disease in a large group of transplant recipients."

In order to more thoroughly evaluate heart disease risk and development in HCT recipients, Dr. Armenian and his team of researchers designed a retrospective study to evaluate factors that may affect a survivor's risk of developing high blood pressure, diabetes, and high cholesterol after HCT. These factors included transplant recipients' exposure to pre-transplant chemotherapy and radiation, conditioning therapy for HCT, their type of HCT transplant, and whether they developed and were treated for GVHD post transplant.

To better determine HCT survivors' incidence of high blood pressure, diabetes, and high cholesterol compared to the general population, researchers analyzed medical records of 1,885 patients who underwent a first-time HCT for a blood cancer at City of Hope between 1995 and 2004 and had survived at least one year. The National Health and Nutrition Examination Survey was used to generate expected heart disease risk factor rates for the general population.