Risk of Atrial Fibrillation ‘Substantial’ in Patients with Certain Blood Cancers After Undergoing Allogeneic Hematopoietic Cell Transplantation

Patients with certain blood cancers who went on to receive an allogeneic hematopoietic cell transplant were at an increased risk of atrial fibrillation not long after treatment to prepare them for the procedure began, according to study results published in the Journal of Clinical Oncology.

Moreover, the results demonstrated that the increased risk continued into long-term survivorship.

“To our knowledge, our study is the first to describe the incidence and risk factors for (atrial fibrillation) in a contemporary cohort of allogeneic patients, allowing us to capture evolving (hematopoietic cell transplantation) practices,” the study authors wrote.

Atrial fibrillation, which is a fast irregular heart rhythm, is the most common cardiac arrhythmia, and leads to a five-times increased risk of stroke; three-times increased risk of heart failure; and two-times increased risk of dementia and death in the general population, alone.

The authors noted that over the past five decades there have been significant improvements in hematopoietic cell transplantation strategies. In fact, there’s been an increasing number of long-term survivors — one that, according to the authors, is expected to double within the next 10 years. The treatment, which is the transplantation of stem cells, is deemed effective for hematological disorders and malignancies. However, certain cardiovascular complications such as stroke and heart failure are associated with long-term morbidity in hematopoietic cell transplantation survivors.

“The burden of (atrial fibrillation) after allogeneic (hematopoietic cell transplantation) population is substantial, and the development of (atrial fibrillation) is associated with poor survival,” the authors wrote. However, they noted, data regarding the incidence and risk factors of de novo atrial fibrillation in this patient population is lacking.

As a result, they aimed to examine the incidence and risk factors of atrial fibrillation following the procedure and what, if any, impact atrial fibrillation has on outcomes.

To reach this conclusion, 487 patients who underwent allogeneic hematopoietic cell transplantation between 2014 and 2016 were examined to characterize patient-and-hematopoietic cell-transplantation-related risk factors. Patients were from the City of Hope National Medical Center in California. Primary cancer diagnoses among the patient population included acute myeloid leukemia (42.3%), acute lymphoblastic leukemia (25.7%), myelodysplastic syndrome or myeloproliferative neoplasms (21.6%) and other (10.5%). Those with a prior history of atrial fibrillation, children and those undergoing a second hematopoietic cell transplantation were excluded.

Fifty patients developed atrial fibrillation. The five-year cumulative incidence of atrial fibrillation was 10.6% for the patient population, according to the results. The median time to atrial fibrillation was 117.5 days, and the largest increase in the incidence of atrial fibrillation was within the first year after allogeneic hematopoietic cell transplantation.

Analyses of the data showed that factors including, but not limited to, older age, diabetes and being of male sex were associated with a greater risk of atrial fibrillation. Overall, one- and five-year survival probabilities were 75.4% and 55.8%, respectively.

Further analysis showed that atrial fibrillation was 12.8-times more likely to be associated with an increased risk of all-cause mortality and 15.8-times more likely to be associated with non-relapse mortality.

To further examine the risks and associations between pre-hematopoietic cell transplantation echocardiographic measures and risk of atrial fibrillation, the study authors gathered echocardiograms from the patients. Of the 50 patients who developed atrial fibrillation, only 78% had an echocardiogram available from pre-treatment. Of the 437 individuals who did not develop atrial fibrillation, 89% had available echocardiograms from pre-hematopoietic cell transplantation.

The study results, according to the authors, could help patients and health care providers make informed decisions to consider monitoring during and after hematopoietic cell transplantation.

“The growing number of patients undergoing allogeneic (hematopoietic cell transplantation) … makes the development of personalized transplant strategies imperative, to ensure that these patients live long and healthy lives well beyond the immediate (hematopoietic cell transplantation) period,” the authors concluded.

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