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Stem Cell Transplants Linked To Higher Risk Of Irregular Heart Beat In Multiple Myeloma Patients

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Published: Dec 7, 2012 1:58 pm

Results from a recent retrospective study indicate that multiple myeloma patients who receive stem cell transplants may be at greater risk than the general population of developing atrial fibrillation, the most common type of irregular heartbeat.

The researchers also found that myeloma patients with kidney failure, heart failure, or high blood pressure were at the greatest risk of developing atrial fibrillation after a stem cell transplant.

The researchers suggest that selecting appropriate patients for stem cell transplantation, correcting risk factors, and using preventative treatment may prevent the occurrence of irregular heart beat in myeloma patients undergoing stem cell transplantation.

However, they also point out that their study was retrospective in nature and that further studies are needed to confirm their findings.

People who have atrial fibrillation may not experience any outward symptoms of the disorder. However, even if the irregular heartbeat is not noticeable, it can increase the risk of stroke. It also can cause chest pain or, in extreme cases, heart failure.

Previous studies have shown that patients often develop an irregular heartbeat a few days to several weeks after a stem cell transplant.

A large retrospective analysis recently also showed that patients who have undergone stem cell transplantation are at higher risk of developing heart disease than the general population (see related Beacon news).

However, according to the study investigators, these previous studies were not limited to multiple myeloma patients and did not identify risk factors associated in particular with an irregular heartbeat.

In the current retrospective study, investigators from the University of Arkansas for Medical Sciences analyzed data from 278 myeloma patients who received an autologous (own) stem cell transplant on an in-patient basis at their institution between January 2000 and December 2009.

The average patient age was 63 years, and all patients received a mean of two autologous stem cell transplants.

Autologous stem cell transplantation involves collecting a patient’s own stem cells before high-dose chemotherapy. The stem cells are then reinfused into the patients to replace the healthy stem cells destroyed by chemotherapy.

Patients who had atrial fibrillation before their multiple myeloma diagnosis or before their first transplant were not included in the analysis.

Overall, 27 percent of the myeloma patients in the study developed atrial fibrillation following their transplant.

According to the study authors, this is significantly higher than the rate of atrial fibrillation seen in the general population, which increases with age and reaches about 9 percent in people over 80 years of age.

The median time to the onset of atrial fibrillation after transplantation was 14.8 days in the study patients.

The Arkansas researchers found that myeloma patients with high blood pressure, heart failure, or kidney failure at the time of diagnosis had an increased risk of developing an irregular heartbeat after transplantation.

For instance, patients in the study who had high blood pressure were found to be 3.6 times more likely to develop atrial fibrillation after their transplant compared to myeloma patients who had a transplant but did not have high blood pressure.

Different forms of heart failure prior to transplantation also were associated with a higher risk of atrial fibrillation after transplantation.

Myeloma patients with an expanded left upper chamber of the heart (a “dilated left atrium”) were 4.9 times more likely to develop atrial fibrillation after their transplant than patients without that heart issue.

Likewise, patients with reduced levels of blood flow from the main pumping chamber of the heart (“reduced left ventricular ejection fraction”) were 9.5 times more likely to develop atrial fibrillation than the patients with normal blood flow from the heart.

The most significant risk factor for atrial fibrillation after transplantation, however, was kidney failure. Reduced kidney function was associated with a 15.2 times greater risk of atrial fibrillation after transplantation.

On the other hand, patients with light-chain myeloma had a lower risk of developing atrial fibrillation after transplantation.

Light and heavy chains are two components of antibodies, which are produced by plasma cells. Myeloma patients tend to have an excess of one of the two types of light chains in their blood stream.

Age, gender, and race were not associated with the development of atrial fibrillation.

All the factors identified by the researchers as being linked to a higher risk of developing atrial fibrillation are factors which, in the general population, also are associated with a higher risk of atrial fibrillation.

In each case, however, the Arkansas researchers found that the risk associated with a specific factor was greater among myeloma patients who have received a stem cell transplant than it is in the general population.

For example, high blood pressure is associated with a 1.4 to 1.6 times higher risk of developing atrial fibrillation in the general population, but a 3.6 times higher risk in myeloma patients who have undergone stem cell transplantation.

For more information, please see the study in Therapeutic Advances in Cardiovascular Disease (abstract).

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One Comment »

  • Gary said:

    Melphalan dosing in transplants at UAMS is indiscriminate …. everybody gets the same amount. It is highly intuitive that irregularities in heart function could have been reduced or eliminated by reducing the melphalan dosage for those patient with heart issues. A prospective study is being planned for UC in the New Year using a personalized dose for melphalan based on the idiosyncrasies of the patient. It is likely that many other side effects beside heart issues will be redecued when an optimal dose is used without sacrificing efficacy.