This concise (393 word) news release from the American Heart Association on a trial that used botulinum toxin to prevent irregular heart rhythms after bypass surgery packs a lot of good information into a small frame. The novel use of botulinum toxin represented in the story is an interesting and potentially important step toward a possible solution. As noted, the research was conducted in a small sample of 60 patients and although the results are impressive, they should be viewed with an understanding that many other potential therapies have failed on subsequent examination. The news release is written in a clear and measured way, although a clarification on the type of botulinum toxin used and the potential costs would have been helpful for reporters and the public.
Atrial fibrillation after coronary bypass surgery is a vexing problem. Most patients who develop atrial fibrillation post-procedure do so within a few days of the procedure so an intraoperative or preoperative solution seems reasonable.Atrial fibrillation can cause serious complications for the patient undergoing heart bypass, extend their stay in the hospital, and substantially drive up the costs of the heart treatment.
The story rightly points out that the development of atrial fibrillation after coronary artery bypass surgery has significant financial implications: “Atrial fibrillation is also always associated with lengthened hospitalization and that means increased healthcare costs.” But we would have liked to have seen some attention paid to the cost of the intervention, namely multiple injections of botulinum toxin. We calculate the cost of one 4mls vial of Xeomin (incobotulinumtoxinA) to be approximately $1000. This cost is likely to be rather small in comparison to the cost of extended hospitalizations, antiarrhythmic therapies and lost productivity from atrial fibrillation.
The story does a good job in detailing the results of the study and the apparent benefit of botulinum toxin injections in this small sample randomized study.
Researchers found that:
The story appropriately points out that there were no additional harms seen in the group injected with the botulinum toxin compared to those who received saline other than those associated with the surgery.
“No complications from the Botox injections were reported,” according to the release. “But complications from the bypass surgery were similar in both groups, including time in intensive care and on a breathing machine, and infection rate.”
The release satisfies this criterion but a few more details would have made the release even better. We are told that 60 subjects were enrolled and were randomly assigned to receive either botulinum toxin of saline. We are also told the study was blinded. Other important details about the study are omitted including baseline differences between the two groups, number of vessels engrafted, duration of bypass or number of off bypass procedures. All are important variables in the development of atrial fibrillation post operatively.
Atrial fibrillation post coronary artery bypass grafting (CABG) can dramatically impact the patient’s quality of life as well as potentially increase morbidity. The story does not over state the impact and provides statistics concerning its prevalence.
The funding sources (The Russian State Research Institute of Circulation Pathology and the Siberian Division of Russian Academy of Medical Sciences) are noted in the release.
Given the impact of post-operative atrial fibrillation, it is reasonable to assume that other attempts have been made to reduce its incidence in this population. A variety of antiarrhythmic drugs and beta adrenergic blockers have been studied with variable results. It would have been very helpful to add a few words about the alternative pharmalogical agents.
Since the release makes no claim that this therapy is ready to be used outside of clinical trials we’ll give this a satisfactory. The story makes it clear that botulinum toxin is available and is routinely used in cosmetic dermatology. For that use it’s sold under the trade name Botox Cosmetic. However, there are four different FDA approved strains of the toxin. Various formulations of the toxin have received FDA approval for use in treating excessive sweating, migraines, dystonia, bladder control issues, and several other non-cosmetic conditions. Those formulations have been available for many years as well. Since this is the first time botulinum toxin has been tested in human hearts, it’s safe to say that it could be several years before it receives approval as a preventative for heart complications. The release is clear that larger studies are needed.
Dr. Steinberg’s comments on the study being the “first in man” establishes the novelty of the approach.
The release does not use unjustifiable language. Instead, the language is very measured and appropriate.