French Study Evaluates TAVR-Related Microbleeds
March 19, 2017—The American College of Cardiology (ACC) announced the results of a single-center study of 84 patients (age ≥ 80 years) undergoing transcatheter aortic valve replacement (TAVR) showing that approximately one-quarter of the patients developed new microbleeds after the procedure. Eric Van Belle, MD, a cardiologist at the Centre Hospitalier Regional in Lille, France, presented the study at the ACC's 66th annual scientific session in Washington, DC.
The background of the investigation is that previous studies of MRI scans in patients age 80 years and older have shown evidence of microbleeds in up to 30% of patients. The study sought to investigate microbleeds and their possible connection to endovascular procedures such as TAVR or anticoagulant use associated with these procedures.
Dr. Van Belle's study revealed increased risks of microbleeding among patients who had undergone a previous cardiovascular intervention and among those with more prolonged exposure to anticoagulant medications. It is the first study to link microbleeding with TAVR and the first to investigate microbleeding as a side effect of any cardiac procedure, noted the ACC announcement.
In the press release, Dr. Van Belle commented, “We are all aware of the potential for silent ischemic strokes after these endovascular procedures, but our study points to the opposite risk—microbleeding—that we have not previously been aware of. With more and more endovascular procedures, which require anticoagulants, it could be that these procedures are one of the main triggers of microbleeding seen in the older population. It raises the concern that we may be increasing the risk of this microbleeding with each intervention we perform.”
As summarized in the ACC announcement, the investigators performed MRI scans and questionnaire-based neurological tests in 84 patients before and after the patients underwent TAVR at Centre Hospitalier Regional in Lille. Patients underwent MRI scans 1 day before and 3 days after TAVR. Questionnaire-based neurological tests were conducted before the TAVR procedure, at 3 days after, and 6 months after the procedure.
Dr. Van Belle reported that before TAVR, MRI scans revealed at least one microbleed in 26% of patients. At 3 days after the procedure, a total of 40% of patients had microbleeds, and 23% had new microbleeds that were not present before TAVR.
Microbleeds observed both before and after TAVR were associated with deficiencies in thinking and memory in the questionnaire-based neurocognitive assessments. Factors that were associated with a significantly higher risk of microbleeds included having a previous cardiovascular intervention, prolonged exposure to anticoagulation, history of bleeding, longer exposure to fluoroscopy during TAVR, and balloon postdilation.
Dr. Van Belle stated that the results strongly suggest that further research is needed to elucidate the causes of microbleeds and determine whether changes in anticoagulation management can help to reduce the risk. He added that the results suggest systematic MRI investigation should be conducted in studies investigating new anticoagulation regimen for patients undergoing TAVR.
Furthermore, he noted that MRI scans of the brain are rarely used to assess safety outcomes in cardiovascular studies, in part because MRI cannot be used in patients with a pacemaker or other types of implanted devices.
Dr. Belle commented in the ACC press release, “It is difficult to do this kind of MRI study in this older population, but based on our results I would say that it is worth it to do so when investigating a new treatment or treatment modification. Both mini-strokes and microbleeds likely play a role in cognitive decline. It is possible that using too much anticoagulation therapy could be as bad as using too little."
The study was limited primarily by its small size, noted Dr. Belle. In addition, it was not able to definitively show whether new microbleeds observed after TAVR were actually caused by TAVR, the use of anticoagulants, or other factors. Further research could be conducted to include a larger study population, involve younger patients, or potentially investigate microbleeding after surgical aortic valve replacement or other cardiac procedures, advised Dr. Belle in the ACC press release.