A new step towards stroke prevention?
The left atrial appendage is often closed by doctors performing open-heart surgery to reduce the risk of stroke for patients with atrial fibrillation, yet it’s not clear whether this can prevent strokes in patients who have not been diagnosed with the condition. The LAACS-2 team aim to gain a fuller picture of whether this operation protects against stroke, as Dr Helena Dominguez explains.
A condition characterised by an irregular cardiac rhythm, atrial fibrillation can lead to the development of blood clots in the upper chamber of the heart, which may provoke a stroke. It has long been common practice for surgeons to close the left atrial appendage, a kind of cul-de-sac in the heart that doesn’t seem to be necessary for cardiac function, as a preventative measure. “It’s known that clots can build up in the left atrial appendage, and surgeons have been cutting it away for many years,” says Dr Helena Dominguez. The LAAOS-3 study showed that this procedure is an effective preventive measure in patients with atrial fibrillation. Dr Dominguez and her colleagues investigated whether this procedure might also protect patients without atrial fibrillation from stroke in an earlier study. “In our study we investigated whether left atrial appendage closure by surgery (LAACS) prevented damage to the brain regardless of whether atrial fibrillation had been diagnosed before surgery, looking at endpoints stroke or new infractions, in CT and MRI scans,” she outlines. “We found a difference between the group who had undergone the LAACS procedure, and those who hadn’t.”
“It’s
looking at the incidence of strokes. Biology samples have been taken from the left and the right heart appendages in a subgroup of patients, to investigate whether there are structural changes that render the heart prone to building up clots, even in the absence of atrial fibrillation.
known that clots can build up in the left atrial appendage, and surgeons have been cutting it away for many years.”
LAACS-2 study
As head of the LAACS-2 study, Dr Dominguez is now looking to gather more evidence on the effectiveness of the procedure for all patients undergoing heart surgery, and also to build a deeper picture of the factors that may heighten the risk of stroke beyond atrial fibrillation. Researchers are following the progress of a randomized group of 1,500 patients from four European sites who had open-heart surgery, although they may not have had atrial fibrillation. “These patients were scheduled for coronary bypass, aortic or mitral valve surgery or any of these combined. They were randomized to undergo surgery as planned or to add a LAACS procedure using clips,” says Dr Dominguez. Researchers are taking a pragmatic approach to this work, following the patients’ e-health records, and
This research will help provide a fuller picture of whether the LAACS procedure helps prevent stroke, which may then inform clinical guidelines for patients, regardless of whether they have atrial fibrillation or not. The evidence from Dr Dominguez’s study and others suggests that the left atrial appendage plays a major role in stroke, and closing it could reduce the risk. “In future it may be recommended to close the appendage in everybody who undergoes open-heart surgery,” she outlines. This line of research continues beyond LAACS-2, as Dr Dominguez has launched a mechanistic study, with further collection of heart tissue, blood and ECG, looking for biomarkers that could be used to identify patients at heightened risk of stroke. “It may be that there are some factors that cause blood to clot, then if you have atrial fibrillation on top, that heightens stroke risk,” she explains.
LAACS-2
Left Atrial Appendage Closure by Surgery-2
The main objective of the project is to determine if Left Atrium Appendage (LAA) closure added to planned open heart surgery protects against future major stroke and minor stroke.
Funded by the Independent Research Fund Denmark, the Innovation Fund Denmark, Novo Nordisk Foundation, Ib Mogens Christiansen, and Bispebjerg-Frederiksberg Research Fund.
Associate Professor Helena Domínguez, PhD Bispebjerg-Frederiksberg Hospital Cardiology dept.
Nordre Fasanvej 57 DK-2000 Frederiksberg
Denmark
T: +45 3816 6162/6148
E: mail mdom0002@regionh.dk W: www.frederiksberghospital.dk
Helena Domínguez graduated in Medicine at Universitat Autònoma de Barcelona in 1988. She has been engaged in research since her studies, along with clinical specialisation as a cardiologist in 2007. She gained her PhD in 2005 at the University of Copenhagen (UCPH). She currently works as a cardiologist in Bispebjerg and Frederiksberg Hospital and is an Associate Professor in the Dept. Biomedicine, UCPH, Denmark.
