Closure of the left atrial appendage during open heart surgery protects the brain from infarctions and stroke, and could be routinely performed in the future, according to the findings from a late-breaking trial presented at the European Society of Cardiology (ESC) congress (26–30 August, Barcelona, Spain).
Presenting the research, principal investigator Jesper Park-Hansen (Bispebjerg-Frederiksberg University Hospital, Copenhagen, Denmark) said: “We found significant results supporting a beneficial effect of left atrial appendage closure. This was a single centre study and we are eager to move on to larger studies and hopefully confirm this beneficial effect, so that in the future it could maybe be part of guidelines to recommend left atrial appendage closure in the majority of patients referred for first time open heart surgery.”
Atrial fibrillation occurs in up to 67% of heart surgery patients, and increases the risk for subsequent stroke. Between 15% and 20% of patients with atrial fibrillation (AF) have clots in the left atrium, of which 90% are evident in the left atrial appendage. Some heart surgeons close the left atrial appendage to protect against stroke, particularly in patients with a history of atrial fibrillation, but to date there is little evidence to support this practice. As yet, no randomised study has shown whether left atrial appendage closure can prevent postoperative cerebral ischaemia.
The LAACS (Left atrial appendage closure by surgery) study was a prospective randomised trial that investigated whether left atrial appendage closure during open heart surgery, regardless of atrial fibrillation history, would minimise long-term ischaemic brain damage. Patients referred for open heart surgery (coronary artery bypass grafting, valve surgery, or both) were eligible, and of the 187 participants enrolled, 101 were randomised to surgical closure of the left atrial appendage and 86 to no closure.
The primary endpoint was the occurrence of stroke/transient ischaemic attack or silent cerebral infarction, demonstrated on MRI or clinical follow-up. Patients underwent brain MRI before surgery, shortly after discharge, and six months or longer after surgery. In all, 19 patients reached the combined endpoint during an average follow-up of 3.65 years. The cumulative probability of an ischaemic event in the brain was consistently lower in the closed than the not-closed group. In the intention-to-treat analysis, the proportion of patients meeting the combined endpoint was 16.3% in the control group and 5% in the left atrial appendage closure group.
However, only 75% of patients were treated as per protocol, which according to Volkmar Falk (German Heart Institute, Berlin, Germany) “makes the statistics a little bit difficult”. He also noted that no power analysis was provided and suggested that the trial may be “severely” underpowered. In his presentation, Park-Hansen explained that block randomisation could compensate for patients not following protocol.
The investigators concluded that LAACS is an important piece of the puzzle but the picture is not yet complete, and that larger randomised controlled trials with some design modifications are needed.
Parks-Hansen described the potential impact of the results as “groundbreaking” in spite of the study’s limitations, and said it was worth proceeding with multicentre studies. The research group have already initiated talks about a larger scale study (LAACS II)
Falk agreed, commenting: “There is a hint that left atrial appendage occlusion may prevent future cerebral vascular events but the trial is actually too small to prove this concept, and the question is still open and has to trigger a larger trial that will finally address this important issue. Currently, we only have a very weak recommendation in the guidelines, IIb only, for left atrial appendage occlusion in patients with atrial fibrillation. The LAACS trial certainly triggers an interesting outcome but we have to understand that this will not be enough to change a guideline.”