Recently I spoke to a cardiothoracic surgeon in Florida who was going to be performing a bypass operation on a patient of mine. To my surprise, despite the patient never having had atrial fibrillation, the surgeon informed me that he was planning to operate on the patient’s left atrial appendage, telling me “Down here, we close the left atrial appendage of all patients undergoing heart surgery.”
For many years now I have been frustrated with the lack of evidence supporting left atrial appendage occlusion (LAAO), a procedure that many surgeons were adding on to the cardiac valve or coronary bypass operations on patients I had referred to them. After I spoke to the Florida surgeon I realized that LAAO in patients who had never had atrial fibrillation was becoming increasingly utilized.
As one who visualizes the LAA routinely by transesophageal echocardiography I see how important the pump function of this appendage is to overall atrial function and how its pump function is essentially eliminated in postoperative patients. What damage was removing or obliterating the LAA doing to overall cardiac function? I even created a website with the URL “I am Joe’s Left Atrial Appendage”, attempting to drum up sympathy for this abused portion of the heart.
Of course, there is strong evidence that the LAA is the major nidus for thrombus formation when the heart persists in atrial fibrillation. This still image from a TEE shows an enlarged LAA without thrombus.
Whereas this video shows a nasty clot wiggling in an enlarged, dysfunctional LAA.
If that clot decides to leave the appendage it launches into the arterial circulation and floats along until it reaches an artery too small to traverse at which point the organ supplied by that artery, deprived of oxygen begins to die. If that organ is the brain that death is called a stroke.
At the American College of Cardiology’s 2021 Scientific Sessions yesterday a hugely important, practice-changing, randomized trial finally provided evidence that LAAO performed at the time of concomitant heart surgery in patients with atrial fibrillation is safe and beneficial.
Richard Whitlock, professor of surgery, at Canada’s McMasters University organized this landmark study (the LAAOS III) and presented the findings. The results were published simultaneously in the New England Journal of Medicine. Twenty-seven countries participated and recruited 4811 patients who were randomized to LAAO versus no LAAO.
Surgeons utilized a variety of closure techniques:
Patients were followed for 3.8 years on average with the primary outcome being ischemic stroke or systemic embolism.
The patients were evenly matched in both groups with average age of 71 years, CHADS2 score of 4.2, permanent afib 29% and 2/3 male.
CABG alone was performed in 20% with 2/3 undergoing concomitant valve procedure.
Overall, 77% of patients were taking oral anticoagulants.
Here’s the Kaplan-Meier curve for the primary outcome:
There was a significant reduction of 33% in the primary endpoint which occurred in 4.8% of LAAO patients versus 7.0% of non-LAAO patients
There was no signal of increased heart failure risk although the 7% rate of hospitalization for heart failure at 3.8 years was improbably low raising the possibility of failure to capture all these episodes.
To my surprise, there was no increase in reoperation for bleeding or 20 day mortality. LAAO procedure resulted in a 6 minute increase of bypass time.
This study now provides support for performing LAAO on high CHADS2 score afib patients at the time of cardiac surgery. Please note that the majority of these patients stayed on oral anticoagulants through the duration of the study and the trial does not support removal of OAC in this situation.
Also, it does not support the approach the surgeon in Florida follows in patients who do not have a history of atrial fibrillation. There are no data supporting that approach.