A Novel Approach to the Prevention of Thromboembolism in Atrial Fibrillation

To the Editor:

The review article on atrial fibrillation (AF) that was recently published in the Texas Heart Institute Journal emphasizes the importance of stroke prevention as a therapeutic goal in AF. ¹ The author advises long-term anticoagulation for all patients with AF who are 75 years or older, and for those patients below 75 years of age who have identifiable risk factors for systemic thromboembolism. While this approach is quite standard, our group has recently published an alternative, surgical solution to the problem of thrombo-embolism in patients with AF. ² Whenever feasible, we extirpate the left atrial appendage in almost all patients undergoing open-heart surgery, irrespective of their rhythm at the time of surgery. The logic of the procedure is simple: the site with the highest potential for thrombus formation is removed in patients already in AF, as well as in those in sinus rhythm who are likely to develop AF later. It is well known that cardiac disease is a risk factor for AF, because AF occurs more frequently in heart patients than in the general population; moreover, in patients with AF of nonrheumatic origin, most atrial clots form in the left atrial appendage. ³

We described our experience with the procedure in 437 patients over a 2-year period. ² The left atrial appendage was excised (and the atriotomy closed with staples or sutures) in patients undergoing open-heart surgery, unless the appendectomy was deemed a technical risk in some cases of reoperation. No intra-atrial clots were found on follow-up after surgery. Any late strokes that occurred were attributable to a source other than an intra-atrial clot. Since the procedure is simple and adds little to the morbidity rate of the main operation or the time taken to complete it, we feel that appendectomy should be considered routinely in all patients undergoing open-heart surgery. The protective advantage of LAA obliteration will become apparent in many of these patients when they develop AF in the years that follow surgery.

After successful animal experiments, we extended the concept further by examining the feasibility of endoscopic obliteration of the left atrial appendage in human beings. Seven patients with AF, who did not have coronary disease but had risk factors for stroke (hypertension, prior embolic episode, diabetes, or recent congestive heart failure), underwent successful thoracoscopic left atrial appendage obliteration through a left thoracotomy. ² Somewhat similar work, although undertaken only in animals and fresh cadavers, was published earlier by Odell and colleagues, ⁴ who recommended the procedure for AF patients unable to take oral anticoagulants. If long-term follow-up in our patients confirms a reduction in the overall incidence of stroke, ² the thoracoscopic procedure will gain wider acceptance—especially for use in patients with AF who have contraindications to oral anticoagulation and in those who are more likely to develop strokes. In the meanwhile, intraoperative removal of the left atrial appendage can still be a routine part of other cardiac surgical procedures.

If one considers that the number of people in the general population who have AF is quite significant (more than 4 million in the United States and Europe) and that about 35% of these patients will have a stroke during their lifetimes (5% annual stroke rate in untreated AF patients), the enormous public health burden of AF becomes evident. ^2,3 Even in patients undergoing anticoagulation, it has been estimated that obliteration of the left atrial appendage should reduce the risk of stroke by an additional 50%. ³

Therefore, the procedure has the potential of being one of the more important public health advances in recent times.