CORRESPONDENCE: LETTER TO THE EDITOR
Does Percutaneous Closure of the Left Atrial Appendage Prevent Stroke in Atrial Fibrillation?
Claudia Stöllberger, MD*,
Josef Finsterer, MD and
Birke Schneider, MD
* KA Rudolfstiftung, 2nd Medical Department, Steingasse 31/18, Juchgasse 25, Vienna A-1030, Austria (Email: claudia.stoellberger{at}chello.at).
With great interest we read the study by Ostermayer et al. concerning percutaneous left atrial appendage (LAA) occlusion using the PLAATO (percutaneous left atrial appendage transcatheter occlusion) system in 111 patients with atrial fibrillation (AF) (1). Although this technique seems very attractive, several concerns remain.
- 1 The investigators state that the PLAATO device has been shown to be safe and effective in animal experiments. However, long-term results are still lacking because follow-up data in 6 of 25 dogs of the initial study have not yet been published (2).
- 2 Transient ischemic attack (TIA) or stroke or embolic risk factors were criteria for patient inclusion. Thus, it remains unclear why only stroke and not TIA was regarded a primary or secondary end point. Were all patients investigated by a neurologist to look for TIA and stroke at the follow-up visits?
- 3 When assessing angiographically the adequacy of LAA occlusion, why did the researchers use the proximal and not the distal dye flow, which appears to be the more logical approach? Apparently both methods were used, but did they yield the same results? Why was LAA occlusion assessed as "successful" also in cases with "mild" or "trace" leaks? The investigators do not exactly state in how many patients complete LAA occlusion was achieved using the angiographic method.
- 4 Evaluating the adequacy of LAA occlusion by echocardiography, it again remains unclear why mild and trace leaks were defined as "successful" as it is known from surgical studies that an incompletely occluded LAA may facilitate thrombus formation and eventually embolism. The data do not show in how many cases leak size increased, decreased, or if new leaks developed. Did patients with leaks immediately after the procedure or during follow-up receive oral anticoagulation? Overall, complete LAA occlusion was present in only 35% of patients at one month and 34% at six months, respectively.
- 5 The 6.6% annual mortality is quite high and exceeds the 4% found in a previous observational AF study (3). An oversized PLAATO device owing to its proximity may impair flow in the circumflex branch of the left coronary artery. Furthermore, the LAA has hemodynamic and endocrine properties, and LAA elimination may aggravate heart failure (4). More detailed information about the cardiac deaths, therefore, would be desirable.
- 6 Despite "successful" LAA closure, two strokes and three TIAs occurred. Thus, the annual event rate for stroke and TIA is 5.5%. Because AF is associated with a prothrombotic state (5), just by closing the LAA not all sites of thrombus formation are eliminated. In addition, one patient required surgery, and nine procedure-related serious adverse events occurred in seven patients, resulting in a complication rate of 6% to 7%.
Overall, the advantage of the PLAATO system in patients with AF and a contraindication for anticoagulant therapy has not at all been proven. Because long-term results are lacking, PLAATO at present cannot be recommended as an alternative to oral anticoagulation in AF patients.
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References
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- Ostermayer SH, Reisman M, Kramer PH, et al. Percutaneous left atrial appendage transcatheter occlusion (PLAATO system) to prevent stroke in high-risk patients with non-rheumatic atrial fibrillation. Results from the international multi-center feasibility trials J Am Coll Cardiol 2005;46:9-14.[Abstract/Free Full Text]
- Nakai T, Lesh MD, Gerstenfeld EP, Virmani R, Jones R, Lee RJ. Percutaneous left atrial appendage occlusion (PLAATO) for preventing cardioembolism. First experience in canine model Circulation 2002;105:2217-2222.[Abstract/Free Full Text]
- Stöllberger C, Chnupa P, Abzieher C, et al. Mortality and rate of stroke or embolism in atrial fibrillation during long-term follow-up in the Embolism in Left Atrial Thrombi (ELAT) study Clin Cardiol 2004;27:40-46.[Medline]
- Stöllberger C, Schneider B, Finsterer J. Elimination of the left atrial appendage to prevent stroke or embolism? Anatomic, physiologic, and pathophysiologic considerations Chest 2003;124:2356-2362.[Abstract/Free Full Text]
- Conway DS, Buggins P, Hughes E, Lip GY. Relationship of interleukin-6 and C-reactive protein to the prothrombotic state in chronic atrial fibrillation J Am Coll Cardiol 2004;43:2075-2082.[Abstract/Free Full Text]
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