Abstract 18131: Canadian Multi-center Experience With WATCHMAN for Percutaneous Left Atrial Appendage Closure
Bibliographic record
Abstract
Background: There is limited data with WATCHMAN for left atrial appendage (LAA) closure in patients with nonvalvular atrial fibrillation (AF) and contraindications to anticoagulation. The purpose of this study was to evaluate the safety and efficacy of WATCHMAN in our early Canadian experience. Methods: We report our consecutive series of patients who underwent WATCHMAN implantation at 4 Canadian centers (Vancouver General Hospital, Montreal Heart Institute, Hamilton General Hospital and Ottawa Heart Institute). Indications for LAA closure were CHADS2≥1, and contraindication/intolerance to or failure on anticoagulation. All cases were done under general anesthesia and TEE guidance. Majority of patients received dual antiplatelet therapy (DAPT) for 3-6 months after implant. Follow-up TEE was typically performed at 1-6 months post-procedure. Results: Ninety patients underwent LAA closure with WATCHMAN from May 2013 to June 2015. The mean age was 75.0 ± 7.9. The mean CHADS2 score was 2.9 ± 1.2, CHADS-VASc score was 4.4 ± 1.5, and HASBLED score was 3.2 ± 1.2. Permanent AF was present in 66.7% and paroxysmal AF in 33.3%. Indications for LAA closure were prior bleeding in 81 patients (90.0%; 74 major bleeding, and 7 minor bleeding), 9 were deemed high-risk for bleeding (renal failure, cirrhosis, labile INR, esophageal ulcers, on DAPT), and 1 with recurrent strokes on warfarin. Procedural success was 97.8% (88/90), with one device embolization (snared percutaneously) and one implant failure due to inadequate LAA depth. There was no procedural stroke/TIA, death, MI, or cardiac tamponade. There were 3 major bleeding that required transfusions. Mean hospital stay was 1.4 ± 1.8 days. Antithrombotic therapy post-implant included DAPT in 66/90 (73.3%), anticoagulant in 21/90 (5 warfarin, 16 direct anticoagulant), and aspirin alone in 3/90. Follow-up TEE was available in 53 patients, there was 1 device-associated thrombus (treated successfully with anticoagulation), and 18 peri-device leaks (all <5mm). Mean follow-up was 173.8 ± 117.3 days, with no stroke or death, but there was 1 TIA and 3 major bleeding. Conclusion: In our early Canadian experience, WATCHMAN for LAA closure in patients contraindicated to anticoagulation is safe and effective.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".