الفهرس 
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Abstract
Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia. Moreover, its prevalence and incidence are expected to increase progressively over the coming decades. The most fearful complication of AF is stroke due to its devastating consequences resulting in disability and in some instances increased mortality. This usually translates into huge social and economic burden for the individuals and health authorities. Besides, AF related strokes are characterized by worse outcome with longer hospital stay, greater disability and higher incidence of recurrence. Thus, stroke prevention in these patients is of paramount importance.Oral anticoagulants have proved efficacy for thrombo-prophylaxis in patients with AF. However, this was associated with a parallel increase in the bleeding complications particularly in patients with high bleeding risk. Extensive research has been done to explore an alternative treatment option with high efficacy and safer profile. In a pivotal study, Blackshear and Odell reviewed 23 studies of patients with AF and identified the left atrial appendage as the primary source of emboli in non-valvular AF accounting for approximately 91% of thrombi.
Based on that hypothesis, mechanical left atrial appendage occlusion (LAAO) has emerged as a substitute for oral anticoagulants for thromboembolic prevention in patients with AF especially in those ineligible for long term anticoagulation. Several devices and approaches have been developed for that purpose with variable results. Several percutaneous and surgical devices are now approved worldwide, and many more are in clinical development and being evaluated in research trials.
The landmark PROTECT-AF trial followed by the PREVAIL study declared that LAAO with the Watchman device was non-inferior to warfarin therapy. However, these studies enrolled patients who were eligible for oral anticoagulation. Subsequently, the Watchman device was approved by the FDA for its use in the United States. On the other hand, several non-randomized registries evaluated LAAO using the Amplatzer occluders and claimed favorable results.
Despite the progress and the growing body of evidence, left atrial appendage occlusion was perceived as an area of controversy and debate. The limitations
and pitfalls of this technology needed to be highlighted along with the advantages it offered. The appropriate application of this therapy and its short and long-term outcomes needed to be studied and addressed.
Therefore, the aim of this study was to explore the different aspects of this technology to demonstrate its merits and flaws with special focus on its safety and effectiveness. For this purpose, we recruited patients with non-valvular AF who were ineligible for long term anticoagulation or with high bleeding risk.
The study was conducted in two distinct consecutive phases. In phase I, 20 patients were offered LAAO using the Watchman device representing the first Egyptian experience of this novel therapy. Phase II was conducted overseas in Liverpool Heart and Chest Hospital and included 83 patients (after screening of 143 referrals) and LAAO was done using the Amulet device. This was followed by Intensive imaging follow up with either transoesophageal echocardiography (TOE) or contrast-enhanced cardiac CT along with close clinical follow up for a mean of 8 and 12 months in phase I and II respectively.
In phase I, technical procedural success was achieved in all 20 patients (mean age 76 and mean CHAD2S2-VASc score 4.3). No major procedure or device- related adverse events were noted. TOE showed adequate LAA seal without any major leaks or device related thrombi. Furthermore, no stroke, systemic embolism or major hemorrhage were reported during clinical follow up. One mortality case of non-cardiovascular cause was noticed.
In phase II, following assessment by a multidisciplinary team, 83 (58%) patients (76±8.2 years, 67.5% men, mean CHAD2S2-VASc score 4.4 ±1.3) were enrolled for LAAO; all were ineligible for long term oral anticoagulation, and 95% had prior history of serious bleeding events including intracranial haemorrhage in 59%. Technical implant success with an Amulet device was achieved in 82 (98.8%). Procedure related adverse events were seen in 5 (6.0%) patients, including 2 device embolizations (both needing open surgery, one leading to in- hospital death), one pulmonary edema, and 2 bleeds requiring blood transfusion. No peri-procedural stroke or pericardial effusion occurred. Dual antiplatelet therapy (DAPT) was prescribed post-procedure for 6 weeks followed by a single antiplatelet drug for 6 months.