Summary
Background
Left atrial appendage (LAA) closure using the WATCHMAN™ device (WM) may be considered in patients with non-valvular atrial fibrillation (AF) and a high-risk of stroke who are ineligible for long-term oral anticoagulation (OAC).
Aim
To report our single-centre preliminary experience, focusing on feasibility, safety and short-term efficacy of this procedure.
Methods
Patients implanted from December 2013 to February 2014 were included. The procedure, performed under general anaesthesia, was guided by fluoroscopy and transoesophageal echocardiography (TOE). Efficacy was defined as the ability to implant the WM with no peridevice leak; safety was defined as the occurrence of in-hospital and 45-day events, including stroke, pericardial effusion and device migration.
Results
Twenty-three patients (mean age: 77.6 years; 16 men [69.6%]; mean CHA 2 DS 2 -VASc score: 5) underwent WM implantation. The indication was gastrointestinal bleeding in 14 (60.9%) patients, cerebral haemorrhage in eight (34.8%) and need for long-term ticagrelor after stent thrombosis on clopidgrel in one (4.3%). Procedural success was 95.7% (95% confidence interval: 77.3–100.0); efficacy was 90.9% (95% confidence interval: 71.0–98.7). The size of the implanted WATCHMAN™ device was in agreement with the prespecified size, based on measurement of the LAA, in 56.5% of cases. In five cases, the criteria were not met, but the device was successfully implanted in four of these, with a good result (80.0%). Treatment at discharge was a reduced dose of anticoagulant plus aspirin in three cases (13.0%) or antiplatelet therapy alone in 20 cases (90.9%). No adverse event occurred during the index hospitalization or at 45 days. At 45 days, the LAA was sealed in 18/19 patients (94.7%) on TOE, with no difference between those who did or did not have an implanted device of the prespecified size.
Conclusion
When performed by an operator trained in the procedure, WM implantation appears to be safe and effective. This procedure may be considered in patients at high-risk of stroke who are ineligible for long-term OAC.
Résumé
Contexte
L’occlusion de l’auricule gauche (AG), par une prothèse de WATCHMAN™, peut être proposée à certains patients présentant une fibrillation auriculaire (FA) non valvulaire, un risque élevé d’accident vasculaire cérébral embolique (AVC) et une contre-indication au traitement anticoagulant oral (ACO) de longue durée.
Objectif
Rapporter les résultats préliminaires de notre centre, en termes de faisabilité, sécurité et efficacité à court terme.
Méthodes
Les premiers patients implantés entre décembre 2013 et février 2015 ont été inclus. L’intervention était réalisée sous anesthésie générale, et la procédure guidée par radioscopie et échographie trans-œsophagien (ETO). L’efficacité de la procédure était définie par l’implantation d’une prothèse sans fuite péri-prothétique résiduelle et la sécurité par la proportion de patients ayant présenté un AVC, un épanchement péricardique ou une migration de prothèse durant l’hospitalisation ou à 45 jours.
Résultats
La procédure a été tentée chez 23 patients (77,6 ans ; 16 hommes [69,6 %] ; 12 FA permanent [52,2 %] ; CHA 2 DS 2 -VASc score moyen : 5 ; HAS-BLED score moyen : 4,8). L’indication était une hémorragie digestive dans 14 cas (60,9 %), cérébrale 8 fois (34,8 %) et la nécessité d’un traitement par ticagrelor justifié par une thrombose de stent survenue sous clopidogrel 1 fois (4,3 %). La prothèse était implantée avec succès dans 95,7 % des cas (intervalle de confiance de 95 % : 77,3–100,0) et de manière efficace dans 90,9 % (intervalle de confiance de 95 % : 71,0–98,7). La taille de la prothèse implantée était celle choisie à partir des mesures des diamètre et longueur maximaux de l’AG dans 56,5 % des cas. Bien que les critères d’implantation ne soient pas tous réunis chez 5 patients, la prothèse était implantée avec succès 4 fois (80,0 %). Le traitement de sortie était une dose réduite d’un anticoagulant 3 fois (13,6 %) et une antiagrégation plaquettaire seule chez 20 patients (90,9 %). Aucun événement n’a été déploré dans les suites de la procédure ou lors du contrôle. À 45 jours, l’AG était occlue chez 18 des 19 patients contrôlés par ETO (94,7 %) sans différence entre ceux pour lesquels la taille de la prothèse respectait les mesures ETO pré-implantation et les autres.
Conclusion
Réalisée par un opérateur expérimenté dans la ponction trans-septale et ayant bénéficié d’une formation spécifique, l’implantation d’un WM est une procédure sûre et efficace. Elle peut être envisagée chez les patients présentant un haut risque d’AVC et une contre-indication au traitement ACO au long cours.
Background
Atrial fibrillation (AF) is the most common sustained arrhythmia, with an estimated prevalence of 6 million among all Europeans . As AF mainly affects elderly people, its prevalence is expected to increase in parallel with the increasing age of the population, with a projected doubling of the disease in the next 50 years .
Stroke is the most serious complication of AF, and occurs in 5% of non-anticoagulated patients every year, with an incidence that increases from 1–5% in individuals aged 50–59 years to 23.5% for those aged 80–89 years . Randomized controlled trials have shown that the oral anticoagulant (OAC) warfarin is effective in preventing stroke – more so than aspirin or the combination of aspirin plus clopidogrel – but is associated with a high-risk of bleeding complications . Non-vitamin K antagonist oral anticoagulant anticoagulants (NOACs) have a favourable risk-benefit profile, with significant reductions in stroke, intracranial haemorrhage and mortality compared with warfarin, but with similar major bleeding complications and an increase in gastrointestinal bleeding .
In autopsy and echocardiography studies, the left atrial appendage (LAA) was shown to be the source of thrombi in > 90% of patients with non-valvular atrial fibrillation and a recent embolic event . Percutaneous catheter-based devices have been developed to close and thereby effectively exclude LAA from the systemic circulation. Pilot studies have shown acceptable risk-benefit ratios for these non-pharmacological alternatives to chronic warfarin therapy . The PROTECT-AF study provided the first evidence from a randomized clinical trial that a strategy of LAA occlusion using the WATCHMAN™ device (Boston Scientific, Natick, MA, USA) can be non-inferior to anticoagulation with warfarin for a combined endpoint of stroke, cardiovascular death and systemic embolism in patients with non-valvular atrial fibrillation .
The objective of this study was to describe our first year of experience with the WATCHMAN™ LAA system in terms of feasibility and safety, and to discuss perspectives to improve patient and device selection.
Methods
Patient selection
Patients with paroxysmal, persistent or permanent non-valvular AF were eligible for LAA closure if they had a definite contraindication to long-term OACs and if the procedure was considered achievable based on images obtained from transoesophageal echocardiography (TOE). The final decision was taken by a medical team, including a gastroenterologist, a neurologist, a geriatrician and the cardiologists involved. The CHA 2 DS 2 -VASc (Cardiac failure, Hypertension, Age ≥ 75 years [Doubled], Diabetes, Stroke [Doubled], Vascular disease, Age 65–74 years and Sex category [Female]) and HAS-BLED (Hypertension, Abnormal liver/renal function, Stroke, Bleeding, Labile international normalized ratio, Elderly [age > 65 years], Drugs/alcohol) risk scores were calculated in all cases.
WATCHMAN™ LAA system
The WATCHMAN™ system is a three-part system consisting of a transseptal access sheath, a delivery catheter and an implantable nitinol device. The system is designed to facilitate device placement via femoral venous access via the transseptal route into the LAA. The 14 F transseptal access sheath is available in a double- or single-curve configuration. The access sheath is used to gain access to the LAA, and serves as a conduit for the delivery catheter. The WATCHMAN™ device comprises a self-expanding nickel titanium (nitinol) frame structure, with fixation barbs and a permeable polyester fabric that covers the atrial facing surface of the device. The implant is constrained in a 12 F sheath (delivery system) until deployment in the LAA. The WATCHMAN™ device is available in diameters of 21, 24, 27, 30 and 33 mm, to accommodate the unique anatomy of each patient’s LAA. The device is deployed by retracting the sheath covering the device; it can be partially recaptured and redeployed if the implant location is deemed unsatisfactory, or recaptured completely if a device of a different size is determined to be more suitable.
Device implantation
All procedures were performed in a catheterization laboratory under general anaesthesia. The medical team involved two interventional cardiologists, one cardiologist specialized in echocardiography and trained for the procedure and one anaesthesiologist. TOE was used for preprocedural evaluation of the LAA and implantation guidance. The presence of a thrombus within the LAA was a contraindication for the procedure. The size of the LAA was determined by the measurement at the landing zone of the device, 10 or 20 mm distal to the orifice, beyond the left lateral ridge, adjacent to the circumflex artery. The diameter at the landing zone was evaluated in four views (0°, 45°, 90° and 135°). The number of lobes was assessed, and the distance between the landing zone and the apex of the primary lobe was measured, as it represents the usable LAA length. If the appendage was particularly angulated, the length was measured before the angulation.
The ratio of maximal to minimal diameter of the LAA defined the shape at its orifice as circular (1.0–1.1), semielliptical (1.2–1.3) or elliptical (≥ 1.4). The choice of the size of the device was based on the maximal diameter at the landing zone and the length of the LAA measured in the primary lobe from the landing zone to the tip, at a mid left atrium pressure level ≥ 10 mmHg.
The device size was chosen to be 8–20% larger than the diameter of the LAA body, to have sufficient compression for stable positioning and anchoring of the device. Therefore, the diameter of the LAA had to be > 17 mm (20% compression of a 21 mm WATCHMAN™ device) or < 30 mm (8% compression of a 33 mm WATCHMAN™ device). Moreover, the length of the LAA had to be greater than or equal to the maximal landing zone diameter, because the sheath-constrained length of the WATCHMAN™ device is very similar to its unconstrained diameter once deployed. Accordingly, a ratio of maximal diameter to maximal length ≤ 1 is required.
After transseptal puncture, the pigtail catheter was carefully advanced through the access sheath into the distal LAA under fluoroscopic guidance. The access sheath was then advanced over the pigtail catheter. Opacification of the LAA is usually done in two oblique views at 20° (cranial 30° and caudal 30°). The access sheath was advanced until the access sheath marker band corresponding to the device size was at the level of the landing zone. Proper device positioning was confirmed by angiography and echocardiography.
The pigtail catheter was slowly removed and the delivery system was advanced into the access sheath under fluoroscopic guidance, until the most distal marker band was aligned with the most distal marker band on the access sheath. The delivery system was stabilized, and the access sheath was retracted and snapped together to form the access sheath/delivery system assembly. The WATCHMAN™ device was deployed by retracting the assembly. Proper positioning and stability were verified by TOE and angiography (tug test) before device release.
After implantation, the size of the device at the landing zone was measured in the four index views, to assess the decompression percentage and to identify a protrusion in the LAA or a peridevice flow. Compression of the implanted device was optimal, suboptimal or inappropriate when it was between 8% and 20% in, respectively, 4, 2, 3 or < 2 views. Transthoracic echocardiography was performed 3 hours later and on day after implantation, to rule out pericardial effusion and device migration.
Medical treatment and follow-up
Heparin was given during the procedure (60 IU/kg), immediately after the transseptal puncture, and was stopped after implantation.
After a successful event-free procedure, patients were discharged with an individualized antithrombotic treatment depending on the characteristics of the bleeding: either aspirin alone (75 mg/day) or combined with clopidogrel (75 mg/day) or an anticoagulant at a low-dose.
TOE imaging was planned at 45 days to assess residual peridevice flow and device stability and position, as well as at follow-up visits at 6 months, 12 months and then every year for neurological assessments.
Endpoints
Feasibility was assessed as the proportion of successful device implantations. Efficacy was determined by the percentage of LAAs that were optimally sealed after the procedure and at 45 days, defined as an absence of or minimal flow around the device (jet ≤ 5 mm) evaluated by TOE.
Compliance with the planned strategy was defined as the proportion of implanted devices with a size in agreement with the prespecified evaluation, based on TOE measurement of the maximal diameter and length of the LAA. The effect of agreement with or deviation from the prespecified evaluation on the immediate and mid-term results was assessed, focusing on compression, protrusion and leakage (jet > 5 mm) after implantation, and sealing or migration at 45 days.
Safety was evaluated by the occurrence of in-hospital events, mainly pericardial effusion, device embolization, procedure-related stroke and 45-day clinical outcome, focusing on stroke or transient ischaemic attack and device embolization.
Statistical analysis
Continuous variables are presented as means, with standard deviations and minimum and maximum values. Estimates of the frequency of occurrence of events are expressed as percentages or rates. PASW Statistics 17.0 software (IBM, Armonk, NY, USA) was used to perform the statistical analysis.
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