Intraoperative Left Atrial Appendage Occluder Implantation with the Amplatzer Cardiac Plug

Abstract

Left atrial appendage occlusion (LAAO) is an emerging alternative to oral anticoagulation for the prevention of thromboembolic events in patients with atrial fibrillation (AF). Up to one-third of patients undergoing cardiovascular surgery have concomitant AF. Surgical occlusion of the LAA – using ligation, sutures, or staplers – and LAA excision are frequently undertaken in patients undergoing cardiac surgery for other indications. There are observational data that suggest a reduced risk of stroke with surgical LAAO; however, surgical LAAO may also be associated with an increased frequency of AF. Furthermore, these procedures can be complicated by postoperative bleeding and myocardial ischemia. In recent years, randomized trials have supported percutaneously implanted LAAO devices as an alternative to oral anticoagulation, specifically noting a reduction in bleeding complications and comparable stroke risk. We performed a small, pilot study to evaluate the feasibility of intraoperative implantation of a percutaneous LAA occluder – the Amplatzer Cardiac Plug (ACP, Abbott, Illinois) as an alternative to traditional surgical LAAO. While there are more robust data demonstrating the efficacy of the WATCHMAN LAAO device (Boston Scientific, Massachusetts), the ACP has been available in Europe since 2013, and has demonstrated efficacy in large observational registries. Currently, outside of the United States, the second-generation Amplatzer LAAO is one of the most widely used LAAO devices. A series of 11 patients with AF scheduled for cardiac surgery (3 CABG, 5 MV, 2 AV, 1 ASD) with planned surgical LAAO were recruited to have intraoperative ACP implanted in lieu of surgical LAAO. All patients provided written, informed consent and the study was approved by the local institutional review board. Surgical implantation involved standard cardiopulmonary bypass, cardioplegic arrest, and left atriotomy. The ostium of the atrial appendage was exposed using separate 4-O Prolene sutures. Device selection was based on preoperative or intraoperative prebypass TEE, sizing 10 mm from the LAA ostium as per manufacturer’s recommendations. The device was pulled into the loader using standard technique, which was then introduced into the left atrial appendage at which point the anchor lobe was deployed at maximal achievable depth (Figure 1a, Video 1). The disc was then retracted into the LAA, pressed against the os and deployed, followed by attachment to the left atrial wall via the previously placed Prolene sutures (Figure 1b). The entire duration required to complete all steps was less than 3 minutes. Seven of the patients (78.0%) were men and the mean patient age was 73.8 ± 3.08 years. The mean CHADS2 score was 2.3 ± 0.42, and 36% (n = 4) of patients had permanent AF. Nine of the 11 patients planned for implantation underwent successful device placement and were included in the analysis. One patient had operative complications prior to attempted device implantation. One patient had a LAA that was larger than suitable for percutaneous implantation, and therefore underwent surgical over-sewing of the LAA. In the remaining nine patients the ACP device was successfully implanted, and clinical and echocardiographic follow-up was available at 7.96 ± 0.77 months. During follow-up. there were no adverse clinical events, including stroke/TIA or death. There were no device-related adverse events or complications noted. At 6 months, TEE met criteria for oral anticoagulation discontinuation in all patients – with complete seals in seven patients and two patients with peri-device leaks less than 5 mm (Figure 1c), No device-related thrombus was noted. In this small cohort study, we evaluated the feasibility of surgical device implantation for LAAO using an approved device designed for percutaneous implantation. Intra-operative TEE was satisfactory for device size selection, and implantation resulted in satisfactory clinical and echocardiographic outcomes out to 6 months. While not designed for surgical implantation, the nitinol base frame was optimal for device compression and seating in the LAA during surgical implantation. While two implants had residual gaps with residual flow, these were within acceptable limits for percutaneous implants and the long-term implications for stroke risk appear to be minimal. Of note, limitations of traditional surgical techniques include incomplete occlusion (10–77%), atrial tears resulting in tamponade and a remnant thrombogenic