The 3rd International Symposium on Left Atrial Appendage (ISLAA) 2015 was held February 6-7, 2015 at the Marina del Rey Marriott in Los Angeles, California. This year’s event included live cases utilizing the LARIAT Suture Delivery Device (SentreHEART, Inc.) and AtriClip (AtriCure, Inc.), updates in clinical trials regarding the left atrial appendage (LAA), how to create a LAA program at a center, and anticoagulation and treatment options in the high-risk patient population.
ISLAA 2015 kicked off with a welcome and overview from course directors Dr. Andrea Natale, Dr. Saibal Kar, and Dr. Dhanunjaya Lakkireddy. Dr. Samuel Asirvatham presented the first session, describing in detail the anatomy of the normal LAA as well as its variations and role in relation to arrhythmias. The LAA is a muscular structure with heterogeneous orientation of muscle fibers towards the LAA apex from the ostium. He also presented the physiological aspects of the LAA, highlighting that it is a major secretor of atrial natriuretic peptide (ANP). Dr. Luigi Di Biase then presented on the role of the LAA in systemic thromboembolization. In discussing the risk of stroke in atrial fibrillation (AF), the LAA is the main contributor in 91% of patients. He correlated the stroke risk with CHADS2 and CHA2DS2-VASc scores, and presented randomized control studies that show the need to provide anticoagulation to patients with a CHADS2 score of 1.
Dr. Andrea Natale explained the role of the LAA in the triggering and maintenance of AF. He focused on the non-pulmonary vein triggers (non-PV) and their role in scar related to AF (including persistent AF). Various studies highlight the importance of ablating non-PV triggers and other methods to exclude the LAA and decrease stroke risk.
Dr. Amin Al-Ahmad presented risk assessment tools for stroke prophylaxis and bleeding. He explained the historical origin, initial trials, and the usefulness of the CHADS2 and CHA2DS2-VASc scoring systems to predict the risk of stroke. He highlighted the role of antiplatelet agents, and focused on the trials that led to the use of warfarin. He also spoke about predicting the risk of bleeding in patients that are taking anticoagulation using the HEMORR2HAGES and HAS-BLED scoring systems.
Dr. Apostolos Tzikas presented on the management of antiplatelet therapy and anticoagulants in patients with coronary artery disease (CAD). He highlighted guidelines that are used to manage patients with CAD and AF, stating that antithrombotic therapy should be individualized based on patient risk and benefit. He focused on antithrombotic treatment protocols that are used in patients undergoing LAA closure, and included an emphasis on ACP closure devices. He concluded by saying LAA closure may be considered in patients with AF and CAD who have an extremely high risk for bleeding.
Dr. Kar and Dr. Moussa Mansour participated in a debate on whether “Everyone with a CHADS2 score of 2 or more should be considered for LAA closure/ligation.” In support, Dr. Kar highlighted the major clinical trials and their incidence of stroke, comparing the PROTECT AF, CAP Registry, PREVAIL, CAP2 Registry, and trials involving the WATCHMAN Left Atrial Appendage Closure Device (Boston Scientific). He said the WATCHMAN device is superior to warfarin in preventing hemorrhaging strokes, and improves survival rates by preventing strokes. He concluded that LAA occlusion should be considered in all patients with a CHADS2 score of 2 or more.
Dr. Mansour opposed this viewpoint, stating that despite good evidence on the WATCHMAN device and little evidence on other LAA closure devices, there are not many completed randomized trials comparing these occlusion devices with warfarin or novel oral anticoagulants (NOACs), and we should proceed with caution. He described the faults and adverse events in these trials, and argued that these devices are not yet ready to be made a first-line therapy. He presented data that supports that NOACs are a better alternative to warfarin. He concluded by asking for more information on the LAA closure devices before patients with a CHADS2 score undergo LAA occlusion.
A practical guide to anatomic implications on the choice of LAA exclusion devices was presented by Dr. Shepal Doshi. He provided an in-depth explanation on the LAA anatomy, focusing on the body/landing zone and left circumflex artery in correlation to a LAA occlusion device. He also described the importance of considering the shape of the LAA when deploying the LAA device, and presented a challenging case.
Dr. John Camm discussed real-world data on long-term morbidity and mortality of patients with AF who can’t take anticoagulation. He outlined the indications for anticoagulation and the LAA occlusion devices. He stressed the importance of anticoagulation in the prevention of stroke, but said caution should be used when making decisions about patients with chronic renal insufficiency and intracranial bleeding risk.
Next, Dr. Randall Lee presented on the management of patients who have failed oral anticoagulation therapy as well as the role of LAA exclusion therapy. He discussed treatment options, with a focus on LAA exclusion. He also explained the available LAA devices in the U.S. and the major trials they were used in. He spoke extensively on the LARIAT, and discussed the effectiveness of using this device for the prevention of strokes and decreased burden of AF in patients with a contraindication to oral anticoagulation therapy.
Dr. Kar then presented multicenter LARIAT data in patients with a contraindication to oral therapy, discussing initial and updated study results as well as adverse events. Data supporting the decrease in event rates to less than 1% in patients with a CHADS2 score of 2 or more, compared to an expected event rate of 6%, is an 80% reduction. He outlined the steps to reduce the complication rates of LARIAT procedures. In his experience, the use of a micropuncture needle has decreased the incidence of pericardial effusions requiring drainage and myocardial perforation compared to the use of a large bore needle. In addition, the use of colchicine and/or NSAIDs post procedure have decreased the incidence of pericarditis.
Dr. James Cox explored the topic of choosing the right candidates for LAA exclusion. He explained the different types of LAA occlusion devices, including a special focus on surgical techniques and the AtriClip procedure. He also presented data on LAA electrical isolation and freedom from AF. He believes that patients with a history of AF who are having open-heart surgery should have the AtriClip procedure performed. When considering the cost of medical management of stroke patients, the cost effectiveness of an LAA exclusion procedure is superior compared to patients on oral anticoagulation protocols.
Dr. Mansour then presented on the evolution of percutaneous techniques in LAA occlusion/exclusion, with a focus on the next generation of devices. He discussed various studies that have been conducted during the evolution of these devices, and presented data on the AMPLATZER Cardiac Plug (ACP) device (St. Jude Medical), of which stroke risk is reduced by 59% and bleeding risk is reduced by 61%. He also talked about the complications and precautions that need to be taken to reduce risk in patients receiving the LARIAT. In general, more data and randomized trials are needed.
Dr. Miguel Valderrábano questioned whether LAA occlusion/exclusion can allow for the discontinuation of Coumadin in patients with AF and a higher risk for thromboembolization. Evidence from previous trials show AF is a hypercoagulable state; Dr. Valderrábano also went over the other risks factors that can predispose AF patients for stroke, such as aortic plaques. He feels that anticoagulation can be withdrawn after LAA occlusion in high CHA2DS2-VASc patients if other risk factors are excluded, such as carotid or aortic atheromatous plaques, and if the patient is at high risk for bleeding.
In Dr. Thorsten Lewalter’s session on the Munich Expert Consensus Document on LAA Closure, he included information on defining pericardial effusions post LAA occlusion, bleeding, and defining what classifies a major bleeding event. This could be the first document on LAA closure that can guide and pave a path to a consensus document for physicians in practice to utilize.
Dr. Vivek Reddy presented 5-year follow-up data on the WATCHMAN device in patients that are eligible for Coumadin. He also presented information from the PROTECT AF and PREVAIL studies, including study design, primary efficacy endpoints, incidence of adverse events, and results. Disabling strokes and hemorrhagic strokes were higher in the warfarin arm compared to the WATCHMAN arm, and device therapy was superior to the use of warfarin. In conclusion, overall safety event rates are similar with local therapy with LAA closure, but there is an upfront risk: 1.2% rate of cardiac tamponade in CAP/PREVAIL/CAP2 combined.
Dr. Lakkireddy spoke on post-procedural LAA exclusion leak, including mechanisms, implications, and treatment. He described the different types of percutaneous and surgical LAA exclusion devices, including efficacy and complications, and also presented data from early surgical experiences, epicardial clip studies, and the EXCLUDE study. Dr. Lakkireddy discussed the mechanisms of leak in different types of devices, focusing on the presentation of thrombus with an LAA excluder. He felt that the presence of a clot has no relation to the presence of a lead or a prominent remnant stump. Clot formation post LARIAT is most likely at the site of the ostium where the knot was placed on the endocardial surface; dual antiplatelet therapy for 4-6 weeks can possibly prevent the thrombus.
Dr. Jacqueline Saw then discussed the differences between the ACP and amulet devices, including information on design as well as mechanical and functional characteristics. No studies comparing the two have been conducted. Dr. Saw explained the advantages of the newer generation amulet device, with the wider lobe, more stabilizing and stiffer wires, larger size (34m), and longer waist length. A head-to-head comparison of the different types of devices, including the amulet and WATCHMAN, is needed.
Two live case presentations with Dr. Kar and Dr. Lee demonstrated the importance of imaging technology and how to avoid possible complications during procedures. They presented factors that need to be taken into consideration when obtaining pericardial access. Once the lasso was in place after the magnets attached, Dr. Kar described potential issues that the operator should be aware of during lasso deployment. A second LARIAT was deployed due to the patient’s posterior lobe. During the procedure, the patient showed signs of ST elevation in the RCA from an air bubble, but this was resolved with 100% oxygen. The patient tolerated the procedure with no adverse events.
Dr. Hasokote Nagaraj presented on post LARIAT management and the efficacy of colchicine. He provided an in-depth review of the pathophysiology behind pericarditis, pericardial effusions, and pleural effusions, and discussed the role of colchicine in other pericardial inflammatory disorders. Dr. Nagaraj presented the protocol for use of colchicine at Nebraska Heart Institute; 0.3 mg colchicine twice a day should be given 3-5 days prior to the procedure and continued for 3-4 weeks post procedure.
Following that session, Dr. Vijay Swarup presented on device sizing and deployment during LAA occlusion using the WATCHMAN device. He explained the available sizes and how to choose the correct one based on the anatomy of the LAA; he also discussed sheath navigation and manipulation of the delivery system based on the position of the lobe. He described the deployment process, the optimal position, post deployment imaging, and follow-up care that should be provided.
The pros and cons of a video-assisted thoracoscopic approach (VATA) versus a minithoracotomy for LAA exclusion were presented by Dr. Basel Ramlawi; this session included pictures and videos of how to exclude the LAA during a VATA and minithoracotomy. Steps need to be taken during the procedure to avoid injury to the left circumflex artery during ligation. He presented studies being conducted using these two methods. He concluded that the surgical approach to exclude the LAA is the best option for patients who have a contraindication to anticoagulation and a high risk for bleeding.
Next, Dr. Tzikas described the steps involved for endocardially deploying an ACP device. Dr. Lewalter and Dr. Doshi spoke on their real-world experience using the WATCHMAN device. Finally, Dr. Ali Khoynezhad presented on the AtriClip procedure with a prerecorded case.
The second day of ISLAA 2015 began with Dr. Asirvatham presenting on systemic anticoagulation and atrial fibrillation, and how to select the right drug for the patient. He discussed the importance of anticoagulation to decrease the risk of stroke, and the effectiveness of warfarin in comparison to newer oral anticoagulants. He also discussed how antithrombotic therapy can predispose patients to intracranial hemorrhage (ICH). It’s important to have protocols in place to guide the use of novel agents.
Dr. Swaminatha Gurudevan provided practical tips for periprocedural use of transesophageal echo (TEE) in LAA exclusion; multiplane TEE is the gold standard, with views including 0˚, 45˚, 90˚, and 135˚. Modes of acquisition and lessons learned using 3D TEE imaging were presented. Multiple TEE images were viewed, analyzing different aspects and parameters in LAA exclusion.
Dr. Tzikas then presented on preventing and managing complications, such as thrombus, perforation, and device embolization, in LAA exclusion procedures. The various characteristics of the LAA (e.g., thin walls, variable anatomy, and blind-ended structure) can also cause complications. Other issues include preventing device embolization by following proper technique and waiting for the device to settle after deployment. It is important to have a management plan for thrombus formation using catheter aspiration and local thrombolysis. He described how air embolism, pericardial effusion, and vascular complications can be avoided by being observant and having clear plans in place.
Novel anticoagulant trials, including RE-LY, ROCKET AF, ARISTOTLE, and ENGAGE AF, were presented by Dr. Michael Ezekowitz. In the RE-LY study, hemorrhagic and major bleeding occurred less in the dabigatran group. The ROCKET AF trial favored rivaroxaban in incidences of ICH and hemorrhagic stroke. He also compared dabigatran and the risk for major bleeding rates, then compared to warfarin. Translating clinical trials into practice must minimize the temporary and permanent discontinuation of the study drug.
Dr. Matthew Earnest presented on post procedural antithrombotic management after LAA exclusion, including incidence of thrombus formation after LAA occlusion in various trials. In a comparison of the WATCHMAN device to the LARIAT procedure in terms of leaks and significance of leaks in relation to strokes, the incidence of thrombus formation post LARIAT was 1.5-2.0%. The presence of clot had no relation to the presence of leak or a prominent remnant stump. More data is needed on anticoagulation and antithrombotic regimen after LAA occlusion.
Next, Dr. Richard Whitlock and Dr. James Edgerton debated on whether the LAA should routinely be ligated during open-heart surgery in patients with AF. Dr. Whitlock described different clinical trials on LAA occlusion and LARIAT data, noting that LAA occlusion appears proactive against stroke in patients with nonvalvular AF. By eliminating the LAA, a 27% reduction in AF burden can occur. Dr. Edgerton highlighted the importance of LAA function and spoke about the LAAOS III study; he argued there is no efficacy in surgical appendage closure, as the stroke rate after 6 months was 11% in patients with successful LAA closure and 15% in unsuccessful LAA closure patients. Routine LAA ligation may be performed if new data can be presented that will identify high-risk AF patients.
Dr. Lakkireddy then presented on LAA exclusion as an adjunctive therapy for AF ablation; he discussed the LAALA AF study, as well as different case series and reports supporting evidence of LAA exclusion. The LAALA AF study focused on LAA ligation and ablation in patients with persistent AF. Recurrence of AF post 12 months in patients with both LAA exclusion and pulmonary vein isolation was 35%, a significant difference compared to patients with pulmonary vein isolation (61%). He concluded that LAA exclusion may reduce the atrial arrhythmia burden by mechanically excluding the triggers, ganglionic plexi, and the substrate for AF propagation.
Dr. Ezekowitz presented a session on the antidotes for oral and systemic anticoagulants that are being developed. He explained different studies, including enrollment criteria, pharmacokinetics, pharmacodynamics, and the preliminary results for idarucizumab (the antidote for dabigatran) and andexanet alfa (for factor Xa inhibitors). These drugs will be useful in treating bleeding associated with new oral anticoagulants.
Dr. John Camm presented on the global burden of AF and the various management options for stroke prophylaxis. He showed data on the practice patterns varying by state, country, and CHADS2 scoring systems based on the ORBIT-AF study, AVERROES study, and the Euro Heart Survey. He concluded that, based on European guidelines on LAA closure, patients with a high stroke risk and contraindicated for long-term anticoagulation were given a Class IIB recommendation.
Dr. Saw discussed the role of CT imaging in LAA exclusion, including the importance of CCTA imaging for evaluating the anatomical characteristics of the LAA (e.g., looking for a thrombus, orifice shape and diameter, LAA shape, and size). She discussed the usefulness of a post closure CT image to assess for leaks, device-associated thrombus, the position of the device, and to rule out pericardial effusion. CT imaging is a feasible alternative to transesophageal echocardiogram for both pre and post LAA closure patients.
Dr. Kar discussed WATCHMAN trials, including characteristics of the device, size, shape, and relevance to the LAA. Pictures and videos were shown to describe the procedural steps, tips, and tricks that attribute to the implant of the WATCHMAN. Dr. Kar also emphasized the importance of the tug test, checking the color flow around the device and reviewing the imaging for evidence of compression.
Dr. Saw explained the characteristics and advantages of the AMPLATZER device, including research trials that have been conducted or are currently in process. The incidence of device embolization was 1.5%, with pericardial effusions being 1.6%. She compared the different devices being used in various research trials, and highlighted the risk of stroke and major adverse events. There are currently 10,000 devices implanted, and the results seem promising. A multicenter, randomized controlled trial comparing the different devices is the next step.
The WaveCrest LAA Occluder (Coherex Medical) and the WAVECREST I Trial were presented by Dr. Brian Whisenant. He described the device, advantages such as retractable anchors, 3 different sizes, and nonthrombogenic and occlusive ePTFE material. He also discussed implantation techniques, stability of the device, and various difficult scenarios. The WAVECREST I Trial showed no device embolization, strokes, or TIAs.
A three-way debate on who should perform a left atrial occlusion/exclusion procedure was conducted by Dr. James Cox (representing the surgical perspective), Dr. Reddy (EP), and Dr. Horst Sievert (interventional). Dr. Cox felt that it is best for the electrophysiologist to be performing the endocardial occlusion, given their expertise in ablation techniques and knowledge of the LAA anatomy. The LARIAT procedure should be performed as a joint procedure between a surgeon and EP expert. The AtriClip and the TigerPaw System (MAQUET) should always be implanted by a surgeon. Dr. Reddy offered his opinion, discussing different techniques. The importance of the CABANA trial will help determine if ablation is a preferred therapy over medical therapy. Dr. Sievert presented different scenarios showing that interventionists can do LAA exclusion/occlusion procedures given their expertise in this field.
Dr. Rodney Horton presented how to set up and grow a successful multidisciplinary LAA exclusion program. He explained the steps and different personnel/roles involved, including the CTA selection criteria, the procedure, and how to manage patient complications. It takes a team approach for a successful LAA program.
Dr. Natale spoke on the cost effectiveness of LAA exclusion compared to long-term oral anticoagulation for risk reduction in patients with AF. He analyzed different strategies for preventing stroke in patients with AF, comparing warfarin to different devices, and LAA occlusion.
Emerging LAA exclusion technologies, such as the Lifetech, Occlutech, Aegis, and PROLIPSIS devices, were presented by Dr. Horton. He differentiated based on epicardial and endocardial advantages and disadvantages.
Dr. Reddy discussed how to design a clinical trial to access the role of LAA exclusion devices in oral anticoagulation therapy patients that are contraindicated for treatment. He explained the need for this type of patient population, why randomization is necessary, and different registries and trials. He noted a correlation in the reduction of stroke in the elderly and those patients on aspirin/Plavix. A randomized trial will be conducted on LAA closure devices.
The symposium concluded with Dr. Natale, Dr. Reddy, Dr. Kar, and Dr. Lakkireddy discussing interesting cases of LAA exclusion. Dr. Lakkireddy thanked the speakers, moderators, and course directors for their help in making this year’s event so successful.
Pre-Symposium Fellow’s Course
Prior to the symposium, Boston Scientific hosted a Fellow’s Summit. Course directors for this event were Dr. Al-Ahmad, Dr. Natale, and Dr. Lakkireddy. An introduction to cardiac anatomy and the cavotricuspid anatomy related to atrial flutter ablation, as well as anatomical barriers that may cause failure of a flutter ablation, were presented by Dr. Asirvatham. He also spoke on different lesion sets, including the pros and cons of different anatomical variations.
Dr. Lakkireddy spoke on new mapping technologies for arrhythmias, stressing that electrophysiologists need to take advantage of all imaging modalities (including CT and MRI) to help guide in the creation of electroanatomical mapping and ablation. Dr. Lakkireddy discussed the various conditions and the use of these technologies for creating a durable ablation lesion set. He briefly spoke on the MediGuide Technology (St. Jude Medical), which has been shown to lead to a decrease in the radiation dosage that patients receive during an ablation.
Dr. Mansour presented a practical approach to the ablation of typical and atypical atrial flutter. He described how to differentiate between the reentrant and focal origins by using the entrainment and overdrive pacing maneuvers. He also explained the annotation technique, using the p wave, and its reliability.
Dr. Noel Boyle offered a session on ablation versus medication in the management of VT. He spoke on the history of medication development for VT, including the various types used and their effectiveness. He also discussed the different trials comparing devices and drugs, and the intricacies behind the device therapies that are used in this patient population. He explained the complications of VT ablation, the algorithm used at UCLA, and the precautions that he feels should be in place at every institution (such as a timeline).
Dr. Natale spoke on ablation of persistent AF and targeting non-PV sites. It is important to know the different types of non-PV triggers, mainly the posterior wall of the left atrium, SVC, coronary sinus, ligament of Marshall, and others that include the LAA, and to look for these during the ablation procedure. Case reports focusing on persistent AF and their results were also presented. He highlighted that as the amount of scar tissue gets worse, the greater the need is to ablate the non-PV triggers in patients with persistent AF.
Dr. Al-Ahmad presenting on mapping and ablation of ventricular tachyarrhythmias. He spoke about the different VT arrhythmia substrates, triggers, morphologies, and the use of imaging for guidance. He delineated different factors that contribute to VT ablation success, various parameters that are influenced during the ablation procedure, and the use of a mechanical support system in patients with low cardiac output.
Concluding this summit was a presentation by Dr. Camm on whether to select a subcutaneous or transvenous ICD for a patient. He explained the characteristics of transvenous and subcutaneous ICDs, their development, complications, and the indications for each type. He also highlighted the effectiveness and guidelines of S-ICDs in clinical trials.
ISLAA 2016 will be held March 11-12th in New York. For more information about the event, and to get videos from the conference, please visit: www.islaasymposium.com