Frequently Asked Questions
1. What is WATCHMAN™
The WATCHMAN™ Left Atrial Appendage (LAA) Closure Device is a minimally invasive device solution designed to help reduce risk of stroke in patients with non-valvular AF. It is designed to be permanently implanted at or slightly distal to the ostium (opening) of the LAA. The device consists of a self-expanding nickel titanium (nitinol) frame structure with fixation anchors and a PET fabric cover designed to prevent clots from exiting the left atrial appendage of the heart, a thumb-sized pouch on top of the left side of the heart, which is known as the main source of emboli responsible for stroke in patients with atrial fibrillation1.
2. What is Atrial Fibrillation (AF) and how many people are affected?
Atrial fibrillation, or AF, is the most common type of arrhythmia, a problem with the rate or rhythm of the heartbeat. During an arrhythmia, the heart can beat too fast, too slow, or with an irregular rhythm. AF occurs if rapid, disorganised electrical signals cause the heart's two upper chambers, the atria, to fibrillate. While AF usually isn't life-threatening, it is a serious medical condition that sometimes requires emergency treatment and can lead to complications, including stroke and heart failure2. Approximately one to two per cent of the general population is affected by AF3. AF is strongly age-dependent, affecting four per cent of individuals older than 60 years and eight per cent of persons older than 80 years. Approximately 25 per cent of individuals aged 40 years and older will develop AF during their lifetime4.
3. Why do patients with AF have a higher risk of stroke
In AF, the heart does not contract as strongly as it should. This can cause blood to pool in the heart and form clots. When the blood clots dislodge, they may move to the brain, where they can become trapped in a narrow brain artery, blocking the blood flow and causing a stroke. AF is estimated to be responsible for approximately 15 per cent of all strokes5,6,7 and for 20 per cent of all ischemic strokes8. AF-related strokes are generally associated with poorer outcomes than non-AF-related strokes, as well as with higher levels of morbidity and higher inpatient costs than other stroke patients9,10.
4. Who is eligible for the WATCHMAN™ implant?
In Australia, WATCHMAN™ is indicated for patients with non-valvular atrial fibrillation who require treatment for potential thrombus formation and are eligible for warfarin therapy11.
5. How does the WATCHMAN™ device work?
Implanting the WATCHMAN™ device is a one-time procedure which aims at reducing the risk of ischemic stroke and systemic thromboembolism in patients with AF. The device is designed to permanently close off the LAA, the main source of emboli responsible for stroke, and thereby avoid the migration of emboli to the brain. To date, more than 5,000 patients have undergone LAA Closure with the WATCHMAN™ device.
6. What do the current guidelines say about LAA closure procedures?
The recent 2012 update of the “Guidelines for Management of Patients with Atrial Fibrillation” issued by the European Society of Cardiology (ESC) recommends LAA closure as a class IIb, level of evidence b, for patients with a high stroke risk and contraindications for long-term oral anticoagulation, based on existing clinical evidence such as the PROTECT AF trial. Already in its previous guidelines published in August 2010, the ESC suggested that closure of the LAA may reduce stroke in AF patients.
7. How does the WATCHMAN™ implant procedure work?
The WATCHMAN™ device is implanted through a femoral access via a trans-septal approach by using a catheter-based delivery system. The WATCHMAN™ device is deployed at or slightly distal to the ostium (opening) of the left atrial appendage to permanently seal off the LAA. The implantation is guided by fluoroscopy and transoesophageal echocardiogram (TOE) to verify proper positioning and stability. It is a minimally-invasive procedure that usually lasts about an hour and procedure is usually performed under general anaesthesia in a catheterisation laboratory setting. Following the procedure, patients typically need to stay in the hospital for 24 hours and should remain on warfarin and aspirin for a minimum of 45 days (INR 2.0 to 3.0). At 45 days after the implantation, a transoesophageal echocardiogram (TOE) is performed for further assessment of the device. Physicians may then decide to discontinue warfarin therapy for individual patients.
8. What adverse events can be associated with WATCHMAN™
As with any procedure, there are up front risks associated with the WATCHMAN™ implant. The most common complication is pericardial effusion. Prior to implanting a WATCHMAN™ device, the implanting physician must complete training geared toward improving implantation technique and familiarity and reducing adverse events that may occur on the operating table.
9. Is LAA Closure with WATCHMAN™ a difficult procedure to perform?
It is a challenging procedure which requires extensive training of each implanting physician and certification to implant. With proper training, it is a safe and effective treatment for patients with non-valvular AF who are at risk of stroke. To educate future implanters on the optimal implant procedure for WATCHMAN™, Boston Scientific has developed a unique and very comprehensive, three-step physician training programme, which exceeds other device trainings currently available and includes online courses, hands-on training with Virtual Reality technology and patient cases at Professional Training Centres as needed.
10. Where is WATCHMAN™ currently available?
The WATCHMAN™ LAA Closure device is now available in 30 countries worldwide, including Australia, New Zealand, Malaysia, Indonesia, and Thailand in the Asia-Pacific region along with many countries in Europe and Latin America. The device received CE Mark in 2005 and obtained TGA/WAND listing for commercialisation in Australia & New Zealand in 2009. In the US, the WATCHMAN™ device is an investigational device, limited by applicable law to investigational use only and not yet available for sale.
11. Is the WATCHMAN™ device clinically proven?
The WATCHMAN™ LAA Closure Device is the most studied LAA closure device in the world and has shown the most consistent results in clinical trials, with more than 4,000 patient years of data supporting its safety and efficacy. It is the only LAA closure device that has been studied in several registries and under a large multicentre, prospective, randomised clinical trial with published results (PROTECT AF)12, a continued access registry (CAP)13 and most recently a prospective registry ASA Plavix Registry (ASAP)14 .
12. What are the major trials for the WATCHMAN™ device?
The WATCHMAN™ device has been studied in three pivotal trials, which all reached their primary endpoints: the PROTECT AF trial, the Continued Access Registry (CAP) and the ASAP Registry. A fourth trial – PREVAIL – is ongoing, after completing enrolment of 407 patients at 42 sites at the end of June 2012.
13. What did the results from PROTECT AF and CAP demonstrate?
The WATCHMAN™ LAA Closure Device for Embolic PROTECTion in Patients with Atrial Fibrillation (PROTECT AF) trial showed WATCHMAN™’s non-inferiority to warfarin and demonstrated a 38 per cent relative risk reduction for a combined measure of stroke, cardiovascular death and systemic embolism compared to long-term warfarin therapy in 707 randomised patients. In addition, the study also showed a 29 per cent relative risk reduction in all stroke. Long-term follow-up in this patient population showed that WATCHMANTM was superior to warfarin with a 40% reduction of stroke, systemic embolism, and cardiovascular/unexplained death compared, a 60% reduction in cardiovascular mortality and a 34% reduction in all-cause mortality compared with warfarin15.
Following the pivotal PROTECT AF trial, WATCHMAN™ was studied in a non-randomised registry of patients undergoing WATCHMAN™ implantation, the Continued Access Protocol (CAP) Registry. Although non-randomised, this registry has the same inclusion and exclusion criteria, procedure/treatment protocol and clinical endpoints as PROTECT AF. It demonstrated a significant decrease (32 per cent) of pericardial effusions, the most common adverse event in the WATCHMAN™ device group, as clinicians gained more experience with the procedure.
14. What is the ASAP registry?
The ASAP registry enrolled 150 patients from four centres in Europe who were contraindicated for long-term warfarin therapy (average CHADS2 score: 2.8). These patients had a history of haemorrhagic and bleeding tendencies or a hypersensitivity to warfarin. After the procedure these patients took clopidogrel (Plavix) over six months as well as an indefinite uptake of Aspirin instead of warfarin. Patients were followed-up for up to one year at intervals of 3, 6, 12, 18, and 24 months. A TOE was conducted at three and twelve months to check proper placement of the device and closure of the LAA.
15. What did results of the ASAP registry show?
The ASAP prospective registry showed a 77% reduction in the expected ischemic stroke rate for patients contraindicated to warfarin with the WATCHMAN™ device as compared to patients on aspirin. Successful implantation of the device was achieved in a total of 142 patients equalling 94.7 per cent (total number of patients enrolled: 150). Successful implantation of the device was achieved in a total of 142 patients equalling 94.7 per cent (total number of patients enrolled: 150).
16. What is PREVAIL
The PREVAIL trial was designed to confirm the results of the PROTECT AF trial and validate the safety of the implant procedure, including a minimum of 20% of randomised patients enrolled at institutions that did not participate in a previous WATCHMAN™study (PROTECT AF or CAP Registry) and a minimum of 25% of randomised patients enrolled by new operators. A total of 407 patients were randomised 2:1 device vs. warfarin control in the PREVAIL trial. Patients enrolled in PREVAIL must have been warfarin eligible and have a CHADS2 score of ≥2. Initial results demonstrate acute procedure and device-related safety events remained low for WATCHMAN™and that the device can be successfully implanted by new operators. Results also showed lower complication rates with both new and experienced operators and significantly lower complications than the early stage of the PROTECT AF trial16. Follow-up is ongoing with more results expected in the coming months.
|1||Randall J. Lee, MD, PhD; Krzysztof Bartus, MD; Steven J. Yakubov, MD, Catheter-Based Left Atrial Appendage (LAA) Ligation for the prevention of Embolic Events Arising From the LAA: Initial Experience in a Canine Model, Circ Cardiovasc Interv 2010;3;224-229.|
|2||National Lung Blood and Heart Institute, National Institutes of Health (NIH), July 1, 2011|
|3||Camm JA et al on behalf of The Task Force for the Management of Atrial Fibrillation of the European Society of Cardiology (ESC) Guidelines for the management of atrial fibrillation European Heart Journal doi:10.1093/eurheartj/ehq278.|
|4||Lloyd-Jones DM, Wang TJ, Leip EP, Larson MG, Levy D, Vasan RS, et al. Lifetime risk for development of atrial fibrillation: the Framingham Heart Study. Circulation. Aug 31 2004;110(9):1042-6.|
|5||Wolf CD, Rudd AG. The Burden of Stroke White paper: Raising awareness of the global toll of stroke related disability and death.|
|6||World Health Organisation. The atlas of heart disease and stroke.|
|7||Marmot MG, Poulter NR. Primary prevention of stroke, Lancet 1992;339:344-7|
|8||Avoiding heart attacks and strokes: don’t be a victim – protect yourself. Publications of the World Health Organisation, 2005. http://www.who.int/cardiovascular_diseases/resources/cvd_report.pdf.|
|9||Steger C, Pratter A, Martinek-Bregel M, Avanzini M, Valentin A, Slany J et al. Stroke patients with atrial fibrillation have a worse prognosis than patients without: data from the Austrian Stroke registry. Eur Heart J 2004;25:1734–40.|
|10||Ghatnekar O, Glader EL. The effect of atrial fibrillation on stroke-related inpatient costs in Sweden: a 3-year analysis of registry incidence data from 2001. Value Health 2008;11:862–8.|
|11||Australian Register of Therapeutic Goods Certificate Boston Scientific Pty Ltd - WATCHMAN LAA Closure Device with Delivery System - Cardiac occluder. ARTG Identifier 198829 Class III, ARTG Start date 28/06/2012 Product Category: Medical Device Included Class III.|
|12||Reddy VY et al. Safety of percutaneous left atrial appendage closure: results from the Watchman Left Atrial Appendage System for Embolic Protection in Patients with AF (PROTECT AF) clinical trial and the Continued Access Registry, Circulation 2011;123(4):417-24|
|13||Reddy VY et al. Safety of Percutaneous Left Atrial Appendage Closure: Results from the Watchman Left Atrial Appendage System for Embolic Protection in Patients with AF (PROTECT AF) Clinical Trial and the Continued Access Registry. Circulation 2011; 123: 417-424|
|14||Vivek Y. Reddy, MD et al. Left Atrial Appendage Closure With the Watchman Device in Patients With a Contraindication for Oral Anticoagulation. JACC Vol. 61, No. 25, 2013|
|15||Vivek Reddy; presented at HRS 2013|
|16||David R Holmes 2013 , TCTMD online|
This product is included on the Australian Register of Therapeutic Goods and is listed on the New Zealand WAND Database.
The material presented on this website is for general informational purposes only and is intended primarily for use by referring physicians. Patients who would like additional details should contact their physician who will determine whether or not this particular device is suitable for them.
ANZ_PSST_12069 Rev C | August 2013