LEFT ATRIAL APPENDAGE CLOSURE
The Watchman Procedure
What is left atrial appendage closure?
Left atrial appendage closure is a minimally invasive cardiac procedure that is used to reduce stroke risk in certain individuals with atrial fibrillation. The procedure involves the delivery of an implant device that seals off the left atrial appendage, thereby preventing clots from escaping the appendage and traveling to the brain.
The Watchman implant device is the new ‘gold standard’ in left atrial appendage closure. The device is a parachute-shaped device that expands to cover the passageway between the left atrial appendage and the left atrium.
What conditions are treated with left atrial appendage closure?
Left atrial appendage closure is used to help prevent stroke in nonvalvular atrial fibrillation. The left atrial appendage is a small sac in the muscle wall that protrudes from the left atrium. In a healthy heart, blood flows in and out of the atrial appendage in a healthy rhythm. In the case of atrial fibrillation, rhythmic disturbances in the atria (the upper chambers of the heart) can cause irregular blood flow patterns in the atrial appendage. These flow disturbances can lead to the formation of blood clot that may dislodge from the appendage and travel to the brain, causing a stroke.¹⁻²
Individuals with atrial fibrillation are divided into ‘valvular’ atrial fibrillation or ‘nonvalvular’ atrial fibrillation to assess the risk of clot formation in the left atrial appendage. Valvular atrial fibrillation describes individuals with atrial fibrillation that also have mitral valve stenosis or artificial heart valves. Because of the unique physiology of the heart in these individuals, they are at a much lower risk of clot formation. On the other hand, nonvalvular atrial fibrillation describes individuals without these specific valvular heart conditions whom are at a much higher risk of clot formation.³⁻⁴
Atrial fibrillation is responsible for 15% of all stroke cases,⁴ and some research suggests that the left atrial appendage is responsible for up to 90% of cardioembolic stroke cases in nonvalvular AF.³ Because of these statistics, atrial fibrillation patients without a device implant are typically prescribed anticoagulants (“blood thinners”) like warfarin to reduce stroke risk. In many cases, individuals can stop taking blood thinners 45 days following implant of the Watchman device.⁵
How is left atrial appendage closure performed?
Left atrial appendage closure requires a minimally invasive procedure to deliver the Watchman device to the left atrial appendage. The procedure is performed by either an interventional cardiologist or an electrophysiologist.
Prior to the procedure, transesophageal electrocardiography (TEE) is used to determine the size of the implant device that will best cover your atrial appendage. Under general anesthesia, a catheter (a small tube) is inserted into your vasculature through a small puncture in your groin. Using fluoroscopic imaging, a transseptal access device is navigated to the right side of the heart and used to make a small puncture in the wall that divides the left side and the right side of the heart (the septum). The Watchman device is then navigated through the transseptal puncture and deployed into the left atrial appendage. Over time, tissue on the inside of the heart grows over the implant device (a process called “endothelization”), effectively sealing off the left atrial appendage.⁵
References
[1] Regazzoli, D., Ancona, F., Trevisi, N., Guarracini, F., Radinovic, A., Oppizzi, M., … Mazzone, P. (2015). Left Atrial Appendage: Physiology, Pathology, and Role as a Therapeutic Target. BioMed Research International, 2015.
[2] Lin, A. C., & Knight, B. P. (2015). Left Atrial Appendage Closure. Progress in Cardiovascular Diseases, 58(2), 195–201.
[3] Molteni, M., Friz, H. P., Primitz, L., Marano, G., Boracchi, P., & Cimminiello, C. (2014). The definition of valvular and non-valvular atrial fibrillation: Results of a physicians’ survey. Europace, 16(12), 1720–1725.
[4] Fauchier, L., Philippart, R., Clementy, N., Bourguignon, T., Angoulvant, D., Ivanes, F., … Bernard, A. (2015). How to define valvular atrial fibrillation? Archives of Cardiovascular Diseases, 108(10), 530–539.
[5] Boston Scientific Inc. (n.d.). Watchman Left Atrial Appendage closure. Retrieved November 14, 2018, from https://www.watchman.com/en-us-hcp/home.html
