Device Interventions for Stroke Prevention in Atrial Fibrillation

Abstract

Atrial fibrillation (AF) is the most common sustained heart rhythm disorder, with an estimated prevalence of 0.4% to 1% in the general population. In addition, AF is responsible for approximately 15% to 20% of ischemic strokes. Device interventions to prevent strokes in patients with AF are nonsurgical procedures to block blood clots (thrombus) from forming and traveling out of the heart. The “quivering” rather than normal contractions of the upper chambers of the heart (atria) from disorganized electric activity (AF) leads to blood stasis and thrombus formation. A small cul-de-sac called the left atrial appendage (LAA) is especially prone to thrombus formation (Figure 1). In AF patients without valvular heart disease, almost all thrombus originates from the LAA. The thrombus travels to and block major vessels in the body. Blocking blood vessels to the brain leads to strokes and transient ischemic attacks (mini-strokes). Figure 1. Transesophageal echocardiogram image of a thrombus in the left atrial appendage (dotted line). Patients with the following risk factors have a higher stroke risk: heart failure, hypertension, age of 75 years or greater, diabetes mellitus, and prior history of strokes or mini-strokes. These are often combined to form the CHADS2 score. The more risk factors you have, the higher your CHADS2 score and risk of stroke are. Blood-thinning medications (anticoagulants) such as warfarin, dabigatran, rivaroxaban, and apixaban are effective stroke prevention therapies. The risks of bleeding associated with long-term anticoagulation led to the development of permanent treatment options like surgery. Closures by sutures (ligation) and removal (amputation) of the LAA …