Cerebral Embolic Protection in Patients Undergoing Left Atrial Appendage Closure

(1) Background: Cerebral magnetic resonance imaging has reported new cerebral ischemic lesions after left atrial appendage (LAA) closure in about one- third of patients. Stroke occurs predominantly periprocedurally. This study evaluated the characteristics of embolized debris captured by the SENTINEL^TM cerebral embolic protection system in patients undergoing LAA closure; (2) Methods: Sixty filters of 30 consecutive patients undergoing LAA closure with the WATCHMAN FLX^TM device were collected and captured debris was analyzed by histopathology and histomorphometry. Clinical outcome measures were disabling and non-disabling stroke within 72 h; (3) Results: In most filters, no material was captured. The predominant captured debris was acute or organized thrombi. The most common pattern was acute fibrin-rich thrombus, which was detected in 11/30 (33.3%) patients. Particles of heart tissue were seen in 6/30 (20%) patients, and foreign material was seen in one (3.3%) patient. The number of particles ranged from 0 to 52 per patient with a maximum of 31 in the distal and 21 in the proximal filter. Particle diameter ranged from 131 to 2614 µm. By logistic regression analysis, only protected time remained a multivariable predictor for larger particles (<i>p</i> = 0.039). There was no disabling or non-disabling stroke. Compared to transfemoral aortic valve replacement, the number of particles is only about 1.5%. (4) Conclusion: LAA occlusion with the WATCHMAN FLX^TM was associated with a very low number of embolized particles captured with the double-filter SENTINEL^TM embolic protection system and no periprocedural stroke.