In the context of LAAO, what does the PASS Seal requirement ensure?

The PASS Seal requirement ensures that there should be no color flow detected across the occlusion. This is critical in the context of Left Atrial Appendage Occlusion (LAAO) because the primary goal of the procedure is to effectively close off the left atrial appendage to prevent blood clots from forming in this region. These clots can lead to strokes, especially in patients with atrial fibrillation.

Demonstrating that there is no color flow across the occlusion indicates that the device has successfully sealed the appendage, thus minimizing the risk of thrombus formation and achieving the desired therapeutic outcome. The absence of color flow signifies that blood is not moving into or out of the appendage, thereby confirming the effective closure of the area.

In contrast, other options may describe characteristics of the device but do not directly relate to the assurance of effective occlusion that the PASS Seal is designed to verify. The focus on flow detection highlights the importance of confirming that the device has performed its function of isolating the left atrial appendage.