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Left atrial appendage (LAA) closure has become a viable alternative to anticoagulant therapy for stroke prevention in patients with atrial fibrillation. The selection of an appropriate closure device size is a crucial factor for successful intervention. A common practice to prevent device undersizing due to a lower left atrium (LA) pressure during the procedure is to give the patient extra fluids ad hoc to increase the LA pressure. Nevertheless, no study has been done to quantify the relationship between the LA pressure and the appendage size. The goal of this study was to quantify the impact of pressure changes in the LA on the size of the LAA ostium.
A patient-specific geometry of the left atrium was reconstructed from CTA images. The geometry consists of the body of the left atrium, LAA, mitral valve annulus, and the pulmonary veins (Fig. 1). Computational simulation was run for various mean blood pressures ranging from 5 to 25 mmHg. The resulting deformation and stress and strain distributions at different pressure were compared.
The peak stresses occur along the appendage rim and around the pulmonary veins. A change in the blood pressure from 5 mmHg to 15 mmHg resulted in 10% increase in the diameter of the appendage. In addition, change of blood pressure from 15 mmHg to 25 mmHg lead to a 3% increase in the diameter of the appendage.
Results of the simulation showed that altering the blood pressure significantly changes the size of the LAA ostium. Therefore, the impact of LA pressure changes should be taken into account in the selection of the size of LAA closure devices.
STRUCTURAL: Left Atrial Appendage Exclusion