Does Left Atrial Appendage Clipping Lead To Left Atrial Functional Alterations In Standalone Atrial Fibrillation Surgery?
Niels J. Verberkmoes, Jill C. van Diggele
Catharina Hospital, Eindhoven, Netherlands
Background Incidence of non-valvular atrial fibrillation (AF) is increasing parallel to increasing interest in left atrial appendage (LAA) closure as stroke prevention therapy in patients with AF. (1) Majority of LAA closure studies were mainly focused on safety and effectiveness of LAA closure procedure, and less on cardiac physiological impact. (2) Our previous study showed significant decrease in blood pressure after LAA clipping, which stimulated our interest to evaluate the left atrial (LA) function via LA velocities after LAA clipping. To date, there is limited data on LA function after LAA closure in standalone AF surgery (3-6) Therefore, we were interested to evaluate the acute isolated impact of LAA clipping on LA function in standalone AF surgery. Methods We conducted a prospective pilot study and selected 20 AF patients who underwent totally thorascopic ablation and LAA clipping. Two echocardiographic examinations were performed shortly before and after LAA clipping to evaluate transmitral- (TMV) and pulmonary venous velocity (PVV) by transoesophageal echocardiography. Differences within the study group were evaluated by paired sample t-test or Wilcoxon signed rank test, depending on the normality of the data. Results Systolic PVV and the ratio between the systolic- and diastolic PVV were significantly decreased after LAA clipping (p = 0.035 resp. p = 0.005). (Figure 1) No significant differences were found for TMV. Conclusions Systolic PVV is related to LA reservoir function, which is influenced by systolic left ventricular function, LA contraction and relaxation. (7) It is known that LAA is more distensible and compliant than the LA that LAA clipping could lead to reduced LA compliance. (3) Hypothetically, a decrease in LA compliance could results in elevated LA afterload relative to pulmonary veins by the increased LA pressure after LAA clipping. (4) This hypothesis is currently evaluated by this ongoing study.
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