Morphometrical features of left atrial appendage in the atrial fibrillation patients subjected to left atrial appendage closure

Background: This study aimed to evaluate the morphometrical features of left atrial appendage (LAA) in patients with atrial fibrillation, subjected to LAA per- cutaneous closure (LARIAT) for stroke prevention.Materials and methods: Computed tomography (CT) scans of 51 patients with atrial fibrillation subjected to LARIAT procedure were comparatively evaluated with 50 patients with sinus rhythm (control group). Three-dimensional reconstructions were created using volume-rendering for evaluation.Results: No differences were found in LAA types of distribution (cauliflower: 25.5 vs. 34.0%, chicken wing: 45.1 vs. 46.0%, arrowhead: 29.4 vs. 20.0%, all p > 0.05) between groups. However, the study group was characterized by LAAs with a lower number of lobes. The LAA orifice anteroposterior and transverse diameters (19.3 +/- 4.12 vs. 17.2 +/- 4.0 mm, p = 0.01 and 25.1 +/- 5.1 vs. 20.5 +/- +/- 4.4 mm, p = 0.001), orifice area (387.2 +/- 133.9 vs. 327.1 +/- 128.3 mm(2), p = 0.02) and orifice perimeter (70.2 +/- 12.5 vs. 61.2 +/- 11.6 mm, p = 0.04) was significantly larger in atrial fibrillation patients. More oval LAA orifices was found in atrial fibrillation group (94.0 vs. 70.4%, p = 0.001). No statistically significant differences were found in LAA body length (47.4 +/- 15.4 vs. 43.7 +/- 10.9 mm, p = 0.17), body width (24.7 +/- 5.6 vs. 24.4 +/- 5.8 mm, p = 0.81), and chamber depth (17.7 +/- 3.5 vs. 16.5 +/- 3.8 mm, p = 0.11). Calculated LAA ejection fraction was significantly lower in study group compared to healthy patients (16.4 +/- 14.9 vs. 48.2 +/- 12.9%, p = 0.001).Conclusions: Important morphometrical differences in LAA orifice have been found, which was significantly larger and more oval in patients with atrial fibrillation compared to healthy controls. Although no difference in LAA body type and size was observed; the LAA ejection fraction was significantly lower in atrial fibrillation rhythm patients.