title: Three-dimensional assessment of left atrial appendage orifice geometry and potential implications for device closure.
abstract: Transcatheter placement of left atrial closure device is an attractive therapy for patients with atrial fibrillation (AF), to avoid anticoagulation and reduce cerebrovascular events; however peri-device leaks occur. The geometry of the left atrial appendage (LAA) is not well understood, largely owing to limitations of 2-dimensional imaging techniques. We sought to better define the LAA orifice geometry, by performing 3-dimensional multi-detector computed tomography measurements. We prospectively recruited 105 consecutive patients referred for pulmonary vein ablation (PVA) and age-matched controls. Area, short and long-axis measurements were performed. Eccentricity was calculated as 1-(short axis/long axis). Multiple clinical variables were tested for their ability to predict appendage orifice eccentricity using univariate linear regression models. The PVA cohort demographics included; 25 (24%) females, mean age 59 years (SD = 10), median height (1.55-2.03), weight 89 (56-139) kg and body surface area 2.1 (1.61-2.58). In the PVA cohort, there was a significant difference between the long and short-axis; median short-axis dimension was 20.5 (12.9-35.4) mm, versus long-axis median 30.4 (17.7-43.8) (p < 0.001). Mean eccentricity score was 0.4. When compared with controls, there was a significant difference in the short and long-axis measurements (p < 0.001) as well as eccentricity (p = 0.04). All clinical variables tested showed limited ability to predict appendage eccentricity (p = NS). LAA ostium is an elliptical structure in the setting of AF with a high eccentricity index and uniformly significant differences between short and long-axis. There were significant differences between these parameters when compared with controls. A deeper appreciation of LAA geometry and eccentricity may allow for reduction in peri-closure leaks.
authors.affiliation: Cardiac Imaging Division, Department of Radiology, St. Paul's Hospital, 1081 Burrard Street, Vancouver, BC, V6Z 1Y6, Canada, juliemobrien@gmail.com.
authors.forename: Julie
authors.initials: J
authors.lastname: O'Brien
authors.forename: Donya
authors.initials: D
authors.lastname: Al-Hassan
authors.forename: Justin
authors.initials: J
authors.lastname: Ng
authors.forename: Madalsa
authors.initials: M
authors.lastname: Joshi
authors.forename: Cameron
authors.initials: C
authors.lastname: Hague
authors.forename: Santabhanu
authors.initials: S
authors.lastname: Chakrabarti
authors.forename: Jonathon
authors.initials: J
authors.lastname: Leipsic
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D020517:Atrial Appendage / Q000000981:diagnostic imaging*; D001281:Atrial Fibrillation / Q000150:complications / Q000000981:diagnostic imaging* / Q000628:therapy*; D006328:Cardiac Catheterization / Q000295:instrumentation*; D016022:Case-Control Studies; D002561:Cerebrovascular Disorders / Q000209:etiology / Q000517:prevention & control; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted