title: Left anterior descending coronary artery wall thickness measured by high-frequency transthoracic and epicardial echocardiography includes adventitia.
abstract: High-frequency, 2-dimensional transthoracic echocardiography (HR-2DTTE) measurements of the left anterior descending (LAD) coronary artery wall thickness are larger than measurements obtained by intravascular ultrasound. We hypothesize that this difference is due to inclusion of the third vascular layer, which may represent adventitia by HR-2DTTE, and that this layer must be increasing in thickness with the development of atherosclerosis. We evaluated the contribution of this third layer to the wall thickness of the normal and atherosclerotic LAD artery imaged by HR-2DTTE using high-frequency epicardial echocardiography (HFEE) as the reference standard. Eighteen patients (10 men, mean age 62 years), 13 with coronary atherosclerosis and 5 with normal coronary arteries, referred for open-heart surgery, underwent preoperative HR-2DTTE evaluation of the LAD artery (SONOS 5500; 3- to 8-MHz transducer) and intraoperative HFEE of the LAD artery (SONOS 5500; 6- to 15-MHz transducer). Wall thickness was greater in patients with coronary atherosclerosis than in those with normal coronary arteries by both HR-2DTTE (1.9 +/- 0.3 vs 1.0 +/- 0.1 mm, p = <0.001) and HFEE (1.8 +/- 0.2 vs 1.0 +/- 0.2 mm, p = <0.001). On HFEE, the average intima plus media thickness was greater in patients with coronary atherosclerosis than in those with normal coronary arteries (0.78 +/- 0.3 vs 0.34 +/- 0.1 mm, p = 0.005). The average thickness of adventitia was also greater in patients with coronary atherosclerosis than in those with normal coronary arteries (0.92 +/- 0.2 vs 0.54 +/- 0.2 mm, p = 0.0005). HR-2DTTE and HFEE measurements of the wall thickness correlated well (r = 0.83 [reader 1], p <0.001; r = 0.61 [reader 2], p <0.01). A third vascular layer, which likely included adventitia, represents a significant portion of the LAD wall thickness imaged by HR-2DTTE and HFEE, and it significantly increases in thickness with the development of atherosclerosis.
authors.affiliation: Krannert Institute of Cardiology, Indianapolis, Indiana 46202, USA. igradus@iupi.edu
authors.forename: Irmina
authors.initials: I
authors.lastname: Gradus-Pizlo
authors.forename: Brian
authors.initials: B
authors.lastname: Bigelow
authors.forename: Yousuf
authors.initials: Y
authors.lastname: Mahomed
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Sawada
authors.forename: Karen
authors.initials: K
authors.lastname: Rieger
authors.forename: Harvey
authors.initials: H
authors.lastname: Feigenbaum
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D004452:Echocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D017539:Tunica Intima / Q000000981:diagnostic imaging; D017540:Tunica Media / Q000000981:diagnostic imaging