Functional Versus Anatomic Assessment of Myocardial Bridging by Intravascular Ultrasound: Impact of Arterial Compression on Proximal Atherosclerotic Plaque.
BACKGROUND
The presence of a myocardial bridge (MB) has been shown to promote atherosclerotic plaque formation proximal to the MB, presumably because of hemodynamic disturbances provoked by retrograde blood flow toward this segment in cardiac systole. We aimed to determine the anatomic and functional properties of an MB related to the extent of atherosclerosis assessed by intravascular ultrasound.


RESULTS
We enrolled 100 patients with angina but no significant obstructive coronary artery disease who had an intravascular ultrasound-detected MB in the left anterior descending artery (median age 54 years, 36% male). The MB was identified with intravascular ultrasound by the presence of an echolucent band (halo). Anatomically, the MB length was 22±13 mm, and halo thickness was 0.7±0.6 mm. Functionally, systolic arterial compression was 23±12%. The maximum plaque burden up to 20 mm proximal to the MB entrance was significantly greater than the maximum plaque burden within the MB segment. Among the intravascular ultrasound-defined MB properties, arterial compression was the sole MB parameter that demonstrated a significant positive correlation with maximum plaque burden up to 20 mm proximal to the MB entrance (r=0.254, P=0.011 overall; r=0.545, P<0.001 low coronary risk). In multivariate analysis, adjusting for clinical characteristics and coronary risk factors, arterial compression was independently associated with maximum plaque burden up to 20 mm proximal to the MB entrance.


CONCLUSIONS
In patients with an MB in the left anterior descending artery, the percentage of arterial compression is related directly to the burden of atherosclerotic plaque located proximally to the MB, particularly in patients who otherwise have low coronary risk. This may prove helpful in identifying high-risk MB patients.
Division of Cardiovascular Medicine, Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA.
Ryotaro
R
Yamada
Division of Cardiovascular Medicine, Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA.
Jennifer A
JA
Tremmel
Division of Cardiovascular Medicine, Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA.
Shigemitsu
S
Tanaka
Division of Cardiovascular Medicine, Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA.
Shin
S
Lin
Division of Cardiovascular Medicine, Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA.
Yuhei
Y
Kobayashi
Division of Cardiovascular Medicine, Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA.
M Brooke
MB
Hollak
Division of Cardiovascular Medicine, Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA.
Paul G
PG
Yock
Division of Cardiovascular Medicine, Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA.
Peter J
PJ
Fitzgerald
Division of Cardiovascular Medicine, Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA.
Ingela
I
Schnittger
Division of Cardiovascular Medicine, Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA crci-cvmed@stanford.edu.
Yasuhiro
Y
Honda
D006328:Cardiac Catheterization / Q000379:methods; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D054084:Myocardial Bridging / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D012307:Risk Factors; D018084:Ultrasonography, Interventional / Q000379:methods
angina; angiography; atherosclerosis; intravascular ultrasound; myocardial bridge