title: The Functional Effects of Intramural Course of Coronary Arteries and its Relation to Coronary Atherosclerosis.
abstract: OBJECTIVE
  This study observed hemodynamic consequences of myocardial bridging and its relation to coronary atherosclerosis.
  
  
  BACKGROUND
  Myocardial bridging is seen as intramural course by computed tomography angiography (CTA) or systolic compression by invasive coronary angiography. Segments with myocardial bridging are in previous studies closely associated with proximal atherosclerotic plaques.
  
  
  METHODS
  We prospectively studied 100 patients 63 ± 7 years of age with intermediate likelihood of coronary artery disease. Segments with superficial (>1 mm) or deep (>2 mm) intramural course were identified using CTA. Myocardial perfusion was studied by 15-Oxygen water positron emission tomography and systolic compression by invasive coronary angiography.
  
  
  RESULTS
  Myocardial bridging was detected in 34 (34%) patients in 48 different vascular segments. Of these, 24 (50%) were deep and systolic compression was present in 14 (29%). In patients without obstructive coronary artery disease, myocardial stress perfusion distal to myocardial bridging was comparable with remote control regions (3.3 ± 0.9 ml/g/min vs. 3.3 ± 0.7 ml/g/min, n = 24, p = 0.88). Stress perfusion was comparable in segments with and without systolic compression (3.0 ± 0.9 vs. 2.7 ± 1.0 ml/g/min, p = 0.43). Atherosclerotic plaques were more frequent in proximal (71%) than myocardial bridging (7%) or distal (21%) segments. The presence of atherosclerosis and the average number of plaques were comparable in coronary arteries with and without myocardial bridging (73% vs. 60%, p = 0.14 and 2.0 ± 1.7 vs. 1.5 ± 1.6, p = 0.06). Median Agatston coronary calcium score was not elevated in vessels with myocardial bridge (15 [interquartile range: 0, 129] vs. 50 [interquartile range: 0, 241], p = 0.21).
  
  
  CONCLUSIONS
  Myocardial bridging of coronary arteries is common on CTA, but only approximately one-third of these show systolic compression. Myocardial bridging is not associated with reduced myocardial perfusion during vasodilator stress. Atherosclerosis is located predominantly proximal to myocardial bridging but atherosclerotic burden and presence of vulnerable plaques were comparable.
authors.affiliation: Turku PET Centre, Turku University Hospital, University of Turku, Turku, Finland. Electronic address: vauusi@utu.fi.
authors.forename: Valtteri
authors.initials: V
authors.lastname: Uusitalo
authors.affiliation: Turku PET Centre, Turku University Hospital, University of Turku, Turku, Finland; Heart Center, Turku University Hospital, University of Turku, Turku, Finland.
authors.forename: Antti
authors.initials: A
authors.lastname: Saraste
authors.affiliation: Heart Center, Turku University Hospital, University of Turku, Turku, Finland.
authors.forename: Mikko
authors.initials: M
authors.lastname: Pietilä
authors.affiliation: Turku PET Centre, Turku University Hospital, University of Turku, Turku, Finland; Department of Clinical Psychology, Nuclear Medicine, and PET, Turku University Hospital, University of Turku, Turku, Finland.
authors.forename: Sami
authors.initials: S
authors.lastname: Kajander
authors.affiliation: Department of Cardiology, Leiden University Medical Center, Leiden, the Netherlands.
authors.forename: Jeroen J
authors.initials: JJ
authors.lastname: Bax
authors.affiliation: Turku PET Centre, Turku University Hospital, University of Turku, Turku, Finland; Department of Clinical Psychology, Nuclear Medicine, and PET, Turku University Hospital, University of Turku, Turku, Finland.
authors.forename: Juhani
authors.initials: J
authors.lastname: Knuuti
mesh_terms: D050197:Atherosclerosis / Q000175:diagnosis* / Q000503:physiopathology; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000503:physiopathology; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D054084:Myocardial Bridging / Q000175:diagnosis* / Q000503:physiopathology; D049268:Positron-Emission Tomography; D012039:Regional Blood Flow; D014057:Tomography, X-Ray Computed
keywords: PET; atherosclerosis; myocardial bridging; perfusion; regional blood flow