title: Extrinsic compression of the left main coronary artery by a dilated pulmonary artery: clinical, angiographic, and hemodynamic determinants.
abstract: Extrinsic compression of the left main coronary artery (LMC) by the pulmonary artery (PA) is a very unusual and poorly understood entity, usually associated with the presence of adult congenital heart disease. We identified 12 patients (age range, 6 months to 55 years) with LMC stenosis (> or = 50%) presumably secondary to compression by a dilated main PA and related to various forms of heart disease (11 congenital, 1 pulmonary hypertension). In all cases, the main PA was dilated with the main PA/aortic root diameter increased (mean, 2.0; normal value, < or = 1.0), and in all but two, PA pressures were increased (> 30 mm Hg systolic). Left coronary trunk stenosis was usually visualized in only one angiographic view (best seen in 45 degrees left anterior oblique, 30 degrees cranial projection). The LMC also appeared to be inferiorly displaced and in close contact with the left aortic sinus (mean angle between sinus and LMC was 23 degrees +/- 13 degrees, a control group was 70 degrees +/- 15 degrees ). In one patient, surgical correction of the dilated PA was associated with a reduction in LMC stenosis from 85% to < 50% and less inferior left main displacement (from 25 degrees to 50 degrees ). Patients with a dilated main PA may exhibit extrinsic LMC compression leading to significant eccentric narrowing and downward displacement of the LMC. In the presence of significant dilatation of the main PA from any etiology, functional and/or anatomic studies should be performed to exclude significant LM obstruction.
authors.affiliation: Cardiac Catheterization Laboratory of the Heart Institute, University of São Paulo, São Paulo, Brazil.
authors.forename: L J
authors.initials: LJ
authors.lastname: Kajita
authors.forename: E E
authors.initials: EE
authors.lastname: Martinez
authors.forename: J A
authors.initials: JA
authors.lastname: Ambrose
authors.forename: P A
authors.initials: PA
authors.lastname: Lemos
authors.forename: A
authors.initials: A
authors.lastname: Esteves
authors.forename: M
authors.initials: M
authors.lastname: Nogueira da Gama
authors.forename: A D
authors.initials: AD
authors.lastname: Jatene
authors.forename: J A
authors.initials: JA
authors.lastname: Ramires
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D017023:Coronary Angiography / Q000379:methods*; D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D003331:Coronary Vessels / Q000503:physiopathology*; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D008875:Middle Aged; D011651:Pulmonary Artery / Q000000981:diagnostic imaging*; D012016:Reference Values; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index