title: Impact of tissue characteristics on luminal narrowing of mild angiographic coronary stenosis: assessment of integrated backscatter intravascular ultrasound.
abstract: Integrated backscatter intravascular ultrasound (IB-IVUS) is a useful method for analyzing coronary plaque tissue. We evaluated whether tissue composition determined using IB-IVUS is associated with the progression of stenosis in coronary angiography. Sixty-three nontarget coronary lesions in 63 patients with stable angina were evaluated using conventional IVUS and IB-IVUS. IB-IVUS images were analyzed at 1-mm intervals for a length of 10 mm. After calculating the relative areas of the tissue components using the IB-IVUS system, fibrous volume (FV) and lipid volume (LV) were calculated through integration of the slices, after which percentages of per-plaque volume (%FV/PV, %LV/PV) and per-vessel volume (%FV/VV, %LV/VV) were calculated. Progression of coronary stenosis was interpreted from the increase in percent diameter stenosis (%DS) from baseline to the follow-up period (6-9 months) using quantitative coronary angiography. %DS was 24.1 ± 12.8 % at baseline and 23.2 ± 13.7 % at follow-up. Using IB-IVUS, LV was 31.7 ± 10.5 mm(3), and %LV/PV and %LV/VV were 45.6 ± 10.3 % and 20.2 ± 6.0 %, respectively. FV, %FV/PV, and %FV/VV were 35.5 ± 12.1 mm(3), 52.1 ± 9.5 %, and 23.4 ± 7.1 %, respectively. The change in %DS was -0.88 ± 7.25 % and correlated closely with %LV/VV (r = 0.27, P = 0.03) on simple regression. Multivariate regression after adjustment for potentially confounding risk factors showed %LV/VV to be correlated independently with changes in %DS (r = 0.42, P = 0.02). Logistic regression analysis after adjusting for confounding coronary risk factors showed LV (odds ratio 1.08; 95 % confidence interval 1.01-1.16; P = 0.03) and %LV/VV (odds ratio 1.13; 95 % confidence interval 1.01-1.28; P = 0.03) to be independent predictors of the progression of angiographic coronary stenosis. Our findings suggest that angiographic luminal narrowing of the coronary artery is likely associated with tissue characteristics. IB-IVUS may provide information about the natural progression of luminal narrowing in coronary stenosis.
authors.affiliation: The Department of Cardiology, Gifu Prefectural General Medical Center, Gifu, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Iwama
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Tanaka
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Noda
authors.forename: Tomonori
authors.initials: T
authors.lastname: Segawa
authors.forename: Masanori
authors.initials: M
authors.lastname: Kawasaki
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nishigaki
authors.forename: Taro
authors.initials: T
authors.lastname: Minagawa
authors.forename: Sachiro
authors.initials: S
authors.lastname: Watanabe
authors.forename: Shinya
authors.initials: S
authors.lastname: Minatoguchi
mesh_terms: D000368:Aged; D060050:Angina, Stable / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D017023:Coronary Angiography; D023921:Coronary Stenosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging; D018450:Disease Progression; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D058226:Plaque, Atherosclerotic / Q000473:pathology; D012189:Retrospective Studies; D012720:Severity of Illness Index; D018084:Ultrasonography, Interventional / Q000379:methods*