title: Physiological Severity of Coronary Artery Stenosis Depends on the Amount of Myocardial Mass Subtended by the Coronary Artery.
abstract: This study investigated the role of fractional myocardial mass (FMM), a vessel-specific myocardial mass, in the evaluation of physiological severity of stenosis. Using computed tomography angiography, the study investigated fractional myocardial mass, a concept of myocardial mass subtended by specific vessel, which could reduce anatomical-physiological mismatch.
  
  
  
  Discordance between anatomical stenosis and physiological severity is common but remains poorly understood.
  
  
  
  This multicenter study enrolled 463 patients with 724 lesions, who underwent coronary computed tomography angiography (CCTA) and invasive coronary angiography with fractional flow reserve (FFR) measurement. FMM was assessed by allometric scaling analysis of arterial tree length and myocardial mass from CCTA.
  
  
  
  FFR <0.80, a criteria for vessel-specific physiological stenosis, was found in 281 vessels (39%). FMM decreased consistently according to the vessel downstream (p < 0.001, all). The frequency of FFR <0.80 increased in proportion to FMM and inverse proportion to angiographic minimal luminal diameter (MLD) (p < 0.001). In per-vessel analysis, FMM per MLD (FMM/MLD) showed good correlation with FFR (r = 0.61) and was superior to diameter stenosis (DS) for FFR <0.80 by receiver operating characteristic and reclassification analysis (C-statistics = 0.84 versus 0.74, net reclassification improvement [NRI] = 0.63, integrated discrimination improvement [IDI] = 0.18; p < 0.001, all). The optimal cutoff of FMM/MLD was 29 g/mm, with sensitivity = 75%, specificity = 77%, positive predictive value = 68%, negative predictive value = 83%, and accuracy = 77%. Addition of FMM/MLD to DS could further discriminate vessels with FFR <0.80 (C-statistic = 0.86 vs. 0.84, NRI = 0.34, IDI = 0.03; p < 0.005, all). In per-range classification analysis, agreement between FFR and FMM/MLD maintained >80% when the severity of disease was away from cutoff.
  
  
  
  FMM/MLD could find physiological severity of coronary artery with higher accuracy than anatomical stenosis. FMM may explain the anatomical-physiological discordance.
authors.affiliation: Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Hyung Yoon
authors.initials: HY
authors.lastname: Kim
authors.affiliation: Department of Cardiology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Hong-Seok
authors.initials: HS
authors.lastname: Lim
authors.affiliation: Department of Medicine, Inje University Ilsan-Paik Hospital, Goyang, Korea.
authors.forename: Joon-Hyung
authors.initials: JH
authors.lastname: Doh
authors.affiliation: Department of Medicine, Keimyung University Dongsan Medical Center, Daegu, Korea.
authors.forename: Chang-Wook
authors.initials: CW
authors.lastname: Nam
authors.affiliation: Department of Cardiology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, South Korea.
authors.forename: Eun-Seok
authors.initials: ES
authors.lastname: Shin
authors.affiliation: Department of Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Bon-Kwon
authors.initials: BK
authors.lastname: Koo
authors.affiliation: Department of Cardiology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Myeong-Ho
authors.initials: MH
authors.lastname: Yoon
authors.affiliation: Department of Cardiology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Seung-Jea
authors.initials: SJ
authors.lastname: Tahk
authors.affiliation: Department of Radiology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Doo Kyoung
authors.initials: DK
authors.lastname: Kang
authors.affiliation: Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Young Bin
authors.initials: YB
authors.lastname: Song
authors.affiliation: Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Joo-Yong
authors.initials: JY
authors.lastname: Hahn
authors.affiliation: Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Seung Hyuk
authors.initials: SH
authors.lastname: Choi
authors.affiliation: Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Hyeon-Cheol
authors.initials: HC
authors.lastname: Gwon
authors.affiliation: Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Sang-Hoon
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Eun-Kyoung
authors.initials: EK
authors.lastname: Kim
authors.affiliation: Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Sung Mok
authors.initials: SM
authors.lastname: Kim
authors.affiliation: Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Yeonhyeon
authors.initials: Y
authors.lastname: Choe
authors.affiliation: Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea; Department of Emergency Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. Electronic address: jhchoimd@gmail.com.
authors.forename: Jin-Ho
authors.initials: JH
authors.lastname: Choi
mesh_terms: D000368:Aged; D019540:Area Under Curve; D000072226:Computed Tomography Angiography; D017023:Coronary Angiography / Q000379:methods*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006785:Hospitals, University; D006801:Humans; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D061330:Multidetector Computed Tomography; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D012042:Registries; D056910:Republic of Korea; D012720:Severity of Illness Index
keywords: anatomical-physiological discordance; coronary artery physiology; fractional myocardial mass; fractional flow reserve