title: Noninvasive Discrimination of Coronary Chronic Total Occlusion and Subtotal Occlusion by Coronary Computed Tomography Angiography.
abstract: OBJECTIVE
  The aim of this study was to investigate whether noninvasive discrimination of chronic total occlusion (CTO), a complete interruption of coronary artery flow, and subtotal occlusion (STO), a functional total occlusion, is feasible using coronary computed tomography angiography (CTA).
  
  
  BACKGROUND
  CTO and STO may be different in pathophysiology and clinical treatment strategy.
  
  
  METHODS
  We included 486 consecutive patients (median age 63 years, 82% male) who showed a total of 553 completely occluded coronary arteries in coronary CTA. The length of occlusion, side branches, shape of proximal stump, and collateral vessels were measured as anatomical findings. Transluminal attenuation gradient, which reflects intraluminal contrast kinetics and functional extent of collateral flow, was measured as a physiological surrogate. All patients were followed by invasive coronary angiography.
  
  
  RESULTS
  Coronary arteries with CTO showed longer occlusion length (cutoff ≥ 15 mm), higher distal transluminal attenuation gradient (cutoff ≥-0.9 Hounsfield units [HU]/10 mm), more frequent side branches, blunted stump, cross-sectional calcification ≥ 50%, and collateral vessels compared with arteries with STO (p < 0.001, all). The combination of these findings could distinguish CTO from STO (c-statistics = 0.88 [95% confidence interval: 0.94 to 0.90], sensitivity 83%, specificity 77%, positive predictive value 55%, negative predictive value 93%; p < 0.001). Percutaneous coronary intervention (PCI) was attempted in 342 arteries and was successful in 279 arteries (82%). The computed tomography findings could predict the unsuccessful PCI (c-statistics = 0.70 [95% confidence interval: 0.65 to 0.75], sensitivity 63%, specificity 73%, positive predictive value 91%, negative predictive value 31%; p < 0.001).
  
  
  CONCLUSIONS
  Noninvasive coronary CTA could discern CTO from STO, and also could predict the success of attempted PCI.
authors: Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea; Department of Emergency Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. Electronic address: jhchoimd@gmail.com.
authors: Jin-Ho
authors: JH
authors: Choi
authors: Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors: Eun-Kyoung
authors: EK
authors: Kim
authors: Department of Radiology, Cardiovascular Imaging Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors: Sung Mok
authors: SM
authors: Kim
authors: Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors: Hyungyoon
authors: H
authors: Kim
authors: Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors: Young Bin
authors: YB
authors: Song
authors: Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors: Joo-Yong
authors: JY
authors: Hahn
authors: Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors: Seung Hyuk
authors: SH
authors: Choi
authors: Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors: Hyeon-Cheol
authors: HC
authors: Gwon
authors: Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors: Sang-Hoon
authors: SH
authors: Lee
authors: Department of Radiology, Cardiovascular Imaging Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors: Yeon Hyeon
authors: YH
authors: Choe
authors: Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea; Department of Internal Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota.
authors: Jae K
authors: JK
authors: Oh
mesh_terms: D002908:Chronic Disease; D003097:Collateral Circulation; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D003326:Coronary Circulation; D054059:Coronary Occlusion / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D011237:Predictive Value of Tests; D012720:Severity of Illness Index; D014654:Vascular Patency
chemical_list: D003287:Contrast Media
keywords: chronic total occlusion; coronary CT angiography; percutaneous coronary intervention; subtotal occlusion