title: Microvascular dysfunction in the immediate aftermath of chronic total coronary occlusion recanalization.
abstract: OBJECTIVE
  The aim of this study was to compare microvascular resistance under both baseline and hyperemic conditions immediately after percutaneous coronary intervention (PCI) of a chronic total occlusion (CTO) with an unobstructed reference vessel in the same patient
  
  
  BACKGROUND
  Microvascular dysfunction has been reported to be prevalent immediately after CTO PCI. However, previous studies have not made comparison with a reference vessel. Patients with a CTO may have global microvascular and/or endothelial dysfunction, making comparison with established normal values misleading.
  
  
  METHODS
  After successful CTO PCI in 21 consecutive patients, coronary pressure and flow velocity were measured at baseline and hyperemia in distal segments of the CTO/target vessel and an unobstructed reference vessel. Hemodynamics including hyperemic microvascular resistance (HMR), basal microvascular resistance (BMR), and instantaneous minimal microvascular resistance at baseline and hyperemia were calculated and compared between reference and target/CTO vessels.
  
  
  RESULTS
  After CTO PCI, BMR was reduced in the target/CTO vessel compared with the reference vessel: 3.58 mm Hg/cm/s vs 4.94 mm Hg/cm/s, difference -1.36 mm Hg/cm/s (-2.33 to -0.39, p = 0.008). We did not detect a difference in HMR: 1.82 mm Hg/cm/s vs 2.01 mm Hg/cm/s, difference -0.20 (-0.78 to 0.39, p = 0.49). Instantaneous minimal microvascular resistance correlated strongly with the length of stented segment at baseline (r = 0.63, p = 0.005) and hyperemia (r = 0.68, p = 0.002).
  
  
  CONCLUSIONS
  BMR is reduced in a recanalized CTO in the immediate aftermath of PCI compared to an unobstructed reference vessel; however, HMR appears to be preserved. A longer stented segment is associated with increased microvascular resistance. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Academic Cardiology, Daisy Building, Castle Hill Hospital, Castle Road, Hull, HU16 5JQ, United Kingdom.
authors.forename: Andrew
authors.initials: A
authors.lastname: Ladwiniec
authors.affiliation: Department of Academic Cardiology, Daisy Building, Castle Hill Hospital, Castle Road, Hull, HU16 5JQ, United Kingdom.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Cunnington
authors.affiliation: Department of Academic Cardiology, Daisy Building, Castle Hill Hospital, Castle Road, Hull, HU16 5JQ, United Kingdom.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Rossington
authors.affiliation: Department of Academic Cardiology, Daisy Building, Castle Hill Hospital, Castle Road, Hull, HU16 5JQ, United Kingdom.
authors.forename: Simon
authors.initials: S
authors.lastname: Thackray
authors.affiliation: Department of Academic Cardiology, Daisy Building, Castle Hill Hospital, Castle Road, Hull, HU16 5JQ, United Kingdom.
authors.forename: Farquad
authors.initials: F
authors.lastname: Alamgir
authors.affiliation: Department of Academic Cardiology, Daisy Building, Castle Hill Hospital, Castle Road, Hull, HU16 5JQ, United Kingdom.
authors.forename: Angela
authors.initials: A
authors.lastname: Hoye
mesh_terms: D002908:Chronic Disease; D003326:Coronary Circulation / Q000502:physiology*; D054059:Coronary Occlusion / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D062645:Percutaneous Coronary Intervention / Q000379:methods*; D012189:Retrospective Studies; D015607:Stents
keywords: CTO; PCI; microvascular resistance