title: Effect of flow competition on internal thoracic artery graft: postoperative velocimetric and angiographic study.
abstract: OBJECTIVE
  To assess the effects of competitive blood flow on internal thoracic artery grafts, we investigated postoperative flow velocity characteristics and angiographic findings of the grafts with various grades of native coronary artery stenosis.
  
  
  METHODS
  Fifty patients who had an internal thoracic artery graft to the left anterior descending artery underwent intravascular Doppler graft velocimetry during postoperative angiography. Patients were divided into 3 groups according to the grade of native coronary stenosis: group H (28 patients), 80% stenosis or greater; group M (16 patients), 60% to 79% stenosis; and group L (6 patients), 40% to 59% stenosis. Phasic flow velocity of the grafts was measured with an intravascular Doppler ultrasound-tipped guide wire during angiography. Graft flow volume was calculated from the diameter and the average peak velocity.
  
  
  RESULTS
  Average peak velocity (group H, 27.1 +/- 8.6 cm/s; group M, 16.9 +/- 3.9 cm/s; group L, 7.2 +/- 3.7 cm/s), distal graft diameter (group H, 2.27 +/- 0.23 mm; group M, 2. 00 +/- 0.28 mm; group L, 1.07 +/- 0.27 mm), and calculated graft flow volume (group H, 33.1 +/- 12.0 mL/min; group M, 16.2 +/- 5.8 mL/min; group L, 2.3 +/- 2.0 mL/min) significantly differed among the 3 groups. Graft flow in diastole and systole also differed among the 3 groups.
  
  
  CONCLUSIONS
  Competitive blood flow reduces internal thoracic artery graft flow and diameter according to the grade of the native coronary artery stenosis. These data suggest that grafting the internal thoracic artery to the coronary artery with stenosis of a low grade can cause graft atrophy and failure.
authors.affiliation: Department of Surgery II, Tokyo Medical University, Shinjuku-ku, Tokyo, Japan. t-shimiz@edu1.tokyo-med.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Shimizu
authors.forename: T
authors.initials: T
authors.lastname: Hirayama
authors.forename: H
authors.initials: H
authors.lastname: Suesada
authors.forename: K
authors.initials: K
authors.lastname: Ikeda
authors.forename: S
authors.initials: S
authors.lastname: Ito
authors.forename: S
authors.initials: S
authors.lastname: Ishimaru
mesh_terms: D000368:Aged; D017023:Coronary Angiography; D003326:Coronary Circulation / Q000502:physiology*; D003327:Coronary Disease / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009204:Myocardial Revascularization; D011183:Postoperative Complications; D011184:Postoperative Period; D012039:Regional Blood Flow / Q000502:physiology; D012212:Rheology