title: Fractional flow reserve of pedicled internal thoracic artery and saphenous vein grafts 6 months after bypass surgery.
abstract: BACKGROUND
  Although the internal thoracic artery was proven superior to saphenous vein graft in long-term patency, it is thought to be a more resistive conduit than the vein graft. Moreover, patency studies comparing both left and right internal thoracic arteries have provided results favoring the former. Fractional flow reserve is an established functional index of coronary blood flow.
  
  
  METHODS
  To compare the fractional flow reserve between both internal thoracic arteries and saphenous vein grafts, 43 bypass grafts were studied 6 months after revascularization. Intra-graft pressures were measured during cardiac catheterization using a pressure-wire advanced to the first distal anastomosis of 12 left internal thoracic arteries (ITAs), 10 right ITAs and of 21 vein grafts. Pressure gradients between the aorta and the graft were measured at baseline and during a maximal hyperemia.
  
  
  RESULTS
  At baseline, pressure gradient was recorded in the left ITA (2.9+/-2.2 mmHg), in the right ITA (1.2+/-1.2 mmHg) and in the vein graft (0.4+/-0.7 mmHg). During maximal hyperemia, pressure gradient increased to 9.6+/-3.2 mmHg in left ITA, to 4.5+/-2.0 mmHg in the right ITA (p<0.001 vs left ITA) and to 3.3+/-2.7 mmHg in vein (p<0.001 vs left ITA; NS vs right ITA). Fractional flow reserve was 0.90+/-0.04 in left ITA, 0.95+/-0.03 in right ITA (p<0.01 vs left ITA) and 0.96+/-0.03 in vein (p<0.001 vs left ITA).
  
  
  CONCLUSIONS
  Internal thoracic arteries and saphenous vein grafts allow myocardial revascularization with minimal resistance to maximal blood flow. The resistance appears significantly higher in left ITA compared to both the right ITA and venous grafts.
authors.affiliation: University Hospital Saint-Luc, Department of Cardiovascular Medicine and Surgery, Brussels, Belgium. david.glineur@clin.ucl.ac.be
authors.forename: David
authors.initials: D
authors.lastname: Glineur
authors.forename: Alain
authors.initials: A
authors.lastname: Poncelet
authors.forename: Gebrine
authors.initials: G
authors.lastname: El Khoury
authors.forename: William
authors.initials: W
authors.lastname: D'hoore
authors.forename: Parla
authors.initials: P
authors.lastname: Astarci
authors.forename: Francis
authors.initials: F
authors.lastname: Zech
authors.forename: Philippe
authors.initials: P
authors.lastname: Noirhomme
authors.forename: Claude
authors.initials: C
authors.lastname: Hanet
mesh_terms: D001794:Blood Pressure; D006328:Cardiac Catheterization; D017023:Coronary Angiography; D001026:Coronary Artery Bypass / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D053805:Fractional Flow Reserve, Myocardial; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D007387:Internal Mammary-Coronary Artery Anastomosis; D008297:Male; D008323:Mammary Arteries / Q000503:physiopathology; D011184:Postoperative Period; D011446:Prospective Studies; D012501:Saphenous Vein / Q000503:physiopathology; D014654:Vascular Patency; D014655:Vascular Resistance