title: Long-term morphofunctional remodeling of internal thoracic artery grafts: a frequency-domain optical coherence tomography study.
abstract: BACKGROUND
  Internal thoracic arteries (ITAs) are frequently anastomosed to the coronary circulation for bypass grafting. The purpose of this research was to investigate in vivo the long-term morphofunctional changes of ITAs after their use as coronary artery bypass conduits, by comparing the morphological features and vasoreactivity of the grafted left ITA (LITA) with the native, nonharvested right ITA (RITA) in the same patient.
  
  
  RESULTS
  At least 10 years after surgery, in 10 patients, LITA graft and nonharvested RITA were assessed by quantitative angiography and frequency-domain optical tomography. Endothelium-dependent and independent vasodilation was tested by selective infusion of acetylcholine and isosorbide dinitrate. Quantitative angiography showed that baseline mean diameter of LITA graft was significantly smaller than that of RITA (2.59 mm [2.29-3.04] versus 3.05 mm [2.75-3.32]; P=0.01). LITA showed a significant intimal thickening (P=0.05) and a nonsignificant medial thinning (P=0.22) compared with RITA, leading to an increased intima-media ratio (intima-media ratio, 0.72 [0.53-0.91] versus 0.23 [0.12-0.38]; P=0.02). The intima-media ratio correlated inversely with the vasodilatatory response in RITA (r=-0.68, P=0.03 for acetylcholine and r=-0.62, P=0.05 for isosorbide dinitrate) but not in LITA (r=-0.18, P=0.63 for acetylcholine and r=-0.11, P=0.75 for isosorbide dinitrate).
  
  
  CONCLUSIONS
  Ten years after implantation to the coronary circulation, LITA grafts show intimal thickening, increased intima/media ratio, and maintained endothelium-derived vasodilation. These changes are likely to be an adaptive answer to the different flow dynamics typical of coronary circulation.
authors.affiliation: Interventional Cardiology Unit, San Donato Hospital, Arezzo, Italy. italo.porto@gmail.com
authors.forename: Italo
authors.initials: I
authors.lastname: Porto
authors.forename: Mario
authors.initials: M
authors.lastname: Gaudino
authors.forename: Giovanni Luigi
authors.initials: GL
authors.lastname: De Maria
authors.forename: Luca
authors.initials: L
authors.lastname: Di Vito
authors.forename: Rocco
authors.initials: R
authors.lastname: Vergallo
authors.forename: Piergiorgio
authors.initials: P
authors.lastname: Bruno
authors.forename: Giorgia
authors.initials: G
authors.lastname: Bonalumi
authors.forename: Francesco
authors.initials: F
authors.lastname: Prati
authors.forename: Leonardo
authors.initials: L
authors.lastname: Bolognese
authors.forename: Filippo
authors.initials: F
authors.lastname: Crea
authors.forename: Massimo
authors.initials: M
authors.lastname: Massetti
mesh_terms: D000368:Aged; D017023:Coronary Angiography; D003326:Coronary Circulation; D005260:Female; D006801:Humans; D007387:Internal Mammary-Coronary Artery Anastomosis; D008297:Male; D008323:Mammary Arteries / Q000000981:diagnostic imaging / Q000187:drug effects / Q000473:pathology* / Q000503:physiopathology / Q000637:transplantation*; D008875:Middle Aged; D011237:Predictive Value of Tests; D013997:Time Factors; D041623:Tomography, Optical Coherence; D016896:Treatment Outcome; D017539:Tunica Intima / Q000473:pathology; D017540:Tunica Media / Q000473:pathology; D014664:Vasodilation; D014665:Vasodilator Agents / Q000008:administration & dosage
chemical_list: D014665:Vasodilator Agents
keywords: endothelium-dependent vasodilation; frequency-domain–optical coherence tomography; left internal thoracic artery; right internal thoracic artery