title: Assessment of left internal mammary artery graft patency by transthoracic Doppler echocardiography.
abstract: BACKGROUND
  The successful application of noninvasive Doppler spectrum analysis has been reported for the hemodynamic assessment of LIMA graft after myocardial revascularization.
  
  
  OBJECTIVE
  The objective of this study was to assess the utility of transthoracic Doppler echocardiography (TTE) in providing information on LIMA flow in patients after coronary artery bypass graft surgery.
  
  
  METHODS
  In all, 22 patients (aged 62 +/- 8 years) with LIMA graft to the left anterior descending (LAD) coronary artery who underwent coronary angiography were assessed using high-frequency (5 MHz) transthoracic Doppler echocardiography. They were compared with 25 patients with angina (control group A, aged 59 +/- 12 years), in whom an ungrafted LIMA was assessed, and with 17 patients (control group B, aged 59 +/- 9 years) with angiographically normal coronary arteries, in whom the LAD was assessed.
  
  
  RESULTS
  A biphasic pattern (systolic and diastolic) was recorded in all cases. In 14 patients with a normal graft or < 70% stenosis (Group 1) and in control group B, blood flow was maximal during diastole. In eight patients with severe graft stenosis > 70% (Group 2) and control group B, blood flow was maximal during systole, with low diastolic flow. The diastolic fraction of the velocity time integrals was 0.81 +/- 0.11 for Group 1 and 0.25 +/-0.06 for Group 2 (p < 0.05). A diastolic velocity time integral fraction < 0.5 predicted > 70% stenosis with a sensitivity and specificity of 100%. The ratio of systolic/diastolic peak velocities was 0.61 +/- 0.31 for Group 1 and 3.21 +/- 0.49 for Group 2 (p < 0.05). A systolic/diastolic peak velocity > 1 predicted stenosis > 70% with a sensitivity and specificity of 100 and 90%, respectively.
  
  
  CONCLUSIONS
  High-frequency TTE is a useful noninvasive method for detecting LIMA graft blood flow. Severe graft stenoses exhibited Doppler velocity patterns, which were different from those of patent grafts, or grafts with moderate stenoses.
authors.affiliation: Department of Cardiology, Tanta Faculty of Medicine, Egypt.
authors.forename: Magdy M
authors.initials: MM
authors.lastname: El-Masry
authors.forename: Mai M
authors.initials: MM
authors.lastname: Salama
authors.forename: Ahmed Z
authors.initials: AZ
authors.lastname: Darwish
authors.forename: Osama
authors.initials: O
authors.lastname: Abd El-Aziz
mesh_terms: D001783:Blood Flow Velocity; D016022:Case-Control Studies; D001026:Coronary Artery Bypass; D003971:Diastole / Q000502:physiology; D015150:Echocardiography, Doppler; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging; D006085:Graft Survival / Q000502:physiology; D006801:Humans; D008323:Mammary Arteries / Q000000981:diagnostic imaging* / Q000637:transplantation*; D008875:Middle Aged; D012680:Sensitivity and Specificity; D013599:Systole / Q000502:physiology; D014654:Vascular Patency / Q000502:physiology*