Configurations of the mitral valve during off-pump coronary artery bypass grafting: endoscopic and three-dimensional analysis.
OBJECTIVE
During off-pump coronary artery bypass grafting (CABG), mitral regurgitation (MR) has been experienced in relation to the procedures. The study aim was to evaluate the mitral valve configuration, with particular focus on annular behavior, during off-pump CABG, using cardiac endoscopy and digital 3-D ultrasound sonomicrometry.


METHODS
Following implantation of six crystals of the digital 3-D ultrasound sonomicrometer around the mitral annulus, and two crystals on the epicardial base of the papillary muscles, off-pump CABG was simulated in seven beagle dogs. The heart was perfused with pellucid Krebs-Henseleit solution in situ, with controlled left ventricular end-diastolic pressure (LVEDP). The behaviors of the mitral annulus and leaflets were then observed endoscopically with only cardiac displacement, 15 min occlusion of the left anterior descending artery (LAD), or 15 min occlusion of the left circumflex artery (LCx) with cardiac displacement. Dimensions between the crystals were also recorded using digital 3-D ultrasound sonomicrometry.


RESULTS
With only cardiac displacement, no MR was observed endoscopically, and no major changes occurred in annular configuration when coronary perfusion was maintained. In one dog, MR was observed only from the anterolateral site after LAD occlusion. MR from the posteromedial site was observed by occlusion of the LCx in all cases, with significant (p < 0.01) enlargement of the mitral annular dimensions.


CONCLUSIONS
Cardiac displacement alone did not cause MR if coronary perfusion was maintained. Occlusion of the LAD rarely caused MR from the anterolateral site, whereas occlusion of the LCx normally caused MR from the posteromedial site; the posteromedial annulus was enlarged, even when the LVEDP was controlled.
Koga
Shugo
S
Department of Thoracic and Cardiovascular Surgery, Saga University Hospital, Saga, Japan.
Okazaki
Yukio
Y
Kataoka
Hiromi
H
Ikeda
Kazuyuki
K
Furukawa
Kojiro
K
Ohtsubo
Satoshi
S
Itoh
Tsuyoshi
T
D000818:Animals; D001794:Blood Pressure; D002306:Cardiac Volume; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D047549:Coronary Artery Bypass, Off-Pump; D004285:Dogs; D019723:Endoscopes; D005336:Fiber Optic Technology; D008943:Mitral Valve / Q000000981:diagnostic imaging* / Q000601:surgery*; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging; D009200:Myocardial Contraction / Q000502:physiology; D014463:Ultrasonography; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology*