Comparitive Research Between Intraoperative Graft Flow And Postoperative Graft Patency In Coronary Artery Bypass Grafting

OBJECTIVETo evaluate the relationship between transit-time flow measurement (TTFM) and 64 multi-slice computed tomography angiography (64-MSCTA) in evaluating the graft patency of coronary artery bypass grafting (CABG).PATIENTS AND METHODS1 The data of 381 patients who underwent CABG and took the MSCTA examination postoperatively were collected and divided into groups according to Fitz Gibbon's criteria. Comparion were made between parameters of transit-time flow measurement (TTFM) and multi-slice computed tomography (MSCT) retrospectively.2 Preoperative coronary angiography (CAG) data were collected to research the influence of different proximal stenosis in the native artery on parameters of TTFM and the grafts patency in MSCT.3 The parameters of TTFM and MSCT were analyzed according to the different anastomosis numbers of saphenous vein graft (SVG).4 The parameters of TTFM and MSCT were analyzed according to the different target coronary artery to which a single SVG anastomosed.5 The parameters of TTFM and MSCT were analyzed according to the two different surgery procedures: off-pump coronary artery bypass (OPCAB) and conventional coronary artery bypass grafting (CCABG).RESULTS1 The mean flow and peak flow in diastolic period (PF-D) were higher, and the pulsatility index (PI value) and insufficiency ratio (IR) were lower in the patent group of MSCT than the other two groups, and there was significant difference between groups. But the grafts should not be diagnosed as stenosis or occluded if the mean flow was lower or the PI value was higher.2 The more severe of the proximal stenosis in the target coronary artery, the bigger of mean flow and the lower of PI showed in the TTFM, and LIMA tended to be occluded if the proximal stenosis of LAD was mild or moderate, but there was no significant difference in the graft patency of SVGs postoperatively though the proximal stenosis of target coronary artery differed.3 The more anastomosis of sequencial SVG had, the bigger mean flow of the grafts showed, but there was no siginificant difference in the PI value and the graft patency showed in MSCT postoperatively.4 There was no significant difference in the mean flow and PI value when SVGs anastomosed to LAD, left circumflex coronary artery(LCX) and right coronary artery(RCA), the patency of SV-LAD was a little higher than the LCXs and the RC As, though the number of patients was small.5 The mean flow and PF-D of LIMA in OPCAB group were lower than that in CCABG group, and there was no other siginificant difference of LIMA in two groups. There were significant differences of SVG in TTFM between the OPCAB and CCABG with the exception for the PF-S. The graft patency of LIMA and SVG in OPCAB and CCABG were similar and there was no significant difference according to the MSCT results. CONCLUSION1 There is a good relationship between TTFM parameters and MSCT results. The better patency of grafts show postoperatively in MSCT, the better of parameters show intraoperatively in TTFM. But the graft shouldn't be diagnosed as stenosis or concluded just according to the lower mean flow and the higher PI value.2 The proximal stenosis of target coronary artery has significant influence on the TTFM parameters. It has significant influence on the patency of the LIMAs postoperatively in MSCT, but there is no significant influence from the competitive flow on the SVGs.3 There mean flow of sequential SVGs grows when the number of anastomosis grows, but not the same as the PI value and the patency of graft postoperatively in MSCT.4 The TTFM parameters are influenced when the SVGs anastomosed to different coronary arteries, the graft patency of different target SVGs need further research.5 The TTFM parameters and MSCT results in the OPCAB and CCABG groups are satisfied equally.