Abstract: Objective To explore the mechanism of lumen loss of the left circumflex ostium after main vessel stent implantation.
Methods Twenty-eight patients undergoing provisional T technique were enrolled in this study. Intravascular ultrasound
(IVUS) examination was performed before and after main vessel stenting and kissing balloon post-dilatation to evaluate the
geometrical changes of the vessels. Results The CSA of LCX ostium lumen decreased significantly from 5.9±2 mm2 to 4.9±1.9
mm2 (P<0.01) after the procedure, and the CSA of LCX ostium P&M increased from 5.4±2.9 mm2 to 5.7±2.9 mm2 (P=0.21) after
the main vessel stenting. The changes in LCX ostium lumen CSA was correlated with the changes of LCX ostium EEM CSA but
not the LCX ostium P&M CSA. After kissing balloon post-dilatation, the CSA of LCX ostium lumen increased from 4.9±1.9
mm2 to 5.5±1.9 mm2 (P<0.01) , and the CSA of LCX ostium P& M showed no obvious changes (5.7±2.9 mm2 vs 5.7±2.6 mm2, P=
0.89). The changes of LCX ostium lumen CSA were correlated with the those of the LCX ostium EEM CSA (R=0.432, P=0.02).
Conclusion After stent implantation from the LMCA to the LAD, most of lumen losses of the LCX are due to carina shift, and
in occasional cases, plaque shift occurs from the distal LMCA to the ostium of the LCX. Kissing balloon technique can adjust
carina shift but can not improve plaque shift.