BACKGROUND - In left main coronary artery (LMCA) bifurcation lesions, hemodynamic and geometrical change in left circumflex artery (LCX) ostium after main branch (MB) stenting has not been known. This study evaluated how accurately intravascular ultrasound (IVUS) predicts the functional compromise of the sidebranch.

METHODS - A single-stent cross-over technique was used to treat LMCA bifurcation lesions in 43 patients with LCX ostial diameter stenosis (DS) of <50%. The fractional flow reserve (FFR) in the LCX was measured after MB stenting, MB and sidebranch pullback IVUS was performed prestenting and poststenting.

RESULTS - After MB stenting, angiographic DS >50% at the LCX ostium was observed in 18 (42%) patients, while only 3 (7%) showed FFR <0.80. A pre-procedural minimal lumen area (MLA) of <3.7 mm(2) within the LCX ostium was predictive of a poststenting FFR <0.80, with a sensitivity of 100%, specificity of 71%, a positive predictive value (PPV) of 16%, and a negative predictive value (NPV) of 100% (area under curve 0.80, P < 0.001). Moreover, pre-procedural plaque burden of >56% at the LCX ostium predicted FFR <0.80, with a sensitivity of 100%, specificity of 65%, a PPV of 14%, and a NPV of 100% (area under curve 0.80, P < 0.001). A poststenting LCX ostial DS >57% predicted FFR <0.80 with a sensitivity of 100%, specificity of 88%, a PPV of 38% and a NPV of 100% (area under curve 0.962, P < 0.001). However, the poststenting MLA within the LCX ostium showed no significant correlation with FFR (r = 0.197, P = 0.391).

CONCLUSIONS - In LMCA bifurcation lesions with mild LCX ostial disease, the use of single-stent technique rarely resulted in the functional LCX compromise. Because the functional LCX stenosis is poorly predicted by a small MLA, sidebranch treatment should be based on the poststenting FFR.

Copyright © 2013 Wiley Periodicals, Inc.