Simple versus complex approaches to treating coronary bifurcation lesions: direct assessment of stent strut apposition by optical coherence tomography.

INTRODUCTION AND OBJECTIVES Stenting of coronary bifurcation lesions carries an increased risk of stent deformation and malapposition. Anatomical and pathological observations indicate that the high stent thrombosis rate in bifurcations is due to malapposition of stent struts. METHODS Strut apposition was assessed with optical coherence tomography (OCT) in bifurcation lesions treated either using the simple technique of stent implantation in the main vessel only or a complex technique (i.e. Culotte's). A strut was regarded as malapposed if the gap between its endoluminal surface and the vessel wall was greater than its thickness plus an OCT resolution error margin of 15 microm. RESULTS Simple and complex (i.e. Culotte's) approaches were used in 17 and 14 patients, respectively. Strut malapposition was significantly more frequent for the half of the bifurcation on same side as the vessel side branch (median, 46.1%; interquartile range [IQR], 35.3-62.5%) than for the half opposite the side branch (9.1%; IQR, 2.2-21.6%), the distal segment (7.5%; IQR, 2.3-20.2%) or the proximal segment (12.6%; IQR, 7.8-23.1%; P< .0001); the gap between strut and vessel wall in malapposed struts was significantly greater in the first segment than the others: 98 microm (IQR, 37-297 microm) vs. 31 microm (IQR, 13-74 microm), 49 microm (IQR, 20-100 microm) and 38 microm (IQR, 17-90 microm), respectively (P< .0001). Using the complex technique had no effect on the prevalence of strut malapposition in the four segments relative to the simple technique (P=.31) but was associated with a smaller gap in the proximal segment (47 microm vs. 60 microm; P=.0008). CONCLUSIONS In coronary bifurcation lesions, strut malapposition occurred most frequently and was most significant close to the side branch ostium. The use of Culotte's technique did not significantly increase the prevalence of strut malapposition compared with a simple technique.