Ultrasound study of the prevalence of plaque at the carina in lesions that affect the coronary bifurcation. Implications for treatment with provisional stent.

Objective: The plaque distribution patterns in coronary bifurcation lesions are not well understood. It has been speculated that carina is free of plaque partly because of high wall shear stress providing an atheroprotective effect. To study plaque distribution with intravascular ultrasound (IVUS) in the coronary bifurcation and the prevalence of carina involvement.

Methods: IVUS study was performed on 195 coronary bifurcation lesions in the main vessel (MV) and on 91 in the side branch (SB). Plaque at the carina was considered when its thickness was > 0.3mm. Plaque burden was measured at different levels: proximal reference, distal, carina and at the point of minimal lumen area (MLA).

Results: The prevalence of plaque at the carina was 32%. Its thickness was 0.8 (0.36) mm, less than that observed at the counter-carina [1.22 (0.54) mm; P<.01]. The prevalence was higher (52%) when the MLA point was distal to the carina. The plaque at the carina was associated with a lower incidence of damage at the SB ostium after stenting the MV (32% vs 54%; P<.04).

Conclusions: The carina is not immune to atherosclerosis, showing plaque at this level in one third of the bifurcations. The incidence of plaque is higher in those bifurcations with the MLA point distal to the carina and seems to be associated with a lower incidence of damage to the SB ostium.