BACKGROUND - Provisional side branch (SB) stenting is correlated with target vessel myocardial infarction (TVMI) in patients with coronary bifurcation lesions. However, the mechanisms underlying this association remain unknown.

OBJECTIVES - To determine the correlation between SB lesion length with vulnerable plaques and TVMI using optical coherence tomography (OCT).

BACKGROUND - The correlation between SB lesion length with vulnerable plaques and TVMI is unknown.

METHODS - A total of 405 patients with 405 bifurcation lesions who underwent preprocedure OCT imaging of both the main vessel (MV) and the SB were enrolled. Patients were divided into long SB lesion (SB lesion length ≥10 mm) and short SB lesion (SB lesion length <10 mm) groups according to quantitative coronary analysis; they were also stratified by the presence of vulnerable plaques identified by OCT. The primary endpoint was the occurrence of TVMI after provisional stenting at 1-year follow-up.

RESULTS - In total, 178 (43.9%) patients had long SB lesions. Vulnerable plaques were predominantly localized in the MV and were more frequently in the long SB lesion group (42.7%) than in the short SB lesion group (24.2%, p < .001). At 1-year follow-up after provisional stenting, there were 31 (7.7%) TVMIs, with 21 (11.8%) in the long SB lesion group and 10 (4.4%) in the short SB lesion group (p = .009). Multivariate regression analysis showed that long SB lesion length (p = .011), absence of vulnerable plaques in the polygon of confluence (p = .001), and true coronary bifurcation lesions (p = .004) were the three independent factors of TVMI.

CONCLUSIONS - The presence of long SB lesion with MV vulnerable plaques predicts the increased risk of TVMI after provisional stenting in patients with true coronary bifurcation lesions. Further studies are warranted to identify the best stenting techniques for coronary bifurcation lesions with long SB lesions.