Systematic side branch intervention compared to conservative strategy in coronary bifurcation lesions

BACKGROUND: Although provisional stenting is the recommended strategy for most coronary bifurcation lesions, the clinical benefit of additional side branch (SB) intervention remains debated. OBJECTIVES: The aim of this study was to determine whether a conservative strategy without systematic SB intervention (SBI) is noninferior to systematic SB intervention regarding periprocedural events. METHODS: The multicenter, international KISS (Keep Bifurcation Single Stenting Simple) trial randomized patients with non-left main bifurcation lesions to 2 groups: no SBI or SBI following main branch stenting with the Resolute Onyx drug-eluting stent and a proximal optimization technique without impairment of SB flow. The primary endpoint was periprocedural myocardial infarction (MI) or myocardial injury, according to the Academic Research Consortium 2 definition. Secondary endpoints included procedural complications and 12-month clinical outcomes, including target lesion failure, defined as the composite of cardiac death, target vessel MI, and target lesion revascularization. RESULTS: Among the 616 included patients, 81% were treated for chronic coronary disease, and the bifurcation mainly involved was between the left anterior descending coronary artery and the diagonal. In the no-SBI group, an intervention on the SB was required in 2.0% of patients (n = 6). Periprocedural MI or myocardial injury occurred in 4.1% (n = 11) in the no-SBI group vs 5.7% (n = 16) in the SBI group (P < 0.001 for noninferiority; P = 0.38 for superiority). There was no significant interaction with age, sex, Medina classification, or SB residual stenosis. Procedure time, radiation dose, and contrast use were significantly lower in the no-SBI group. Procedural complications were rare, but SB dissection was more frequently observed in the SBI group (2.9% vs 0.0%; P = 0.004). There was no difference in target lesion failure at 1 year (4.9% [n = 15] vs 6.4% [n = 20] in the no-SBI and SBI groups respectively; P = 0.442). CONCLUSIONS: The KISS trial demonstrates that a conservative strategy without systematic SB intervention is associated with very rare procedural complications and is noninferior to a systematic SB intervention regarding periprocedural MI and myocardial injury.