BACKGROUND: "Stepwise provisional stenting" is the most adopted approach for percutaneous coronary interventions (PCI) in bifurcation lesions. During these procedures, side-branch (SB) may deserve treatment, but the best ballooning technique is still undetermined. OBJECTIVES: To compare the stent configurations obtained by two SB ballooning sequences after the main vessel (MV) stent implantation: proximal-optimization-technique (POT)+kissing-balloon-inflation+final POT (PKP) versus POT+isolated-SB-dilation+final POT (PSP). METHODS: We conducted a 1:1 prospective, randomized, single-center trial to compare bifurcation PCI performed with either PKP or PSP in left main or large (SB diameter >
2.75 mm) coronary bifurcations (NCT05559424). The achieved stent configurations (in terms of expansion, apposition and eccentricity at five different bifurcation segments) were evaluated using optical coherence tomography (OCT) in the MV. The pre-defined primary study endpoint was minimum stent expansion (MSE) at the distal MV segment. RESULTS: A total of 60 patients undergoing bifurcation PCI according to "stepwise provisional stenting" were enrolled (30 randomized to PKP and 30 to PSP). At post-intervention OCT, MSE at the distal-MV segment was significantly higher with PKP as compared with PSP (99.3±12.7% vs. 83.8±19.5%
p<
0.001). Additional relevant findings included higher rate of malapposition in the bifurcation core and distal-MV with PSP and improved SB scaffolding with PKP. No significant differences in terms of stent eccentricity were noted between PSP and PKP in all the segments analyzed. CONCLUSIONS: The results of the present randomized trial show that during stepwise provisional stenting in left main or large bifurcations, the PKP ballooning sequence is associated with better stent configuration compared to the PSP.