Role of optical coherence tomography for distal left main stem angioplasty

Objective: The objective is to analyze the acute and midterm angiographic outcome of percutaneous treatment of left main coronary stem (LM-PCI) guided by optical coherence tomography (OCT). Background: LM-PCI is a complex procedure, and several anatomical factors may impair its outcome. Intravascular imaging is emerging as a useful tool to guide the procedure. Methods: We conducted a retrospective analysis of patients undergoing LM-PCI at three European centers between 2014 and 2017 with a control angiography at 6–12 months. Patients were divided into two groups: OCT-guidance (pre- and post-PCI) and control group (standard angiographic guidance with/out intravascular ultrasound [IVUS]). A blinded core lab analyzed all angiographic images. Primary endpoint was late lumen loss (LLL) after 6 months. Results: A total of 112 patients entered the study, 55 in the OCT group and 57 in the control group (10 IVUS). Baseline and procedural characteristics were similar between groups. Overall, reference vessel diameter of the LM was 3.98 ± 0.65 mm. OCT guidance detected four cases of stent underexpansion (7.2%) and six cases of acute malapposition (10.9%). After a median of 207 ± 23 days, LLL of LM tended to be lower in the OCT group (0.12 ± 0.41 vs. 0.26 ± 0.52 mm, p =.10), and was significantly reduced in the distal portion of the main vessel (0.03 ± 0.45 vs. 0.24 ± 0.53 mm, p =.025). Percent diameter stenosis was also lower (14 ± 9 vs. 19 ± 16%, p =.05). Adverse event rates were similar in the two groups. Conclusions: In this study, systematic OCT guidance during LM-PCI allowed a timely detection and correction of acute stent underexpansion and malapposition, and was associated with signs of improved angiographic outcome at midterm, compared to standard practice.