Coronary calcification represents one of the main challenges in percutaneous coronary intervention (PCI), as it is associated with suboptimal stent expansion, higher complication rates, and an increased risk of long-term adverse events. Intracoronary imaging, particularly optical coherence tomography (OCT), enables accurate calcium quantification, facilitates adequate lesion preparation, and optimizes stent implantation.

In this prespecified subanalysis of ILUMIEN IV, the impact of OCT guidance versus conventional angiography was assessed in patients with moderately or severely calcified coronary lesions.
A total of 1,082 patients from the main trial with single treated lesions and moderate/severe calcification confirmed by a core lab were included. The OCT-guided strategy was compared with angiography guidance, with the primary clinical endpoint (PCE) being target vessel failure (TVF) at 2 years —a composite of cardiac death, target vessel myocardial infarction, or ischemia-driven revascularization. The primary imaging endpoint was post-PCI minimum stent area (MSA).
OCT-guided PCI was associated with a larger post-procedure MSA (5.57 ± 1.86 vs. 5.33 ± 1.78 mm²; p=0.03) and better stent expansion. It also showed lower rates of edge dissection, significant malapposition, and focal residual disease in reference segments.
Clinically, the OCT-guided strategy significantly reduced 2-year events: lower TVF (6.8% vs. 9.7%; adjHR 0.62; 95%CI: 0.40–0.96; p=0.03), fewer serious MACE (2.8% vs. 4.7%; adjHR 0.49; p=0.03), reduced target vessel myocardial infarction (1.9% vs. 4.0%; adjHR 0.36; p=0.01), and fewer stent thromboses (0.2% vs. 1.5%; adjHR 0.11; p=0.04). A significant reduction in serious adverse events at 30 days was also observed.
Conclusions
In patients with angiographically relevant coronary calcification, OCT-guided PCI demonstrated sustained 2-year clinical benefits, attributable to better lesion preparation and stent optimization. These findings support the use of OCT in this complex patient subgroup.
Original Title: Optical coherence tomography- vs angiography-guided coronary stent implantation in calcified lesions: the ILUMIEN IV trial.
Reference: Ali ZA, Shin D, Vijayvergiya R, Gawalkar AA, Shlofmitz RA, Alfonso F, Calligaris G, Canova P, Sakai K, Price MJ, Leistner D, Prati F, Mintz G, Matsumura M, McGreevy RJ, McNutt RW, Nie H, Buccola J, Landmesser U, Maehara A, Stone GW. Optical coherence tomography- vs angiography-guided coronary stent implantation in calcified lesions: the ILUMIEN IV trial. Eur Heart J. 2025 Aug 21;46(32):3201-3210. doi: 10.1093/eurheartj/ehaf331. PMID: 40470719; PMCID: PMC12369818.
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