Highlights
– In the OCCUPI trial, 71% (549/773) of OCT‑guided PCI procedures met predefined OCT optimization criteria; optimized procedures had a 1‑year primary event rate of 2.9% versus 9.4% when criteria were not met (HR 0.30, 95% CI 0.16–0.58, P < .001).
– Long lesions and small‑vessel disease were independent predictors of OCT sub‑optimization.
– Key OCT components—adequate stent expansion, minimal malapposition, and absence of major edge dissection—were each strongly associated with improved outcomes.
Background: Why intravascular imaging and optimization matter
Percutaneous coronary intervention (PCI) for complex coronary disease (long lesions, bifurcations, small vessels, heavy calcification) carries higher risks of restenosis, target vessel failure and stent thrombosis than straightforward lesions. Angiography alone can underestimate stent underexpansion, malapposition, and edge injury. Optical coherence tomography (OCT) provides high‑resolution intravascular imaging that enables detailed assessment of stent expansion, apposition, and peri‑stent vessel injury, potentially guiding corrective measures at the time of index PCI.
Prior randomized and observational work has suggested that intravascular imaging can improve procedural metrics and, in selected settings, clinical outcomes. However, optimal criteria for stent “optimization” on OCT and the prognostic importance of achieving those criteria in complex PCI warrant prospective evaluation. The OCCUPI trial (Lee et al., 2025) prospectively examined the incidence, determinants, and clinical impact of achieving OCT‑defined stent optimization during OCT‑guided PCI for complex lesions.
Study design
OCCUPI was a randomized trial comparing OCT guidance with angiography guidance in patients undergoing PCI for complex coronary lesions. The present analysis focuses on the as‑treated population that had OCT‑guided PCI with post‑stenting OCT assessment. Operators classified each case according to predefined OCCUPI‑OCT optimization criteria into OCT Optimization (criteria met) or OCT Sub‑Optimization (criteria not met).
The primary endpoint for this analysis was the composite of cardiac death, myocardial infarction (MI), stent thrombosis, or ischemia‑driven target‑vessel revascularization (TVR) at 1 year. Multivariable models examined predictors of sub‑optimization, and associations between achievement of each OCT optimization component and outcomes were explored.
OCCUPI‑OCT optimization criteria (key components)
The OCCUPI investigators prespecified a practical set of OCT thresholds to define “optimized” stent result. The three core domains were:
- Stent expansion: minimal stent area (MSA) criteria expressed as either MSA ≥80% of mean reference lumen, or ≥100% of distal reference lumen area, and absolute MSA >4.5 mm2.
- Apposition: absence of clinically significant malapposition, defined as malapposed distance <400 μm.
- Edge integrity: absence of major edge dissection.
Key results
Among 773 patients who underwent OCT‑guided PCI with post‑stenting OCT, 549 (71.0%) met the OCCUPI‑OCT optimization criteria (OCT Optimization group) and 224 (29.0%) did not (OCT Sub‑Optimization group).
Primary endpoint at 1 year (composite of cardiac death, MI, stent thrombosis, ischemia‑driven TVR):
- OCT Optimization: 2.9% (n reported in publication)
- OCT Sub‑Optimization: 9.4% (HR 0.30 versus Sub‑Optimization, 95% CI 0.16–0.58, P < .001)
- Angiography guidance arm (as randomized comparator): 7.5% (HR 0.38 versus angiography, 95% CI 0.22–0.66, P < .001 for OCT Optimization group)
These findings indicate that achieving OCT‑defined optimization after stent implantation was associated with a roughly 60–70% relative reduction in the composite clinical endpoint compared with either sub‑optimized OCT cases or routine angiography guidance.
Predictors of OCT sub‑optimization: On multivariable analysis, long lesions and small‑vessel disease independently predicted failure to meet optimization criteria. This suggests lesion complexity and vessel size are important determinants of technical success in achieving an optimal OCT result despite imaging guidance.
Individual OCT components and outcomes: Each component of the OCCUPI‑OCT criteria—adequate expansion (MSA metrics), limited malapposition (malapposed distance <400 μm), and absence of major edge dissection—was independently associated with more favourable outcomes (all P < .001). In other words, both global optimization and its constituent elements conveyed prognostic signal.
Safety: The report did not identify unexpected safety signals related to intraprocedural OCT imaging; procedural complications related to additional optimization steps were not reported as significantly increased in the OCT‑optimized group in the primary publication.
Interpretation and clinical implications
OCCUPI provides contemporary randomized‑trial–derived evidence that, among patients who undergo OCT‑guided PCI for complex coronary disease, achieving predefined OCT optimization thresholds is associated with markedly lower rates of major cardiac events at 1 year. There are several practical implications:
- OCT guidance can do more than identify problems—it permits objective, reproducible targets for correction. When those targets are reached, outcomes are substantially better. This elevates OCT from a diagnostic adjunct to a tool for actionable optimization.
- Operators should anticipate particular difficulty achieving optimization in long lesions and small vessels. These lesion subsets may require pre‑emptive strategies (adequate lesion preparation, use of intravascular lithotripsy or atherectomy in heavy calcification, tailored stent sizing, and aggressive post‑dilation) to increase the chance of meeting OCT targets.
- Specific OCT thresholds (MSA relative to reference, absolute MSA >4.5 mm2, malapposition <400 μm, absence of major edge dissection) provide concrete intra‑procedural goals and can be adopted into standardized optimization protocols in experienced centers.
Where this fits with prior evidence
Guidelines increasingly recognize the role of intravascular imaging in complex PCI. The 2018 ESC/EACTS guidelines on myocardial revascularization recommend consideration of intracoronary imaging to guide stent implantation in selected patients and to optimize stent deployment in complex anatomy (Neumann et al., 2019). OCCUPI supplies prospective randomized‑trial data that not only supports imaging use but clarifies that achieving prespecified OCT optimization endpoints appears to be the key determinant of improved outcomes.
Limitations and cautions
Several caveats should be noted when interpreting the OCCUPI optimization analysis:
- As‑treated subgroup analysis: The present report describes outcomes among those who underwent OCT‑guided PCI with post‑stent OCT. Although embedded within a randomized trial, analyses of optimization vs sub‑optimization are observational and subject to residual confounding (for example, lesion complexity may both cause sub‑optimization and drive worse outcomes).
- Selection and operator effects: Achieving optimization depends on operator decisions, experience, and institutional protocols; results from high‑volume centers with OCT expertise may not generalize to all settings.
- Optimization thresholds: The OCCUPI criteria are pragmatic but not universally validated across all plaque morphologies and stent platforms. Absolute MSA cutoffs may have different predictive value in very small or large vessels.
- Resource and workflow considerations: Routine post‑stent OCT and additional corrective maneuvers carry procedural time, contrast load, and cost; economic analyses and investigation of patient selection strategies are needed.
Practical recommendations for clinicians
Based on OCCUPI and the broader literature, clinicians performing complex PCI should consider the following:
- Use intravascular imaging (OCT or IVUS) in complex lesions to guide sizing and to detect suboptimal results not apparent on angiography.
- Establish and apply clear optimization criteria tailored to the imaging modality (OCT thresholds as in OCCUPI can be adopted where appropriate) and institute corrective steps—additional post‑dilation, high‑pressure ballooning, or adjunctive plaque modification—when targets are not met.
- Anticipate the greatest technical challenges in long lesions and small vessels; plan lesion preparation and stent selection accordingly.
- Balance potential benefits against procedural time, contrast exposure, and costs; prioritize imaging‑guided optimization for patients and lesions at highest risk of adverse events.
Future research directions
Remaining questions include whether routine, protocolized OCT optimization (versus selective use) improves outcomes and is cost‑effective, how to adapt optimization thresholds to very small or large vessels and different stent platforms, and which lesion subsets derive the largest absolute benefit. Head‑to‑head randomized comparisons of strategy‑level optimization protocols, incorporation of physiologic endpoints, and health‑economic analyses would be valuable next steps.
Conclusion
The OCCUPI trial demonstrates that in OCT‑guided PCI for complex coronary lesions, achieving prespecified OCT‑based stent optimization criteria is associated with substantial reductions in 1‑year major cardiac events compared with sub‑optimized results and with angiography guidance. Stent expansion, apposition, and edge integrity were the three components most predictive of favourable outcomes. These data support the adoption of standardized OCT‑guided optimization protocols in complex PCI while highlighting important practical challenges—particularly in long and small‑vessel lesions—that merit attention and further study.
Funding and trial registration
Trial funding and registration details are reported in the original publication (Lee et al., 2025).
References
Lee SJ, Lee SJ, Hong SJ, Cho DK, Kim JW, Kim SM, Hur SH, Heo JH, Jang JY, Koh JS, Won H, Lee JW, Hong SJ, Kim DK, Choe JC, Lee JB, Yang TH, Lee JH, Hong YJ, Ahn JH, Lee SH, Lee YJ, Ahn CM, Kim JS, Ko YG, Choi D, Hong MK, Jang Y, Lee JY, Kim BK. Optical coherence tomography‑guided stent optimization for complex coronary lesions: the OCCUPI trial. Eur Heart J. 2025 Nov 19:ehaf884. doi: 10.1093/eurheartj/ehaf884. Epub ahead of print. PMID: 41259082.
Neumann FJ, Sousa‑Uva M, Ahlsson A, et al. 2018 ESC/EACTS Guidelines on myocardial revascularization. Eur Heart J. 2019;40(2):87–165. (Guideline document on the role of imaging in revascularization.)