Intravascular imaging guided optimization in complex percutaneous coronary intervention (PCI)—does clinical presentation matter?

The complexity of coronary artery disease (CAD) significantly impacts the effectiveness of revascularization procedures. Angiographically guided percutaneous coronary intervention (PCI) is limited by the 2-dimensional (2D) representation of a complex 3D structure, thereby only providing an assessment of coronary luminal geometry. The lack of adequate procedural guidance with an angiographic-guided PCI approach may yield suboptimal PCI results, increasing the risk of stent under expansion and long-term major adverse cardiovascular events (MACEs) (1,2). In this context, intravascular imaging (IVI) techniques like intravascular ultrasound (IVUS) and optical coherence tomography (OCT) have emerged as supplementary diagnostic tools with the ability to provide serial cross-sectional images of coronary arteries. IVI allows operators to determine plaque characteristics, and appropriate device size, ensure optimal stent expansion, and identify procedural complications including stent edge dissections, incomplete strut apposition, tissue protrusion, and endoluminal thrombosis (3,4). Three large recent randomized trials have recently evaluated the clinical benefit of IVI during complex PCI (5-7). As a result, the European Society of Cardiology has adopted a Class 1a recommendation for the utilization of IVI guidance by IVUS or OCT when PCI is performed on anatomically complex lesions (8). However, the extent to which the benefits of IVI apply across the clinical spectrum of coronary syndromes remains uncertain. Indeed, acute coronary syndrome (ACS) and chronic coronary syndrome (CCS) differ significantly in terms of underlying pathophysiology, plaque morphology, revascularization benefit, and the risk of future adverse events (9).

To address this evidence gap, the RENOVATE-COMPLEX-PCI trial group conducted a prespecified, stratified subgroup analysis on the impact of IVI-guided stent optimization on outcomes based on clinical presentation in patients with complex coronary artery lesions undergoing PCI with modern drug-eluting stents (DES) (10). The original RENOVATE-COMPLEX-PCI trial evaluated 1,639 patients across 20 sites in Korea who were randomly assigned to IVI-guided PCI [n=1,092; IVUS (n=813), OCT (n=278)] or angiographic-guided PCI (n=547), demonstrating decreased rates of target vessel failure (TVF) in the IVI cohort (7). For this subgroup analysis, patients were categorized in treatment arms according to clinical presentation, that being either ACS [n=832 (50.8%)] or CCS [n=807 (49.2%)]. The study’s primary endpoint was TVF, defined as a composite measure that included cardiac death, target vessel-related myocardial infarction (MI), or clinically driven target vessel revascularization. The findings demonstrated a higher incidence of the primary endpoint in ACS patients than in those with CCS [event rates at 3 years, 11.7% (84/832) vs. 6.9% (52/807); hazard ratio (HR): 1.64; 95% confidence interval (CI): 1.16–2.32; P=0.005]. However, no statistically significant interaction was observed between clinical presentation and the use of IVI in relation to the risk of TVF (P for interaction =0.19). In the ACS subgroup, the IVI-guided PCI cohort exhibited a numerically lower TVF risk compared to the angiography-guided PCI group [10.4% (51/560) vs. 14.6% (33/272); HR: 0.74; 95% CI: 0.48–1.15; P=0.18], largely due to a reduced risk of cardiac death [1.9% (8/560) vs. 5.9% (11/272); HR: 0.35; 95% CI: 0.14–0.86; P=0.02]. For the CCS subgroup, the IVI-guided PCI approach significantly lowered the TVF risk compared to angiography-guided PCI [5.0% (25/532) vs. 10.4% (27/275); HR: 0.46; 95% CI: 0.27–0.80; P=0.006], with the reduction being predominantly driven by a decrease in target vessel-related MI [1.7% (8/532) vs. 6.4% (17/275); HR: 0.24; 95% CI: 0.10–0.55; P=0.001]. Additionally, the study found that achieving stent optimization criteria in the ACS IVI-guided PCI group was associated with a significantly lower risk of the primary endpoint compared with those patients who failed to meet optimization criteria.

This subgroup analysis provides further insights into the elevated risk of TVF among patients with complex coronary lesions who experience ACS, a finding corroborated by previous studies (11). However, the beneficial effects of IVI-guided PCI appear to be consistent regardless of clinical presentation, with a pronounced risk reduction observed in the low-risk CCS group. The significant reduction in TVF in the ACS cohort who satisfied the prespecified imaging criteria highlights the critical importance of achieving optimized stent outcomes in this high-risk population. Of note, stent optimization was achieved in 50.4% of patients in the ACS group, leaving unresolved whether higher optimization rates could have resulted in greater clinical benefits compared with angiographic guidance. In contrast to previous trials (1,2), approximately 25% of the ACS participants underwent OCT-guided PCI. The key strength of OCT compared with IVUS is higher imaging resolution, deeper penetration of calcified plaque, and an enhanced ability to detect strut malposition, tissue prolapse, and edge dissection (12). Notably, this study found that OCT led to higher rates of stent optimization in ACS lesions, with 70% (121/174 lesions) optimized, compared to 61% (368/608 lesions) achieved with IVUS IVI. While the technical advantages of OCT may enhance stent optimization, whether it translates into improved long-term clinical outcomes remains uncertain. In the absence of robust evidence, the application of IVI in routine clinical practice must be informed by a nuanced understanding of the advantages and limitations of each imaging modality, which should be employed complementarily based on the specific clinical context.

A notable limitation of the study is the lack of a standardised imaging protocol in the IVI group, resulting in only 75.3% of target lesions being evaluated by IVI before and after PCI (7). This may have led to an underappreciation of critical plaque characteristics, which may explain the suboptimal rates of stent optimization observed. The current lack of clear guidelines creates ambiguity for clinicians, making it difficult to determine the optimal utilization of IVI. Furthermore, only East Asian patients were included in the trial, of whom more than half were enrolled at a single centre and this has the potential to restrict the broader applicability of the results. The lack of an analysis between TVF, excluding periprocedural MI, and clinical presentation limits deeper insight into the differential impact of periprocedural MI across the spectrum of coronary syndromes. Finally, the use of IVI extends procedural time, fluoroscopic use and raises costs compared with angiography-guided PCI, thereby restricting IVI utilization in clinical practice. However, recent cost-effective analyses are reassuring, demonstrating reduced cumulative costs and improved quality of life with IVI-guided PCI (13), potentially leading to a change in the treatment paradigm for eligible patients.

In summary, this subgroup analysis of the RENOVATE-COMPLEX-PCI trial concludes that IVI benefits are consistent across the spectrum of clinical presentations in patients with complex coronary lesions. The observed benefits in a low-risk cohort add weight to the argument for broader use of IVI across more patient populations. Additionally, the analysis underscores the importance of stent optimization with IVI, particularly in patients presenting with an ACS. Overall, this study provides more compelling evidence that IVI-guided PCI offers significant long-term advantages, suggesting it should be considered more widely in clinical practice.

Acknowledgments

None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, AME Clinical Trials Review. The article has undergone external peer review.

Peer Review File: Available at https://actr.amegroups.com/article/view/10.21037/actr-24-154/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://actr.amegroups.com/article/view/10.21037/actr-24-154/coif). A.J.B. declares consulting fees from Abbott Vascular and speaker fees from Boston Scientific. The other authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

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