Intravascular Ultrasound–Guided or Angiography-Guided Complex High-Risk PCI

Authors, Journal, Affiliations, Type, DOI

• Roberto Diletti, Joost Daemen (co-first authors), Benjamin Faurie, Marco Barbierato, Didier Tchétché, Thomas Hovasse, and 23 additional co-authors for the IVUS-CHIP Investigators
• 29 institutions across 7 European countries (Netherlands, France, Italy, Germany, Belgium, Spain, UK); lead site: Erasmus University Medical Center, Rotterdam
• The New England Journal of Medicine, published March 30, 2026
• Type: Investigator-initiated, international, open-label, event-driven, randomised controlled superiority trial
• DOI: 10.1056/NEJMoa2601521
• Funded by Boston Scientific (unrestricted grant + IVUS catheters; no role in design, analysis, or publication)
• ClinicalTrials.gov: NCT04854070

Overview

The IVUS-CHIP trial randomised 2,020 patients undergoing complex high-risk PCI at 37 European centres to routine IVUS-guided PCI (with prespecified stent-optimisation criteria) versus angiography-guided PCI. At a median follow-up of 19.0 months, target-vessel failure (TVF) occurred in 13.9% of the IVUS group versus 11.1% in the angiography group (HR 1.25; 95% CI 0.97–1.60; P=0.08), failing to demonstrate superiority. Despite longer procedures (+22.6 min) and higher rates of post-dilation (91.3% vs 84.5%) in the IVUS arm, no reduction in ischaemic events was observed. These findings contrast with several prior Asian trials and challenge the Class IA guideline recommendation for routine IVUS use in complex PCI in the European high-volume centre context.

Keywords

Intravascular ultrasound, percutaneous coronary intervention, complex coronary lesions, stent optimisation, target-vessel failure, CHIP, SYNTAX score, calcification, angiography-guided PCI, randomised controlled trial

Key Takeaways

Background and Rationale

• IVUS guidance during PCI is associated in meta-analyses and predominantly Asian RCTs with improved stent optimisation and fewer adverse events in complex lesions
• European guidelines upgraded IVUS/OCT use to Class IA for anatomically complex PCI lesions prior to this trial
• Real-world adoption of IVUS in Western Europe remains low; evidence from European practice was limited
• Complex lesions defined as: severe calcifications, left main disease, ostial lesions, true bifurcation (side branch ≥2.5 mm), chronic total occlusion, in-stent restenosis, or lesion length >28 mm

Methods

• Randomisation: 1:1 IVUS-guided vs angiography-guided PCI; stratified by site and clinical presentation (ACS vs stable)
• All target lesions treated with everolimus-eluting platinum-chromium stents (Synergy/Synergy Megatron, Boston Scientific)
• IVUS group: OptiCross HD IVUS Catheter; motorised pullback mandatory; prespecified stent-optimisation criteria; bail-out angiography-guided permitted if medically mandated (luminal haze, suspected dissection)
• Primary endpoint: Target-vessel failure (TVF) = composite of cardiac death, target-vessel MI, or clinically indicated target-vessel revascularisation
• Key secondary endpoints: hierarchical testing of TVF components, target-lesion failure, stent thrombosis

Patient Characteristics

• 2,020 patients randomised November 2021–August 2023; mean age 69 years, 79.4% male
• 27.4% presented with ACS (non-STEMI or unstable angina); 72.6% stable ischaemic heart disease
• Mean SYNTAX score: 25±14 in both groups — high anatomical complexity
• 42.2% had severe calcifications (vs 13.5% in RENOVATE-COMPLEX-PCI control); predominantly type B2 or C lesions
• Complete follow-up: 95.9%

Procedural Details

• IVUS performed in 98.7% of IVUS-group patients undergoing PCI
• IVUS findings specifically triggered additional optimisation manoeuvres in 40.5% of patients
• Mean procedure duration: 88.8 min (IVUS) vs 66.2 min (angiography)
• Post-stent balloon dilation: 91.3% vs 84.5%
• Mean stent length: 64.0±38.7 mm vs 59.6±37.3 mm
• Mean maximum stent diameter: 3.50±0.54 mm vs 3.38±0.52 mm
• Stent-optimisation criteria met in only 48.0% of fully analysable lesions (53.3% at patient level); most common reason for non-optimisation: plaque burden >50% within 5 mm of stent edge

Primary Outcome

• TVF at median 19.0 months: 13.9% (IVUS) vs 11.1% (angiography); HR 1.25 (95% CI 0.97–1.60); P=0.08
• IVUS-guided PCI was NOT superior to angiography-guided PCI

Secondary Outcomes

• All hierarchical secondary end points were not met (primary was non-significant, stopping testing)
• Definite stent thrombosis: 0.2% (IVUS) vs 1.0% (angiography); HR 0.20 (95% CI 0.04–0.90) — lower in IVUS group
• Cardiac death, target-vessel MI, and target-vessel revascularisation individually appeared similar between groups
• Procedural complications: 11.3% vs 10.2% (similar)

Discussion — Why Results Were Neutral

1. Event rate in angiography control lower than expected (improving PCI standards in past two decades)
2. Severe calcification + high SYNTAX score may dilute lesion-level IVUS benefit
3. Investigator bias: operators experienced in high-volume IVUS may have recalibrated angiography-guided strategy (more systematic lesion prep, better stent sizing), narrowing the performance gap
4. Similar neutral result seen in ILUMIEN IV (OCT vs angiography); both large Western trials show low residual benefit of intracoronary imaging when systematic post-stent dilation is used

Limitations of the Document

• Open-label design: operator behaviour in angiography arm may have been influenced by knowledge of IVUS arm performance standards
• Relatively low use of rotational atherectomy and intravascular lithotripsy compared with contemporary registry data
• Conducted exclusively in high-volume European centres with experienced IVUS operators — limits generalisability to lower-volume settings and non-European populations
• Median follow-up of 19 months may be insufficient to detect late divergence of outcomes
• Stent-optimisation criteria met in only 48% of lesions — uncertain whether better adherence to IVUS optimisation would have altered results

Key Concepts Mentioned

• concepts/Intracoronary-Imaging-Guided-PCI — central intervention; trial tests IVUS vs angiography guidance for complex PCI

Key Entities Mentioned

• entities/Chronic-Coronary-Disease — patient population includes stable ischaemic heart disease and post-ACS
• entities/Left-Main-Coronary-Disease — left main disease is one of the complex lesion types included

Wiki Pages Updated

• wiki/sources/ivus-chip-nejm-2026.md — created (this file)
• wiki/concepts/Intracoronary-Imaging-Guided-PCI.md — created
• wiki/entities/Left-Main-Coronary-Disease.md — created
• wiki/entities/Chronic-Coronary-Disease.md — updated with intracoronary imaging section
• wiki/wikiindex.md — updated
• wiki/sourceindex.md — updated