Ivus or angiography guidance for PCI in complex coronary bifurcation lesions (DKCRUSH-VIII)
Reported from ACC.26
Nicola Ryan provides her take on DKCRUSH-VIII, a randomised controlled trial comparing IVUS versus angiography guidance for PCI, predominantly using the DKCRUSH technique in patients with complex bifurcation lesions, as presented by Shaoliang Chen at ACC.26 in New Orleans.
Why this study – the rationale/objective?
Coronary bifurcation lesions provide specific technical challenges for PCI, with increased risk of procedural complications and MACE. In particular complex bifurcation lesions are associated with poorer outcomes. The OCTOBER trial has demonstrated reduced adverse events with OCT-guided PCI compared to angiography-guided PCI in complex coronary bifurcations (1). In the OCTOBER trial, 64.3% of patients were treated with a two-stent technique with the choice of technique at the operator's discretion. In the DKCRUSH trial, the authors compared IVUS guidance in complex bifurcation PCI using the DKCRUSH technique to angiography guidance.
How was it executed - the methodology?
Designed by Nicola Ryan. Source: PCRonline.com
DKCRUSH-VIII was a randomised multicentre controlled superiority trial in patients undergoing PCI for a de novo Medina 0,1,1 or 1,1,1 bifurcation stenosis classified as complex according to the DEFINITION criteria (2) with a side branch diameter ≥2.5mm. All main branch lesions were assessed with QFR, and functional significance (QFR <0.8) was required for inclusion. DKCRUSH PCI was carried out by operators with experience with ≥20 procedures following the standard 6 steps.
IVUS was mandated pre, peri and post procedure in the IVUS group to assess stent sizing, rewiring confirmation and evaluation of apposition/expansion. Optimal IVUS criteria for non–left main lesions:
- MLA in the stented segment >5.0 mm2 (side branch or distal main vessel) and >6.0 mm2 for proximal main vessel or >90% of the MLA at the distal reference segments;
- plaque burden 5 mm proximal or distal to the stent edge was <55% and
- no dissection involving the media >3mm in length. MLA criteria for left main lesions: an absolute MLA of >10 mm2 for the left main, >7 mm2 for the ostial/ proximal left anterior descending artery, or >6 mm2 for the ostial/proximal left circumflex artery.
- The primary endpoint was TVF (a composite of cardiac death, target vessel MI, or clinically driven TVR) at 12 months.
- Secondary endpoints included the individual components of the primary endpoint, all-cause death, any revascularisation and in-stent restenosis.
- The safety endpoint was ARC defined definite or probable stent thrombosis, intraprocedural complications and contrast-induced nephropathy.
What is the main result?
From December 2018 to September 2024 DKCRUSH-VIII randomised 556 patients, 278 to each group, with one patient in the IVUS group withdrawing consent prior to the procedure. The population was predominantly male 77.5% with a median age of 67 years. Unstable angina (69.9%) was the most common clinical presentation, with a high prevalence of common cardiovascular risk factors. The majority of bifurcation lesions were LAD/D1 (approx. 52%) or distal LMS (approx. 44%), three fifths of patients had a SYNTAX score ≥32. The vast majority of lesions were treated with DKCRUSH.
- Target vessel failure was significantly lower in the IVUS guided group 17 patients compared to 41 in the angiography guided group at one year (6.1% vs. 14.7%, HR 0.40, 95%CI 0.23-0.71, p=0.002)
- Excluding periprocedural MI the risk of TVF remained lower in the IVUS guided group (3.6% vs 12.2%, HR 0.28, 95%CI 0.14-0.57, p<0.001)
- In the IVUS guided group, there was a lower rate of TVF in the group who met optimal PCI criteria (2.6% vs. 15.9%, p<0.0001)
- Target vessel revascularisation at one year was lower in the IVUS guided group (2.5% vs 6.8% HR 0.26, 95%CI 0.15-0.86, p=0.02)
- Target vessel MI was lower in the IVUS guided arm (4.3% vs 9.4%, HR 0.46, 95%CI 0.23-0.90, p=0.02) driven by lower rates of spontaneous MI.
- There was no difference in all-cause or cardiac death between the groups at one year
Critical reading and the relevance for clinical practice
The results of this study show that IVUS-guided DKCRUSH is superior to angiography-guided DKCRUSH at one year in complex coronary bifurcation strategy in terms of target vessel failure. The reduction in TVF was predominantly driven by a reduction in target vessel MI and clinically driven revascularisation with no differences in cardiac death between groups.
The IVUS protocol for the trial required IVUS assessment pre-procedure at each of the steps of the procedure and at the conclusion of the procedure. Adherence to IVUS protocol was high with baseline IVUS in 98.2%, after the first balloon crush in 92.8%, after 1st rewiring in 82.7%, post-stent crush in 85.6%, after second witing in 85.6% and after final POT in 92.4%. Suboptimal results were identified at each stage of the procedure and corrective action was required, i.e. incorrect wiring, incomplete crushing, under-expansion of the stent. The median procedural time in the IVUS group was 98 minutes compared to 76 in the angiography group (p<0.0001). Meticulous attention to detail at each step of the IVUS assessment and corrective action likely contributes to the improved outcomes in the IVUS group. Omission of one or more of these IVUS assessments may lead to less optimal outcomes, though that has not been formally assessed.
Optimal IVUS criteria were met in three quarters of patients with inadequate MSA in the distal main vessel, suboptimal expansion in the side branch and high plaque burden at the side stent edges the common reasons for failing to meet optimal criteria. When compared to patients with meeting optimal IVUS criteria outcomes were worse in the suboptimal group and comparable to the angiography-guided group.
A note of caution when interpreting the results, one must bear in mind that all operators were committed high-volume DK crush operators, the coronary disease in DKCRUSH-VII was complex, therefore the magnitude of benefit may not be applicable to noncomplex bifurcations, or a provisional strategy ending in either a single or two stent technique. However, the results of the OCTOBER trial support OCT guidance in complex coronary bifurcations where a third of patients did not have stents implanted in the side branch.
In summary DKCRUSH-VIII provides randomised evidence supporting an IVUS-guided strategy in complex coronary bifurcations. The comparable outcomes between the angiography-guided group and the group who did not meet optimal IVUS criteria highlight the importance of not only obtaining the IVUS images but reacting appropriately to the information provided by them.
References
- Holm NR, Andreasen LD, Neghabat O, Laanmets P, Kumsars I, Bennett J, et al. OCT or Angiography Guidance for PCI in Complex Bifurcation Lesions. N Engl J Med. 2023 Oct 19;389(16):1477–87. doi:10.1056/NEJMoa2307770 PubMed PMID: 37634149.
- Chen SL, Sheiban I, Xu B, Jepson N, Paiboon C, Zhang JJ, et al. Impact of the complexity of bifurcation lesions treated with drug-eluting stents: the DEFINITION study (Definitions and impact of complEx biFurcation lesIons on clinical outcomes after percutaNeous coronary IntervenTIOn using drug-eluting steNts). JACC Cardiovasc Interv. 2014 Nov;7(11):1266–76. doi:10.1016/j.jcin.2014.04.026 PubMed PMID: 25326748.
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