A Bioresorbable Everolimus-Eluting Scaffold Versus a Metallic Everolimus-Eluting Stent IV - ABSORB IV

Contribution To Literature:

The ABSORB IV trial showed that Absorb BVS is noninferior to cobalt-chromium-based Xience DES at 30 days for cardiovascular outcomes in fairly simple lesion types, with lower acute procedural success.

Description:

The goal of the trial was to assess the safety and efficacy of Absorb bioresorbable vascular scaffold (BVS) compared with Xience drug-eluting stent (DES) using appropriate implantation techniques.

Study Design

Patients were randomized in a 1:1 fashion to either Absorb BVS (n = 1,296) or cobalt-chromium-based Xience DES (n = 1,308). Patients were stratified by presence of diabetes and similarity to ABSORB III. In the BVS arm, a strategy of PSP was utilized for appropriate implantation (predilation, appropriate sizing, and post-dilation to high pressures).

  • Total number of enrollees: 2,604
  • Duration of follow-up: 1 year
  • Mean patient age: 63 years
  • Percentage female: 28%
  • Percentage with diabetes: 32%

Inclusion criteria:

  • Age >18 years
  • Stable ischemic heart disease, non-ST elevation acute coronary syndrome, ST-segment elevation myocardial infarction (STEMI) >72 hours; troponin positive or negative
  • 1, 2, or 3 de novo target lesions in up to 2 native coronary arteries (maximum 2 lesions per artery) ± 1 nontarget lesion
  • Diameter stenosis ≥50% and <100% with TIMI flow ≥1
  • If diameter stenosis <70%, abnormal noninvasive or invasive functional test, unstable angina, or post-infarct angina
  • Reference vessel diameter (RVD) ≥2.50 mm and ≤3.75 mm (visually estimated)
  • Quantitative coronary angiography (QCA) or intravascular ultrasound/optical coherence tomography strongly recommended if visually estimated RVD ≤2.75 mm and 2.5 mm device intended
  • Lesion length ≤24 mm (visually estimated)

Exclusion criteria:

  • Left ventricular ejection fraction <30%
  • Glomerular filtration rate <30 ml/min/1.73 mm2 or dialysis
  • Any contraindication to DAPT for ≥12 months
  • Target lesion: left main, ostial, bifurcation with side branch ≥2 mm or stenosis >50% or requiring dilatation, in or distal to bypass graft, or within 5 mm of prior stent
  • Proximal vessel or target lesion: moderate/severe calcification, extreme angulation (≥90°) or excessive tortuosity (≥ two 45° angles)
  • Target vessel percutaneous coronary intervention (PCI) within prior 12 months, or any future planned PCI (except staged procedures for study lesions)
  • Receiving or will require chronic oral anticoagulation
  • Unsuccessful pre-dilatation

Other salient features/characteristics:

  • Prior PCI: 32%
  • One lesion treated: 89%; target vessel: left anterior descending 44%, left circumflex: 30%
  • Lesion length: 15 mm
  • RVD: 2.90 mm; <2.25 mm: 2.7%
  • Intravascular imaging: 13%
  • Post-dilation performed: 82.6% vs. 54.1% for BVS vs. everolimus-eluting stent, p < 0.001

Principal Findings:

The primary outcome, target lesion failure (cardiac death, target vessel MI [TV-MI], ischemia-driven target lesion revascularization) for BVS vs. Xience at 30 days, was 5.0% vs. 3.7%, p for noninferiority = 0.02, p for superiority = 0.11.

  • Death: 0.1% vs. 0.1%, p = 0.99
  • TV-MI: 4.4% vs. 3.6%, p = 0.29
  • Ischemia-driven revascularization: 1.4% vs. 0.6%, p = 0.046

Secondary outcomes:

  • Acute success: 94.6% vs. 99.0%, p < 0.0001
  • Immediately post-procedure QCA: In-device minimal lumen diameter: 2.66 mm vs. 2.74 mm, p < 0.0001; acute gain: 1.85 vs. 1.92 mm, p < 0.0001
  • Device thrombosis: 0.6% vs. 0.2%, p = 0.06

Interpretation:

The results of the ABSORB IV trial indicate that Absorb BVS is noninferior to cobalt-chromium-based Xience DES at 30 days for cardiovascular outcomes in fairly simple lesion types. In this trial, two important design changes were made compared with ABSORB III – all treated vessels had to have a RVD of >2.25 mm, and a PSP technique of pre- and post-dilation and appropriate sizing was followed routinely. Although the results are better for BVS compared with ABSORB III, results in the Xience DES arm improved as well. As a result, BVS event rates were still numerically higher compared with Xience DES.

ABSORB III was the pivotal trial towards US FDA approval of Absorb BVS, but the stent was recently commercially withdrawn in the US given poor sales. Physicians have also been concerned about many of the safety signals noted in the ABSORB trials. ABSORB IV adds to the data on first-generation BVS. Longer-term data as well as trials with improved stent design and implementation techniques are awaited.

References:

Presented by Dr. Gregg W. Stone at the Transcatheter Cardiovascular Therapeutics meeting (TCT 2017), Denver, CO, October 31, 2017.

Clinical Topics: Acute Coronary Syndromes, Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Aortic Surgery, Interventions and ACS, Interventions and Coronary Artery Disease, Interventions and Imaging, Angiography, Nuclear Imaging

Keywords: Absorbable Implants, Acute Coronary Syndrome, Angina, Unstable, Chromium, Cobalt, Constriction, Pathologic, Coronary Angiography, Coronary Artery Disease, Diabetes Mellitus, Dilatation, Drug-Eluting Stents, Myocardial Infarction, Myocardial Ischemia, Myocardial Revascularization, Percutaneous Coronary Intervention, TCT17, Thrombosis, Tomography, Transcatheter Cardiovascular Therapeutics, Troponin


< Back to Listings