A Bioresorbable Everolimus-Eluting Scaffold Versus a Metallic Everolimus-Eluting Stent II - ABSORB II
Data for bioabsorbable stents have been promising. Absorb BVS is an everolimus-eluting stent (EES) with a polymeric bioresorbable scaffold. The current trial sought to compare outcomes after implantation of Absorb BVS versus Xience DES.
Contribution to the Literature: The ABSORB II trial showed that PCI with the bioabsorbable EES, Absorb BVS, results in inferior angiographic outcomes at 1 year but similar clinical outcomes at 2 years compared with the metallic durable polymer EES, Xience.
- Up to two de novo lesions in different epicardial vessels
- Planned overlapping allowed in lesions ≤48 mm
- Reference vessel diameters: 2.5-3.5 mm
Number of enrollees: 501
Duration of follow-up: 1 and 2 years
Mean patient age: 61 years
Percentage female: 22%
- Known hypersensitivity or contraindication to aspirin, both heparin and bivalirudin, antiplatelet medication specified for use in the study (clopidogrel and prasugrel and ticlopidine, inclusive), everolimus, poly (L-lactide), poly (DL-lactide), cobalt, chromium, nickel, tungsten, acrylic and fluoro polymers, or contrast sensitivity that cannot be adequately premedicated
- Subject has a known diagnosis of acute MI at any time preceding the index procedure and relevant cardiac enzymes have not returned within normal limits at the time of procedure
- Evidence of ongoing acute MI in electrocardiogram prior to the procedure
- Subject has current unstable arrhythmias
- Left ventricular ejection fraction <30%
- Subject has received a heart transplant or any other organ transplant or is on a waiting list for any organ transplant
- Subject is receiving immunosuppressant therapy and/or has known immunosuppressive or autoimmune disease
- Elective surgery is planned within 2 years after the procedure that will require discontinuing antiplatelet agent
- Subject has a platelet count <100,000 cells/mm3 or >700,000 cells/mm3, a white blood cell count of <3,000 cells/mm3, or documented or suspected liver disease
- Known renal insufficiency (e.g., estimated glomerular filtration rate <60 ml/kg/1.73 m2 or serum creatinine level of >2.5 mg/dl, or subject on dialysis)
- History of bleeding diathesis or coagulopathy or will refuse blood transfusions
- Subject has had a cerebrovascular accident or transient ischemic neurological attack within the past 6 months
- Target lesion that prevents adequate (residual stenosis at target lesion/s is ≤40% by visual assessment) coronary predilatation
- Target lesion in left main trunk
- Aorto-ostial target lesion (within 3 mm of the aorta junction)
- Target lesion located within 2 mm of the origin of the LAD or left circumflex artery
- Target lesion located distal to a diseased (vessel irregularity per angiogram and >20% stenosed lesion) arterial or saphenous vein graft
- Target lesion involving a bifurcation lesion with side branch ≥2 mm in diameter, or with a side branch <2 mm in diameter requiring guidewire protection or dilatation
- Total occlusion (TIMI flow 0), prior to wire crossing
- Excessive tortuosity (≥2, 45° angles), or extreme angulation (≥90°) proximal to or within the target lesion
- Restenotic from previous intervention
- Heavy calcification proximal to or within the target lesion
- Subject has a high probability that a procedure other than pre-dilatation and study device implantation and (if necessary) post-dilatation will be required at the time of index procedure for treatment of the target vessel (e.g., atherectomy, cutting balloon)
Angiographic exclusion criteria:
- Vasomotion assessed by change in minimum lumen diameter (MLD) between pre- and post-nitrate at 3 years
- MLD at 3 years post-nitrate minus MLD post-procedure post-nitrate
- Device success
- Procedural success
- Scaffold/stent thrombosis
Patients were randomized in a 2:1 ratio to percutaneous coronary intervention (PCI) with either Absorb BVS or Xience DES.
A total of 501 patients were randomized, 335 to BVS and 166 to Xience. Baseline characteristics were fairly similar between the two arms. Approximately 22% were current smokers, and 24% had diabetes. Nearly two thirds of the patients underwent PCI for stable angina, and another 12% had silent ischemia. The vast majority (84%) had single-vessel disease, with the left anterior descending artery (LAD) being the target vessel in 45%. All patients in the BVS arm and 99% in the EES arm had their lesions predilated prior to stent placement.
Acute recoil was similar, but the post-dilation balloon size was slightly larger in the EES arm (3.08 vs. 3.16 mm, p = 0.02). Acute device success was >99%. The median lesion length was 13.8 mm, with similar pre-procedure reference vessel diameter, but smaller post-procedure reference vessel diameter in the BVS arm (2.64 vs. 2.8 mm, p < 0.0001). Thus, acute gain was also lower in the BVS arm (1.15 vs. 1.46 mm, p < 0.0001). On intravascular ultrasound (IVUS) imaging, post-procedure mean lumen area was lower with BVS (4.9 vs. 5.7 mm2, p < 0.001). There were two definite scaffold thrombosis events in the BVS arm (one acute, one subacute), but no stent thrombosis in the Xience arm up to 1 year.
The composite major adverse cardiac event (MACE) endpoint at 1 year for Absorb BVS vs. Xience was similar (4.8% vs. 3.0%, p = 0.35), including target vessel myocardial infarction (MI) (4.2% vs. 1.2%, p = 0.07) and target lesion revascularization (1.2% vs. 1.8%, p = 0.69).
Two-year outcomes of MACE for Absorb BVS vs. Xience: 7.6% vs. 4.3%, p = 0.16; target-lesion failure: 7.0% vs. 3.0%, p = 0.07; mortality: 1.2% vs. 0.6%, p = 0.67; stent thrombosis: 1.54% vs. 0%, p = 0.17.
The results of the ABSORB II trial indicate that PCI with the bioabsorbable EES, Absorb BVS, results in inferior angiographic outcomes at 1 year, compared with the metallic EES, Xience. Specifically, acute gain on quantitative coronary angiography and IVUS were both lower with the Absorb BVS. There were two definite thrombotic events with the BVS, with a thrombosis risk of 0.6% at 1 year. At 2 years, clinical adverse events were numerically higher with Absorb BVS, including a stent thrombosis rate of 1.5%. These data are helpful, and add to the growing body of literature with the Absorb BVS. It is currently not available for commercial use in the United States, but is widely used in Europe and Asia.
Presented by Dr. Bernard R. Chevalier at the Transcatheter Cardiovascular Therapeutics meeting (TCT 2015), San Francisco, CA, October 12, 2015.
Serruys P, Chevalier B, Dudek D, et al. A bioresorbable everolimus-eluting scaffold versus a metallic everolimus-eluting stent for ischaemic heart disease caused by de novo native coronary artery lesions (ABSORB II): an interim 1-year analysis of clinical and procedural secondary outcomes from a randomized controlled trial. Lancet 2014;Sep 14:[Epub ahead of print].
Presented by Dr. Patrick Serruys at the Transcatheter Cardiovascular Therapeutics meeting (TCT 2014), Washington, DC, September 14, 2014.
Keywords: Angina, Stable, Coronary Angiography, Drug-Eluting Stents, Myocardial Infarction, Percutaneous Coronary Intervention, Sirolimus, Stents, Thrombosis, Transcatheter Cardiovascular Therapeutics
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