A Bioresorbable Everolimus-Eluting Scaffold Versus a Metallic Everolimus-Eluting Stent: China - ABSORB China
Contribution To Literature:
The ABSORB China trial showed that Absorb BVS is similar to cobalt-chromium based Xience DES at 2 years for angiographic and clinical outcomes in noncomplex coronary lesions in Chinese patients.
The goal of the trial was to assess the safety and efficacy of Absorb BVS, an everolimus-eluting bioresorbable vascular scaffold, compared with Xience, a cobalt–chromium drug-eluting stent (DES) at 2 years in Chinese patients.
Patients were randomized in a 1:1 ratio to either Absorb BVS (n = 241) or cobalt–chromium-based Xience DES (n = 239).
- Total number of enrollees: 475
- Duration of follow-up: Up to 2 years
- Mean patient age: 57.5 years
- Percentage female: 28%
Other salient features/characteristics:
- Diabetes: 24%
- Prior percutaneous coronary intervention (PCI): 9%
- Stable angina: 18%
- Single-vessel disease: 60%
- Bifurcation lesion: 50%
- Lesion length: 13 mm
- Reference vessel diameter (RVD): 2.65 mm
- Post-dilatation required for BVS vs. Xience: 63% vs. 54.4%, p = 0.05
- Intravascular imaging: 0.4%
- >18 years old
- Evidence of myocardial ischemia (stable/unstable/post-infarction angina or silent ischemia)
- One or two de novo target lesions in up to two native coronary arteries (maximum one lesion per artery)
- RVD ≥2.50 mm and ≤3.75 mm
- Lesion length ≤24 mm
- 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 myocardial infarction (AMI) 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 AMI in electrocardiogram prior to procedure
- Subject has current unstable arrhythmias
- Left ventricular ejection fraction <30%
- Prior PCI in target vessel within 12 months or nontarget vessel in 30 days
- Subject has received a heart transplant or any other organ transplant or is on a waiting list for any organ transplant
- History of bleeding diathesis or coagulopathy or will refuse blood transfusions
- Subject had a cerebrovascular accident or transient ischemic neurological attack within the past 6 months
Angiographic exclusion criteria:
- Target lesion which 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 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
- Heavy calcification proximal to or within the target lesion
The primary outcome, in-segment late lumen loss at 1 year, for Absorb BVS vs. Xience, was 0.19 vs. 0.13 mm (p = 0.01 for noninferiority).
Secondary outcomes for Absorb BVS vs. Xience:
- Acute success: 97.5% vs. 98.3%, p = 0.75
- Immediately post-procedure quantitative coronary angiography (QCA): In-device minimum lumen diameter (MLD): 2.48 mm vs. 2.59 mm, p = 0.002; acute gain: 1.51 vs. 1.59 mm, p = 0.04
- 1-year QCA: In-device MLD: 2.27 mm vs. 2.5 mm, p < 0.0001
- All-cause death, MI, or any revascularization: 8% vs. 9.7%, p = 0.51
- Target-lesion failure: 3.4% vs. 4.2%, p=0.62
- Target-lesion revascularization: 2.9% vs. 3.0%, p = 0.99; ischemia-driven target-vessel revascularization: 2.5% vs. 2.1%, p = 0.77
- Device thrombosis: 0.4% vs. 0.0%, p = 1.0
Outcomes at 2 years:
- All-cause death, MI, or revascularization for BVS vs. Xience: 10.1% vs. 11.4%, p = 0.66
- All-cause mortality: 0.4% vs. 2.5%, p = 0.12
- MI: 3.0% vs. 2.1%, p = 0.56
- Target lesion revascularization: 8.9% vs. 8.4%, p = 0.87
- Scaffold thrombosis: 0.8% vs. 0%, p = 0.5 (very late thrombosis: 0.4% vs. 0%)
The results of this trial indicate that Absorb BVS is noninferior to cobalt–chromium-based Xience DES at 1 year for angiographic outcomes in noncomplex coronary lesions in Chinese patients. However, as observed in other ABSORB trials, in-device acute gain was lower and late lumen loss at 1 year tended to be higher. Clinical outcomes were low and similar between the two arms. At 2 years, clinical event rates were still similar. Scaffold thrombosis beyond 1 year was present in about 0.4% of patients, somewhat lower than reported in ABSORB II (0.9%/year).
ABSORB China is the pivotal trial towards Chinese regulatory approval of Absorb BVS and adds to the growing body of literature with the stent. Longer-term data are awaited to see if Absorb BVS perform is better than Xience beyond 1 year, as bioabsorbable platforms have a theoretical advantage over durable polymer platforms beyond this time frame.
Presented by Dr. Runlin Gao at the Transcatheter Cardiovascular Therapeutics meeting (TCT 2016), Washington, DC, October 30, 2016.
Gao R, Yang Y, Han Y, on behalf of the ABSORB China Investigators. Bioresorbable Vascular Scaffolds Versus Metallic Stents in Patients With Coronary Artery Disease: ABSORB China Trial. J Am Coll Cardiol 2015;66:2298-2309.
Presented by Dr. Runlin Gao at the Transcatheter Cardiovascular Therapeutics meeting (TCT 2015), San Francisco, CA, October 12, 2015.
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