Dynamics of vessel wall changes following the implantation of the Absorb everolimus-eluting bioresorbable vascular scaffold: a multi-imaging modality study at 6, 12, 24 and 36 months.

Selected in EuroIntervention by S. Brugaletta

References

Authors

Serruys PW, Onuma Y, Garcia-Garcia HM, Muramatsu T, van Geuns RJ, de Bruyne B, Dudek D, Thuesen L, Smits PC, Chevalier B, McClean D, Koolen J, Windecker S, Whitbourn R, Meredith I, Dorange C, Veldhof S, Hebert KM, Rapoza R, Ormiston JA.

Reference

EuroIntervention. 2014 Mar 20;9(11):1271-84 published online ahead of print December 2013

Published

March 2014

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Aims

To assess observations with multimodality imaging of the Absorb bioresorbable everolimus-eluting vascular scaffold performed in two consecutive cohorts of patients who were serially investigated either at 6 and 24 months or at 12 and 36 months.

Methods and results

In the ABSORB multicentre single-arm trial, 45 patients (cohort B1) and 56 patients (cohort B2) underwent serial invasive imaging, specifically quantitative coronary angiography (QCA), intravascular ultrasound (IVUS), radiofrequency backscattering (IVUS-VH) and optical coherence tomography (OCT). Between one and three years, late luminal loss remained unchanged (6 months: 0.19 mm, 1 year: 0.27 mm, 2 years: 0.27 mm, 3 years: 0.29 mm) and the in-segment angiographic restenosis rate for the entire cohort B (n=101) at three years was 6%. On IVUS, mean lumen, scaffold, plaque and vessel area showed enlargement up to two years. Mean lumen and scaffold area remained stable between two and three years whereas significant reduction in plaque behind the struts occurred with a trend toward adaptive restrictive remodelling of EEM. Hyperechogenicity of the vessel wall, a surrogate of the bioresorption process, decreased from 23.1% to 10.4% with a reduction of radiofrequency backscattering for dense calcium and necrotic core. At three years, the count of strut cores detected on OCT increased significantly, probably reflecting the dismantling of the scaffold; 98% of struts were covered. In the entire cohort B (n=101), the three-year major adverse cardiac event rate was 10.0% without any scaffold thrombosis.

Conclusions

The current investigation demonstrated the dynamics of vessel wall changes after implantation of a bioresorbable scaffold, resulting at three years in stable luminal dimensions, a low restenosis rate and a low clinical major adverse cardiac events rate. Clinical Trial Registration Information: http://www.clinicaltrials.gov/ct2/show/NCT00856856

My Comment

What is known

The Absorb BVS device has been tested in the ABSORB A and B trials. The latter enrolled 101 patients subdivided into two groups of patients: the first group (45 patients, group B1) underwent invasive imaging with QCA, IVUS greyscale, IVUS-VH and OCT at six and 24 months, whereas the second group (56 patients, group B2), which is reported in detail in the current manuscript, underwent invasive imaging at 12 months and at 36 months.

Major findings

  • Between one and three years, late luminal loss remained unchanged (6 months: 0.19 mm, 1 year: 0.27 mm, 2 years: 0.27 mm, 3 years: 0.29 mm).
  • On IVUS, mean lumen, scaffold, plaque and vessel area showed enlargement up to two years. Mean lumen and scaffold area remained stable between two and three years whereas significant reduction in plaque behind the struts occurred with a trend toward adaptive restrictive remodelling of EEM.
  • Hyperechogenicity of the vessel wall, a surrogate of the bioresorption process, decreased from 23.1% to 10.4% with a reduction of radiofrequency backscattering for dense calcium and necrotic core. At three years, the count of strut cores detected on OCT increased significantly, probably reflecting the dismantling of the scaffold; 98% of struts were covered.
  • In the entire cohort B (n=101), the three-year major adverse cardiac event rate was 10.0% without any scaffold thrombosis.

My comments  

The present paper is the final report from the ABSORB B trial, which shows the safety and feasibility of this technology in simple lesions. It is important to note that rarely a novel revascularisation technique has been so intensively scrutinised during the early days of its development by means of various imaging technique, such as IVUS, VH, OCT, palpography, echogenicity. All the data presented here and in other papers seem to provide sufficient evidence about the physiological advantages of ABSORB as compared to conventional metallic stents, such as recovery of vasomotion, capping of plaque, lack of caging, etc. The ultimate expectation of this novel technology is the occurrence of late lumen enlargement, associated with wall thinning and adaptive remodelling, which probably requires a longer follow-up. We also need data showing how all these physiological advantages may translate in a clinical advantage from patient’s point of view. In view of these considerations, the coming trials testing ABSORB vs. Xience in STEMI and in all-comer patients, powered for clinical endpoints, will be of utmost importance. It would be also interesting that each reader would share his/her personal experience about use of ABSORB in clinical practise. 

2 comments

  • Lorenzo Azzalini 15 Apr 2014

    I agree: BVS are the latest milestone in coronary intervention and their unique features have aroused great interest. As you mention, the ultimate challenge for BVS will be to demonstrate non-inferiority (and maybe superiority) to metallic stents in all-comers (ACS, complex lesions, etc.) as far as clinical endpoints are concerned. In particular, long-term safety (ISR, ST) in all-comers (the ABSORB patient population is a rather selected one) is a major goal to be met.

  • Sunip BANERJEE 11 May 2014

    Why 10% MACE in absence of scaffold thrombosis, was drug therapy adequate? was TVR