Original ArticleMedium-Term Bioresorbable Scaffold Outcomes Utilising Data From an Australian Clinical Quality Registry
Introduction
Bioresorbable scaffolds (BRS) are a novel and highly promising new technology for the treatment of coronary disease. Despite significant improvements in coronary stent design over the last 20 years [1], the long-term persistence of metallic stent struts in contact with the vessel wall is thought to be a risk factor for late stent thrombosis and restenosis secondary to chronic vascular inflammation [2]. Vascular scaffolds that gradually dissolve over a period of months/years offer a number of potential advantages over metallic stents. They provide early mechanical support and drug delivery similar to conventional stents. Later, as they are slowly resorbed, there is the potential for restoration of normal arterial pulsatility and vascular function, and the potential for a reduced risk of the very late thrombosis and restenosis previously linked with drug-eluting stent (DES) polymer [3].
The most studied BRS, the Absorb BRS (Abbott Vascular, Santa Clara, CA, USA), received CE mark approval in 2011 [3] after demonstration of non-inferiority in target lesion failure (TLF) at 1 year compared to a second-generation metallic DES [4]. It became commercially available in Australia in 2013. Despite its initial efficacy, the subsequent longer ABSORB III trial and Amsterdam Investigator-initiated Absorb Strategy All-comers (AIDA) trial [5] found that the Absorb BRS had higher rates of TLF at 2 years follow-up and increased risk of scaffold thrombosis compared to metallic DES. Further analysis of seven completed randomised trials demonstrated increased rates of target vessel-related myocardial infarction (MI) and ischaemia-driven target lesion revascularisation at 3 years follow-up compared with DES, a higher rate of device thrombosis, but no change in cardiac mortality [[6], [7], [8]]. In response, the Absorb BRS device was withdrawn from sale by the manufacturer in May 2017 [9] following the issuing of a Safety Alert by the Therapeutic Goods Administration regarding the device [10].
This study was conducted as a post-marketing surveillance of Abbott Absorb BRS use in a large state jurisdiction, utilising the Victorian Cardiac Outcomes Registry—a clinical quality registry of percutaneous coronary intervention (PCI) that encompasses all hospitals performing PCI in the state of Victoria, Australia. The purpose of the study was to determine medium-term outcomes following BRS implantation, including rates of very-late stent thrombosis and target vessel failure and to ascertain independent predictors of poor outcome.
Section snippets
Materials and Methods
The Victorian Cardiac Outcomes Registry (VCOR) dataset was interrogated to identify all procedures within the registry that used at least one Abbott Absorb BRS until the withdrawal of the Abbott Absorb device from market on 2 May 2017. Individual site data coordinators were approached to verify that the cases identified in VCOR matched local hospital records for BRS cases to ensure accuracy. Site-identified BRS cases that were not in the VCOR dataset because the site had not yet started
Results
A total of 192 BRS procedures were performed among 186 patients. In the non-BRS PCI cohort, 31,773 procedures were performed on 27,231 patients. Bioresorbable scaffolds procedural mean age was 61.6±10.5 (standard deviation) years, 79% were male. Bioresorbable scaffolds procedures were performed in 18 of the 30 centres participating in the VCOR registry, with five sites performing ≥10 procedures. A total of 40 different operators were involved, with five operators performing ≥10 procedures, nine
Discussion
In this study, we present medium-term outcomes for Abbott Absorb BRS use in an Australian setting using data from a clinical quality registry. With follow-up to 4.2 years (mean 27 months), rates of composite and individual safety and efficacy endpoints were comparable to international BRS registry and trial data [[6], [7], [8]]. We found that in line with manufacturers’ guidelines, BRS were used in patients with less comorbidity and simpler coronary lesions compared to non-BRS PCI. There was
Conclusions
Bioresorbable scaffolds were initially seen as a promising development in the treatment of coronary disease. However, long-term outcomes with the first-generation devices have been disappointing. We have shown that medium-term Abbott Absorb BRS outcomes in an Australian setting are comparable to international trial and registry data, with adherence to most manufacturer guidelines for both BRS patient selection and device implantation technique. However, there was poor adherence to high-pressure
Funding
The VCOR was initially funded by Medibank Private from 2011–2014 and the Victorian Department of Health and Human Services (DHHS). Ongoing funding has been provided from the DHHS and Victorian Cardiac Clinical Network.
Acknowledgments
The Victorian Cardiac Outcomes Registry would not be possible without the efforts of doctors, nurses, data managers and other relevant hospital staff who contribute data to VCOR. The principal investigators and other lead clinical staff from participating sites are also gratefully acknowledged. The Department of Health and Human Services Victoria, Australia and the Victorian Cardiac Clinical Network have provided start-up and ongoing funding for VCOR. Start-up funding was also provided by
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