Abstract
Background
Available data on the use of the ABSORB bioresorbable vascular scaffold (BVS) (Abbott Vascular, Santa Clara, CA) in real-world patients is limited. The aim of this study was to assess the mid-term clinical outcomes in a real-world population treated with ABSORB BVS.
Methods and materials
We retrospectively evaluated all patients treated with ABSORB at Papworth Hospital, Papworth Everard, UK between July 2012 and July 2014. A total of 108 patients (126 lesions) were identified. Clinical follow-up was performed on all subjects by clinic visit or telephone interview.
Results
Most patients were male (91.7%) with a relative high incidence of previous myocardial infarction (MI) (40.7%). Clinical presentation was equally divided between stable angina and acute coronary syndrome (ACS) (51.8% vs. 48.2%, p = 0.59). Of the ACS patients, 26.9% presented with ST-elevation myocardial MI. Intravascular imaging was used in all cases. Predilatation (92.9%) and postdilatation (82.5%) were frequently performed. Major adverse cardiac event (MACE) rates defined as the composite of all-cause death, follow-up MI and target vessel revascularization were 2.5% at 6-month and 4.5% at 1-year. The 1-year target lesion failure rate, defined as the composite of cardiac death, target-vessel MI and target lesion revascularization was 1.9%. There was 1 case of subacute stent thrombosis.
Conclusions
The use of ABSORB BVS in real-world patients appears to be associated with good mid-term clinical outcomes when guided by intravascular imaging. Larger studies are required to evaluate further the role of BVS in routine clinical practice and examine how this compares to metallic devices.
Summary
Available data on the use of the ABSORB BVS in real-world patients is limited. We retrospectively evaluated all patients treated with ABSORB BVS between July 2012 and July 2014. A total of 108 patients (126 lesions) were identified. Clinical presentation was equally divided between stable angina and acute coronary syndrome (51.8% vs. 48.2%, p = 0.59). Predilatation (92.9%) and postdilatation (82.5%) were frequently performed. Estimated MACE rates at 6-month and 1-year were 2.5% and 4.5% respectively, with a 1-year TLF rate of 1.9%. These results suggest that the use of ABSORB BVS use in the real-world is associated with good mid-term clinical outcomes when guided by intravascular imaging.
Highlights
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Bioresorbable vascular scaffolds (BVS) offer the potential of potential of revolutionizing the percutaneous treatment of coronary artery disease.
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Results from early clinical trials have been promising.
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Data regarding the role of these devices in the ‘real-word’ is limited.
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We report the mid-term clinical outcomes of a ‘real-world’ population treated with ABSORB BVS at a single UK center.
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Results demonstrate that use of BVS in ‘real-world’ patients is associated with clinical outcomes comparable to those seen with conventional devices.
1
Introduction
Bioresorbable vascular scaffolds (BVS) offer a new and exciting option in the percutaneous treatment of coronary artery disease (CAD) as their eventual resorption renders the artery free from a permanent metallic ‘cage’. This allows for normal vasomotor vessel function to be restored while also maintaining access for future coronary artery bypass grafting (CABG) if required . Results from clinical trials with the commercially available ABSORB BVS (Abbott Vascular, Santa Clara, CA, USA) have been encouraging with low rates of adverse events at mid- to long-term follow-up and clinical outcomes comparable to those observed with its metallic counterpart . The role of ABSORB BVS in unselected real-world patients however has not been fully evaluated. Results from small studies suggest that ABSORB BVS can be used in a range of patients including those with ST-segment elevation myocardial infarction (MI), long diffuse disease and in those requiring 2-stent strategies for complex bifurcation disease with good results in the short-term . The aim of this study was to assess mid-term clinical outcomes of ABSORB BVS in a real-world population treated at a single-center in the United Kingdom where use of ABSORB is limited.
2
Materials and methods
We examined all BVS ABSORB procedures performed at Papworth Hospital, Papworth Everard, UK between July 2012 and July 2014. Each procedure was entered into a percutaneous coronary intervention (PCI) database at the time of the procedure and subsequently all clinical parameters were verified by inspecting the case records. Using these criteria, 108 consecutive patients with 126 lesions treated with ABSORB BVS were identified. Over the same interval 3847 patients were treated with metallic stents of which 75.8% received drug-eluting stents (DES). The decision to implant ABSORB was largely at the operators’ discretion although this was guided by local guidelines. In general ABSORB implantation was avoided, in patients older than 80 years of age, where concerns regarding the tolerability of 12 month dual antiplatelet therapy (DAPT) were present. Finally, it was mandatory for all operators to receive formal training on the recommended implantation technique for ABSORB prior to incorporating the device to their PCI practice.
All patients provided informed consent for both the procedure and subsequent data collection and analysis. Intracoronary imaging, either optical coherence tomography (OCT, DragonFly C7, St. Jude Medical, Saint Paul, USA) or intravascular ultrasound (IVUS, Boston Scientific, Natick, USA), was performed both prior and post scaffold implantation to assess target and lesion vessel characteristics as well as BVS expansion and apposition. With regard to predilatation and postdilatation, these were routinely performed except in patients presenting with ST-segment elevation MI. In these cases, postdilatation was only performed when scaffold underexpansion or strut malapposition was present on intravascular imaging in order to minimize the risks of distal embolization. If OCT suggested the presence of a large entry or exit dissection at the scaffold implantation site a further BVS was implanted. All patients received DAPT (aspirin and clopidogrel) for 12 months and aspirin alone thereafter.
Clinical follow-up was performed on all subjects by clinic visit or telephone interview. Clinical outcomes reported represent patient-specific data unless otherwise stated. Clinical device success was defined as successful delivery and deployment of stent or scaffold at the target lesion and successful withdrawal of the delivery system with attainment of a final residual stenosis of < 30%. Procedural success was defined as clinical device success without the occurrence of ischemia driven major adverse cardiac events (MACE) during the hospital stay with a maximum of the first seven days after the index procedure. MACE was defined as the composite of all-cause death, follow-up MI and target vessel revascularization (TVR). Death was considered cardiac in origin unless obvious non-cardiac causes were identified. MI definitions were in accordance with the most recent universal definition of MI . TVR was defined as repeat PCI or coronary artery bypass graft (CABG) in the target vessel. Target lesion revascularization (TLR) was defined as repeat PCI or CABG for the lesion in the previously treated segment or in the adjacent 5 mm. Target lesion failure (TLF) was defined as the composite of cardiac death, target-vessel MI and TLR. The occurrence of stent thrombosis (ST) was defined on the basis of the Academic Research Consortium definition .
Values are presented as mean ± standard deviation (SD) for continuous variables or as counts and percentages for categorical variables. Continuous variables were compared by the independent sample t or Mann–Whitney U tests. Categorical variables were compared by the Chi-square statistic or Fisher’s exact test. A p-value of < 0.05 was considered to be statistically significant and all reported p-values are two-sided. Time-to-event curves were generated using the Kaplan–Meier method. Analyses were carried out using SPSS for Windows, version 19.0 (SPSS Inc., Chicago, Illinois).
2
Materials and methods
We examined all BVS ABSORB procedures performed at Papworth Hospital, Papworth Everard, UK between July 2012 and July 2014. Each procedure was entered into a percutaneous coronary intervention (PCI) database at the time of the procedure and subsequently all clinical parameters were verified by inspecting the case records. Using these criteria, 108 consecutive patients with 126 lesions treated with ABSORB BVS were identified. Over the same interval 3847 patients were treated with metallic stents of which 75.8% received drug-eluting stents (DES). The decision to implant ABSORB was largely at the operators’ discretion although this was guided by local guidelines. In general ABSORB implantation was avoided, in patients older than 80 years of age, where concerns regarding the tolerability of 12 month dual antiplatelet therapy (DAPT) were present. Finally, it was mandatory for all operators to receive formal training on the recommended implantation technique for ABSORB prior to incorporating the device to their PCI practice.
All patients provided informed consent for both the procedure and subsequent data collection and analysis. Intracoronary imaging, either optical coherence tomography (OCT, DragonFly C7, St. Jude Medical, Saint Paul, USA) or intravascular ultrasound (IVUS, Boston Scientific, Natick, USA), was performed both prior and post scaffold implantation to assess target and lesion vessel characteristics as well as BVS expansion and apposition. With regard to predilatation and postdilatation, these were routinely performed except in patients presenting with ST-segment elevation MI. In these cases, postdilatation was only performed when scaffold underexpansion or strut malapposition was present on intravascular imaging in order to minimize the risks of distal embolization. If OCT suggested the presence of a large entry or exit dissection at the scaffold implantation site a further BVS was implanted. All patients received DAPT (aspirin and clopidogrel) for 12 months and aspirin alone thereafter.
Clinical follow-up was performed on all subjects by clinic visit or telephone interview. Clinical outcomes reported represent patient-specific data unless otherwise stated. Clinical device success was defined as successful delivery and deployment of stent or scaffold at the target lesion and successful withdrawal of the delivery system with attainment of a final residual stenosis of < 30%. Procedural success was defined as clinical device success without the occurrence of ischemia driven major adverse cardiac events (MACE) during the hospital stay with a maximum of the first seven days after the index procedure. MACE was defined as the composite of all-cause death, follow-up MI and target vessel revascularization (TVR). Death was considered cardiac in origin unless obvious non-cardiac causes were identified. MI definitions were in accordance with the most recent universal definition of MI . TVR was defined as repeat PCI or coronary artery bypass graft (CABG) in the target vessel. Target lesion revascularization (TLR) was defined as repeat PCI or CABG for the lesion in the previously treated segment or in the adjacent 5 mm. Target lesion failure (TLF) was defined as the composite of cardiac death, target-vessel MI and TLR. The occurrence of stent thrombosis (ST) was defined on the basis of the Academic Research Consortium definition .
Values are presented as mean ± standard deviation (SD) for continuous variables or as counts and percentages for categorical variables. Continuous variables were compared by the independent sample t or Mann–Whitney U tests. Categorical variables were compared by the Chi-square statistic or Fisher’s exact test. A p-value of < 0.05 was considered to be statistically significant and all reported p-values are two-sided. Time-to-event curves were generated using the Kaplan–Meier method. Analyses were carried out using SPSS for Windows, version 19.0 (SPSS Inc., Chicago, Illinois).
3
Results
ABSORB was implanted successfully in 99.1% (n = 109) of patients where this was intended to be used. The 1 case of device failure occurred with a 3.5 × 18 mm scaffold, which could not be delivered in the distal right coronary artery due to excessive tortuosity and significant calcification despite the use of the ‘buddy wire’ and ‘mother-in-child’ techniques. Procedural success rate was also 99.1%. Baseline clinical characteristics of the patients treated with ABSORB are summarized in Table 1 . The majority of treated patients were male (91.7%) with a relatively high incidence of previous MI (40.7%). Clinical presentation was equally divided between stable angina and acute coronary syndrome (ACS) (51.8% vs. 48.2%, p = 0.59). Of the ACS patients, 26.9% presented with ST-elevation MI. Procedural characteristics are shown in Table 2 . Most cases were performed via the radial route (92.6%) with the left anterior descending (LAD) artery being the vessel most commonly treated (56.3%). A significant percentage (34.9%) of lesions treated was classified as calcified on the basis of fluoroscopic or intravascular imaging findings and 18.3% involved a bifurcation ( Fig. 1 ). Intravascular imaging was performed in all patients prior and post-BVS implantation with OCT being the modality most commonly utilized (97.6%). Predilatation was routinely performed (92.9%) with a balloon of similar diameter, albeit slightly smaller, to that of the subsequent implanted BVS (2.9 vs. 3.1 mm, p < 0.01). 1:1 balloon:vessel diameter predilatation was utilized in 51.6% of the cases. Overlapping BVS ( Fig. 2 ) was implanted in 22.0% of patients to treat diffuse disease (> 20 mm). Postdilatation was also frequently performed (82.5%) and often with a bigger diameter balloon to that of the implanted BVS. This however did, not exceed the scaffold’s 0.5 mm postdilatation potential (3.4 vs. 3.1 mm, p < 0.01) as per manufacturer’s guidelines.
