ABSORB II randomized controlled trial: a clinical evaluation to compare the safety, efficacy, and performance of the Absorb everolimus-eluting bioresorbable vascular scaffold system against the XIENCE everolimus-eluting coronary stent system in the treatment of subjects with ischemic heart disease caused by de novo native coronary artery lesions: rationale and study design

Evolutionary perspective of drug eluting stents: from thick polymer to polymer free approach

BACKGROUND

Introduction of Bare Metal Stents (BMS) was itself a revolutionary step in the history of the medical industry; however, Drug Eluting Stents (DES) maintained its superiority over BMS in every aspect from restenosis rate to late lumen loss. The reason behind the magnanimous position of the DES in the stent market is the degree of improvement with which it evolves. New and better stents come into the market every year, surpassing their predecessors by many folds.

LITERATURE REVIEW

This review paper discusses the journey of DES with supporting clinical trials in detail. In the first generation, there were stainless-steel stents with thicker coatings. Although they had superior results compared to BMS, there was still room for improvement. Afterward came the second-generation stents, which had superior metal platforms with thinner struts and thin coatings. The drugs were also changed from Paclitaxel and Sirolimus to Zotrolimus and Everolimus. These stents performed best; however, there was an issue of permanent coating, which remained intact over the stent surface after complete drug elution and started to cause issues in longer-term studies. Hence, an improved version of DES was introduced to these permanent coatings called the third generation of drug eluting stents, which initially utilized biodegradable polymer and ultimately moved towards polymer free drug coatings. This generation has introduced a unique amalgam of technologies to achieve its polymer free coatings; however, researchers have numerous prospects of growth in this field. This review paper highlights the major coups of stent technology evolution from BMS to DES, from thick polymeric coatings to thin coatings and from durable polymers to polymer free DES.

CONCLUSION

In conclusion, though the medical industry promptly accepted BMS as the best treatment option for cardiovascular diseases; however, DES has provided even better results than BMS. In DES, the first and second generation has ruled the technology for many years and are still on the shelves. Still, the issues aroused due to durable polymer shifted the attention towards biodegradable drug eluting stents, the third generation growing rapidly. But the scientific community has not restricted themselves and is investigating bioresorbable stents that completely eliminate the polymer intervention in drug eluting stent technology.

Everolimus eluting bioresorbable vascular scaffolds in patients with acute coronary syndromes: Two-year results from the German-Austrian ABSORB registry

OBJECTIVES

To identify potential differences in 2-year outcome between patients who underwent coronary revascularization using bioresorbable vascular scafffolds (BVS) in stable coronary artery disease (CAD) and acute coronary syndromes (ACS).

BACKGROUND

Data from randomized trials suggest a significantly higher event rate following coronary revascularization using everolimus-eluting BVS as compared to new generation drug eluting stents. Whether particular patient subgroups are at increased risk for scaffold thrombosis and target lesion failure (TLF) has not clearly been demonstrated.

METHODS

German-Austrian ABSORB RegIstRy is a prospective all-comer multi-center observational study of consecutive patients who were considered for coronary revascularization with BVS. We compared 1499 patients with stable CAD to 1594 patients with ACS. Endpoints were major adverse cardiac events (MACE), TLF, and scaffold thrombosis.

RESULTS

While single vessel disease was more prevalent in ACS (46% vs. 37%, p < 0.0001), lesion complexity (B2/C stenosis 37% vs. 36%, bifurcation 2.4% vs. 3.4%, p < 0.05), number of implanted scaffolds/patient (1.34 vs. 1.43), scaffold length (18 vs. 18 mm) or the rate of high pressure postdilatation (68% vs. 70%) did not differ between ACS and stable CAD. Two-year MACE rates were 11.6% in ACS and 11.4% in stable CAD, TLF occurred in 7.0% versus 7.4% and target vessel revascularization in 8.8 versus 10.2% (n.s. for all). Definite scaffold thrombosis rates were not significantly different (ACS 1.9% vs. stable CAD 2.1%).

CONCLUSION

Real-world 2-year event rates after coronary revascularization with BVS are not significantly different between individuals with ACS as compared to stable CAD.

Durable polymer everolimus-eluting stents: history, current status and future prospects

INTRODUCTION

Coronary percutaneous interventions have evolved from plain old balloon angioplasty (POBA) to stent implantation, which itself evolved from bare-metal stents (BMS) to the new biodegradable stents which try to restore endothelial function. Currently, the most commonly used stent is the everolimus-eluting stent.

AREAS COVERED

This review will cover the current status of durable polymer everolimus-eluting stent, its history, and future perspectives. Nowadays, the everolimus-eluting stent is the most used device in the acute and chronic settings due to its safety and efficacy.

EXPERT OPINION

Durable polymer everolimus-eluting stent, supported by much evidence, has demonstrated its efficacy and safety, not only in de novo artery lesions, but in multiples scenarios, such as the acute setting and diabetic population, becoming one of the most polyvalent stents available. Nowadays, research is focused on the reduction of antiplatelet treatment duration. Similar rates of stent thrombosis with short dual antiplatelet treatment regimens of 1 to 3 months compared to pronged treatment have been observed. However, specific studies should be performed to evaluate this possibility.

The Absorb bioresorbable vascular scaffold in real-world practice: long-term follow-up of the AMC Single Centre Real World PCI Registry

BACKGROUND

Bioresorbable scaffolds have been introduced to overcome the shortcomings of drug-eluting stents. Higher rates of device thrombosis, however, have been reported up to 3 years after implantation of the Absorb bioresorbable vascular scaffold (BVS). In the current article, we therefore report long-term clinical outcomes of the AMC Absorb Registry.

METHODS AND RESULTS

In the AMC Absorb Registry, all patients who underwent a percutaneous coronary intervention with Absorb BVS implantation between 30 August 2012 and 5 August 2013 at the Amsterdam University Medical Centre-Academic Medical Centre were included. The composite endpoint of this analysis was target-vessel failure (TVF). The median follow-up of the study cohort of the AMC Absorb Registry was 1534 days. At the time of the cross-sectional data sweep the clinical status at 4 years was known in 124 of 135 patients (91.9%). At long-term follow-up, the composite endpoint of TVF had occurred in 27 patients. The 4‑year Kaplan-Meier estimate of TVF was 19.8%. At 4 years cardiac death had occurred in 4 patients (3.2%) and target-vessel myocardial infarction in 9 (6.9%) patients. Definite scaffold thrombosis occurred in 5 (3.8%) patients. We found 1 case of very late scaffold thrombosis that occurred at 911 days after device implantation in a patient who was not on dual anti-platelet therapy.

CONCLUSION

In a patient population reflecting routine clinical practice, we found that cases of TVF continued to accrue beyond 2 years after Absorb BVS implantation.

The impact of the use of bioresorbable vascular scaffolds and drug-coated balloons in coronary bifurcation lesions

BACKGROUND

Despite the improvement in techniques and tools, coronary lesions involving a bifurcation are still challenging and the outcome with drug-eluting stents is not always optimal. The role of bioresorbable vascular scaffolds (BVS) and drug-coated balloons (DCB) in this setting has not been adequately investigated yet.

RESULTS

From the databases of 6 italian centers with high proficiencies in newer technologies, we retrospectively collected all consecutive cases of coronary bifurcations managed or attempted with the implantation of at least one BVS in the main vessel and the use of one DCB in the side branch (SB). Primary study endpoint was the occurrence of major adverse cardiovascular events (MACE) at the longest available follow-up. Fourty patients fulfilled the enrollment criterion, 22.5% had diabetes and 50% an acute coronary syndrome. Average syntax score was 15.04 ± 7.18, all lesions were de novo, and 27 patients (67.5%) had a type 1,1,1 Medina lesion. Twenty-three lesions (57.5%) involved the proximal left anterior-descending artery/first diagonal branch. Only 32.5% of patients underwent an intravascular imaging-guided angioplasty. Average lesion length was 21.4 mm in the main vessel and 11.49 mm in the SB. MV was always predilated and BVS received a postdilation in 100% of the cases. In 42.5% of the cases, the DCB was used during final kissing balloon inflation, and in no cases, a stent/BVS was required in the SB. Procedural success was achieved in 100% of the cases. After an average follow-up of 15.5 (± 11.5) months, we observed no MACE with only one case of target vessel revasularization (2.5%).

CONCLUSIONS

Management of coronary bifurcation lesions with the use of newer technologies including BVS and DCB seems feasible and effective at mid-term and long-term clinical follow-up.

The relationship of pre-procedural Dmax based sizing to lesion level outcomes in Absorb BVS and Xience EES treated patients in the AIDA trial

Due to expansion limits of the Absorb bioresorbable scaffold a meticulous implantation with correct sizing is required. We sought to investigate the clinical outcomes based on the sizing of the device related to the maximal lumen diameter measured by quantitative coronary angiography in Absorb BVS and Xience EES treated lesions in the AIDA trial. Sizing of Absorb bioresorbable vascular scaffold (BVS) and Xience everolimus eluting stent (EES) was graded according to the definitions of device non-oversize and device oversize on pre-procedural angiography. Lesion-oriented outcomes (LOCE) (device thrombosis, TLR and TVMI) that occurred during 2 years follow-up were related to device non-oversized or oversized status. In the Absorb BVS group, LOCE occurred in 48 (7.4%) lesions in the oversized group and in 32 (8.2%) lesions in the non-oversized group (HR 0.91; 95% CI 0.58-1.42; p = 0.681), whereas TLR occurred in 34 (5.3%) lesions and in 23 lesions (5.9%), respectively (HR 0.89; 95% CI 0.52-1.51; p = 0.666). Definite scaffold thrombosis occurred in 11 (1.7%) device oversized treated lesions against 16 (4.1%) device non-oversized treated lesions (HR 0.41; 95% CI 0.19-0.89; p = 0.020). There were no differences in event rates between oversized and non-oversized groups in lesions treated with Xience EES. There was no significant difference in LOCE between oversized and non-oversized treated Absorb BVS and Xience EES treated lesions. Non-oversized Absorb BVS implantation was associated with a higher risk of scaffold thrombosis at complete 2 years follow-up. The majority of very late scaffold thrombosis occurred in properly sized devices.

Pharmacokinetic Study of Sirolimus-Eluting BioResorbable Vascular Scaffold System for Treatment of De Novo Native Coronary Lesions: A Sub-Study of MeRes-1 Trial

Background

MeRes100™ (Meril Life Sciences Pvt. Ltd., Vapi, India) is a novel sirolimus-eluting bioresorbable vascular scaffold (BRS). The purpose of this sub-study of MeRes-1 trial is to evaluate the systemic release of sirolimus from MeRes100 BRS implanted for the treatment of de novo native coronary artery lesions.

Methods

The MeRes-1 is a prospective, multicenter, first-in-human trial of sirolimus-eluting MeRes100 BRS. The pharmacokinetic sub-study was conducted at two Indian sites in 10 patients who were implanted with the MeRes100 BRS loaded with sirolimus at a dose of 1.25 µg/mm². Venous blood samples were collected at pre-dose and 12-time points after implantation of the scaffold. Sirolimus concentration was successively analyzed using ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry method.

Results

A total of 12 scaffolds were implanted in 10 patients. Non-compartmental analysis demonstrated time to reach peak concentration of sirolimus between 0.5 h to 3 h after scaffold implantation. The peak concentration (C_max) was deduced to be 7.47 ± 2.61 ng/mL, AUC was 436.45 ± 171.24 h·ng/mL, and the t_½ was observed at 98.59 ± 33.58 h. The clearance was 0.66 ± 0.16 L/h and lower limit of quantification was detectable at 14.1 days.

Conclusions

The MeRes-1 pharmacokinetic sub-study confirmed that MeRes100 BRS is safe and tolerable at limited systemic exposure of sirolimus.

Relation between bioresorbable scaffold sizing using QCA-Dmax and long-term clinical outcomes in 1,232 patients from three study cohorts (ABSORB Cohort B, ABSORB EXTEND, and ABSORB II)

AIMS

This study sought to investigate the long-term clinical outcomes related to scaffold sizing based on quantitative coronary angiography.

METHODS AND RESULTS

A total of 1,248 patients who received Absorb bioresorbable scaffolds in the ABSORB Cohort B, ABSORB EXTEND, and ABSORB II trials were included in the analysis. The incidence of MACE (a composite of cardiac death, any myocardial infarction [MI], and ischaemia-driven target lesion revascularisation [ID-TLR]) was analysed according to the Dmax subclassification of oversized scaffold group versus non-oversized (any undersize) scaffold group. At three years, event rates were similar in both groups in MACE (9.4% vs. 9.8%, p=0.847), target vessel MI (5.2% vs. 4.8%, p=0.795), and ID-TLR (4.8% vs. 5.8%, p=0.445). Landmark analysis after one year showed that the non-oversized scaffold group had higher rates of MACE (3.2% vs. 6.9%, log-rank p=0.004), target vessel MI (0.7% vs. 2.7%, log-rank p=0.007), and ID-TLR (2.5% vs. 4.7%, log-rank p=0.041).

CONCLUSIONS

Implantation of an undersized scaffold was associated with a higher risk of MACE between one and three years, while in the previous report an oversized scaffold was associated with a higher risk of MACE up to one year. This implies different mechanisms for early and late events after scaffold implantation.

Multianalysis with optical coherence tomography and vasomotion in everolimus-eluting stents and everolimus-eluting biovascular scaffolds: the MOVES trial

Aims

To compare endothelium-dependent vasomotor function and vascular healing 15 months after implantation of two new-generation drug-eluting stents and biovascular scaffolds (BVS).

Methods and results

A total of 28 patients previously treated with a SYNERGY stent (bioabsorbable polymer everolimus-eluting stents (BP-EES)), a PROMUS stent (persistent polymer everolimus-eluting stents (PP-EES)) or an ABSORB (BVS) underwent control coronary angiography, 15 months after implantation, coupled with optical coherence tomography imaging and supine bicycle exercise. Intracoronary nitroglycerin was administered after exercise testing. Coronary vasomotor response was assessed using quantitative coronary angiography at rest, during supine bicycle exercise and after nitroglycerin. The primary end point was the percent change in mean lumen diameter compared with baseline. Secondary end points were strut coverage and apposition.There were no significant differences in vasomotor response between the three treatment groups. Patients with PP-EES showed significant vasoconstriction of the proximal peristent segment at maximum exercise (P=0.02). BP-EES (2.7%, 95% CI 0 to 5.5) and BVS (3.2%, 95% CI 0 to 6.7) showed less uncovered struts than PP-EES (12.1%, 95% CI 2.9 to 21.3, P=0.02 and 0.09, respectively). Complete strut apposition was more frequently seen with BP-EES (99.6%, 95% CI 99.2 to 100) than with BVS (98.9%, 95% CI 98.2 to 99.6, P=0.04) or PP-EES (95.0%, 95% CI 91.6 to 98.5, P=0.001).

Conclusion

BVS and thin strut BP-EES have a reassuring vasomotion profile, suggesting minimal endothelial dysfunction 15 months after implantation.

Coronary calcification as a mechanism of plaque/media shrinkage in vessels treated with bioresorbable vascular scaffold: A multimodality intracoronary imaging study

BACKGROUND AND AIMS

Whether coronary calcification is correlated with plaque/media shrinkage (PS) remains unclear. The aim of this study was to assess the relationship between the calcification process and PS, combining serial optical coherence tomography (OCT) and intravascular ultrasound (IVUS) in vessels treated with bioresorbable vascular scaffolds (BVS).

METHODS

In 15 patients (16 vessels), OCT and IVUS images were matched using anatomic landmarks at post-procedure and five years. PS was defined as relative decrease in plaque/media area >5%. The association between the calcification process and PS was investigated. Mixed effect models were used to assess correlations and changes over time.

RESULTS

Seventy-two OCT and IVUS paired cross sections in- and out-scaffolded segments were matched at baseline and follow-up (432 images). In total, 35 out of the 72 cross sections showed PS, and 37 cross sections showed no PS (non-PS) at 5-year follow-up. Delta (Δ) plaque/media area showed negative correlation with Δ OCT calcium area (r = -0.29, p = 0.004), Δ OCT calcium arc (r = -0.42, p < 0.001), Δ OCT calcium length (r = -0.5, p < 0.001), and Δ IVUS calcium arc (r = -0.31, p = 0.024), respectively. On echogenicity analysis, Δ plaque/media area was positively associated with Δ hypoechogenic area (r = 0.47, p = 0.002). An increase in calcium area was negatively correlated to Δ hypoechogenicity (r = -0.29, p < 0.016). The increase in calcium area was positively correlated with Δ lumen area (r = 0.24, p = 0.044).

CONCLUSIONS

In segments treated with BVS, the calcification process was associated with PS, decrease in the hypoechogenic tissue and late luminal enlargement. Combining IVUS and OCT provides a unique method to assess the correlation between the calcification process and plaque/media shrinkage.

Effect of Technique on Outcomes Following Bioresorbable Vascular Scaffold Implantation: Analysis From the ABSORB Trials

BACKGROUND

Procedural technique may affect clinical outcomes after bioresorbable vascular scaffold (BVS) implantation. Prior studies suggesting such a relationship have not adjusted for baseline patient and lesion characteristics that may have influenced operator choice of technique and outcomes.

OBJECTIVES

This study sought to determine whether target lesion failure (TLF) (cardiac death, target-vessel myocardial infarction, or ischemia-driven target lesion revascularization) and scaffold thrombosis (ScT) rates within 3 years of BVS implantation are affected by operator technique (vessel size selection and pre- and post-dilation parameters).

METHODS

TLF and ScT rates were determined in 2,973 patients with 3,149 BVS-treated coronary artery lesions from 5 prospective studies (ABSORB II, ABSORB China, ABSORB Japan, ABSORB III, and ABSORB Extend). Outcomes through 3 years (and between 0 to 1 and 1 to 3 years) were assessed according to pre-specified definitions of optimal technique (pre-dilation, vessel sizing, and post-dilation). Multivariable analysis was used to adjust for differences in up to 18 patient and lesion characteristics.

RESULTS

Optimal pre-dilation (balloon to core laboratory-derived reference vessel diameter ratio ≥1:1), vessel size selection (reference vessel diameter ≥2.25 mm and ≤3.75 mm), and post-dilation (with a noncompliant balloon at ≥18 atm and larger than the nominal scaffold diameter, but not by >0.5 mm larger) in all BVS-treated lesions were performed in 59.2%, 81.6%, and 12.4% of patients, respectively. BVS implantation in properly sized vessels was an independent predictor of freedom from TLF through 1 year (hazard ratio [HR]: 0.67; p = 0.01) and through 3 years (HR: 0.72; p = 0.01), and of freedom from ScT through 1 year (HR: 0.36; p = 0.004). Aggressive pre-dilation was an independent predictor of freedom from ScT between 1 and 3 years (HR: 0.44; p = 0.03), and optimal post-dilation was an independent predictor of freedom from TLF between 1 and 3 years (HR: 0.55; p = 0.05).

CONCLUSIONS

In the present large-scale analysis from the major ABSORB studies, after multivariable adjustment for baseline patient and lesion characteristics, vessel sizing and operator technique were strongly associated with BVS-related outcomes during 3-year follow-up. (ABSORB II Randomized Controlled Trial [ABSORB II]; NCT01425281; ABSORB III Randomized Controlled Trial [RCT] [ABSORB-III]; NCT01751906; A Clinical Evaluation of Absorb Bioresorbable Vascular Scaffold [Absorb BVS] System in Chinese Population-ABSORB CHINA Randomized Controlled Trial [RCT] [ABSORB CHINA]; NCT01923740; ABSORB EXTEND Clinical Investigation [ABSORB EXTEND]; NCT01023789; AVJ-301 Clinical Trial: A Clinical Evaluation of AVJ-301 [Absorb BVS] in Japanese Population [ABSORB JAPAN]; NCT01844284).

Arterial Remodeling After Bioresorbable Scaffolds and Metallic Stents

BACKGROUND

Although previous observational studies have documented late luminal enlargement and expansive remodeling following implantation of a bioresorbable vascular scaffold (BVS), no comparison with metallic stents has been conducted in a randomized fashion.

OBJECTIVES

This study sought to compare vessel remodeling patterns after either Absorb BVS or Xience metallic drug-eluting stent (DES) implantation (Abbott Vascular, Santa Clara, California) and determine the independent predictors of remodeling.

METHODS

In the ABSORB II randomized trial, 383 lesions (n = 359) were investigated by intravenous ultrasound both post-procedure and at 3-year follow-up. According to vessel and lumen area changes over 3 years, we categorized 9 patterns of vessel remodeling that were beyond the reproducibility of lumen and vessel area measurements.

RESULTS

The relative change in mean vessel area was significantly greater with the BVS compared to the DES (6.7 ± 12.6% vs. 2.9 ± 11.5%; p = 0.003); the relative change in mean lumen area was significantly different between the 2 arms (1.4 ± 19.1% vs. -1.9 ± 10.5%, respectively; p = 0.031). Multivariate analysis indicated that use of the BVS, female sex, balloon-artery ratio >1.25, expansion index ≥0.8, previous percutaneous coronary intervention, and higher level of low-density lipoprotein cholesterol were independent predictors of expansive remodeling. Furthermore, in the BVS arm, necrotic core pre-procedure was an independent determinant of expansive remodeling.

CONCLUSIONS

Expansive vessel wall remodeling was more frequent and intense with the BVS than the metallic DES and could be determined by patient baseline characteristics and periprocedural factors. The clinical effect of the observed lumen and vessel remodeling must be investigated in further large clinical studies to optimize the clinical outcome of patients and lesions treated by bioresorbable scaffolds. (ABSORB II Randomized Controlled Trial; NCT01425281).

Applicability and procedural success rate of bioresorbable -vascular scaffolds for percutaneous coronary intervention in an all-comer cohort of 383 consecutive patients

Objectives The purpose of this study was to determine applicability and procedural success of bioresorbable vascular scaffolds (BVS) for percutaneous coronary intervention (PCI) in an all-comer cohort. Background BVS use in bifurcations and severely calcified lesions is not recommended, and a relatively large crossing profile may cause limitations. It is has never been studied how widely BVS can be applied in all-comer cohorts. Methods In 383 consecutive patients (acute coronary syndrome: 124, stable coronary disease 259), a BVS (Absorb) was used as first-line device unless any of the following contraindications were present: bifurcation with side branch >2.0 mm, reference diameter <2.5 mm or >4.0 mm, required device length <12 mm, in-stent stenosis, or contraindications to 6 months of DAPT. Patients and lesions were evaluated regarding suitability for BVS treatment, procedural success (successful BVS placement and residual stenosis <30%), and outcome. Results Of 588 lesions, 303 (52%) were unsuitable for BVS placement due to presence of a bifurcation (30% of unsuitable lesions), reference -diameter >4.0 mm (13%) or <2.5 mm (12%), contraindication to 6 months DAPT (13%), in-stent stenosis (14%), and desired device length <12 mm (4%). If BVS use was attempted, procedural success with a scaffold was 95% (271/285). Crossing failure occurred in 14 cases (5%), affected lesions were significantly more calcified. After a mean follow-up period of 259 days, definite/probable scaffold thrombosis occurred in 1.1% of patients. Conclusions Approximately one-half of lesions in an all-comer population can successfully be treated with BVS. Crossing failure is rare.

Randomised comparison of a bioresorbable everolimus-eluting scaffold with a metallic everolimus-eluting stent for ischaemic heart disease caused by de novo native coronary artery lesions: the 2-year clinical outcomes of the ABSORB II trial

AIMS

The one-year randomised data of the ABSORB II trial showed that the everolimus-eluting bioresorbable scaffold and the everolimus-eluting metallic stent were comparable for the composite secondary clinical outcomes of patient-oriented composite endpoint (PoCE) and device-oriented composite endpoint (DoCE)/target lesion failure (TLF), MACE and TVF. This report describes the two-year clinical outcomes of the ABSORB II trial.

METHODS AND RESULTS

Patients were randomly assigned in a 2:1 ratio to receive treatment with an everolimus-eluting bioresorbable scaffold (Absorb; Abbott Vascular, Santa Clara, CA, USA) or treatment with an everolimus-eluting metallic stent (XIENCE; Abbott Vascular). The trial enrolled 501 patients. Clinical follow-up at two years was available in 320 patients in the Absorb BVS arm and 160 patients in the XIENCE arm. At two years, the PoCE for the Absorb and XIENCE arms was 11.6% and 12.8% (p=0.70) and the DoCE/TLF was 7.0% and 3.0% (p=0.07), respectively. The hierarchical ID-MACE rate was 7.6% vs. 4.3% (p=0.16) and the rate of TVF was 8.5% vs. 6.7% (p=0.48). The definite/probable thrombosis rate was 1.5% in the Absorb arm vs. 0% in the XIENCE arm (p=0.17). Thirty-six percent and 34% of patients remained on DAPT at two years, respectively. Ninety-two percent of patients in both arms remained on aspirin.

CONCLUSIONS

Two-year clinical results demonstrate sustained low rates of PoCE, MACE, DoCE and TVF with the Absorb BVS as compared to the XIENCE stent.

Diagnostic Accuracy of Coronary CT Angiography for the Evaluation of Bioresorbable Vascular Scaffolds

OBJECTIVES

The purpose of this study was to assess the diagnostic accuracy of coronary computed tomography angiography (CTA) for bioresorbable vascular scaffold (BVS) evaluation.

BACKGROUND

Coronary CTA has emerged as a noninvasive method to evaluate patients with suspected or established coronary artery disease. The diagnostic accuracy of coronary CTA to evaluate angiographic outcomes after BVS implantation has not been well established.

METHODS

In the ABSORB II (A Bioresorbable Everolimus-Eluting Scaffold Versus a Metallic Everolimus-Eluting Stent II) study, patients were randomized either to receive treatment with the BVS or everolimus-eluting metallic stent. At the 3-year follow-up, 238 patients (258 lesions) treated with BVS underwent coronary angiography with intravascular ultrasound (IVUS) evaluation and coronary CTA. The diagnostic accuracy of coronary CTA was assessed by the area under the receiver-operating characteristic curve with coronary angiography and IVUS as references.

RESULTS

The mean difference in coronary CTA-derived minimal luminal diameter was -0.14 mm (limits of agreement -0.88 to 0.60) with quantitative coronary angiography as reference, whereas the mean difference in minimal lumen area was 0.73 mm² (limits of agreement -1.85 to 3.30) with IVUS as reference. The per-scaffold diagnostic accuracy of coronary CTA for detecting stenosis based on coronary angiography diameter stenosis of ≥50% revealed an area under the receiver-operating characteristic curve of 0.88 (95% confidence interval [CI]: 0.82 to 0.92) with a sensitivity of 80% (95% CI: 28% to 99%) and a specificity of 100% (95% CI: 98% to 100%), whereas diagnostic accuracy based on IVUS minimal lumen area ≤2.5 mm² showed an area under the receiver-operating characteristic curve of 0.83 (95% CI: 0.77 to 0.88) with a sensitivity of 71% (95% CI: 44% to 90%) and a specificity of 82% (95% CI: 75% to 87%). The diagnostic accuracy of coronary CTA was similar to coronary angiography in its ability to identify patients with a significant lesion based on the IVUS criteria (p = 0.75).

CONCLUSIONS

Coronary CTA has good diagnostic accuracy to detect in-scaffold luminal obstruction and to assess luminal dimensions after BVS implantation. Coronary angiography and coronary CTA yielded similar diagnostic accuracy to identify the presence and severity of obstructive disease. Coronary CTA might become the method of choice for the evaluation of patients treated with BVS.

Bioresorbable Scaffolds: Clinical Outcomes and Considerations

Bioresorbable scaffolds (BRS) have been engineered to eliminate the theoretic stimulus to late coronary events, a caveat of conventional metallic drug-eluting stents (DESs). Outcome benefits of BRSs over current-generation DESs are expected to accrue after complete bioresorption. Before this timeframe, BRSs need to prove at least similarly safe and effective compared with DESs. Several randomized studies of the Absorb BRS have been made available. Several manufacturers are at the beginning of their line of clinical development of competing BRSs. This article reviews the contemporary clinical outcomes of the Absorb scaffold, and provides an updated state of the art on the other players in the BRS arena.

First experience of drug-coated balloons for treatment of bioresorbable vascular scaffold restenosis

OBJECTIVES

The aim of this study is to evaluate the role of drug-coated balloons (DCB) for the management of bioresorbable vascular scaffold (BVS) restenosis.

METHODS AND RESULTS

In a series of 25 BVS restenosis discovered during systematic angiographic follow up of 246 consecutive BVS implantations at our institution, DCB was used as a primary therapeutic tool in 9 patients and 3 different types of DCB were used. Follow-up coronary angiography at 12months after DCB treatment was performed to all the patients. Among the 9 patients treated with DCB, angiographic follow up revealed failure in two patients that experienced type III restenosis (both of them treated with the same type of DCB). Both patients were treated with drug eluting stent implantation.

CONCLUSIONS

In this case series of consecutive patients with BVS restenosis, the use of certain types of DCB is safe and effective in order to maintain vessel patency at mid-term follow up. Despite the small sample size and the study limitations, DCB can provide therefore an alternative treatment option in this setting, avoiding the implantation of further metallic stents in a patient where a different strategy was initially planned.

Follow-up of coronary artery patency after implantation of bioresorbable coronary scaffolds: The emerging role of magnetic coronary artery imaging

Bioresorbable vascular scaffolds (BVSs) represent the newest tool in the treatment of coronary artery disease (CAD). Conversely to the previous metal stents and thanks to the polylactate-based backbone, BVSs could be visualized by magnetic resonance imaging (MRI) without artifacts. These properties allow a potential non-invasive assessment of coronary artery patency after percutaneous coronary intervention (PCI), avoiding cardiac catheterization included iodine contrast and radiation exposure, and potentially more sophisticated imaging tool as the optical coherence tomography (OCT). We reviewed the available medical literature on the coronary MRI evaluation of BVS after PCI, also discussing its potential diagnostic role in the long-term follow-up of these patients.

Bioresorbable coronary stent for the treatment of complex coronary lesions: Data from an all-comer registry

BACKGROUND

The study aimed to report the results from an all-comers registry of patients undergoing coronary angioplasty and treated with bioresorbable vascular scaffold (BVS).

METHODS

Fifty-five consecutive patients with type B/C coronary lesions according to the AHA classification and treated with BVS were enrolled in the study. The clinical and procedural characteristics of enrolled patients were recorded. Fifty-five consecutive subjects with coronary lesions type B/C treated with everolimus eluting stent (EES) were used as control group.

RESULTS

The incidence of adverse events was not statistically significant comparing subjects treated with BVS with those treated with EES. Non significant differences were also found in the follow-up considering the presence of diabetes, multivessel disease, use of more than one stent at the same time, diagnosis (STEMI vs UA/NSTEMI), use of coronary stents in overlapping. The differences were significant considering the type of lesion (Log-Rank p<0.05), stenoses treated in correspondence of a coronary bifurcation (p<0.05), the SYNTAX score (cut off 22) (p<0.001); after multivariable correction for age and gender, however, differences remained significant only for SYNTAX score.

CONCLUSIONS

The use of BVS in an all-comers registry of patients undergoing coronary angioplasty on complex coronary lesions is associated with a safety profile comparable to that obtained with EES; the use of BVS in particular conditions, such as very high SYNTAX score, should be further assessed.

Comparative assessment of "plaque/media" change on three modalities of IVUS immediately after implantation of either everolimus-eluting bioresorbable vascular scaffold or everolimus-eluting metallic stent in Absorb II study

The purpose of the study to assess the comparability of immediate changes in plaque/media volume (PV) on three modalities of intravascular ultrasound (IVUS) after implantation of either bioresorbable vascular scaffold (BVS) or everolimus-eluting metallic stent (EES) in Absorb II Study. The two devices have different device volume and ultrasound backscattering that may interfere with the “plaque/media” assessed by three modalities on IVUS: grayscale, backscattering of radiofrequency and brightness function. In a multicenter randomized controlled trial, 501 patients with stable or unstable angina underwent documentary IVUS pre- and post- implantation. The change in plaque/media volume (PV) was categorized into three groups according to the relative PV change in device segment: PV “increased” >+5% (PVI), PV unchanged ±5% (PVU), and PV decreased <−5% (PVD). The change in PV was re-evaluated three times: after subtraction of theoretical device volume, after analysis of echogenicity based on brightness function. In 449 patients, 483 lesions were analyzed pre- and post-implantation. “PVI” was more frequently observed in BVS (53.8%) than EES group (39.4%), p = 0.006. After subtraction of the theoretical device volume, the frequency of “PVI” decreased in both BVS (36.2%) and EES (32.1%) groups and became comparable (p = 0.581). In addition, the percentage of “PVI” was further reduced in both device groups after correction for either radiofrequency backscattering (BVS 34.4% vs. EES 22.6%) or echogenicity (BVS 25.2% vs. EES 9.7%). PV change in device segment was differently affected by BVS and EES devices implantation due to their differences in device volume and ultrasound backscattering. It implies that the lumen volume was also artifactually affected by the type of device implanted. Comparative IVUS assessment of lumen and plaque/media volume changes following implantation of BVS and EES requires specific methodological adjustment.

Comparison of an everolimus-eluting bioresorbable scaffold with an everolimus-eluting metallic stent for the treatment of coronary artery stenosis (ABSORB II): a 3 year, randomised, controlled, single-blind, multicentre clinical trial

BACKGROUND

No medium-term data are available on the random comparison between everolimus-eluting bioresorbable vascular scaffolds and everolimus-eluting metallic stents. The study aims to demonstrate two mechanistic properties of the bioresorbable scaffold: increase in luminal dimensions as a result of recovered vasomotion of the scaffolded vessel.

METHODS

The ABSORB II trial is a prospective, randomised, active-controlled, single-blind, parallel two-group, multicentre clinical trial. We enrolled eligible patients aged 18-85 years with evidence of myocardial ischaemia and one or two de-novo native lesions in different epicardial vessels. We randomly assigned patients (2:1) to receive treatment with an everolimus-eluting bioresorbable scaffold (Absorb; Abbott Vascular, Santa Clara, CA, USA) or treatment with an everolimus-eluting metallic stent (Xience; Abbott Vascular, Santa Clara, CA, USA). Randomisation was stratified by diabetes status and number of planned target lesions. At 3 year follow-up, the primary endpoint was superiority of the Absorb bioresorbable scaffold versus the Xience metallic stent in angiographic vasomotor reactivity after administration of intracoronary nitrate. The co-primary endpoint is the non-inferiority of angiographic late luminal loss. For the endpoint of vasomotion, the comparison was tested using a two-sided t test. For the endpoint of late luminal loss, non-inferiority was tested using a one-sided asymptotic test, against a non-inferiority margin of 0·14 mm. The trial is registered at ClinicalTrials.gov, number NCT01425281.

FINDINGS

Between Nov 28, 2011, and June 4, 2013, we enrolled 501 patients and randomly assigned them to the Absorb group (335 patients, 364 lesions) or the Xience group (166 patients, 182 lesions). The vasomotor reactivity at 3 years was not statistically different (Absorb group 0·047 mm [SD 0·109] vs Xience group 0·056 mm [0·117]; p_superiority=0·49), whereas the late luminal loss was larger in the Absorb group than in the Xience group (0·37 mm [0·45] vs 0·25 mm [0·25]; p_{non-inferiority}=0·78). This difference in luminal dimension was confirmed by intravascular ultrasound assessment of the minimum lumen area (4·32 mm² [SD 1·48] vs 5·38 mm² [1·51]; p<0·0001). The secondary endpoints of patient-oriented composite endpoint, Seattle Angina Questionnaire score, and exercise testing were not statistically different in both groups. However, a device-oriented composite endpoint was significantly different between the Absorb group and the Xience group (10% vs 5%, hazard ratio 2·17 [95% CI 1·01-4·70]; log-rank test p=0·0425), mainly driven by target vessel myocardial infarction (6% vs 1%; p=0·0108), including peri-procedural myocardial infarction (4% vs 1%; p=0·16).

INTERPRETATION

The trial did not meet its co-primary endpoints of superior vasomotor reactivity and non-inferior late luminal loss for the Absorb bioresorbable scaffold with respect to the metallic stent, which was found to have significantly lower late luminal loss than the Absorb scaffold. A higher rate of device-oriented composite endpoint due to target vessel myocardial infarction, including peri-procedural myocardial infarction, was observed in the Absorb group. The patient-oriented composite endpoint, anginal status, and exercise testing, were not statistically different between both devices at 3 years. Future studies should investigate the clinical impact of accurate intravascular imaging in sizing the device and in optimising the scaffold implantation. The benefit and need for prolonged dual antiplatelet therapy after bioresorbable scaffold implantation could also become a topic for future clinical research.

FUNDING

Abbott Vascular.

Complex bifurcation lesions: Randomized comparison of a fully bioresorbable modified t stenting strategy versus bifurcation reconstruction with a dedicated self-expanding stent in combination with bioresorbable scaffolds, an OCT study: Rationale and design of the COBRA II trial

OBJECTIVE

There is an ongoing controversy regarding the efficacy and safety of different percutaneous stenting techniques for coronary bifurcation lesions needing >1 stent. The promise of safe vessel restoration with bioresorbable scaffolds (BRS) may not be transferable to complex double BRS bifurcation techniques, and permanent metallic scaffolding of the bifurcation core may be needed. We identified modified-T stenting as the most promising fully bioresorbable 2-stent strategy in a preclinical setting. The objective of this study is to assess acute performance and compare long-term vessel healing with this strategy, versus an approach combining BRS with a dedicated metallic drug-eluting bifurcation stent.

STUDY DESIGN

In a single center, 60 consecutive patients with true and complex coronary bifurcation lesions will be randomly assigned to treatment with the dedicated self-expanding Axxess^™ biolimus-eluting bifurcation stent in the proximal main vessel and additional Absorb^™ everolimus-eluting BRS in the branches versus a modified T technique using Absorb^™ only. Angiography and optical coherence tomography (OCT) will be performed immediately after implantation and at 30 months, and clinical follow-up is foreseen up to 5 years after implantation. The primary endpoint is the change in minimal luminal area assessed with OCT from baseline to 30 months in pre-specified bifurcation segments.

CONCLUSION

To date the use of Absorb^™ BRS in complex coronary bifurcations has not been evaluated in a randomized clinical trial setting. The COBRA II study will examine the role and safety of a double BRS strategy in coronary bifurcations, alone or in combination with a metallic dedicated bifurcation device. © 2016 Wiley Periodicals, Inc.

Use of bioresorbable vascular scaffold: a meta-analysis of patients with coronary artery disease

BACKGROUND

Differences in outcomes between bioresorbable vascular scaffold (BVS) systems and drug-eluting metal stents (DES) have not been fully evaluated. We aimed to compare clinical and angiographic outcomes in randomised studies of patients with coronary artery disease (CAD), with a secondary analysis performed among registry studies.

METHODS

A meta-analysis comparing outcomes between BVS and DES in patients with CAD. Overall estimates of treatment effect were calculated with random-effects model and fixed-effects model.

RESULTS

In 6 randomised trials (3818 patients), BVS increased the risk of subacute stent thrombosis (ST) over and above DES (OR 2.14; CI 1.01 to 4.53; p=0.05), with a trend towards an increase in the risk of myocardial infarction (MI) (125 events in those assigned to BVS and 50 to DES; OR 1.36; CI 0.97 to 1.91; p=0.07). The risk of in-device late lumen loss (LLL) was higher with BVS than DES (mean difference 0.08 mm; CI 0.03 to 0.13; p=0.004). There was no difference in the risk of death or target vessel revascularisation (TVR) between the two devices. In 6 registry studies (1845 patients), there was no difference in the risk of death, MI, TVR or subacute ST between the two stents. Final BVS dilation pressures were higher in registry than in randomised studies (18.7±4.6 vs 15.2±3.3 atm; p<0.001).

CONCLUSIONS

Patients treated with BVS had an increased risk of subacute ST and slightly higher LLL compared with those with DES, but this might be related to inadequate implantation techniques, in particular device underexpansion.

Bioresorbable scaffolds in daily clinical routine: a practical review of all-comers results

PURPOSE OF REVIEW

Bioresorbable scaffolds (BRS) are a major advancement in interventional cardiology, but experience with BRS use in daily routine is currently limited. Here, we review technical features of commercially available BRS and place them in context with current clinical scientific evidence.

RECENT FINDINGS

Everolimus and novolimus-eluting poly-L-lactic acid (PLLA)-based BRS are commercially available in Europe. The everolimus-eluting BRS is the most widely investigated BRS and several all-comers investigations with this device are ongoing. Of the patients in these studies, 37-100% underwent catheterization due to acute coronary syndrome and up to 25% were diabetic. Up to 64.7% of all lesions treated were considered to be complex. Follow-up varied between 30 days and 1 year. The target lesion revascularization rate was up to 10% and scaffold thrombosis was 0-3%.

SUMMARY

Accumulating data on BRS application are now available. Several studies have demonstrated that BRS implantation is technically feasible in a variety of different patient subsets and clinical presentations, and follow-up results support BRS use. Patients with acute coronary syndrome represent the most investigated subpopulation, and results suggest that BRS use for this indication is reasonable.

Two-year clinical outcomes of Absorb bioresorbable vascular scaffold implantation in complex coronary artery disease patients stratified by SYNTAX score and ABSORB II study enrolment criteria

AIMS

This study presents the two-year clinical outcomes of the Amsterdam ABSORB registry stratified by lesion and patient characteristics complexity (SYNTAX score and ABSORB II study enrolment criteria).

METHODS AND RESULTS

Patients treated with BVS were included in this prospective registry and stratified according to the ABSORB II trial inclusion and exclusion criteria and the SYNTAX score. The registry comprises 135 patients (59±11 years, 73% male, 18% diabetic) with 159 lesions. Median follow-up duration was 774 days (742-829). Median SYNTAX score was 11.5 (Q1-Q3: 6-17.5). Two-year event rates were cardiac death 0.7%, MI 5.3%, TVR 13.6%, TLR 11.4%, definite ST 3.0% and TVF 14.4%, respectively. Stratified analyses showed a significantly higher revascularisation rate in patients not meeting ABSORB II criteria (TVR: 2.3% vs. 19.2%, p=0.010, and TLR: 2.3% vs. 15.8%, p=0.025) and patients with SYNTAX score ≥11.5 (TVR: 4.8% vs. 21.8%, p=0.006, and TLR: 3.2% vs. 17.4%, p=0.007).

CONCLUSIONS

The use of Absorb BVS in patients meeting the ABSORB II trial inclusion criteria or those with low SYNTAX scores is associated with acceptable clinical outcomes at two-year follow-up. Patients with more complex characteristics have significantly higher revascularisation rates.

Outcomes of DES in Diabetic and Nondiabetic Patients with Complex Coronary Artery Disease after Risk Stratification by the SYNTAX Score

Diabetes mellitus (DM) increases the risk of adverse outcomes after coronary revascularization. Controversy persists regarding the optimal revascularization strategy for diabetic patients with multivessel coronary artery disease (MVD).

Design Principles of Bioresorbable Polymeric Scaffolds

The concept for a bioresorbable vascular scaffold combines the best features of the first 3 generations of percutaneous coronary intervention (namely), balloon angioplasty, bare metallic stents, and drug-eluting stents, into a single device. The principles of operation of a BRS follow 3 phases of functionality that reflect the different physiologic requirements over time; revascularization, restoration, and resorption. Most BRS designs make use of the continuum of hydrolytic degradation in aliphatic polyesters, such as poly(l-lactide), in which molecular weight, strength, and mass decrease progressively in 3 distinct stages, consistent with the in vivo requirements of each performance phase.

Percutaneous coronary intervention with everolimus-eluting bioresorbable vascular scaffolds in routine clinical practice: early and midterm outcomes from the European multicentre GHOST-EU registry

AIMS

Clinical data on the early and midterm outcomes of bioresorbable vascular scaffolds (BVS) in routine clinical practice are limited. To fill this gap, we report on the early and midterm clinical outcomes of PCI with everolimus-eluting BVS from the large multicentre GHOST-EU registry.

METHODS AND RESULTS

Between November 2011 and January 2014, 1,189 patients underwent percutaneous coronary intervention with one or more BVS (Absorb BVS; Abbott Vascular, Santa Clara, CA, USA) at 10 European centres. The primary outcome of interest was target lesion failure (TLF), defined as the combination of cardiac death, target vessel myocardial infarction, or clinically driven target lesion revascularisation (TLR). A total of 1,731 Absorb BVS were implanted at a mean of 12.3±3.4 atm. Technical success was achieved in 99.7% of cases. TLF was recorded in 67 of 1,189 patients at a median of 109 (interquartile range 8-227) days after implantation. The cumulative incidence of TLF was 2.2% at 30 days and 4.4% at six months. The annualised rate of TLF was 10.1%. At six months, the rate of cardiac death was 1.0%, target vessel myocardial infarction was 2.0%, TLR was 2.5%, and target vessel revascularisation was 4.0%. Diabetes mellitus was the only independent predictor of TLF (hazard ratio 2.41, 95% confidence interval: 1.28-4.53; p=0.006). The cumulative incidence of definite/probable scaffold thrombosis was 1.5% at 30 days and 2.1% at six months, with 16 of 23 cases occurring within 30 days.

CONCLUSIONS

"Real-world" outcomes of BVS showed acceptable rates of TLF at six months, although the rates of early and midterm scaffold thrombosis, mostly clustered within 30 days, were not negligible.

Drug-eluting stents: the past, present, and future

Since the advent of percutaneous coronary intervention, enormous advances have been made in the treatment of coronary artery disease. Angioplasty and bare metal stents were plagued by high rates of restenosis leading to repeat revascularization procedures. Examination of the underlying pathophysiology of restenosis led to the development of drug-eluting stents to reduce neointimal hyperplasia. However, as restenosis rates declined, length of dual antiplatelet therapy use and risk of long-term stent thrombosis associated with drug-eluting stents increased. Subsequent generations have improved each facet of stent design. Novel alloys maintain durability and reduce strut thickness to increase deliverability, biocompatible polymers decrease the inflammatory response and improve drug elution kinetics, and new generations of drugs predictably inhibit restenosis. Developments on the horizon include stents with bioabsorbable polymers and platforms. The purpose of this review is to assess the evolution of stent design and the evidence behind each generation and to peer into the future of stent technology.

The Safety and Efficacy of Absorb Bioresorbable Vascular Scaffold: A Systematic Review

Bioresorbable stents are novel devices designed to overcome the long-term limitations of permanent stent implantation. The Absorb bioresorbable vascular scaffold (BVS; Abbott Vascular, Santa Clara, CA) was the first bioresorbable stent with Conformité Européenne mark approval in coronary vessels and has been the subject of multiple clinical studies. Despite its potential advantages, the safety and efficacy of BVS remain unclear. To address this, we conducted a systematic review to examine the safety and efficacy of BVS. The MEDLINE, Embase, Current Index to Nursing & Allied Health Literature (CINAHL), Cochrane, and Science Citation Index Expanded (SCIE) databases were searched for studies examining BVS safety and efficacy. Our search was restricted to studies published in English or French. Outcomes of interest include cardiac death, myocardial infarction, target-lesion revascularization, restenosis, and composite endpoints. Eleven studies met our inclusion criteria (n = 2990), which included 1 randomized controlled trial and 10 cohort studies (2 controlled). These studies varied in size (11-1189) and follow-up duration (1-60 months). The incidence of major adverse cardiac events ranged from 2.6% to 15.5%, with no statistically significant difference between BVS and control in studies that included a comparison group. Although available data are limited, current evidence is promising and suggests that the use of BVS is not associated with a significant increase in major cardiac events in the short term. Numerous randomized controlled trials are currently in progress that will further improve our understanding of the safety and efficacy of this device.

Short-term outcomes in patients with acute coronary syndrome treated with direct bioresorbable scaffold deployment

BACKGROUND

Direct coronary stenting is a validated therapeutic option for coronary lesions. We studied the feasibility of direct deployment with a bioresorbable vascular scaffold (BVS) in acute coronary syndrome (ACS).

METHODS

Demographic, procedural, and survival data were obtained for patients who had direct scaffold deployment with BVS from 1 May 2013 to 1 April 2014.

RESULTS

We performed a retrospective review of nine patients which included eight patients having ST-elevation myocardial infarction. There were no cases of worsening coronary flow, scaffold thrombosis, target lesion revascularization or death up to 30 days post intervention.

CONCLUSION

Direct BVS deployment in ACS appears safe and feasible.