Delayed arterial healing and increased late stent thrombosis at culprit sites after drug-eluting stent placement for acute myocardial infarction patients: an autopsy study

Five-year follow-up of polymer-free sirolimus- and probucol-eluting stents versus new generation zotarolimus-eluting stents in patients presenting with st-elevation myocardial infarction

BACKGROUND

Patients with ST-segment elevation myocardial infarction (STEMI) undergoing drug-eluting stent (DES) implantation are at increased risk of late adverse events, partly explained by an exaggerated inflammatory reaction to durable-polymer stent coatings.

OBJECTIVES

We sought to investigate whether implantation of polymer-free DES would reduce this risk.

METHODS

In the ISAR-TEST 5 (the Intracoronary Stenting and Angiographic Results: Test Efficacy of Sirolimus- and Probucol- and Zotarolimus-Eluting Stents) trial, patients were randomly allocated to receive a polymer-free sirolimus- and probucol-eluting stent or a new generation durable-polymer zotarolimus-eluting stent. We analyzed late clinical outcomes in the subgroup of patients presenting with STEMI. The primary endpoint was the combined incidence of cardiac death, target vessel-related myocardial infarction or target lesion revascularization at 5 years.

RESULTS

311 patients with STEMI were randomized to receive sirolimus- and probucol-eluting stents (n = 215) or zotarolimus-eluting stents (n = 96). At 5 years, there was no difference in the incidence of the primary endpoint in patients treated with sirolimus- and probucol-eluting stents versus zotarolimus-eluting stents (18.3% versus 20.1% respectively, hazard ratio = 0.87, 95% CI, 0.50-1.51; P = 0.62). Rates of the individual components of the primary endpoint were also comparable in both groups. The incidence of definite/probable stent thrombosis was 1.4% versus 1.0% respectively (hazard ratio = 1.35, 95% CI, 0.14-12.94, P = 0.80).

CONCLUSIONS

Long-term outcomes of patients with STEMI treated with polymer-free sirolimus- and probucol-eluting stents versus durable-polymer zotarolimus-eluting stents were similar. Stent thrombosis rates were low and comparable in both treatment groups, with no events beyond 12 months.

CLINICAL TRIAL REGISTRATION

Registered at ClinicalTrials.gov (Identifier NCT 00598533) © 2016 Wiley Periodicals, Inc.

Optical Coherence Tomography Findings in Bioresorbable Vascular Scaffolds Thrombosis

BACKGROUND

Everolimus-eluting bioresorbable vascular scaffolds have been developed to improve late outcomes after coronary interventions. However, recent registries raised concerns regarding an increased incidence of scaffold thrombosis (ScT). The mechanism of ScT remains unknown.

METHODS AND RESULTS

The present study investigated angiographic and optical coherence tomography findings in patients experiencing ScT. Fifteen ScT (14 patients, 79% male, age 59±10 years) occurred at a median of 16 days (25%-75% interquartile range: 1-263 days) after implantation. Early ScT (<30 days) occurred in 8 cases (53%). Possible causal factors in these patients included insufficient platelet inhibition in 2 cases and procedural factors (scaffold underexpansion, undersizing, or geographical miss) in 4 cases. No obvious cause could be found in 2 early ScT. In late (>1 month) and very late (>1 year) ScT (respectively, 5 and 2 cases), 5 scaffolds showed intimal neovessels or marked peristrut low-intensity areas. Scaffold fractures were additionally found in 2 patients, and scaffold collapse was found in 1 patient with very late ScT. Extensive strut malapposition was the presumed cause for ScT in 1 case. One scaffold did not show any morphological abnormality. Thrombectomy specimens were analyzed in 3 patients and did not demonstrate increased numbers of inflammatory cells.

CONCLUSIONS

The mechanisms of early ScT seem to be similar to metallic stents (mechanical and inadequate antiplatelet therapy). The predominant finding in late and very late ScT is peristrut low-intensity area.

Pioglitazone Attenuates Drug-Eluting Stent-Induced Proinflammatory State in Patients by Blocking Ubiquitination of PPAR

The inflammatory response after polymer-based drug-eluting stent (DES) placement has recently emerged as a major concern. The biologic roles of peroxisome proliferator-activated receptor-γ (PPAR-γ) activators thiazolidinedione (TZD) remain controversial in cardiovascular disease. Herein, we investigated the antiinflammatory effects of pioglitazone (PIO) on circulating peripheral blood mononuclear cells (MNCs) in patients after coronary DES implantation. Methods and Results. Twenty-eight patients with coronary artery disease and who underwent DES implantations were randomly assigned to pioglitazone (30 mg/d; PIO) or placebo (control; Con) treatment in addition to optimal standard therapy. After 12 weeks of treatment, plasma concentrations of high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and matrix metalloproteinase-9 (MMP-9) were significantly decreased in PIO group compared to the Con group (P = 0.035, 0.011, 0.008, and 0.012, resp.). DES-induced mRNA expressions of IL-6, TNF-α, and MMP-9 in circulating MNC were significantly blocked by PIO (P = 0.031, 0.012, and 0.007, resp.). In addition, PIO markedly inhibited DES-enhanced NF-κB function and DES-blocked PPAR-γ activity. Mechanically, DES induced PPAR-γ ubiquitination and degradation in protein level, which can be totally reversed by PIO. Conclusion. PIO treatment attenuated DES-induced PPAR loss, NF-κB activation, and proinflammation, indicating that PIO may have a novel direct protective role in modulating proinflammation in DES era.

Comparative Efficacy and Safety of Everolimus-Eluting Bioresorbable Scaffold Versus Everolimus-Eluting Metallic Stents: A Systematic Review and Meta-analysis

BACKGROUND

Theoretically, the everolimus-eluting bioresorbable vascular scaffold (BVS) could eliminate stent thrombosis and improve outcomes in patients having percutaneous coronary intervention.

PURPOSE

To estimate the incidence of stent thrombosis after BVS implantation and to compare the efficacy and safety of BVSs versus everolimus-eluting metallic stents (EESs) in adults having percutaneous coronary intervention.

DATA SOURCES

PubMed, EMBASE, Cochrane Central Register of Controlled Trials, conference proceedings, and relevant Web sites from inception through 20 January 2016.

STUDY SELECTION

6 randomized, controlled trials and 38 observational studies, each involving at least 40 patients with BVS implantation.

DATA EXTRACTION

Two reviewers independently extracted study data and evaluated study risk of bias.

DATA SYNTHESIS

The pooled incidence of definite or probable stent thrombosis after BVS implantation was 1.5 events per 100 patient-years (PYs) (95% CI, 1.2 to 2.0 events per 100 PYs) (126 events during 8508 PYs). Six randomized trials that directly compared BVSs with EESs showed a non-statistically significant increased risk for stent thrombosis (odds ratio [OR], 2.05 [CI, 0.95 to 4.43]; P = 0.067) and myocardial infarction (OR, 1.38 [CI, 0.98 to 1.95]; P = 0.064) with BVSs. The 6 observational studies that compared BVSs with EESs showed increased risk for stent thrombosis (OR, 2.32 [CI, 1.06 to 5.07]; P = 0.035) and myocardial infarction (OR, 2.09 [CI, 1.23 to 3.55]; P = 0.007) with BVSs. The relative rates of all-cause and cardiac death, revascularization, and target lesion failure were similar for BVSs and EESs.

LIMITATION

Scarce comparative data, no published data from large trials with long-term follow-up, and limited quality and incomplete reporting of observational studies.

CONCLUSION

Compared with EESs, BVSs do not eliminate and might increase risks for stent thrombosis and myocardial infarction in adults having percutaneous coronary intervention. Results of large trials with long-term follow-up are critically needed to establish the safety or at least the noninferiority of BVSs compared with EESs.

PRIMARY FUNDING SOURCE

None.

Optical Coherence Tomography Guided Percutaneous Coronary Intervention With Nobori Stent Implantation in Patients With Non-ST-Segment-Elevation Myocardial Infarction (OCTACS) Trial: Difference in Strut Coverage and Dynamic Malapposition Patterns at 6 Months

BACKGROUND

Incomplete strut coverage has been documented an important histopathologic morphometric predictor for later thrombotic events. This study sought to investigate whether optical coherence tomography (OCT)-guided percutaneous coronary intervention with Nobori biolimus-eluting stent implantation in patients with non-ST-segment-elevation myocardial infarction would provide improved strut coverage at 6 months in comparison with angiographic guidance only.

METHODS AND RESULTS

One hundred patients were randomized 1:1 to either OCT-guided or angio-guided Nobori biolimus-eluting stent implantation. Postprocedure OCT was performed in all patients. In the OCT-guided group, prespecified criteria indicating additional intervention were related to (1) stent underexpansion, (2) strut malapposition, (3) edge dissection(s), and (4) residual stenosis at the distal or proximal reference segment(s). A final OCT was performed in case of reintervention. Six-month OCT follow-up was available in 85 patients. Twenty-three (46%) OCT-guided patients had additional postdilation or stenting. The percentage of acutely malapposed struts was substantially lower in the OCT-guided group (3.4% [interquartile range, 0.3-7.6] versus 7.8% [interquartile range, 2.3-19.4]; P<0.01). At 6-month follow-up, the OCT-guided group had a significantly lower proportion of uncovered struts; 4.3% [interquartile range, 1.2-9.8] versus 9.0% [interquartile range, 5.5-14.5], P<0.01. Furthermore, OCT-guided patients had significantly more completely covered stents: 17.5% versus 2.2%, P=0.02. The percentages of malapposed struts and struts being both uncovered and malapposed at follow-up were comparable between groups.

CONCLUSIONS

OCT-guided optimization of Nobori biolimus-eluting stent implantation improves strut coverage at 6-month follow-up in comparison with angiographic guidance alone.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02272283.

Are BVS suitable for ACS patients? Support from a large single center real live registry

OBJECTIVES

To investigate one-year outcomes after implantation of a bioresorbable vascular scaffold (BVS) in patients presenting with acute coronary syndrome (ACS) compared to stable angina patients.

BACKGROUND

Robust data on the outcome of BVS in the setting of ACS is still scarce.

METHODS

Two investigator initiated, single-center, single-arm BVS registries have been pooled for the purpose of this study, namely the BVS Expand and BVS STEMI registries.

RESULTS

From September 2012-October 2014, 351 patients with a total of 428 lesions were enrolled. 255 (72.6%) were ACS patients and 99 (27.4%) presented with stable angina/silent ischemia. Mean number of scaffold/patient was 1.55±0.91 in ACS group versus 1.91±1.11 in non-ACS group (P=0.11). Pre- and post-dilatation were performed less frequent in ACS patients, 75.7% and 41.3% versus 89.0% and 62.0% respectively (P=0.05 and P=0.001). Interestingly, post-procedural acute lumen gain and percentage diameter stenosis were superior in ACS patients, 1.62±0.65mm (versus 1.22±0.49mm, P<0.001) and 15.51±8.47% (versus 18.46±9.54%, P=0.04). Major adverse cardiac events (MACE) rate at 12months was 5.5% in the ACS group (versus 5.3% in stable group, P=0.90). One-year definite scaffold thrombosis rate was comparable: 2.0% for ACS population versus 2.1% for stable population (P=0.94), however, early scaffold thromboses occurred only in ACS patients.

CONCLUSIONS

One-year clinical outcomes in ACS patients treated with BVS were similar to non-ACS patients. Acute angiographic outcomes were better in ACS than in non-ACS, yet the early thrombotic events require attention and further research.

Stenting for ST-segment elevation myocardial infarction is associated with less neointimal hyperplasia in the pooled IVUS analysis from HORIZONS-AMI and the TAXUS IV and V and ATLAS workhorse, long lesion, and direct stent studies

OBJECTIVE

To investigate the difference in neointimal hyperplasia (NIH) between ST-segment elevation myocardial infarction (STEMI), stable angina pectoris (SAP), and unstable angina pectoris (UAP).

PATIENTS AND METHODS

From formal core laboratory intravascular ultrasound substudies, we compared NIH after paclitaxel-eluting stents (PES) or bare metal stents (BMS) in STEMI lesions from HORIZONS-AMI trial with SAP and UAP lesions from TAXUS IV, V, and ATLAS studies.

RESULTS

At follow-up, %NIH at the minimum lumen area (MLA) site was less in STEMI (n=212) than in UAP (n=233) and SAP (n=440) lesions treated with PES (19.6 vs. 26.2 vs. 25.0%, P=0.002; all intravascular ultrasound data shown as least-square means in abstract) and less in STEMI (n=66) than in UAP (n=72) and SAP (n=143) lesions treated with BMS (34.0 vs. 26.7 vs. 45.5%, P=0.0003). As a result, MLA at follow-up was larger in STEMI than in UAP and SAP lesions treated with PES (5.9 vs. 5.2 vs. 5.0 mm, P<0.0001) or treated with BMS (5.1 vs. 4.3 vs. 4.0 mm, P=0.002). Net volume obstruction ([NIH/stent volume]×100) at follow-up was significantly less in STEMI than in UAP and SAP lesions treated with PES (7.8 vs. 13.4 vs. 13.4%, P<0.0001) or BMS (20.6 vs. 28.5 vs. 32.1%, P<0.0001). Multivariate linear regression analysis showed that STEMI was correlated independently and inversely with net volume obstruction compared with SAP (regression coefficient -6.99, P<0.0001) or UAP (regression coefficient -6.29, P<0.0001).

CONCLUSION

Implantation of PES or BMS in STEMI compared with UAP and SAP was associated with less NIH.

Effect of stents coated with a combination of sirolimus and alpha-lipoic acid in a porcine coronary restenosis model

The aim of this study was to evaluate antiproliferative sirolimus- and antioxidative alpha-lipoic acid (ALA)-eluting stents using biodegradable polymer [poly-L-lactic acid (PLA)] in a porcine coronary overstretch restenosis model. Forty coronary arteries of 20 pigs were randomized into four groups in which the coronary arteries had a bare metal stent (BMS, n = 10), ALA-eluting stent with PLA (AES, n = 10), sirolimus-eluting stent with PLA (SES, n = 10), or sirolimus- and ALA-eluting stent with PLA (SAS, n = 10). A histopathological analysis was performed 28 days after the stenting. The ALA and sirolimus released slowly over 30 days. There were no significant differences between groups in the injury or inflammation score; however, there were significant differences in the percent area of stenosis (56.2 ± 11.78% in BMS vs. 51.5 ± 12.20% in AES vs. 34.7 ± 7.23% in SES vs. 28.7 ± 7.30% in SAS, P < 0.0001) and fibrin score [1.0 (range 1.0-1.0) in BMS vs. 1.0 (range 1.0-1.0) in AES vs. 2.0 (range 2.0-2.0) in SES vs. 2.0 (range 2.0-2.0) in SAS, P < 0.0001] between the four groups. The percent area of stenosis based on micro-computed tomography corresponded with the restenosis rates based on histopathological stenosis in different proportions in the four groups (54.8 ± 7.88% in BMS vs. 50.4 ± 14.87% in AES vs. 34.5 ± 7.22% in SES vs. 28.9 ± 7.22% in SAS, P < 0.05). SAS showed a better neointimal inhibitory effect than BMS, AES, and SES at 1 month after stenting in a porcine coronary restenosis model. Therefore, SAS with PLA can be a useful drug combination for coronary stent coating to suppress neointimal hyperplasia.

Two-Year Safety and Efficacy of Biodegradable Polymer Drug-Eluting Stent Versus Second-Generation Durable Polymer Drug-Eluting Stent in Patients With Acute Myocardial Infarction: Data from the Korea Acute Myocardial Infarction Registry (KAMIR)

BACKGROUND

Despite improved long-term safety of biodegradable polymer (BP) drug-eluting stents (DES) compared to first-generation durable polymer (DP) DES, data on the safety and efficacy of BP-DES compared with second-generation (2G) DP-DES in patients with acute myocardial infarction (AMI) are limited.

HYPOTHESIS

To evaluate the safety and efficacy of BP-DES compared with 2G-DP-DES in the higher stent thrombosis (ST) risk setting of AMI.

METHODS

A total of 3359 AMI patients who received either BP-DES (n = 261) or 2G-DP-DES (n = 3098) were included from the Korea Acute Myocardial Infarction Registry (KAMIR). Differences in baseline clinical and angiographic characteristics were adjusted using a 1:5 propensity score matching analysis (n = 261 for BP-DES and n = 1305 for 2G-DP-DES). The primary outcome was the incidence of major adverse cardiac events (MACE) including all-cause death, recurrent myocardial infarction (re-MI), and target vessel revascularization (TVR). The rate of definite or probable ST was also investigated.

RESULTS

In adjusted analysis, there was no significant difference between the 2 groups in baseline clinical and angiographic characteristics; 2-year MACE (10.7% and 9.9% in the BP-DES group and 2G-DP-DES group, respectively, P = 0.679); ST incidence (0.8% vs 0.9%, respectively, P = 1.0), and rates of all-cause death, re-MI, and TVR. By multivariate analysis, old age, diabetes mellitus, renal dysfunction, and left ventricular dysfunction were the independent predictors of MACE after BP-DES or 2G-DP-DES implantation.

CONCLUSIONS

BP-DES and 2G-DP-DES appear to have comparable 2-year safety and efficacy for the treatment of AMI. However, longer-term follow-up is needed.

1-year outcomes with the Absorb bioresorbable scaffold in patients with coronary artery disease: a patient-level, pooled meta-analysis

BACKGROUND

Compared with metallic drug-eluting stents, bioresorbable vascular scaffolds (BVS) offer the potential to improve long-term outcomes of percutaneous coronary intervention. Whether or not these devices are as safe and effective as drug-eluting stents within the first year after implantation is unknown.

METHODS

We did a patient-level, pooled meta-analysis of four randomised trials in which 3389 patients with stable coronary artery disease or a stabilised acute coronary syndrome were enrolled at 301 academic and medical centres in North America, Europe, and the Asia-Pacific region. These patients were randomly assigned to the everolimus-eluting Absorb BVS (n=2164) or the Xience cobalt-chromium everolimus-eluting stent (CoCr-EES; n=1225). The primary endpoints were the 1-year relative rates of the patient-oriented composite endpoint (all-cause mortality, all myocardial infarction, or all revascularisation) and the device-oriented composite endpoint of target lesion failure (cardiac mortality, target vessel-related myocardial infarction, or ischaemia-driven target lesion revascularisation). All analyses were by intention to treat. The four randomised trials included in our meta-analysis are all registered with ClinicalTrials.gov, numbers NCT01751906, NCT01844284, NCT01923740, and NCT01425281.

FINDINGS

The summary treatment effect for the 1-year relative rates of the patient-oriented composite endpoint did not differ significantly different between BVS and CoCr-EES (relative risk [RR] 1·09 [0·89-1·34], p=0·38). Similarly, the 1-year relative rates of the device-oriented composite endpoint did not differ between the groups (RR 1·22 [95% CI 0·91-1·64], p=0·17). Target vessel-related myocardial infarction was increased with BVS compared with CoCr-EES (RR 1·45 [95% CI 1·02-2·07], p=0·04), due in part to non-significant increases in peri-procedural myocardial infarction and device thrombosis with BVS (RR 2·09 [0·92-4·75], p=0·08). The relative rates of all-cause and cardiac mortality, all myocardial infarction, ischaemia-driven target lesion revascularisation, and all revascularisation did not differ between BVS and CoCr-EES. Results were similar after multivariable adjustment for baseline imbalances, and were consistent across most subgroups and in sensitivity analysis when two additional randomised trials with less than 1 year of follow-up were included.

INTERPRETATION

In this meta-analysis, BVS did not lead to different rates of composite patient-oriented and device-oriented adverse events at 1-year follow-up compared with CoCr-EES.

FUNDING

Abbott Vascular.

The melding of nanomedicine in thrombosis imaging and treatment: a review

Thromboembolic diseases constitute a plague in our century, wherein an imbalance of hemostasis leads to thrombus formation and vessels constriction reducing blood flow. Hence, the recent rise of nanomedicine gives birth to advanced diagnostic modalities and therapeutic agents for the early diagnosis and treatment of such diseases. Multimodal nanoagents for the detection of intravascular thrombi and nanovehicles for thrombus-targeted fibrinolytic therapy are few paradigms of nanomedicine approaches to overcome current diagnostic treatment roadblocks and persistent clinical needs. This review highlights the nanomedicine strategies to improve the imaging and therapy of acute thrombi by nanoparticles and nanotheranostics, the detailed imaging of thrombogenic proteins and platelets via atomic force microscopy with the knowledge basis of thrombosis pathophysiology and nanotoxicity.

Lay abstract: The present review highlights the perspectives of nanomedicine in enhancing the diagnostic and therapeutic strategies to deal with thrombosis. The basics in thrombosis are highlighted to provide the reader with better comprehension of the application of nanotools and various multimodal nanocarriers for diagnosis, targeted therapy and monitoring of the disease. The visualization and treatment of acute thrombi using multifunctional nanoparticles and nanotheranostics, along with the structural investigation of the blood-clotting proteins exploiting the atomic force microscopy capabilities are comprehensively described. At the same time, toxicity and biocompatibility issues regarding nanoparticles are discussed.

An update on the clinical use of drug-coated balloons in percutaneous coronary interventions

INTRODUCTION

Drug-coated balloons (DCB) promise to deliver anti-proliferative drugs and prevent restenosis leaving nothing behind. Although, randomized clinical trials have demonstrated their efficacy for the treatment of in-stent restenosis, clinical evidence supporting their use in other coronary applications is still lacking.

AREAS COVERED

This review summarizes the development status of clinically available DCB technologies and provides an update on the current data for their coronary use.

EXPERT OPINION

Current generation DCB prevent restenosis by delivering paclitaxel particles on the surface of the vessel wall. Although clinically available technologies share a common mechanism of action, important differences in pharmacokinetic behavior and safety profiles do exist. Future technological improvements include the development of coatings displaying: high transfer efficiency; low particle embolization potential; and alternative drug formulations. Optimized balloon-based delivery systems and drug encapsulation technologies also promise to improve the technical limitations of current generation DCB. Although proving clinical superiority against DES may prove to be difficult in mainstream applications (i.e., de novo), new generation DCB technologies have the potential to achieve a strong position in the interventional field in clinical settings in which the efficacy of DES use is not proven or justified (i.e., bifurcations).

Long-term outcomes of biodegradable versus durable polymer drug-eluting stents in patients with acute ST-segment elevation myocardial infarction: a pooled analysis of individual patient data from three randomised trials

AIMS

Arterial plaque rupture and thrombus characterise ST-elevation myocardial infarction (STEMI) and may aggravate delayed arterial healing following durable polymer drug-eluting stent (DP-DES) implantation. Biodegradable polymer (BP) may improve biocompatibility. We compared long-term outcomes in STEMI patients receiving BP-DES vs. durable polymer sirolimus-eluting stents (DP-SES).

METHODS AND RESULTS

We pooled individual patient-level data from three randomised clinical trials (ISAR-TEST-3, ISAR-TEST-4 and LEADERS) comparing outcomes from BP-DES with DP-SES at four years. The primary endpoint (MACE) comprised cardiac death, MI, or target lesion revascularisation (TLR). Secondary endpoints were TLR, cardiac death or MI, and definite or probable stent thrombosis. Of 497 patients with STEMI, 291 received BP-DES and 206 DP-SES. At four years, MACE was significantly reduced following treatment with BP-DES (hazard ratio [HR] 0.59, 95% CI: 0.39-0.90; p=0.01) driven by reduced TLR (HR 0.54, 95% CI: 0.30-0.98; p=0.04). Trends towards reduction were seen for cardiac death or MI (HR 0.63, 95% CI: 0.37-1.05; p=0.07) and definite or probable stent thrombosis (3.6% vs. 7.1%; HR 0.49, 95% CI: 0.22-1.11; p=0.09).

CONCLUSIONS

In STEMI, BP-DES demonstrated superior clinical outcomes to DP-SES at four years. Trends towards reduced cardiac death or myocardial infarction and reduced stent thrombosis require corroboration in specifically powered trials.

Clinical outcomes in patients with ST-segment elevation myocardial infarction treated with everolimus-eluting stents versus bare-metal stents (EXAMINATION): 5-year results of a randomised trial

BACKGROUND

Data for the safety and efficacy of new-generation drug-eluting stents at long-term follow-up, and specifically in patients with ST-segment elevation myocardial infarction, are scarce. In the EXAMINATION trial, we compared everolimus-eluting stents (EES) with bare-metal stents (BMS) in an all-comer population with ST-segment elevation myocardial infarction. In this study, we assessed the 5-year outcomes of the population in the EXAMINATION trial.

METHODS

In the multicentre EXAMINATION trial, done in Italy, Spain, and the Netherlands, patients with ST-segment elevation myocardial infarction were randomly assigned in a 1:1 ratio to receive EES or BMS. The random allocation schedule was computer-generated and central randomisation (by telephone) was used to allocate patients in blocks of four or six, stratified by centre. Patients were masked to treatment assignment. At 5 years, we assessed the combined patient-oriented outcome of all-cause death, any myocardial infarction, or any revascularisation. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00828087.

FINDINGS

1498 patients were randomly assigned to receive either EES (n=751) or BMS (n=747). At 5 years, complete clinical follow-up data were obtained for 731 patients treated with EES and 727 treated with BMS (97% of both groups). The patient-oriented endpoint occurred in 159 (21%) patients in the EES group versus 192 (26%) in the BMS group (hazard ratio 0·80, 95% CI 0·65-0·98; p=0·033). This difference was mainly driven by a reduced rate of all-cause mortality (65 [9%] vs 88 [12%]; 0·72, 0·52-0·10; p=0·047).

INTERPRETATION

Our findings should be taken as a point of reference for the assessment of new bioresorbable polymer-based metallic stents or bioresorbable scaffolds in patients with ST-segment elevation myocardial infarction.

FUNDING

Spanish Heart Foundation.

Everolimus-eluting bioresorbable stent vs. durable polymer everolimus-eluting metallic stent in patients with ST-segment elevation myocardial infarction: results of the randomized ABSORB ST-segment elevation myocardial infarction-TROFI II trial

AIMS

Patients with ST-segment elevation myocardial infarction (STEMI) feature thrombus-rich lesions with large necrotic core, which are usually associated with delayed arterial healing and impaired stent-related outcomes. The use of bioresorbable vascular scaffolds (Absorb) has the potential to overcome these limitations owing to restoration of native vessel lumen and physiology at long term. The purpose of this randomized trial was to compare the arterial healing response at short term, as a surrogate for safety and efficacy, between the Absorb and the metallic everolimus-eluting stent (EES) in patients with STEMI.

METHODS AND RESULTS

ABSORB-STEMI TROFI II was a multicentre, single-blind, non-inferiority, randomized controlled trial. Patients with STEMI who underwent primary percutaneous coronary intervention were randomly allocated 1:1 to treatment with the Absorb or EES. The primary endpoint was the 6-month optical frequency domain imaging healing score (HS) based on the presence of uncovered and/or malapposed stent struts and intraluminal filling defects. Main secondary endpoint included the device-oriented composite endpoint (DOCE) according to the Academic Research Consortium definition. Between 06 January 2014 and 21 September 2014, 191 patients (Absorb [n = 95] or EES [n = 96]; mean age 58.6 years old; 17.8% females) were enrolled at eight centres. At 6 months, HS was lower in the Absorb arm when compared with EES arm [1.74 (2.39) vs. 2.80 (4.44); difference (90% CI) -1.06 (-1.96, -0.16); Pnon-inferiority < 0.001]. Device-oriented composite endpoint was also comparably low between groups (1.1% Absorb vs. 0% EES). One case of definite subacute stent thrombosis occurred in the Absorb arm (1.1% vs. 0% EES; P = ns).

CONCLUSION

Stenting of culprit lesions with Absorb in the setting of STEMI resulted in a nearly complete arterial healing which was comparable with that of metallic EES at 6 months. These findings provide the basis for further exploration in clinically oriented outcome trials.

Vascular Response to Experimental Stent Malapposition and Under-Expansion

Up to 80% of all endovascular stents have malapposed struts, and while some impose catastrophic events others are inconsequential. Thirteen stents were implanted in coronary arteries of seven healthy Yorkshire pigs, using specially-designed cuffed balloons inducing controlled stent malapposition and under-expansion. Optical coherence tomography (OCT) imaging confirmed that 25% of struts were malapposed (strut-wall distance <strut thickness) to variable extent (max. strut-wall distance malapposed group 0.51 ± 0.05 mm vs. apposed group 0.09 ± 0.05 mm, p = 2e-3). Imaging at follow-up revealed malapposition acutely resolved (<1% of struts remained malapposed at day 5), with strong correlation between lumen and the stent cross-sectional areas (slope = 0.86, p < 0.0001, R (2) = 0.94). OCT in three of the most significantly malapposed vessels at baseline showed high correlation of elastic lamina area and lumen area (R (2) = 0.96) suggesting all lumen loss was related to contraction of elastic lamina with negligible plaque/intimal hyperplasia growth. Simulation showed this vascular recoil could be partially explained by the non-uniform strain environment created from sub-optimal expansion of device and balloon, and the inability of stent support in the malapposed region to resist recoil. Malapposition as a result of stent under-expansion is resolved acutely in healthy normal arteries, suggesting existing animal models are limited in replicating clinically observed persistent stent malapposition.

Everolimus-Eluting Stents Reduce Monocyte Expression of Toll-Like Receptor 4

PURPOSE

Toll-like receptors (TLR) are well known components of the innate immune system. Among them, TLR4 is related to the inflammatory processes involved in atherosclerotic plaque formation. Our purpose was to compare the monocytic expression of TLR4 following implantation of drug-eluting (DES) and bare stents (BMS).

METHODS

In this study, patients with chronic stable angina undergoing elective percutaneous coronary intervention (PCI) in ShahidMadani Heart Hospital, Tabriz, Iran were included. Ninety-five patients receiving DES and 95 patients receiving BMS were selected between 2012 and 2014.Everolimus eluting stents were implanted for DES group. Both groups received similar medications and procedure. Blood samples were taken before PCI, 2 hours and 4 hours after termination of PCI. Expression of TLR4 on monocytes was measured using flowcytometry. Patients were matched for age, sex and coronary artery disease risk factors, but not for TLR4 expression rate before PCI.

RESULTS

A significant difference was seen between DES and BMS in TLR4 expression before (21.3±2.8% vs. 15.5±2.7%; P< 0.05) and four hours after PCI (30.1 ± 3.3% vs 39.2 ± 3.2%, P< 0.05). Due to the unmatched rate of TLR4+ expression before PCI, we measured the percentage of increase in TLR4 expression between groups. DES compared to BMS significantlycaused less increase in the TLR4 expression (50.23%±10.03% vs. 446.35%±70.58%, p<0.001).

CONCLUSION

Our findings suggest thateverolimuseluted from the stents can decrease PCI induced increase in the TLR4 expression on the surface of monocytes.

Very Late Stent Thrombosis 11 Years after Implantation of a Drug-Eluting Stent

Very late stent thrombosis is an infrequent yet potentially fatal complication associated with drug-eluting stents. We report the case of an 88-year-old man who sustained an ST-segment-elevation myocardial infarction 11 years after initial sirolimus-eluting stent implantation. Optical coherence tomograms of the lesion showed that the focal incomplete endothelialization of the stent struts was the likely cause; neointimal formation, neoatherosclerosis, and late stent malapposition might also have contributed. To our knowledge, this is the longest reported intervening period between stent insertion and the development of an acute coronary event secondary to very late stent thrombosis. The associated prognostic and therapeutic implications are considerable, because they illuminate the uncertainties surrounding the optimal duration of antiplatelet therapy in patients who have drug-eluting stents. Clinicians face challenges in treating these patients, particularly when competing medical demands necessitate the discontinuation of antiplatelet therapy. In addition to the patient's case, we discuss factors that can contribute to very late stent thrombosis.

Safety and efficacy of the Yukon Choice Flex sirolimus-eluting coronary stent in an all-comers population cohort

AIMS

The use of biodegradable-polymer drug-eluting stents has been shown to provide favorable results when compared with durable polymer drug-eluting stents and long-term follow up data have recently shown significant reductions in terms of very late stent thrombosis. Aim of the present study was to assess the safety and efficacy profile of a novel biodegradable polymer DES, the Yukon Choice Flex sirolimus-eluting stent.

METHODS

We report here the one-year clinical outcomes associated with the use of the Yukon Choice Flex sirolimus-eluting stent in an all-comers patient population. The present stent represents a further refinement of the stent platform tested in the ISAR TEST 3 and 4 randomized clinical trials. A total of 778 consecutive patients undergoing implantation of this stent were enrolled in the present observational study and prospectively followed for one year.

RESULTS

The use of the Yukon Choice Flex stent in a patient population with complex coronary lesion morphology was associated with optimal immediate angiographic results. At one year follow up the rates of death, myocardial infarction, definite stent thrombosis and ischemia-driven target lesion revascularization were respectively 2.4%, 1.9%, 0.3% and 11.3%.

CONCLUSIONS

The use of the sirolimus-eluting biodegradable polymer Yukon Choice Flex stent in an all-comers population of patients with complex coronary artery disease is associated with a favorable safety and efficacy profile up to one year follow up.

Preclinical evaluation of a novel abluminal surface coated sirolimus eluting stent with biodegradable polymer matrix

BACKGROUND

Second generation of drug eluting stents (DES) has attempted to improve safety using abluminal sirolimus drug delivery with biodegradable polymers matrix. The present preclinical study was designed to investigate the safety and efficacy profile of Abluminus™ stents (SES). This is a new coronary stent with sirolimus and biodegradable polymer matrix coated on abluminal stent and balloon surface.

METHODS

SES were compared with two controls: bare metal stent (BMS) and BMS + polymer coated stents (PC). All devices (40 stents) were implanted in porcine coronary arteries with primary endpoint of endothelialization at 7 days and subsequent histological and morphometric evaluations at 7, 30 and 90 days.

RESULTS

Early endothelialization at seven days was complete in all stents. Histology at 30 days revealed minimum inflammation in all groups and increased at 90 days in PC group while it was absent at 180 days. Thirty day morphometry showed significantly reduction of neointimal area in Abluminus™ (SES 0.96±0.48 mm(2); BMS 1.83±0.34 mm(2); PC 1.76±0.55 mm(2); P<0.05); after 90 days neointimal area was 1.10±0.54 mm(2) for SES; 1.92±0.36 mm(2) for BMS; and 1.94±0.48 mm(2) for PC; P<0.05). Neointimal thickness at 30 and 90 days respectively was 0.15±0.07 and 0.18±0.10 mm for SES, 0.57±0.08 and 0.61±0.09 mm for BMS and 0.52±0.09 and 0.59±0.08 mm, P<0.001 for PC group.

CONCLUSIONS

The most significant experimental evidence appears to be earlier endothelialization at 7 days for SES which led to safety of the device. Efficacy of the device was also observed by a reduced neointimal thickness and minimized inflammatory score at all follow-ups. Termination of antiplatelet at 30 days has not shown any further complications. Polymer thickness was almost in negligible amount at 180 days with no inflammation.

Four-year clinical follow-up of the first-in-man randomized comparison of a novel sirolimus eluting stent with abluminal biodegradable polymer and ultra-thin strut cobalt-chromium alloy: the INSPIRON-I trial

BACKGROUND

The Inspiron™ sirolimus-eluting stent (SES) is a low-dose, ultra-thin-strut cobalt-chromium stent abluminally coated with biodegradable polymers (BP). Previous results from the INSPIRON-I trial, a first-in-man study, have proven the efficacy of the novel stent in reducing neointimal proliferation. The present report aims at evaluating the long-term clinical outcomes of patients enrolled into the INSPIRON-I trial (Clinical Trials Gov. identifier: NCT01093391).

METHODS

A total of 57 patients (60 lesions) were randomly allocated in a 2:1 ratio to treatment with the Inspiron™ SES vs. its equivalent Cronus™ bare metal stent (BMS, both by Scitech Medical™, Aparecida de Goiânia, Goiás, Brazil), in four tertiary centers. The primary endpoint of the present analysis was the occurrence of major adverse cardiac events (MACE) [death, myocardial infarction (MI), target vessel revascularization (TVR) and/or target lesion revascularization (TLR)] at 4 years.

RESULTS

Baseline clinical and angiographic characteristics of both groups were similar. After 4 years, the primary endpoint occurred in 7.9% vs. 23.5% of patients in Inspiron and control groups respectively (P=0.11). The rate of death/MI was similar between the groups, but there was a significant decrease in the risk of repeat revascularization in the Inspiron group compared to the control arm TLR (0.0% vs. 23.5% respectively, P=0.02). There were no stent thromboses in the study population.

CONCLUSIONS

The novel Inspiron™ SES showed a sustained safe and effective clinical profile after 4-year of follow-up, with very low adverse events and null stent thrombosis (ST) occurrence.

Percutaneous Coronary Intervention Planning and Optimization with Optical Coherence Tomography

Coronary angiography confirms or excludes coronary artery disease, assesses lesions severity, and helps to decide percutaneous coronary interventions (PCI). Coronary angiography has clear limitations. Intravascular imaging guides PCI. Frequency domain optical coherence tomography (OCT) gained attention for accurate planning and guidance of complex PCI. High-speed OCT image acquisition enables prompt vessel assessment in stable and unstable patients. The high-resolution images provide precise tissue characterization and a reliable quantitative assessment of the coronary pathology. Immediately after stent implantation, OCT allows accurate evaluation of stent expansion and symmetry. Real-time angio-OCT co-registration integrates OCT into the PCI workflow for accurate decision making.

Early Phase Arterial Reaction Following Drug-Eluting and Bare-Metal Stent Implantation in Patients With ST-Segment Elevation Myocardial Infarction

The early phase arterial reaction after implantation of second-generation drug-eluting stents (2nd DES) and baremetal stents (BMS) in patients with ST-segment elevation myocardial infarction (STEMI) remains unclear.The MECHANISM pilot study is a multi-center prospective registry that enrolled 24 STEMI patients (from 11 centers) who had undergone implantation of everolimus-eluting (n = 6), biolimus A9-eluting (n = 6) or zotarolimus-eluting stents (n = 6), or BMS (n = 6). Scheduled optical coherence tomography (OCT) was performed 2 weeks after implantation, and images were independently analyzed at a core laboratory in a blinded fashion. Intra-stent thrombus was quantitatively analyzed in terms of the maximal area and the percentage of cross-sections with thrombus (the numbers of cross-section with thrombus × 100 divided by total number of cross-sections within the stented segment). More than 90% of struts were already covered 2 weeks after the index procedure, regardless of the stent type. There were no differences in stent diameter, minimal lumen diameter, minimal lumen area, neointimal thickness, or the frequencies of malapposed and uncovered struts among the 4 groups. The quantity of intra-stent thrombus also did not differ among the 4 groups.The results of this pilot study suggest that the 2-week vascular responses seem to be similar among 2nd DES and BMS in STEMI patients. Considering the possible advantage of 2nd DES in the prevention of restenosis, 2nd DES are a feasible option for the treatment of patients with STEMI.

Safety and feasibility of a PAclitaxel-eluting balloon angioplasty in Primary Percutaneous coronary intervention in Amsterdam (PAPPA): one-year clinical outcome of a pilot study

AIMS

In primary percutaneous coronary intervention (PPCI), stenting has been shown to reduce the need for repeat target lesion revascularisation (TLR) compared to balloon angioplasty alone, but did not result in a reduction of recurrent myocardial infarction (MI) or cardiac death. Meanwhile, stent-related adverse events such as stent thrombosis continue to be of concern. Our aim was to evaluate the safety and feasibility of drug- coated balloon (DCB) angioplasty without stenting in PPCI.

METHODS AND RESULTS

One hundred patients presenting with ST-elevation MI were prospectively enrolled in this pilot study. They underwent PPCI with DCB angioplasty; additional stenting was allowed only in case of type C to F coronary dissection or residual stenosis >50%. All patients were treated with i.v. bivalirudin. The primary endpoint was the composite of cardiac death, recurrent MI and TLR. A total of 59 patients received treatment with DCB angioplasty alone, whereas additional stenting was required in 41 patients. One-year clinical follow-up was completed in 98 patients. A total of five major adverse cardiac events were reported (5%). Cardiac death was seen in two patients, while three patients underwent TLR.

CONCLUSIONS

This first study of a DCB angioplasty-only strategy in the setting of PPCI showed good one-year clinical results.

Healing arterial ulcers: Endothelial lining regeneration upon vascular denudation injury

Thrombosis and restenosis are the most prevalent late complications of coronary artery stenting. Current standards of clinical care focus on prevention of smooth muscle cell proliferation by the use of drug-eluting stents able to release anti-proliferative drugs. Unfortunately, these drugs also block endothelial cell proliferation and, in this manner, prevent recovery of endothelial cell coverage. Continued lack of endothelial repair leaves the root cause of thrombosis and restenosis unchanged, creating a vicious cycle where drug-mediated prevention of restenosis simultaneously implies promotion of thrombosis. In this issue of Vascular Pharmacology, Hussner and colleagues provide in vitro evidence and a mechanistic basis for the use of atorvastatin in stents as a way to bypass this roadblock. Here we review the pathological mechanisms and therapeutic approaches to restore flow in occluded arteries. We argue that rational design of drug eluting stents should focus on specific inhibition of smooth muscle cell proliferation with concurrent stimulation of endothelial regeneration. We comment on the current poor understanding of the cellular and molecular regulation of endothelial cell proliferation in the context of a functional artery, and on the pitfalls of extrapolating from the well-studied process of neovascularization by sprouting vessel formation.

Resveratrol-Induced Vascular Progenitor Differentiation towards Endothelial Lineage via MiR-21/Akt/β-Catenin Is Protective in Vessel Graft Models

Background and Purpose

Vessel graft failure is typically associated with arteriosclerosis, in which endothelial dysfunction/damage is a key event. Resveratrol has been shown to possess cardioprotective capacity and to reduce atherosclerosis. We aimed to study the influence of resveratrol on the behavior of resident stem cells that may contribute to graft arteriosclerosis.

Experimental Approach

Vascular resident progenitor cells and embryonic stem cells were treated with resveratrol under differentiating conditions and endothelial markers expression was evaluated. Expression of miR-21 and β-catenin was also tested and exogenously modified. Effects of resveratrol treatment in an ex vivo re-endothelialization model and on mice undergone vascular graft were evaluated.

Key Results

Resveratrol induced expression of endothelial markers such as CD31, VE-cadherin and eNOS in both progenitor and stem cells. We demonstrated that resveratrol significantly reduced miR-21 expression, which in turn reduced Akt phosphorylation. This signal cascade diminished the amount of nuclear β-catenin, inducing endothelial marker expression and increasing tube-like formation by progenitor cells. Both the inhibition of miR-21 and the knockdown of β-catenin were able to recapitulate the effect of resveratrol application. Ex vivo, progenitor cells treated with resveratrol produced better endothelialization of the decellularized vessel. Finally, in a mouse model of vessel graft, a resveratrol-enhanced diet was able to reduce lesion formation.

Conclusions and Implications

We provide the first evidence that oral administration of resveratrol can reduce neointimal formation in a model of vascular graft and elucidated the underpinning miR-21/Akt/β-catenin dependent mechanism. These findings may support the beneficial effect of resveratrol supplementation for graft failure prevention.

GPU-accelerated framework for intracoronary optical coherence tomography imaging at the push of a button

Frequency domain optical coherence tomography (FD-OCT) has become one of the important clinical tools for intracoronary imaging to diagnose and monitor coronary artery disease, which has been one of the leading causes of death. To help more accurate diagnosis and monitoring of the disease, many researchers have recently worked on visualization of various coronary microscopic features including stent struts by constructing three-dimensional (3D) volumetric rendering from series of cross-sectional intracoronary FD-OCT images. In this paper, we present the first, to our knowledge, "push-of-a-button" graphics processing unit (GPU)-accelerated framework for intracoronary OCT imaging. Our framework visualizes 3D microstructures of the vessel wall with stent struts from raw binary OCT data acquired by the system digitizer as one seamless process. The framework reports the state-of-the-art performance; from raw OCT data, it takes 4.7 seconds to provide 3D visualization of a 5-cm-long coronary artery (of size 1600 samples x 1024 A-lines x 260 frames) with stent struts and detection of malapposition automatically at the single push of a button.

Dual antiplatelet therapy duration after the placement of a drug-eluting stent: what are the data?

OPINION STATEMENT

The data supporting the immediate use of dual antiplatelet therapy (DAPT) post implantation of drug-eluting stents (DESs) is irrefutable. DAPT in this early period is necessary to prevent stent thrombosis during endothelialization of the stent, a process known to be delayed when DESs are placed. In addition, DAPT helps prevent thrombosis from plaque rupture that occurs outside of the initial stented area and/or at neo-atherosclerotic lesions within a previously coated stent. The ACC/AHA current guidelines (Levine et al. J Am Coll Cardiol. 58(24):e44-122, 2011) recommend 12 months of DAPT post DES implantation. As the result of several randomized clinical trials (Task Force on Myocardial Revascularization of the European Society of Cardio-Thoracic Surgery (EACTS) et al. Eur Heart J. 31(20):2501-55, 2010) showing the safety of a shorter duration of DAPT, the European Heart Society altered their recommendations to 6-12 months of DAPT post DES implantation. However, recent data from the DAPT trial (Mauri et al. N Engl J Med. 371(23):2156-66, 2014) clearly demonstrated less ischemic events with 30 months of DAPT. This trial and others have established that an increased DAPT duration increases bleeding risk which, in turn, increases subsequent morbidity and mortality. The current conundrum lies in defining the optimal time of DAPT post DES to adequately reduce ischemic events while minimizing bleeding risks. Future studies are required to better stratify patients into low and high risk for both ischemic and bleeding risks to assess whether shorter or longer courses of DAPT are the most appropriate for any specific patients. Until then, instead of a "one size fits all" approach to patients who receive DESs, the treating physician must consider both procedural and patient factors when deciding the optimal duration of DAPT for each patient.

Clinical use of optical coherence tomography to identify angiographic silent stent thrombosis

OBJECTIVES

Patients previously treated with coronary stents may suffer an acute coronary syndrome (ACS) without any evidence of thrombus formation on coronary angiography (CAG). This may be due to partial, nonocclusive stent thrombosis with microembolization. In this paper, we illustrate possible mechanisms both with optical coherence tomography (OCT) and histology.

DESIGN

We present two cases with ACS from very late stent thrombosis who have been previously treated with first-generation drug-eluting stents (DES).

RESULTS

The first patient had ACS 15 months after DES implantation. The angiogram (CAG) was near normal with slight peri-stent contrast staining. OCT revealed abnormalities including thrombus not visible on CAG. These are findings that may explain the ACS. The second patient had subclinical episodes with chest pain after DES implantation. The patient died from stent thrombosis in a DES. Postmortem histological examination of the coronary arteries revealed stent struts with little or no neointimal coverage, persistent peri-strut fibrin deposition, inflammatory cells, malapposition, and small luminal platelet-rich thrombi. Old spotty myocardial infarctions were found in the supplied territory possibly caused by earlier episodes of embolizing thrombus.

CONCLUSIONS

In patients with previous implanted DES presenting with ACS, OCT may detect abnormalities and thrombus formation not visible on CAG. Such findings may impact the treatment strategy in these patients.