Stent thrombosis: incidence, predictors and new technologies

Three-Year Clinical Outcomes With the Cilotax Dual Drug-Eluting Stent vs Everolimus-Eluting Stents in Patients With Acute Myocardial Infarction

BACKGROUND

This study compared the safety and effectiveness of paclitaxel/cilostazol-eluting Cilotax stents with those of everolimus-eluting stents in patients with acute myocardial infarction. Real-world data from the Korea Acute Myocardial Infarction Registry were examined.

METHODS

A total of 5,472 patients with acute myocardial infarction underwent percutaneous coronary intervention with Cilotax stents (n = 212) or everolimus-eluting stents (n = 5,260). The primary end point was the 3-year rate of target lesion failure. The other end points were major adverse cardiovascular events (a composite of cardiac death, target vessel myocardial infarction, and ischemia-driven target lesion revascularization), target vessel revascularization, and stent thrombosis. A propensity score matching analysis was performed to adjust for potential confounders by using a logistic regression model; propensity score matching generated 2 well-balanced groups (Cilotax group, n = 180; everolimus-eluting stents group, n = 170; N = 350). After propensity score matching, baseline clinical characteristics were similar between the groups.

RESULTS

After percutaneous coronary intervention, compared with the everolimus-eluting stents group, the Cilotax group more often had major adverse cardiovascular events (24.1% vs 18.5%; P = .042), myocardial infarction (8.0% vs 3.2%; P < .001), target lesion revascularization (8.0% vs 2.6%; P < .001), target vessel revascularization (11.3% vs 4.5%; P < .001), and stent thrombosis (4.7% vs 0.5%; P < .001) before matching. Even after matching, the Cilotax group had more frequent target lesion revascularization (9.4% vs 2.9%; P = .22) and stent thrombosis (5.6% vs 1.2%; P = .34).

CONCLUSION

In patients with acute myocardial infarction who underwent percutaneous coronary intervention, use of the Cilotax stent was associated with higher rates of target lesion revascularization, target vessel revascularization, and stent thrombosis than were everolimus-eluting stents. Use of the Cilotax dual drugeluting stent should be avoided in the treatment of myocardial infarction.

Long-Term Assessment of Thin-Strut BioMime Coronary Stent System in Real-World Population at Single-Center: A Retrospective Observational Study

Background

The short-term clinical outcomes of first-generation thicker-strut durable polymer-based drug-eluting stents (DES) have been widely examined. However, there is a scarcity on qualitative research on the long-term usage of DES that evaluated the thinner strut biodegradable stents for coronary artery disease. Hence, we sought to investigate the long-term safety and performance of thinner strut biodegradable polymer-based BioMime sirolimus-eluting coronary stent system in real-world patients with symptomatic ischemic heart disease.

Methods

This was a retrospective, observational, single-center, post-marketing clinical follow-up study. The primary endpoints were the incidence of major adverse cardiac events (MACE), defined as a composite of cardiac death, myocardial infarction (MI) attributed to target vessel revascularization (TVR), and target lesion revascularization (TLR) at 1-, 2-, 3- and 4-year follow-ups. The secondary endpoints were cardiac death, MI, TLR, TVR, device and procedural success rates, and stent thrombosis (ST).

Results

In all, 1,188 consecutive patients were enrolled, and 1,333 (1,257 de novo and 76 in-stent restenotic lesions) out of 1,565 lesions were treated with the study device. The mean age of patients was 53.26 ± 10.31 years and 86.2% were male. The quantitative coronary angiographic derived mean lesion length and diameter were 29.62 ± 9.62 mm and 3.01 ± 0.29 mm, respectively. The average length and diameter of the study device implanted were 30.89 ± 6.31 mm and 3.17 ± 0.25 mm, respectively. The cumulative incidence of MACE at 1-, 2-, 3-, and 4 years was 0.61%, 1.47%, 2.08%, and 3.40%, respectively, and cumulative deaths due to cardiac causes were 0.61%, 1.13%, 1.22%, and 1.83%, respectively. There were no cases of TLR or TVR at 1-year follow-up. The cumulative rate of TLR at 2-, 3-, and 4 years was 0.35%, 0.87%, and 1.57%, respectively, while that of TVR was 0.61%, 1.47%, and 2.35%, respectively. Three (0.3%) incidences of probable ST occurred during the 6-month follow-up; no new cases were reported further. In subgroup analysis, MACEs were comparable across the long- and short-length stent groups through 4-year follow-up.

Conclusions

This long-term study demonstrates the safety and performance of the ultra-thin BioMime sirolimus-eluting stent with satisfactory clinical outcomes in patients with symptomatic ischemic heart disease in real-world scenario.

Migration of endothelial cells on the surface of anodized Ni-Ti stent strut

Background

Stent is widely regarded as the main treatment for curing cardiovascular diseases such as stenosis. Previous research has revealed that the damage of endothelial cells (EC), i.e., the components of endothelium, during stent implantation, could lead to severe complications, such as restenosis. To prevent restenosis, enhancements have been made to surface biocompatibility to accelerate the stent endothelialization process. Anodization on the Ni-Ti is a simple and efficient surface modification method to improve the biocompatibility of the Ni-Ti stent surfaces by enhancing the surface hydrophilicity, leading to an increase in the EC activities. The EC activity is known to be affected by the blood flow. Flow change by stent structure may result in EC dysfunctions, thereby leading to restenosis. It is thus essential to investigate the EC activities resulting from the anodization on the Ni-Ti surface under flow conditions.

Objective

To study the influence of the endothelialization process on the Ni-Ti stent surface through anodization. The EC attachment and morphology on the anodized stent strut were observed under both with and without the flow conditions.

Method

A parallel plate flow chamber was designed to generate a constant wall shear stress (WSS) to study the flow effect on the EC behavior. The hydrophilicity of the Ni-Ti stent strut surface was enhanced by a TiO2 layer fabricated via anodization. The EC distribution on the surface of the anodized nitinol stent strut was observed after 24 h of static (without flow) and flow exposure (with flow) experiment.

Results

Under the static condition, the EC density on the surface of the anodized Ni-Ti stent strut was higher compared with the control. Under the flow condition, the enhancement of the EC density on the surface of the stent strut with anodization was reduced. The EC demonstrates a long and thin spindle-shaped morphology under the flow condition.

Conclusion

Unlike the static condition, the EC is demonstrating a long and thin morphology in response to the flow under the flow condition. By improving the surface hydrophilicity, the anodization could enhance the EC migration onto the strut surface, and subsequently, accelerate the Ni-Ti stent endothelialization process. The improvement of the surface hydrophilicity is lower under the flow conditions when compared with the static conditions.

Biofunctionalization of cardiovascular stents to induce endothelialization: Implications for in- stent thrombosis in diabetes

Stent thrombosis remains one of the main causes that lead to vascular stent failure in patients undergoing percutaneous coronary intervention (PCI). Type 2 diabetes mellitus is accompanied by endothelial dysfunction and platelet hyperactivity and is associated with suboptimal outcomes following PCI, and an increase in the incidence of late stent thrombosis. Evidence suggests that late stent thrombosis is caused by the delayed and impaired endothelialization of the lumen of the stent. The endothelium has a key role in modulating inflammation and thrombosis and maintaining homeostasis, thus restoring a functional endothelial cell layer is an important target for the prevention of stent thrombosis. Modifications using specific molecules to induce endothelial cell adhesion, proliferation and function can improve stents endothelialization and prevent thrombosis. Blood endothelial progenitor cells (EPCs) represent a potential cell source for the in situ-endothelialization of vascular conduits and stents. We aim in this review to summarize the main biofunctionalization strategies to induce the in-situ endothelialization of coronary artery stents using circulating endothelial stem cells.

Short-term dual antiplatelet therapy in diabetic patients admitted for acute coronary syndrome treated with a new-generation drug-eluting stent

BACKGROUND

The optimal duration of dual antiplatelet therapy (DAPT) in patients with diabetes mellitus (DM) admitted with acute coronary syndrome (ACS) and treated with a drug-eluting stent (DES) remains unclear. This is a prespecified sub-study from the Randomised Evaluation of short-term DUal antiplatelet therapy in patients with acute Coronary syndromE treated with a new generation DES (REDUCE) trial that was designed to determine the efficacy and safety of short-term versus standard 12 months DAPT in diabetic patients with ACS undergoing percutaneous coronary intervention (PCI) using the COMBO stent.

METHODS

In this study we included ACS diabetic patients enroled in the REDUCE trial treated with the COMBO stent and randomly assigned to either 3 or 12 months of DAPT. The primary study endpoint was the composite of all-cause mortality, myocardial infarction (MI), stent thrombosis (ST), stroke, target vessel revascularisation (TVR), and bleeding complications at 12 and 24 months follow-up.

RESULTS

A total of 307 diabetic patients were included, of which 162 (52.8%) in the 3 months DAPT group and 145 (47.2%) in the 12 months DAPT group. Patient characteristics, PCI success, and number of stents used were similar in the 3 and 12 months DAPT groups. Occurrence of the primary study endpoint at 12 and 24 months follow-up was comparable between the two groups (3.1 vs. 3.5%, p = 0.865, and 15.8 vs. 14.9%, p = 0.824, respectively). Moreover, the prevalence of the specific clinical outcome parameters (all-cause mortality), MI, ST, stroke, TVR, and bleeding was similar in both study groups.

CONCLUSIONS

This sub-analysis shows similar clinical outcomes following 3 months DAPT as compared to 12 months DAPT in diabetic patients undergoing PCI for ACS using the COMBO stent. These results suggest that, even in this particular subset of patients, short duration of DAPT might be considered safe. Future larger studies are warranted to provide more precise estimations in terms of safety and efficacy of short term DAPT in these high-risk patients.

Management of Stent Thrombosis Post-Percutaneous Coronary Intervention and Associated Rare Complications

Stent thrombosis is a devastating complication of percutaneous coronary intervention (PCI) associated with significant morbidity and mortality. Progressive technical advancements from balloon angioplasty to bare-metal stent and drug-eluting stent placement have reduced the incidence of stent thrombosis. Definitive management and preventive methods are still negligible. Here, we describe two cases of definite subacute stent thrombosis of the right coronary complicated by pericarditis and very late left anterior descending stent thrombosis after the intervention in the right coronary artery. In both cases, antiplatelet treatment with clopidogrel showed excellent compliance. Therefore, after successful PCI, we switched both cases from clopidogrel to potentially more potent antiplatelet treatment, such as ticagrelor, to reduce the occurrence of stent thrombosis in the future.

Incidence and Predictors of Stent Thrombosis in Patients Treated with Stents for Coronary Bifurcation Narrowing (From the BIFURCAT Registry)

Percutaneous coronary interventions performed at coronary bifurcations yield high rates of stent thrombosis (ST). The aim of the present study was to investigate the predictors of ST in contemporary coronary bifurcation percutaneous coronary interventions. We retrospectively investigated the BIFURCAT (comBined Insights From the Unified RAIN and COBIS bifurcAtion regisTries) registry on coronary bifurcations to assess the incidence and predictors of definite ST, which were the study primary endpoints. Predictors of ST among patients on dual antiplatelet therapy (DAPT) were also examined. A total of 5330 patients were included. After a mean 2-years follow-up, 64 (1.2%) patients experienced ST. 42 (65.6%) ST patients were on DAPT. At multivariable analysis, age (HR 1.02, CI 1.01 to 1.05, p = 0,027), smoking status (HR 2.57, CI 1.49 to 4.44, p = 0.001), chronic kidney disease (HR 2.26, CI 1.24 to 4.12, p = 0.007) and a 2-stent strategy (HR 2.38, CI 1.37 to 4.14, p = 0.002) were independent predictors of ST, whereas intracoronary imaging (HR 0.42, CI 0.23 to 0.78, p = 0.006) and final kissing balloon (FKB) (HR 0.48, CI 0.29 to 0.82, p = 0.007) were protective against ST. Among patients on DAPT, smoking status and a 2-stent strategy significantly increased the risk of ST, while intracoronary imaging and FKB reduced the risk. In conclusion, age, smoking status, chronic kidney disease and a 2-stent strategy were significant predictors of ST, whereas intracoronary imaging use and FKB had a protective effect. Only smoking status and a 2-stent strategy significantly predicted ST in DAPT subgroup, while intracoronary imaging and FKB had a protective role.

Computer Simulation of Platelet Adhesion around Stent Struts in the Presence and Absence of Tissue Defects around Them

Aim

To predict platelet accumulation around stent struts in the presence or absence of tissue defects around them.

Methods

Computer simulations were performed using virtual platelets implementing the function of the three membrane proteins: glycoprotein (GP) Ibα, GPIIb/IIIa, and GPVI. These platelets were perfused around the stent struts implanted into the vessel wall in the presence or absence of tissue defects around them using within the simulation platform. The number of platelets that adhered around stent struts was calculated by solving the blood flow using Navier-Stokes equation along with the adhesion of membrane protein modeled within the platform.

Results

Platelet accumulation around stent struts occurred mostly at the downstream region of the stent strut array. The majority of platelets adhered at the downstream of the first bend regardless of the tissue defect status. Platelet adhesion around stent struts occurred more rapidly in the presence of tissue defects.

Conclusion

Computer simulation using virtual platelets suggested a higher rate of platelet adhesion in the presence of tissue defects around stent struts.

Efficacy and Safety of Dual-Drug-Eluting Stents for de Novo Coronary Lesions in South Korea-The Effect Trial

Background: Drug-eluting stents (DESs) are commonly used in percutaneous coronary intervention (PCI) procedures; however, complications including in-stent restenosis and stent thrombosis are significant challenges. The dual-DES is a stent that elutes two drugs to target various stages of the restenosis reaction. This study investigated the safety and efficacy of dual-DES in clinical practice. Methods: This study included 375 patients who underwent PCI with Cilotax^™ or DXR^™ dual-DESs at one of 13 centers in South Korea. The primary endpoint was target lesion failure (TLF) within 1 year. The secondary endpoints were cardiac death, myocardial infarction (MI), target lesion revascularization (TLR), and stent thrombosis. Results: The rates of TLF in dual-DESs (3.7%) were comparable to those reported in conventional DES. In addition, the DXR^™ group had a significantly lower rate of TLF than the Cilotax^™ group. In multivariate analysis, the DXR^™ group had a lower risk of TLF (adjusted hazard ratio (HR) 0.30, 95% CI 0.09–0.92, p = 0.036) and MI (adjusted HR 0.16, 95% CI 0.03–0.82, p = 0.027) than the Cilotax^™ group. Conclusion: Dual-DESs had similar clinical outcomes regarding efficacy and safety as conventional DES. Among the dual-DES, the DXR^™ stent as a new generation dual-DES had more favorable clinical outcomes than the Cilotax^™ stent.

Validity of the Stent Thrombosis Risk Score in Predicting Early Stent Thrombosis after Primary Percutaneous Coronary Intervention

Background

The thrombosis of the stent is one of the most important complications of percutaneous interventions, resulting in complete occlusion of the stented vessel. Aim of this study was to determine the validity of Stent Thrombosis Risk Score (STRS) in predicting early stent thrombosis (ST) after primary Percutaneous Coronary Intervention (PCI).

Methods

For this study, 569 consecutive patients undergone primary PCI from July 2018 to December 2018 were recruited. Early ST was defined as ST occurred during or within 30 days after the procedure. The STRS was calculated as proposed, developed, and validated in a past study. The receiver operating characteristic curve analysis was performed to determine the optimal cut-off value and area under the curve (AUC).

Results

A total of 569 patients were included, the median age was 56 [61-50] years. Early ST was observed in 33 (5.8%) patients. The median STRS was 4 [5-3] vs. 3 [4-2]; p = 0.009 for patients with and without Early ST respectively. STRS was found to be an independent predictor of early ST with an adjusted odds ratio of 1.41 (1.02-1.95). AUC was 0.631 and the optimal cut-off value was ≥5. Early ST rate was 3.3% at STRS of 0-2, which raised to 5.0% at STR of 3-4, and 17.2% at STRS of ≥5.

Conclusions

In conclusion, STRS was found to be an independent predictor of early ST after primary PCI and has significant discriminating power. The rate of early stent thrombosis after primary PCI exponentially increased at STRS cut-off value of ≥5.

A simple score for the prediction of stent thrombosis in patients with ST elevation myocardial infarction: TIMI risk index

Introduction: The present study aimed to evaluate the potential utility of thrombosis in myocardial infarction (TIMI) risk index (TRI) for the prediction of stent thrombosis (ST) in ST elevation myocardial infarction (STEMI) patients who were treated with primary percutaneous coronary intervention ( pPCI ). Methods: This retrospective study was related to the clinical data of 1275 consecutive STEMI patients who underwent pPCI from January 2013 to January 2018. The TRI was calculated for each patient, and the following equation was used; TRI = heart rate x [age/10]2/systolic blood pressure. For the definition of ST, the criteria as proposed by the Academic Research Consortium were applied. Results: The incidence of ST was 3.2% (n=42 patients) in the study. The median value of the TRI was significantly elevated in patients with ST compared to those without ST (22 [17-32] vs. 16 [11-21], P<0.001, respectively). In a multivariate logistic regression analysis, the TRI was an independent predictor of ST (odds ratio [OR]: 1.061; 95% CI: 1.038-1.085; P<0.001). In a receiver operating characteristic curve analysis, the optimal value of the TRI for the prediction of ST was 25.8 with a sensitivity of 45.2% and a specificity of 86.4%. Conclusion: The present study finding has demonstrated that the TRI may be an independent predictor of ST in STEMI patients who were treated with pPCI . To the best of our knowledge, this is the first study in the literature in which the TRI and its relationship with ST was evaluated in STEMI patients treated with pPCI .

Novel Mechanism of Delayed Coronary Obstruction after Transcatheter Aortic Valve Replacement for Severe Aortic Stenosis: "Uppercut Phenomenon"

Delayed coronary obstruction is a rare complication after transcatheter aortic valve replacement (TAVR), and leads to a high in-hospital mortality rate. Here, we present a case of unpredictable delayed coronary obstruction in the left main trunk (LMT) after self-expandable device implantation because the left coronary height was enough over 15 mm. LMT obstruction was caused by a heavy calcification that was pushing up from the outside of the LMT, like an "uppercut" phenomenon. Stent-in-stent technique was a useful option for this type of LMT obstruction.

Biodegradable polymer versus second-generation durable polymer drug-eluting stents in patients with coronary artery disease: A meta-analysis

AIMS

Biodegradable polymer drug-eluting stents (BP-DES) were developed in hopes of reducing the risk of stent thrombosis. The comparison of this new stent platform with second-generation durable polymer drug-eluting stents (DP-DES) has not been well described. We, therefore, performed a meta-analysis to evaluate the safety and efficacy profiles of BP-DES versus second-generation DP-DES in patients with coronary artery disease.

METHODS AND RESULTS

Electronic database searches were conducted, from their dates of inception to June 2018, to identify randomized controlled trials (RCTs) comparing patients with either BP-DES or second-generation DP-DES. Risk estimates were expressed as risk ratios (RRs) with 95% confidence intervals (CIs). We also performed a landmark analysis beyond 1 year and sensitivity analyses based on different variables. A total of 24,406 patients from 19 RCTs were included in the present meta-analysis. There were no significant differences between BP-DES and second-generation DP-DES for the risks of definite or probable stent thrombosis (RR 0.88; 95% CI, 0.69-1.12; P = 0.29), myocardial infarction (RR 0.97; 95% CI, 0.86-1.09; P = 0.59), cardiac death (RR 1.08; 95% CI, 0.92-1.28; P = 0.34), all-cause death (RR 1.02; 95% CI, 0.91-1.13; P = 0.77), target lesion revascularization (RR 1.05; 95% CI, 0.94-1.17; P = 0.38), and target vessel revascularization (RR 1.05; 95% CI, 0.95-1.16; P = 0.36). Similar outcomes were observed regardless of anti-proliferative drug and duration of dual antiplatelet therapy (all P > 0.05).

CONCLUSION

Our findings demonstrate similar safety and efficacy profiles between BP-DES and second-generation BP-DES, with comparable rates of stent thrombosis.

A novel method of inducing thrombosis in target arteries using coronary stents for therapeutic occlusion

OBJECTIVES

Peripheral artery embolizations are often required for therapeutic purposes. The therapeutic embolizations are usually performed using embolization particles and coils. These procedures are also associated with complications. Coils and their delivery cables, and the expertise are not always available in all catheterization centers. Hence, a novel, simple controlled technique for arterial closure would be useful in emergency settings.

RESULTS

Following is a report of seven cases where embolization was performed successfully on an emergency basis after stenting using coronary stents for better closure of the target artery. Six patients underwent bronchial artery embolization for recurrent massive hemoptysis, and one another patient had pseudoaneurysm following percutaneous nephrolithotomy, and presented with hematuria and persistent and increasing blood discharge in drainage catheter. The stents were deployed in the target artery using 6F Judkin's diagnostic catheter over the 014 wires, which are easily available in all cardiac catheterization laboratories. This is a novel method to establish a metal platform inside the target arteries using coronary stents for better closure of the target arteries in combination with embolization techniques. The procedures were performed as lifesaving measures when small coils and the delivery cables were not available at the time of the procedures.

Endovascular management of pancreatitis-related pseudoaneurysms: A review of techniques

Objectives

To present the various techniques used in the management of pancreatitis-related pseudoaneurysms of visceral vessels.

Methods

The retrospective clinical study was carried out at the Department of Diagnostic and Interventional Radiology at Poznan University of Medical Sciences from 2011 to 2016. The fifteen patients included in the study were diagnosed with pseudoaneurysms of visceral arteries, as a complication of chronic pancreatitis. The diagnosis was made using contrast-enhanced computed tomography, followed by angiography. On admission, all patients were symptomatic, with varying degrees of abdominal pain. One patient was haemodynamically unstable. Treatments with endovascular techniques were analysed, along with their efficacy and outcomes. Coil embolisation was performed in 5 patients. Stent graft was used in 1 patient. Liquid embolic agents were used in 7 cases, of which 5 patients were treated with thrombin injection and 2 with Squid. A combination of techniques was used in 2 patients.

Results

The most common artery affected by pseudoaneurysm formation was the splenic artery (7/15; 46.7%), and the size of the pseudoaneurysms ranged from 27 mm to 85 mm. Primary technical success was achieved in 14 out of 15 patients (93.3%). One patient required reintervention. Two patients required splenectomy after embolisation due to splenic ischemia. No recanalisation was present at the follow-up computed tomography performed after 1 to 3 weeks, and no mortality was observed within 30 days.

Conclusion

Vascular complications of pancreatitis require accurate diagnosis and immediate treatment. Endovascular intervention is highly effective and is the preferred treatment option. The technique used is determined based on vascular anatomy and the patient’s haemodynamic status.

Coronary Bioresorbable Vascular Scaffold Use in the Treatment of Coronary Artery Disease

Bioresorbable vascular scaffolds (BVS) represent a promising novel approach for the treatment of coronary artery disease. BVS promise to address some of the well-known limitations of current drug-eluting stents, while providing a transient scaffolding of the vessel to prevent acute vessel closure/recoil. Drug elution by BVS prevents neointimal proliferation in a similar fashion to drug-eluting stents, and complete bioresorption is associated with late vessel lumen enlargement, plaque regression, and restoration of vasomotion. Based on the pathophysiological reasons and on the results derived from clinical studies, BVS are increasingly being used in clinical practice. The aim of this review is to provide an overview of the current evidence supporting the use of BVS in clinical practice. In particular, we will discuss the randomized controlled trials and registries evaluating the clinical outcome of these devices, with a special focus on their application in patients with acute coronary syndrome and in specific lesion subsets (bifurcations, chronic total occlusions, and in-stent restenosis).

Clopidogrel non-responsiveness in patients undergoing percutaneous coronary intervention using the VerifyNow test: frequency and predictors

Objectives

Stent thrombosis and death after percutaneous coronary intervention (PCI) can be caused by a phenomenon known as clopidogrel non-responsiveness which has been shown to occur in approximately 5%–44% of patients. We investigated the responsiveness of clopidogrel in an Iraqi series of cases. Our aim was to determine for the first time the frequency and predictors of clopidogrel non-responsiveness among Iraqi patients with ischaemic heart disease undergoing PCI.

Methods

The study was conducted at the Cardiac Catheterization Center, Baghdad Teaching Hospital, Medical City, from January to May 2014, and included patients who presented for PCI. A platelet aggregation test was performed for those patients using the VerifyNow system.

Results

A total of 115 patients (mean age: 58.3±10.1 years; male sex: 73.9%) were included in the study. 18.3% of the study population were clopidogrel non-responders, which was comparable with the results of a Chinese study (20.28%, P=0.796) but contrasted with other reports from Jordan, Brazil and Thailand. The major independent predictive factor for non-responsiveness in our report was diabetes mellitus (OR 5.96, 95% CI 2.23 to 13.71; P=0.001), followed by hypertension (OR 4.135, P=0.035), obesity (OR 3.44, P=0.037) and male sex (OR 3.039, P=0.045). Previous use of clopidogrel (OR 0.17, P=0.02) and younger age (OR 0.72, P=0.026) were identified as protective factors.

Conclusions

In this study, 18.3% of patients were non-responders to clopidogrel and the major independent predictive factors for non-responsiveness were diabetes mellitus, hypertension, obesity and male sex.

Bioresorbable vascular scaffold to treat in-stent restenosis: Single-center experience

AIMS

The management of patients with in-stent restenosis (ISR) is still a major clinical challenge even in the era of drug-eluting stents (DES). Recent studies have demonstrated acceptable clinical outcomes for the everolimus-eluting bioresorbable vascular scaffold (BVS) ABSORB™ in patients with stable coronary artery disease but data are scarce on its use in patients with ISR. We report the long-term results of our preliminary experience with this novel approach at our institution.

METHODS AND RESULTS

We investigated the safety and efficacy of BVS implantation to treat ISR. 34 consecutive patients (37 lesions) underwent PCI for ISR with BVS implantation between May 2013 and June 2015 at our institution and were included in the current analysis. Follow-up was available in 91.9% of the patients. Mean follow-up period was 801.9 ± 179 days. One patient had definite scaffold thrombosis (ScT) 2 months after stent implantation which was treated with DES. Five patients (six lesions) experienced target lesion revascularization (TLR). The composite endpoint rate of TLR, ScT, myocardial infarction, and death occured in 6/37 lesions at follow-up (16.2%).

CONCLUSIONS

These real-world data using BVS in patients with ISR demonstrates that ISR treatment with ABSORB™ BVS is feasible but could have slightly higher target lesion failure rates as compared to DES. This proof of concept could be hypothesis-generating for larger randomized controlled studies.

Case Report: INTRAPROCEDURAL STENT THROMBOSIS IN PERCUTANEOUS CORONARY ANGIOPLASTY

Stent thrombosis is a rare complication of PCI but associated with STEMI and sudden cardiac death. Intra procedural stent thrombosis (IPST) was defined new or increasing (compared with baseline) thrombus within or adjacent to a deployed stent occurring the index PCI procedure whether occlusive or nonocclusive. We describe a case with double vessel disease who has complication cardiac arrest and intra procedural stent thrombosis in LAD and Left Main coronary artery after deployed stent in bifurcation LAD-D1. Thrombectomy and rescucitation were performed, and the patient completed her hospital course without complications.

A risk scoring system to predict coronary stent thrombosis

OBJECTIVE

Stent thrombosis (ST) is a potentially life-threatening complication of percutaneous coronary intervention (PCI). We aimed to develop a scoring system to predict the risk of ST following PCI.

RESEARCH DESIGN AND METHODS

Odds ratios (ORs) for risk factors associated with ST were identified from a meta-analysis based on a systematic literature review, and through consensus expert opinion (Delphi-RAND method). The combined ORs were used to calculate risk scores for acute (within 24 hours), early (within 30 days) and late (31 days to 1 year) ST. Risk scores were validated against patient-level data from the TRITON-TIMI 38 study. Twenty risk factors were identified.

RESULTS

The most highly predictive factor for early and late ST was "incomplete duration of dual antiplatelet therapy". Derived total risk scores ranged from 0 to 22 for acute and early ST, and from 0 to 20 for late ST. Increasing scores were associated with an increasing risk of ST when applied to trial data. Model discrimination was 0.60 (p = .0028), 0.67 (p < .0001) and 0.66 (p < .0001) for acute, early and late ST respectively, indicating good discriminatory power for predicting ST. Key limitations included a lack of published data on acute ST, resulting in a risk score for this time point being based predominantly on expert opinion, and that it was not possible to map all risk factors to variables collected in the TRITON-TIMI 38 study.

CONCLUSION

Our weighted scoring system may help to stratify ST risk and individualize antiplatelet therapy in patients undergoing PCI.

Strut protrusion and shape impact on endothelial shear stress: insights from pre-clinical study comparing Mirage and Absorb bioresorbable scaffolds

Protrusion of scaffold struts is related with local coronary flow dynamics that can promote scaffold restenosis and thrombosis. That fact has prompted us to investigate in vivo the protrusion status of different types of scaffolds and their relationship with endothelial shear stress (ESS) distributions. Six Absorb everolimus-eluting Bioresorbable Vascular Scaffolds (Absorb, Abbott Vascular) and 11 Mirage sirolimus-eluting Bioresorbable Microfiber Scaffolds (Mirage, Manli Cardiology) were implanted in coronaries of eight mini pigs. Optical coherence tomography (OCT) was performed post-scaffold implantation and obtained images were fused with angiographic data to reconstruct the three dimensional coronary anatomy. Blood flow simulation was performed and ESS distribution was estimated for each scaffold. Protrusion distance was estimated using a dedicated software. Correlation between OCT-derived protrusion and ESS distribution was assessed for both scaffold groups. A significant difference was observed in the protrusion distances (156 ± 137 µm for Absorb, 139 ± 153 µm for Mirage; p = 0.035), whereas difference remained after adjusting the protrusion distances according to the luminal areas. Strut protrusion of Absorb is inversely correlated with ESS (r = −0.369, p < 0.0001), whereas in Mirage protrusion was positively correlated with EES (r = 0.192, p < 0.0001). Protrusion distance was higher in Absorb than in Mirage. The protrusion of the thick quadratic struts of Absorb has a tendency to lower shear stress in the close vicinity of struts. However, circular shape of the less thick struts of Mirage didn’t show this trend in creating zone of recirculation around the struts. Strut geometry has different effect on the relationship between protrusion and shear stress in Absorb and Mirage scaffolds.

Long-Term Clinical Outcomes After Bioresorbable Vascular Scaffold Implantation for the Treatment of Coronary In-Stent Restenosis: A Multicenter Italian Experience

BACKGROUND

Treatment of in-stent restenosis (ISR) is still challenging. In this setting, the use of bioresorbable vascular scaffold (BVS) seems attractive because it allows drug delivery combined with transient vessel scaffolding. We aimed to investigate the long-term results after BVS use in ISR lesions.

METHODS AND RESULTS

A prospective analysis was performed on all patients who underwent percutaneous coronary intervention with BVS implantation for ISR at 7 Italian Centers. Primary end point was the device-oriented composite end point (cardiac death, target vessel myocardial infarction, and ischemia-driven target lesion revascularization) at the longest follow-up available. From April 2012 to June 2014, 116 patients (127 lesions) underwent percutaneous coronary intervention for ISR with BVS implantation. Among the ISR lesions, the majority were drug-eluting stent ISR (78, 61.6%), de novo ISR (92, 72.4%), and diffuse ISR (81, 63.8%). Procedural success was achieved for all (100%) patients. No in-hospital death, myocardial infarction, or revascularization occurred. At 15 months of follow-up, the incidence of the device-oriented composite end point estimated with the Kaplan-Meier method was 9.1%. No significant differences were reported between drug-eluting stent and bare-metal stent ISR groups in terms of device-oriented composite end point (10.9% versus 6.4%; hazard ratio, 1.7; 95% confidence interval, 0.5-6.5; P=0.425) and its singular components (cardiac death: 2.8% versus 2.0%, hazard ratio, 1.3; 95% confidence interval, 0.1-14.1, P=0.843; target vessel myocardial infarction: 1.5% versus 0%, P=0.421; ischemia-driven target lesion revascularization: 9.6% versus 4.4%, hazard ratio, 2.3; 95% confidence interval, 0.5-10.8, P=0.309).

CONCLUSIONS

Our registry suggests that the use of BVS implantation for the treatment of complex drug-eluting stent and bare-metal stent ISR lesions might be associated with acceptable long-term clinical outcomes.

SUB-ACUTE STENT THROMBOSIS AND IN-STENT RESTENOSIS ASSOCIATED WITH ANTIPLATELETS CLOPIDOGREL RESISTANCE AND PROTEIN S DEFICIENCY

Protein S deficiency and antiplatelets clopidogrel resistance may uncommonly be responsible for coronary artery thrombosis. Hereby we report a patient presented with coronary disease, who had undergone PCI. However, two days later the patient was found in-stent thrombosis. Primary PCI was performed later with good result, but after 4 months evaluation with treadmill test we found significant ST depression in related region. It was suspected the patient had in-stent re-stenosis incidence. Further hematologic investigation showed that this patient had antiplatelets clopidogrel resistance and protein S deficiency. Double antiplatelet with another kind of antiplatelets and anticoagulant had given in this case. However, the remaining consideration is the choice for reperfusion strategy.

Clinical usefulness of red cell distribution width to angiographic severity and coronary stent thrombosis

Background

Red cell distribution width (RDW) is a quantitative measurement and shows heterogeneity of red blood cell size in peripheral blood. RDW has recently been associated with cardiovascular events and cardiovascular diseases, and it is a novel predictor of mortality. In this study, we aimed to evaluate the clinical usefulness of measuring RDW in patients with coronary stent thrombosis.

Patients and methods

We retrospectively reviewed 3,925 consecutive patients who presented with acute coronary syndrome and who underwent coronary angiography at the Siyami Ersek Hospital between May 2011 and December 2013. Of the 3,925 patients, 73 patients (55 males, mean age 59±11 years, 55 with ST elevated myocardial infarction) with stent thrombosis formed group 1. Another 54 consecutive patients who presented with acute coronary syndrome (without coronary stent thrombosis, 22 patients with ST elevated myocardial infarction, 44 males, mean age 54±2 years) and underwent percutaneous coronary intervention in May 2011 formed group 2. Data were collected from all groups for 2 years. The RDW values were calculated from patients 1 month later at follow-up. Syntax scores were calculated for all the patients. The patients were also divided as low syntax score group and moderate–high syntax score group.

Results

The patients in group 1 with stent thrombosis had significantly higher RDW level (13.85) than the patients in group 2 without stent thrombosis (12) (P<0.001). In addition, in all study patients, the moderate–high syntax score group had significantly higher RDW level (13.6) than the low syntax score group (12.9) (P=0.009). A positive correlation was determined between RDW and syntax scores (r=0.204).

Conclusion

RDW is a new marker of poor prognosis in coronary artery disease. Increased RDW level is correlated with angiographic severity of coronary artery disease, and RDW may be an important clinical marker of coronary stent thrombosis in patients undergoing coronary intervention.

Long-term outcome of full plastic jacket treatment for bare metal in-stent restenosis

We report the long-term outcome of a case of "full plastic jacket" treatment consisting of three bioresorbable scaffolds to manage a subtotally occluded left anterior descending artery with associated severe bare metal in-stent restenosis. Angiography 36months' post procedure revealed an excellent result with negative fractional flow reserve result. Bioresorbable scaffolds may be an attractive option for in-stent restenosis due to the avoidance of an additional metallic layer, and this case is unusual regarding the total scaffold length used and long term angiographic follow-up.

Optimisation of percutaneous coronary intervention: indispensables for bioresorbable scaffolds

INTRODUCTION

With new developments in percutaneous coronary intervention (PCI), such as the introduction of bioresorbable scaffolds (BRS), percutaneous treatment of coronary artery diseases has entered a new era. Without metallic remnants, BRSs appear able to overcome several limitations of the existing metallic stents and provide a physiologic treatment of coronary artery pathology.

AREAS COVERED

BRS have different mechanical properties compared to the traditional metallic stents that should be taken into account during their implantation. Lesion selection, device sizing and satisfied pre-dilatation should be implemented prudently. Although intravascular imaging is not mandatory for the implantation of BRSs it may have a value in optimizing device deployment assess final results and reduce the risk of device related adverse events such as re-stenosis, or scaffold thrombosis. This review aims to reveal the crucial points about the methods of optimization in each steps of BRS implantation. Expert commentary: The target lesions for BRS should be selected meticulously. Pre-dilatation, post-dilatation and intra-vascular imaging techniques should be implemented appropriately to avoid undesirable events after scaffold implantation.

Clinical Outcomes of Bioresorbable Scaffold in Coronary Artery Disease: A Systematic Literature Review

OBJECTIVES

We aim to perform a systematic literature review on all studies reporting the clinical outcomes of the use of bioresorbable scaffolds (BRS) in different settings of coronary artery disease (CAD).

BACKGROUND

BRS are designed to provide early support of the vessel wall postangioplasty, deliver antiproliferative agents to prevent excessive hyperplastic healing responses and finally "disappear" when no longer required. Emerging data have provided evidence of their use in specific clinical scenarios.

METHODS

A comprehensive literature search was performed by 2 independent reviewers utilizing MEDLINE, EMBASE, and Cochrane Library databases. The only 2 CE marked BRS: everolimus-eluting Bioresorbable vascular scaffold ABSORB BVS and the myolimus-eluting DESolve Bioresorbable Coronary Scaffold (BCS) System were included.

RESULTS

The studies were categorized into: ST elevation myocardial infarction (STEMI), stable CAD, and "all-comers" group. Thirty-one studies were included; 8 in STEMI patients (all ABSORB), 15 in stable CAD patients. In the STEMI group (n = 606), acute procedural success ranged from 96% to 100%, cardiac mortality 0-9.1%, recurrent MI and stent thrombosis rates were 0-4.3%. In the stable CAD group, the 13 ABSORB studies (n = 3259) demonstrated cardiac mortality rate of 0-0.6%, recurrent MI rate 0-4.5%, and stent thrombosis rate 0-4.3%

CONCLUSIONS

Current clinical data suggest the BRS, especially the ABSORB BVS, may represent a reasonable alternative to DES in uncomplicated coronary anatomy.

Optimization of Drug Delivery by Drug-Eluting Stents

Drug-eluting stents (DES), which release anti-proliferative drugs into the arterial wall in a controlled manner, have drastically reduced the rate of in-stent restenosis and revolutionized the treatment of atherosclerosis. However, late stent thrombosis remains a safety concern in DES, mainly due to delayed healing of the endothelial wound inflicted during DES implantation. We present a framework to optimize DES design such that restenosis is inhibited without affecting the endothelial healing process. To this end, we have developed a computational model of fluid flow and drug transport in stented arteries and have used this model to establish a metric for quantifying DES performance. The model takes into account the multi-layered structure of the arterial wall and incorporates a reversible binding model to describe drug interaction with the cells of the arterial wall. The model is coupled to a novel optimization algorithm that allows identification of optimal DES designs. We show that optimizing the period of drug release from DES and the initial drug concentration within the coating has a drastic effect on DES performance. Paclitaxel-eluting stents perform optimally by releasing their drug either very rapidly (within a few hours) or very slowly (over periods of several months up to one year) at concentrations considerably lower than current DES. In contrast, sirolimus-eluting stents perform optimally only when drug release is slow. The results offer explanations for recent trends in the development of DES and demonstrate the potential for large improvements in DES design relative to the current state of commercial devices.

Surface modification of Ni-Ti alloys for stent application after magnetoelectropolishing

The constant demand for new implant materials and the multidisciplinary design approaches for stent applications have expanded vastly over the past decade. The biocompatibility of these implant materials is a function of their surface characteristics such as morphology, surface chemistry, roughness, surface charge and wettability. These surface characteristics can directly influence the material's corrosion resistance and biological processes such as endothelialization. Surface morphology affects the thermodynamic stability of passivating oxides, which renders corrosion resistance to passivating alloys. Magnetoelectropolishing (MEP) is known to alter the morphology and composition of surface films, which assist in improving corrosion resistance of Nitinol alloys. This work aims at analyzing the surface characteristics of MEP Nitinol alloys by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The wettability of the alloys was determined by contact angle measurements and the mechanical properties were assessed by Nanoindentation. Improved mechanical properties were observed with the addition of alloying elements. Cyclic potentiodynamic polarization tests were performed to determine the corrosion susceptibility. Further, the alloys were tested for their cytotoxicity and cellular growth with endothelial cells. Improved corrosion resistance and cellular viability were observed with MEP surface treated alloys.

Optical coherence tomography-guided treatment of very late stent thrombosis caused by inaccurate stent deployment in a bifurcation

: A 65-year-old man presented at our institution with anterior wall reinfarction, due to very late stent thrombosis, 4 years after primary angioplasty on the first bifurcation of the left anterior descending artery. Using intravascular optical coherence tomography, we identified stent malapposition in the proximal left anterior descending artery, occurring during the first primary angioplasty, as the probable cause of the very late stent thrombosis. Imaging with optical coherence tomography guided our treatment strategy of mechanical and pharmacological thrombectomy, followed by staged stent postdilatation.

Very late stent thrombosis following the placement of a crossing Y-stent with dual closed-cell stents for the coiling of a wide-necked aneurysm

The crossing Y-stent technique is a viable option for coiling of wide-necked bifurcation aneurysms. However, little is known about the long-term impact of this technique. Very late (>1 year) stent thrombosis following the placement of a crossing Y-stent with dual closed-cell stents for the coiling of a wide-necked basilar tip aneurysm, which has not been reported to date, is described.

New-generation drug-eluting stents: focus on Xience V® everolimus-eluting stent and Resolute® zotarolimus-eluting stent

Compared to bare metal stent angioplasty, first-generation drug-eluting stents (DES) have markedly reduced the incidence of in-stent restenosis. However, given the increased concerns over late and very late stent thrombosis, newer-generation DES were developed. To date, these DES have virtually replaced the use of first-generation DES worldwide. In this review article, we carefully consider the pre-clinical and clinical trials that have been performed with currently available, european conformity-marked and Food and Drug Administration-approved new-generation Resolute(®) and Xience V(®) DES.

Triple, simultaneous, very late coronary stent thrombosis

Coronary artery stent thrombosis is an uncommon but potentially catastrophic complication. The risk of very late stent thrombosis (VLST) raises important safety issues regarding the first generation of drug-eluting stents (DES). Although several complex mechanisms for VLST have been suggested and various predictors have been described, its pathophysiology is not completely understood and it is not known whether longer-term dual antiplatelet therapy reduces the risk. We present a rare case of simultaneous very late DES thrombosis in the three vascular territories, following discontinuation of antiplatelet therapy seven years after stent placement, presenting as cardiogenic shock.