A comparison of clinical presentations, angiographic patterns and outcomes of in-stent restenosis between bare metal stents and drug eluting stents

Prognostic impact of in-stent restenosis in normal weight, overweight, and obese patients undergoing percutaneous coronary intervention

BACKGROUND

Among patients undergoing percutaneous coronary intervention (PCI), in-stent restenosis (ISR) is related with a worse prognosis, while higher body mass index (BMI) values are associated with better outcomes. It is unclear whether the prognostic impact of ISR varies in function of BMI.

METHODS

Patients undergoing PCI at a large center from 2012 to 2019 not presenting with an acute myocardial infarction (MI) were included. Subjects with BMI < 18.5 kg/m2 or treated with bare metal stents were excluded. Patients were stratified according to type of lesion treated (ISR vs. no-ISR) and into four BMI categories: normal weight (BMI 18.5-25 kg/m2 ), overweight (25.0-29.9 kg/m2 ), class I obesity (30.0-34.9 kg/m2 ), class II-III obesity (≥35.0 kg/m2 ). The primary outcome was major adverse cardiovascular events (MACE), a composite of all-cause death, MI, and target vessel revascularization (TVR) at 1 year.

RESULTS

Out of 16,234 patients, 3694 (23%) underwent PCI for ISR. ISR as compared to no-ISR was associated with a consistent increased risk of MACE within the normal weight (18.8% vs. 7.8%, adj. hazard ratio (HR): 1.99, 95% confidence interval [CI]: 1.51-2.64), overweight (19.1% vs. 6.4%, adj. HR: 2.35, 95% CI: 1.91-2.88), class I obesity (18.3% vs. 6.8%, adj. HR: 1.95, 95% CI: 1.47-2.57), and class II-III obesity (16.4% vs. 7.4%, adj. HR: 1.61, 95% CI: 1.09-2.37) groups (interaction p-value: 0.192). The ISR-related risks were mostly driven by an excess of TVR.

CONCLUSIONS

At 1 year, ISR was associated with an increased risk of MACE irrespective of BMI, mostly due to an excess of TVR after ISR.

Coronary In-Stent Restenosis: JACC State-of-the-Art Review

The introduction and subsequent iterations of drug-eluting stent technologies have substantially improved the efficacy and safety of percutaneous coronary interventions. However, the incidence of in-stent restenosis (ISR) and the resultant need for repeated revascularization still occur at a rate of 1%-2% per year. Given that millions of drug-eluting stents are implanted each year around the globe, ISR can be considered as a pathologic entity of public health significance. The mechanisms of ISR are multifactorial. Since the first description of the angiographic patterns of ISR, the advent of intracoronary imaging has further elucidated the mechanisms and patterns of ISR. The armamentarium and treatment strategies of ISR have also evolved over time. Currently, an individualized approach using intracoronary imaging to characterize the underlying substrate of ISR is recommended. In this paper, we comprehensively reviewed the incidence, mechanisms, and imaging characterization of ISR and propose a contemporary treatment algorithm.

In-hospital and 1-Year Outcomes of Repeated Percutaneous Coronary Intervention for In-stent Restenosis With Acute Coronary Syndrome Presentation

BACKGROUND

In-stent restenosis (ISR) is the Achilles' heel of percutaneous coronary intervention (PCI). There have been controversial data about outcomes of repeated PCI (redo-PCI) for ISR. This study aims to determine the predictors of major adverse cardiac events (MACE) in patients underwent redo-PCI for ISR.

METHODS

In this retrospective study, all patients with acute coronary syndrome who were underwent successful PCI for ISR at Tehran Herat Center (between 2004 and 2019) were eligible for inclusion. Patients with moderate to severe valvular heart disease and/or hematological disorders were excluded. Participants were divided into 2 groups based on the occurrence of the MACE [composite of cardiovascular death, myocardial infarction (MI), coronary artery bypass grafting, target vessel revascularization, and target lesion revascularization]; then, the study variables were compared between the 2 groups. Finally, the predictors of MACE were identified using Cox regression analysis.

RESULTS

Of 748 redo-PCI patients (mean age: 65.2 ± 10.1; 71.0% males), 631 patients had met the inclusion criteria. Fifty-four patients (9.8%) developed MACE within a 1-year follow-up period. Multivessel disease, primary PCI, Ad-hoc PCI, history of non-ST-segment elevation MI, and diabetes mellitus were independent predictors for MACE. In a subgroup analysis, 30 patients who experienced third PCI (target lesion revascularization/target vessel revascularization) were followed more as 1-year MACE. Among these patients, 14 MACEs were observed during the last follow-up (till June 2020).

CONCLUSIONS

Multivessel disease, primary PCI, and history of non-ST-segment elevation MI were the predictors of higher 1-year MACE, whereas Ad-hoc PCI and diabetes mellitus had a protective effect on MACE.

Is Coronary Brachytherapy Staging a Comeback for the Treatment of In-Stent Restenosis?

PURPOSE OF REVIEW

The catheter-based coronary intervention has become a well-established therapeutic modality for obstructive coronary artery disease. However, in-stent restenosis remains a significant limitation of coronary intervention despite the use of newer devices. Intravascular brachytherapy was introduced to treat recurrent in-stent restenosis but only modestly adopted. This review will discuss the mechanism of intracoronary brachytherapy, available clinical evidence of brachytherapy in recurrent in-stent restenosis treatment, and the future of coronary brachytherapy in coronary intervention.

RECENT FINDINGS

Drug-eluting stents have an inherent limitation as they leave a permanent metal layer inside an artery when deployed. Recently, drug-coated balloon technology has emerged to treat coronary artery disease as a combination of balloon angioplasty and local drug delivery without leaving a metal layer behind. Recent European guidelines recommended using drug-coated balloons when treating in-stent restenosis treatment, while the US guidelines have not yet addressed the use of drug-coated balloons in such cases. Coronary brachytherapy is a valuable addition to treat these challenging diseases despite several logistic issues. If there are newer technologies with easier setup, such as drug-coated balloons, coronary brachytherapy resurgence is improbable in the contemporary era, although it may not become obsolete.

Procedural Results and Long-Term Outcomes of Percutaneous Coronary Intervention for in-Stent Restenosis Chronic Total Occlusion Compared with de novo Chronic Total Occlusion

Background

In-stent restenosis (ISR) chronic total occlusion (CTO) represents a challenging subgroup for revascularization of CTO by percutaneous coronary intervention (PCI). There are limited data on the treatment and outcomes of PCI for ISR CTO.

Objective

We aimed to evaluate the procedural results and 2-year outcomes of PCI for ISR CTO compared with de novo CTO.

Methods

Patients undergoing attempted CTO PCI between January 2017 and December 2019 were prospectively enrolled. We analyzed the procedural results and 2-year major adverse cardiac events (MACE) in patients undergoing ISR CTO and those undergoing de novo CTO PCI.

Results

A total of 426 patients undergoing 484 consecutive CTO PCI (ISR CTO PCI, n=84; de novo CTO, n=400) were enrolled during the study period. Patients undergoing de novo CTO PCI had a significantly greater syntax score than those undergoing ISR CTO PCI [23.0 (17.5, 30.5) vs 21.5 (14.5, 27.0), p=0.039]. Technical (73.8% vs 79.0%, p=0.296) and procedural (73.8% vs 78.0, p=0.405) success rates, as well as the incidence of major procedural complications (1.2% vs 2.3%, p=0.842), were comparable between the two groups. After a median follow-up of 20 months, patients who underwent ISR CTO PCI had a significantly higher incidence of MACE (33.3% vs 10.3%, p<0.001), mainly attributed to the higher TVR rates (24.7% vs 7.6%, p<0.001). ISR CTO was the only independent predictor of MACE (hazard ratio, 4.124; 95% confidence interval, 1.951–8.717; p<0.001) during follow-up in patients who underwent CTO PCI.

Conclusion

ISR CTO PCI shows comparable technical and procedural success, as well as major procedural complications compared with de novo CTO PCI. However, patients who underwent ISR CTO PCI had a significantly worse prognosis than those who underwent de novo CTO PCI, in terms of MACE, driven by TVR. ISR CTO was the only independent predictor of MACE during the follow-up.

Influences of Stent Design on In-Stent Restenosis and Major Cardiac Outcomes: A Scoping Review and Meta-Analysis

Thanks to the developments in implantable biomaterial technologies, invasive operating procedures, and widespread applications especially in vascular disease treatment, a milestone for interventional surgery was achieved with the introduction of vascular stents. Despite vascular stents providing a solution for embolisms, this technology includes various challenges, such as mechanical, electro-chemical complications, or in-stent restenosis (ISR) risks with long-term usage. Therefore, further development of biomaterial technologies is vital to overcome such risks and problems. For this purpose, recent research has focused mainly on the applications of surface modification techniques on biomaterials and vascular stents to increase their hemocompatibility. ISR risk has been reduced with the development and prevalent usage of the art technology stent designs of drug-eluting and biodegradable stents. Nevertheless, their problems have not been overcome completely. Furthermore, patients using drug-eluting stents are faced with further clinical challenges. Therefore, the bare metal stent, which is the first form of the vascular stent technology and includes the highest ISR risk, is still in common usage for vascular treatment applications. For this reason, further research is necessary to solve the remaining vital problems. In this scoping review, stent-based major cardiac events including ISR are analyzed depending on different designs and material selection in stent manufacturing. Recent and novel approaches to overcome such challenges are stated in detail.

Comparison of clinical outcomes between percutaneous coronary intervention for de novo lesions versus in-stent restenosis lesions

In-stent restenosis (ISR) remains the primary concern after a percutaneous coronary intervention (PCI) and is considered to be associated with worse clinical outcomes. However, comparative data on ISR and de novo lesions are rare. Therefore, we aimed to compare PCI-related clinical outcomes between patients with de novo lesions and those with ISR lesions. We undertook a retrospective analysis of patients who had undergone a PCI between 2013 and 2020. The incidences of major adverse cardiac and cerebrovascular events (MACCE) and all-cause death over a 2-year follow-up period were evaluated. In total, 1538 patients were enrolled and divided into two groups: a de novo lesions group (n = 1258, 81.8%) and an ISR lesions group (n = 280, 18.2%). Patients in the ISR lesions group were significantly older, with a higher prevalence of hypertension, diabetes mellitus, dyslipidemia, and chronic kidney disease than those in the de novo lesions group. Kaplan-Meier curves showed no significant between-group differences in the incidence of MACCE (log-rank, p = 0.93) and all-cause death (p = 0.09). After adjustment for other covariates, PCIs for ISR lesions were not found to be significantly associated with MACCE (hazard ratio [HR], 1.10; 95% confidential interval [CI] 0.49-2.49; p = 0.81) and all-cause death (HR, 0.58; 95% CI 0.26-1.31; p = 0.19). PCIs for ISR lesions were not associated with worse clinical outcomes compared with PCIs for de novo lesions.

Long-Term Outcomes of Percutaneous Coronary Intervention for Patients With In-Stent Chronic Total Occlusion Versus De Novo Chronic Total Occlusion

Limited data are available on long-term outcomes and health status in the treatment of in-stent coronary chronic total occlusion (IS-CTO) and de novo coronary chronic total occlusion (de novo CTO). This study compared the long-term clinical outcomes and health status of percutaneous coronary intervention (PCI) for patients with IS-CTO versus patients with de novo CTO in the drug-eluting stent era. We screened 483 consecutive patients with 1 CTO lesion, including 81 patients with IS-CTO and 402 patients with de novo CTO. Propensity score matching was used to balance baseline characteristics between the 2 groups. The clinical end point was major adverse cardiac events (MACE). The success rates of CTO lesion revascularization were similar in both groups. In the propensity score-matched patients, after a median follow-up of 36 months, MACE was observed in 32.8% of patients with IS-CTO versus 13.5% of the patients with de novo CTO (P < .001), mainly driven by target-vessel revascularization (21.9% vs 6.7%; P < .01). Moreover, patients with IS-CTO had significantly worse Seattle Angina Questionnaire anginal stability scores than the patients with de novo CTO. In conclusion, patients with IS-CTO after PCI had a worse clinical outcome, mainly MACE, and a poorer anginal stability in the long term than patients with de novo CTO.

Effect of Glycemic Control During Follow-up on Late Target Lesion Revascularization After Implantation of New-Generation Drug-Eluting Stents in Patients With Diabetes - A Single-Center Observational Study

Background: Few studies have investigated the importance of glycemic control in patients with diabetes mellitus (DM) for reducing the incidence of late target lesion revascularization (TLR) after implantation of new-generation drug-eluting stents (DES).

Methods and Results: We retrospectively identified 1,568 patients who underwent new-generation DES implantation. Patients were divided into 3 groups based on diabetic status and glycemic control 1 year after the procedure: those without DM (non-DM group; n=1,058) and those with DM at follow-up with either good (HbA1c <7%; n=328) or poor (HbA1c ≥7%; n=182) control. The cumulative 5-year incidence of clinically driven late TLR after the index procedure was significantly higher in DM with poor control at follow-up than in those with good control at follow-up or non-DM (14%, 4.8%, and 2.9%, respectively; P<0.0001). Multivariate analysis revealed that poor control at follow-up was significantly associated with a higher risk of clinically driven late TLR compared with the non-DM group (hazard ratio [HR] 4.58, 95% confidence interval [CI] 2.50–8.16, P<0.0001). However, good control at follow-up group was not associated with a higher risk of clinically driven late TLR compared with the non-DM group (HR 1.35, 95% CI 0.68–2.56, P=0.38).

Conclusions: DM patients with poor glycemic control at follow-up had a significantly higher risk of clinically driven late TLR than non-DM patients.

In-stent restenosis of drug-eluting stents: clinical presentation and outcomes in a real-world scenario

BACKGROUND

Drug-eluting stents (DES) have substantially reduced the incidence of coronary in-stent restenosis (ISR), but the problem persists. Clinical presentation and outcomes of DES-ISR in a real-world scenario remains underreported.

RESULTS

In this retrospective study, we examined medical records of 191 consecutive patients with DES-ISR (210 ISR lesions) hospitalized between January 2013 and December 2017. ISR clinical presentation was classified as acute coronary syndrome (ACS) or non-ACS. Clinical, angiographic features and 1-year outcomes [composite of death, myocardial infarction (MI) and repeat-target lesion revascularization] for these two groups were compared. The mean age of study population was 61 ± 10 years and 81.2% were males. ACS was the dominant clinical presentation mode occurring in 118 (61.8%) patients. MI was seen in 66 (34.6%) patients. Female gender (odds ratio, 2.71; 95% confidence interval [CI], 1.13-6.52; P = 0.026) and chronic kidney disease (odds ratio, 3.85; 95% CI, 1.05-14.20; P = 0.043) correlated significantly with ACS ISR presentation. A majority [104 (54.5%)] of patients underwent percutaneous coronary intervention (PCI), of whom 72 (69.2%) received a new DES. The rest either underwent CABG (26.2%) or received medical therapy (19.4%). Patients presenting with ACS had a significantly worse clinical outcome at 1-year follow-up (ACS versus non-ACS presentation: hazard ratio [HR], 2.66; 95% CI, 1.09-6.50; P = 0.032).

CONCLUSIONS

DES-ISR presents most commonly as ACS. Female gender and chronic kidney disease seem to be associated with ACS presentation. ACS presentation of ISR is associated with worse 1-year outcomes. Early identification of those with ACS risk and closer follow-up may improve outcomes.

A comparison of procedural success rate and long-term clinical outcomes between in-stent restenosis chronic total occlusion and de novo chronic total occlusion using multicenter registry data

Background

There have been little data about outcomes of percutaneous coronary intervention (PCI) for in-stent restenosis (ISR) chronic total occlusion (CTO) in the drug eluting stent (DES) era. This study aimed to compare the procedural success rate and long-term clinical outcomes of ISR CTO and de novo CTO.

Methods and results

Patients who underwent PCI for ISR CTO (n = 164) versus de novo CTO (n = 1208) were enrolled from three centers in Korea between January 2008 and December 2014. Among a total of ISR CTO, a proportion of DES ISR CTO was 79.3% (n = 130). The primary outcome was major adverse cardiac events (MACEs); a composite of all-cause death, non-fatal myocardial infarction (MI), or target lesion revascularization (TLR). Following propensity score-matching (1:3), the ISR CTO group (n = 156) had a higher success rate (84.6% vs. 76.0%, p = 0.035), mainly driven by high success rate of PCI for DES ISR CTO (88.6%), but showed a higher incidence of MACEs [hazard ratio (HR): 2.06; 95% confidence interval (CI) 1.37–3.09; p < 0.001], mainly driven by higher prevalence of MI [HR: 9.71; 95% CI 2.06–45.81; p = 0.004] and TLR [HR: 3.04; 95% CI 1.59–5.81; p = 0.001], during 5 years of follow-up after successful revascularization, as compared to the de novo CTO group (n = 408).

Conclusion

The procedural success rate was higher in the ISR CTO than the de novo CTO, especially in DES ISR CTO. However, irrespective of successful revascularization, the long-term clinical outcomes for the ISR CTO were significantly worse than those for the de novo CTO, in terms of MI and TLR.

Graphic abstract

In-Stent Restenosis of Drug-Eluting Stents Compared With a Matched Group of Patients With De Novo Coronary Artery Stenosis

Drug-eluting stents (DES) significantly reduced the incidence of in-stent restenosis (ISR). However, ISR still exists in the contemporary DES era. Previously deemed to be a benign process, ISR leads to complex presentation and intervention. This study aimed to compare the presentation and outcome of DES-ISR versus de novo lesions. We performed a retrospective analysis of 11,666 patients receiving percutaneous coronary intervention from 2003 to 2017 and divided them into 2 groups by de novo stenosis and ISR. They were matched based on common cardiovascular risk factors at a 4:1 ratio, respectively. After matching, a total of 1,888 patients with 3,126 de novo lesions and 472 patients with 508 ISR lesions were analyzed. Patients with ISR presented more often with unstable angina (61% vs 45%, p <0.001) and less often with myocardial infarction (6% vs 14%, p <0.001). One-year composite major adverse cardiovascular event, defined as death, Q-wave myocardial infarction, and target vessel revascularization, was 10% in the de novo group and 17% in the ISR group (hazard ratio 1.98, 95% confidential interval 1.58 to 2.46, p <0.001). After adjusting for myocardial infarction presentation, hazard ratio of major adverse cardiovascular events was still higher for the ISR group at 1 year (2.03, 95% confidential interval 1.62 to 2.55, p <0.001). ISR of DES remains a therapeutic challenge and leads to complex presentation and worse outcomes compared with matched de novo patients. These data show that DES-ISR demands better appreciation and prevention with more precise stent technique and should motivate the continued development of fully bioresorbable scaffolds.

Third generation dual-source CT enables accurate diagnosis of coronary restenosis in all size stents with low radiation dose and preserved image quality

OBJECTIVES

To investigate the diagnostic performance of low dose stent imaging in patients with large (≥ 3 mm) and small (< 3 mm) calibre stents by third-generation dual-source CT.

METHODS

Symptomatic patients suspected of having in-stent restenosis (ISR) were prospectively enrolled. Coronary computed tomography angiography (CCTA) and invasive coronary angiography (ICA) were performed within 1 month for correlation. Binary ISR was defined as an in-stent neointimal proliferation with diameter stenosis ≥ 50%. The radiation dose and image quality of CCTA were also assessed.

RESULTS

Sixty-nine patients with 140 stents were ultimately included for analysis. The mean total radiation dose of CCTA was 1.3 ± 0.72 mSv in all patients and 0.95 ± 0.17 mSv in patients with high pitch acquisition. The overall diagnostic accuracy of CCTA stent imaging of patient-based, lesion-based and stent-based analysis was 95.7%, 94.1% and 94.3%, respectively. Further, the diagnostic accuracy of CCTA in the small calibre stent group (diameter < 3 mm) was slightly lower than that of the large calibre stent group (diameter ≥ 3 mm) (88.5% versus 98.7%, p = 0.01).

CONCLUSIONS

Third-generation dual-source CT enables accurate diagnosis of coronary ISR of both large and small calibre stents. Low radiation dose could be achieved with preserved image quality.

KEY POINTS

• Third-generation DSCT enables accurate diagnosis of coronary ISR of all size stents. • Low radiation dose could be achieved with preserved image quality. • The diagnostic accuracy of CCTA of small calibre stents was 88.5%.

Controlled release of paclitaxel using a drug-eluting stent through modulation of the size of drug particles in vivo

Drug-eluting stents (DESs) are generally used in percutaneous coronary intervention. Paclitaxel (PTX) is widely used in DESs to suppress neointima, which causes restenosis. However, the PTX release profile is slow owing to its hydrophobic properties, resulting in negative effects on re-endothelialization in vessels. In this study, we assessed the effects of the controlled release of PTX particles of specific sizes on in-stent restenosis (ISR). PTX particle sizes were controlled by adjusting the evaporating temperature of the solvent from 25 to 80°C during ultrasonic coating, and DESs were prepared. The properties of prepared films and DESs were analyzed, and cell viability was assessed in vitro and in vivo. Poly(lactic-co-glycolic acid) (PLGA)/PTX500-loaded stents showed the most rapid release for 58 days, and smaller drug particles exhibited lower PTX release rates. In vivo, PLGA/PTX50-, PLGA/PTX250-, and PLGA/PTX500-loaded stents showed good efficacy for alleviating ISR as compared with bare metal stents and PLGA/PTX5-loaded stents. However, PLGA/PTX250- and PLGA/PTX500-loaded stents exhibited strut exposure and reduced recovery of the vascular compared with PLGA/PTX50-loaded stents. PTX drug particles of approximately 50 nm were most effective in vivo, and the control of particle size is a promising strategy for improving the performance of PTX-eluting stents. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2275-2283, 2018.

Difference in clinical presentations and related angiographic findings among early, late, and very late sirolimus-eluting stent failures requiring target lesion revascularization

BACKGROUNDS

The difference in clinical presentations (acute coronary syndrome [ACS] and stable coronary artery disease [SCAD]) and related angiographic morphologies of sirolimus-eluting stent (SES) failure requiring target lesion revascularization (TLR) during early-term (<1year), late-term (1-5years), and very late-term periods (>5years) remains unknown.

METHODS

Among 4484 lesions undergoing SES implantation, clinically-driven TLR was performed on 105 lesions during early-term, 169 lesions during late-term, and 147 lesions during very late-term period. Angiographic morphological patterns were divided into focal or non-focal patterns and stent-edge or stent-body patterns.

RESULTS

The proportion of ACS substantially increased in very late TLR lesions (57.1%) from early (40.0%, p=0.01) and late TLR lesions (36.7%, p<0.001). The proportions of both stent-edge and non-focal patterns were higher in very late TLR lesions than in early and late TLR lesions. Although the stent-edge pattern tended to be more prevalent in SCAD lesions than in ACS lesions during the early- and late-term periods, it was more frequently observed in ACS lesions than in SCAD lesions during the very late-term period (65.5% vs. 47.6%, p=0.04). The non-focal pattern was more frequent in ACS lesions than in SCAD lesions during all 3 periods. However, the proportion of the non-focal pattern in ACS lesions was extremely high during the very late-term (90.5%) compared with the early- (47.6%, p<0.001) and late-term periods (48.4%, p<0.001).

CONCLUSIONS

Stent-related ACS became more common beyond 5years after SES implantation. Stent-edge and non-focal patterns were the main angiographic morphologies of very late SES failure, particularly causing ACS.

Targeting AGGF1 (angiogenic factor with G patch and FHA domains 1) for Blocking Neointimal Formation After Vascular Injury

Background

Despite recent improvements in angioplasty and placement of drug‐eluting stents in treatment of atherosclerosis, restenosis and in‐stent thrombosis impede treatment efficacy and cause numerous deaths. Research efforts are needed to identify new molecular targets for blocking restenosis. We aim to establish angiogenic factor AGGF1 (angiogenic factor with G patch and FHA domains 1) as a novel target for blocking neointimal formation and restenosis after vascular injury.

Methods and Results

AGGF1 shows strong expression in carotid arteries; however, its expression is markedly decreased in arteries after vascular injury. AGGF1^+/− mice show increased neointimal formation accompanied with increased proliferation of vascular smooth muscle cells (VSMCs) in carotid arteries after vascular injury. Importantly, AGGF1 protein therapy blocks neointimal formation after vascular injury by inhibiting the proliferation and promoting phenotypic switching of VSMCs to the contractile phenotype in mice in vivo. In vitro, AGGF1 significantly inhibits VSMCs proliferation and decreases the cell numbers at the S phase. AGGF1 also blocks platelet‐derived growth factor‐BB–induced proliferation, migration of VSMCs, increases expression of cyclin D, and decreases expression of p21 and p27. AGGF1 inhibits phenotypic switching of VSMCs to the synthetic phenotype by countering the inhibitory effect of platelet‐derived growth factor‐BB on SRF expression and the formation of the myocardin/SRF/CArG‐box complex involved in activation of VSMCs markers. Finally, we show that AGGF1 inhibits platelet‐derived growth factor‐BB–induced phosphorylation of MEK1/2, ERK1/2, and Elk phosphorylation involved in the phenotypic switching of VSMCs, and that overexpression of Elk abolishes the effect of AGGF1.

Conclusions

AGGF1 protein therapy is effective in blocking neointimal formation after vascular injury by regulating a novel AGGF1‐MEK1/2‐ERK1/2‐Elk‐myocardin‐SRF/p27 signaling pathway.

Restenosis of the Coronary Arteries: Past, Present, Future Directions

Restenosis is a pathologic response to vascular injury, characterized by neointimal hyperplasia and progressive narrowing of a stented vessel segment. Although advances in stent design have led to a dramatic reduction in the incidence of restenosis, it continues to represent the most common cause of target lesion failure following percutaneous coronary intervention. Efforts to maximize restenosis prevention, through careful consideration of modifiable risk factors and an individualized approach, are critical, as restenosis, once established, can be particularly difficult to treat. Novel approaches are on the horizon that have the potential to alter the natural history of this stubborn disease.

miR-125a-5p Modulates Phenotypic Switch of Vascular Smooth Muscle Cells by Targeting ETS-1

MicroRNAs are key regulators of vascular smooth muscle cells (VSMCs) phenotypic switch, one of the main events responsible for bare metal in-stent restenosis after percutaneous coronary intervention. miR-125a-5p is an important modulator of differentiation, proliferation, and migration in different cell types; however, its role in VSMCs is still unknown. The aim of this study was to evaluate the role of miR-125a-5p in VSMCs phenotypic switch. Our results suggest that miR-125a-5p is highly expressed in VSMCs, but it is down-regulated after vascular injury in vivo. Its overexpression is sufficient to reduce VSMCs proliferation and migration, and it is able to promote the expression of selective VSMCs markers such as alpha smooth muscle actin, myosin heavy chain 11, and smooth muscle 22 alpha. Interestingly, miR-125a-5p directly targets ETS-1, a transcription factor implicated in cell proliferation and migration and is crucial in PDGF-BB pathway in VSMCs. Thus, miR-125a-5p in this context inhibits PDGF-BB pathway and is therefore a potential regulator of VSMCs phenotypic switch.

MicroRNAs for Restenosis and Thrombosis After Vascular Injury

Percutaneous revascularization revolutionized the therapy of patients with coronary artery disease. Despite continuous technical advances that substantially improved patients' outcome after percutaneous revascularization, some issues are still open. In particular, restenosis still represents a challenge, even though it was dramatically reduced with the advent of drug-eluting stents. At the same time, drug-eluting stent thrombosis emerged as a major concern because of incomplete or delayed re-endothelialization after vascular injury. The discovery of microRNAs revealed a previously unknown layer of regulation for several biological processes, increasing our knowledge on the biological mechanisms underlying restenosis and stent thrombosis, revealing novel promising targets for more efficient and selective therapies. The present review summarizes recent experimental and clinical evidence on the role of microRNAs after arterial injury, focusing on practical aspects of their potential therapeutic application for selective inhibition of smooth muscle cell proliferation, enhancement of endothelial regeneration, and inhibition of platelet activation after coronary interventions. Application of circulating microRNAs as potential biomarkers is also discussed.

In-stent Restenosis

In-stent restenosis (ISR) is the narrowing of a stented coronary artery lesion. The mean time from percutaneous coronary intervention (PCI) to ISR was 12 months with drug-eluting stents (DES) and 6 months with bare metal stents (BMS). ISR typically presents as recurrent angina. The use of DES has significantly reduced the rate of ISR compared with BMS. Predictors of ISR include patient, lesion, and procedural characteristics. Intravascular ultrasound, optical coherence tomography, and fractional flow reserve are important tools for the anatomic and hemodynamic assessment of ISR. Treatment options for ISR include percutaneous coronary intervention with DES.

Treatment strategies for coronary in-stent restenosis: systematic review and hierarchical Bayesian network meta-analysis of 24 randomised trials and 4880 patients

STUDY QUESTION

What is the most safe and effective interventional treatment for coronary in-stent restenosis?

METHODS

In a hierarchical Bayesian network meta-analysis, PubMed, Embase, Scopus, Cochrane Library, Web of Science, ScienceDirect, and major scientific websites were screened up to 10 August 2015. Randomised controlled trials of patients with any type of coronary in-stent restenosis (either of bare metal stents or drug eluting stents; and either first or recurrent instances) were included. Trials including multiple treatments at the same time in the same group or comparing variants of the same intervention were excluded. Primary endpoints were target lesion revascularisation and late lumen loss, both at six to 12 months. The main analysis was complemented by network subanalyses, standard pairwise comparisons, and subgroup and sensitivity analyses.

STUDY ANSWER AND LIMITATIONS

Twenty four trials (4880 patients), including seven interventional treatments, were identified. Compared with plain balloons, bare metal stents, brachytherapy, rotational atherectomy, and cutting balloons, drug coated balloons and drug eluting stents were associated with a reduced risk of target lesion revascularisation and major adverse cardiac events, and with reduced late lumen loss. Treatment ranking indicated that drug eluting stents had the highest probability (61.4%) of being the most effective for target lesion vascularisation; drug coated balloons were similarly indicated as the most effective treatment for late lumen loss (probability 70.3%). The comparative efficacy of drug coated balloons and drug eluting stents was similar for target lesion revascularisation (summary odds ratio 1.10, 95% credible interval 0.59 to 2.01) and late lumen loss reduction (mean difference in minimum lumen diameter 0.04 mm, 95% credible interval -0.20 to 0.10). Risks of death, myocardial infarction, and stent thrombosis were comparable across all treatments, but these analyses were limited by a low number of events. Trials had heterogeneity regarding investigation periods, baseline characteristics, and endpoint reporting, with a lack of information at long term follow-up. Direct and indirect evidence was also inconsistent for the comparison between drug eluting stents and drug coated balloons.

WHAT THIS STUDY ADDS

Compared with other currently available interventional treatments for coronary in-stent restenosis, drug coated balloons and drug eluting stents are associated with superior clinical and angiographic outcomes, with a similar comparative efficacy.

FUNDING, COMPETING INTERESTS, DATA SHARING

This study received no external funding. The authors declare no competing interests. No additional data available.

Impact of technological developments in drug-eluting stents on patient-focused outcomes: a pooled direct and indirect comparison of randomised trials comparing first- and second-generation drug-eluting stents

AIMS

To establish whether technological improvements in drug-eluting stent (DES) technology introduced in second-generation (G2) DES have contributed to improving patient-focused outcomes.

METHODS AND RESULTS

We performed a systematic review of randomised clinical trials (RCT) comparing first-generation (G1) and G2 DES with a>9-month clinical follow-up. The primary endpoint for efficacy was ischaemia-driven target lesion revascularisation (ID-TLR); safety endpoints were all-cause death, myocardial infarction (MI) and stent thrombosis (ST). Sixteen RCTs involving 25,427 patients met eligibility criteria (17 comparisons). In these trials, paclitaxel (PES) and sirolimus (SES) were compared with everolimus (EES), zotarolimus (ZES) or biolimus A9 (BES) DES. G2 varied in metal alloy, strut thickness and type of drug-eluting matrix. Overall, G2 DES were associated with a 26% relative risk reduction (RRR) of MI (relative risk [RR]=0.74, 95% CI: 0.61-0.90, p=0.003) and ST (RR=0.70, 95% CI: 0.55-0.89, p=0.004), while no significant benefit was observed for ID-TLR and death. Use of 2G DES was associated with a significant reduction in the risk of ID-TLR (RR=0.66, 95% CI: 0.51-0.85, p=0.002), MI (RR=0.60, 95% CI: 0.49-0.72, p<0.001) and ST (RR=0.41, 95% CI: 0.26-0.65, p=0.001) when compared with PES. Strut thickness ≤91 µm in G2 DES was associated with a significantly lower risk of MI (RR=0.54, 95% CI: 0.51-0.86, p=0.002).

CONCLUSIONS

The introduction of thinner stent struts and other technological improvements made in G2 DES technology have translated into better patient outcomes. Overall, the net benefit of G2 DES over G1 DES is expressed in terms of ID-TLR and ST risk reduction but it could be masked by heterogeneities in the use of G1 comparators and the use of non-inferiority study designs in RCTs.

Clinical Presentation and Outcomes of Coronary In-Stent Restenosis Across 3-Stent Generations

Background—

Clinical presentation of bare metal stent in-stent restenosis (ISR) in patients undergoing target lesion revascularization is well characterized and negatively affects on outcomes, whereas the presentation and outcomes of first- and second-generation drug-eluting stents (DESs) remains under-reported.

Methods and Results—

The study included 909 patients (1077 ISR lesions) distributed as follows: bare metal stent (n=388), first-generation DES (n=425), and second-generation DES (n=96), categorized into acute coronary syndrome (ACS) or non-ACS presentation mode at the time of first target lesion revascularization. ACS was further classified as myocardial infarction (MI) and unstable angina. For bare metal stent, first-generation DES and second-generation DES, ACS was the clinical presentation in 67.8%, 71.0%, and 66.7% of patients, respectively ( P =0.470), whereas MI occurred in 10.6%, 10.1%, and 5.2% of patients, respectively ( P =0.273). The correlates for MI as ISR presentation were current smokers (odds ratio, 3.02; 95% confidence interval [CI], 1.78–5.13; P <0.001), and chronic renal failure (odds ratio, 2.73; 95% CI, 1.60–4.70; P <0.001), with a protective trend for the second-generation DES ISR (odds ratio, 0.35; 95% CI, 0.12–1.03; P =0.060). ACS presentations had an independent effect on major adverse cardiac events (death, MI, and re-target lesion revascularization) at 6 months (MI versus non-ACS: adjusted hazard ratio, 4.06; 95% CI, 1.84–8.94; P <0.001; unstable angina versus non-ACS: adjusted hazard ratio, 1.98; 95% CI, 1.01–3.87; P =0.046).

Conclusions—

ISR clinical presentation is similar irrespective of stent type. MI as ISR presentation seems to be associated with patient and not device-related factors. ACS as ISR presentation has an independent effect on major adverse cardiac events, suggesting that ISR remains a hazard and should be minimized.

Coronary stent occlusion: reverse attenuation gradient sign observed at computed tomography angiography improves diagnostic performance

OBJECTIVES

To evaluate the incidence and diagnostic performance of reverse attenuation gradient (RAG) sign in patients with coronary stent occlusion.

METHODS

We retrospectively included patients with suspected restenosis who underwent both coronary computed tomography angiography (CCTA) and invasive coronary angiography (ICA) within 2 weeks. Stent occlusion at CCTA was defined as (1) complete contrast filling defect of large calibre stents (at least 3 mm), or (2) presence of RAG sign in patients with small calibre stents (less than 3 mm) or (3) presence of RAG sign in patients with non-diagnostic image quality of stents. The diagnostic performance of RAG sign was further assessed by comparison to ICA results.

RESULTS

A total of 162 patients with 231 implanted stents were included. ICA confirmed stent occlusion in 59 patients (99 stents). RAG sign was present in 59.3% (35/59) of all stent occlusions. As shown by patient-based analysis, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of our diagnostic criteria for detection of stent occlusion were 79.7% (47/59), 100% (103/103), 100% (47/47) and 89.6% (103/115) respectively. Superior diagnostic performance was confirmed by receiver operating characteristic (ROC) analysis with an area under the curve of 0.898.

CONCLUSIONS

RAG sign observed at CCTA in patients with coronary stenting represents reverse collateral flow distal to stents and is highly specific to indicate stent occlusion.

KEY POINTS

• RAG sign in patients with previous stents represents retrograde collateral flow. • RAG sign in patients with previous stents indicates stent occlusion. • RAG sign improves detection of stent occlusion in small calibre stents.

Incidence and classification of neointimal proliferation and in-stent restenosis in post-stenting patients at 1-year interval: findings from non-invasive coronary computed tomography angiography

OBJECTIVES

To evaluate the incidence of coronary in-stent restenosis (ISR) and neointimal proliferation by coronary CT angiography (CCTA) at 1-year follow-up in asymptomatic patients.

METHODS

234 patients (mean age: 67 ± 10.2 years, range 39-88 years, 180 males and 54 females) with 379 stents were prospectively enrolled in this study. Binary ISR was classified by CCTA into 4 types using Mehran classification. Neointimal proliferation was similarly classified into focal and diffuse types. All patients with CCTA-revealed ISR or neointimal proliferation underwent further invasive coronary angiography (ICA) for validation. Fisher's exact test was used for comparison.

RESULTS

ICA revealed patent stents with neointimal proliferation in 39 patients (16.7%, 39/234) and binary ISR in 23 patients (9.8%, 23/234). Lesion-based analysis showed 12 type I ISR lesions, 4 type II ISR lesions, 1 type III ISR lesion and 7 type IV ISR lesions. Among cases with neointimal proliferation, 27 lesions were classified as focal type whereas 13 lesions were classified as diffuse type. Patients with diabetes mellitus were associated with higher incidence of CCTA-revealed neointimal proliferation (21/77 vs. 18/157, p=0.002) as well as ISR (12/77 vs. 11/157, p=0.038), compared to patients without diabetes. CCTA was found to have good diagnostic performance for neointimal proliferation and ISR detection as well as classification, with an overall accuracy of 84.4% (54/64).

CONCLUSIONS

Silent ISR as well as neointimal proliferation is not uncommon findings in asymptomatic post-stenting patients at 1-year interval, as revealed by CCTA. Patients with diabetes are prone to have higher incidence of neointimal proliferation.

The association of diabetes mellitus with clinical outcomes after coronary stenting: a meta-analysis

Background

Previous studies have shown inconsistent results on the association between diabetes mellitus (DM) and some clinical outcomes. We conducted a meta-analysis of observational studies to assess effect of DM on clinical outcomes after coronary stenting.

Methods

We searched for studies without language restriction in PubMed, Embase and Cochrane library prior to 2012. The clinical outcomes including in-stent restenosis (ISR), major adverse cardiac events (MACE), stent thrombosis (ST), target lesion revascularization (TLR) and target vessel revascularization (TVR). Adjusted odds ratio (OR), and the corresponding 95% confidence interval (95% CI) was summarized.

Results

55 studies involving 128,084 total patients (38,416 DM patients and 89,668 controls) were eligible for our analysis. Overall, there were significant associations between DM and ISR (OR = 1.70, 95% CI: 1.53–1.89, I² = 0.0%), MACE (OR = 1.54, 95% CI: 1.36–1.73, I² = 29.0%), ST (OR = 2.01, 95% CI: 1.36–2.97, I² = 47.7%), TLR (OR = 1.46, 95% CI: 1.26–1.68, I² = 43.3%) as well as TVR (OR = 1.33, 95% CI: 1.17–1.51, I² = 48.3). Subgroup analysis showed that the associations were similar between BMS and DES implantation. Moreover, there was no significant association in the ST subgroup after 1–3 years follow-up.

Conclusions

Our meta-analysis suggests that after coronary stent implantation, DM is associated with ISR, MACE, ST, TLR and TVR. DM appears to be a vital risk factor of these clinical outcomes.

Treatment of sirolimus-eluting stent restenosis: additional stent, balloon angioplasty, and coronary artery bypass graft

OBJECTIVE

Sirolimus-eluting stent (SES) has shown a significant efficacy in reducing restenosis after percutaneous coronary interventions. However, an increase in total number of SES use along with targeting more complex lesions generated a large number of SES restenosis. This study aimed to investigate the clinical and angiographic outcomes of different revascularization strategies for SES restenosis.

METHODS AND RESULTS

A total of 176 lesions in 149 patients were included in the study. Fifteen patients underwent coronary artery bypass graft surgery (CABG group) and the remaining patients were treated with percutaneous coronary intervention (PCI). Stent reimplantation was performed in 88 patients (Stent group), whereas 46 patients received balloon therapy (Balloon group). Among 176 lesions, major cardiac adverse event (MACE) occurred in 41 lesions (23.3%) during a median follow-up of 310 days (interquartile range: 146-517 days). The Kaplan-Meier method with a log-rank test revealed no significant difference in MACE rates between the three groups (6%, 25%, 26%, p = 0.13; CABG group, Stent group, Balloon group, respectively). However, when the Balloon group and Stent group were combined together as a PCI group, PCI group had a significantly higher rate of MACE compared with the CABG group (p = 0.04). In addition, angiographic restenosis was significantly less prevalent in the CABG group when compared with the other two groups (8%, 57%, 46%, p = 0.006; CABG group, Stent group, Balloon group, respectively).

CONCLUSIONS

CABG surgery for patients with SES restenosis is associated with the better clinical outcomes as well as better angiographic outcomes when compared with that of PCI.

Restenosis after PCI. Part 2: prevention and therapy

The techniques and materials used during percutaneous coronary intervention have advanced considerably over the past 3 decades, yet restenosis remains one of the major drawbacks of this procedure. Many innovative technologies, including drug-eluting stents, with or without specific polymers, and fully biodegradable stents have been and continue to be developed in the search for a safe and effective antirestenosis therapy. Remarkable advances in stent design and nanoparticle delivery systems ('nanovehicles') have already fueled revolutionary changes in the prevention and treatment of in-stent restenosis. In this Review we provide an overview of the latest innovations for optimizing outcomes of coronary stenting, and up-to-date information about prevention and treatment of in-stent restenosis.

In-stent restenosis in the drug-eluting stent era

The introduction of the drug-eluting stent (DES) proved to be an important step forward in reducing rates of restenosis and target lesion revascularization after percutaneous coronary intervention. However, the rapid implementation of DES in standard practice and expansion of the indications for percutaneous coronary intervention to high-risk patients and complex lesions also introduced a new problem: DES in-stent restenosis (ISR), which occurs in 3% to 20% of patients, depending on patient and lesion characteristics and DES type. The clinical presentation of DES ISR is usually recurrent angina, but some patients present with acute coronary syndrome. Mechanisms of DES ISR can be biological, mechanical, and technical, and its pattern is predominantly focal. Intravascular imaging can assist in defining the mechanism and selecting treatment modalities. Based upon the current available evidence, an algorithm for the treatment approaches to DES restenosis is proposed.