Restenosis after successful percutaneous transluminal coronary angioplasty: serial angiographic follow-up of 229 patients

Update on drug-eluting coronary stents

The introduction of drug-eluting stents (DES) to interventional cardiology practice has resulted in a significant improvement in the long-term efficacy of percutaneous coronary interventions. DES successfully combine mechanical benefits of bare-metal stents and stabilizing the lumen, with direct delivery and the controlled elution of a pharmacologic agent to the injured vessel wall to suppress further neointimal proliferation. The dramatic reduction in restenosis has resulted in the implementation of DES in clinical practice, and has rapidly expanded the whole spectrum of successfully treatable coronary conditions, particularly in high-risk patients and complex lesions. In this review the authors present current data on DES. Currently, two types of DES are available in the USA: sirolimus-eluting stents (SES) CYPHER (Cordis Corp., FL, USA) and paclitaxel-eluting stents (PES) TAXUS (Boston Scientific, MA, USA), and many more are on the way to approval. In addition to sirolimus and paclitaxel, several other drugs have been successfully used in DES. Everolimus and ABT-578 are both analogs of sirolimus that also have immunosuppressive and antiproliferative properties. Another approach in the development of DES is to use drugs that can accelerate re-endothelialization and restore normal endothelial function following vascular injury. Recent advances in vascular gene transfer have also demonstrated potential new treatment modalities for cardiovascular disease, particularly in the treatment of vascular restenosis.

Head-to-head comparison of a drug-free early programmed dismantling polylactic acid bioresorbable scaffold and a metallic stent in the porcine coronary artery: six-month angiography and optical coherence tomographic follow-up study

BACKGROUND

We aimed to evaluate a new drug-free fully bioresorbable lactic acid-based scaffold designed to allow early dismantling synchronized with artery wall healing in comparison with a bare metal stent (BMS).

METHODS AND RESULTS

Twenty-three BMS (3.0×12 mm) and 36 lactic acid-based bioresorbable scaffolds (BRS, 3.0×11 mm) were implanted in porcine coronary arteries. QCA and optical coherence tomographic analyses were performed immediately after implantation and repeated after 1, 3, and 6 months. Microcomputed tomography was used to detect scaffold dismantling. Polymer degradation was evaluated throughout the study. The primary end-point was late lumen loss, and the secondary end-points were scaffold/stent diameter and acute recoil. Acute recoil was low and comparable between the BRS and the BMS groups (4.6±6.7 versus 4.6±5.1%; P=0.98). BRS outer diameter increased significantly from 1 to 6 months indicating late positive scaffold remodeling (P<0.0001), whereas BMS diameter remained constant (P=0.159). Late lumen loss decreased significantly from 1 to 6 months in the BRS group (P=0.003) without significant difference between BRS and BMS groups at 6 months (P=0.68). Microcomputed tomography identified BRS dismantling starting at 3 months, and weight-average molar masses of scaffold parts were 20% and 14% of their initial values at 3 and 6 months.

CONCLUSIONS

BRS and BMS have similar 6-month outcomes in porcine coronary arteries. Interestingly, BRS dismantling was detected from 3 months and resulted in late lumen enlargement by increased scaffold diameter at 6 months.

Influence of the angiotensin converting enzyme insertion or deletion genetic variant and coronary restenosis risk: evidence based on 11,193 subjects

The insertion/deletion (I/D) polymorphism of the gene encoding angiotensin converting enzyme is a controversial risk factor for restenosis after percutaneous transluminal coronary angioplasties (PTCA) in patients. Genetic association studies can be problematic to reproduce due to insufficient power, phenotypic heterogeneity, population stratification, small effect of the variant and even publication biases. To derive a more precise estimation of the relationship as well as to quantify the between-study heterogeneity and potential bias, a meta-analysis including 11,193 patients from 33 published cohort studies was performed. In a combined analysis, the summary per-allele odds ratio for restenosis was 1.31 (95% CI: 1.08-1.58, P = 0.006), and 1.22 (95% CI: 0.95-1.56, P = 0.12), for PTCA-stent and PTCA-balloon, respectively. In the subgroup analysis by ethnicity, significantly increased restenosis risks after PTCA-stent were found in Asians for the polymorphism; whereas no significant associations were found among Caucasians. As for restenosis risks after PTCA-balloon, no evidence of any gene-disease association was obtained in the stratified analyses according to ethnicity and study size. In conclusion, this meta-analysis demonstrated that the DD homozygous of ACE I/D polymorphism was significantly associated with elevated restenosis susceptibility after PTCA-stent among Asian populations.

Decorin mimic inhibits vascular smooth muscle proliferation and migration

Over the past 10 years, the number of percutaneous coronary intervention procedures performed in the United States increased by 33%; however, restenosis, which inhibits complete functional recovery of the vessel wall, complicates this procedure. A wide range of anti-restenotic therapeutics have been developed, although many elicit non-specific effects that compromise vessel healing. Drawing inspiration from biologically-relevant molecules, our lab developed a mimic of the natural proteoglycan decorin, termed DS-SILY, which can mask exposed collagen and thereby effectively decrease platelet activation, thus contributing to suppression of vascular intimal hyperplasia. Here, we characterize the effects of DS-SILY on both proliferative and quiescent human SMCs to evaluate the potential impact of DS-SILY-SMC interaction on restenosis, and further characterize in vivo platelet interactions. DS-SILY decreased proliferative SMC proliferation and pro-inflammatory cytokine secretion in vitro in a concentration dependent manner as compared to untreated controls. The addition of DS-SILY to in vitro SMC cultures decreased SMC migration and protein synthesis by 95% and 37%, respectively. Furthermore, DS-SILY decreased platelet activation, as well as reduced neointimal hyperplasia by 60%, in vivo using Ossabaw swine. These results indicate that DS-SILY demonstrates multiple biological activities that may all synergistically contribute to an improved treatment paradigm for balloon angioplasty.

Mechanism of edge restenosis after drug-eluting stent implantation. Angulation at the edge and mechanical properties of the stent

BACKGROUND

Edge restenosis is not an unusual finding after implantation of drug-eluting stents (DES). We hypothesized that mechanical stress imposed on the stent edge would cause vessel wall injury and inflammation, which may consequently lead to edge restenosis.

METHODS AND RESULTS

In total, 1,496 patients were implanted with a sirolimus-eluting stent (SES), paclitaxel-eluting stent (PES) or zotarolimus-eluting stent (ZES) in Seoul National University Hospital between 2007 and 2009. Binary restenosis occurred in 161 lesions in 119 patients. We retrospectively compared the 3 DES with regard to the percentage of edge stent restenosis among all cases of restenosis. We also evaluated the maximal, minimal, and Δ (maximal angle-minimal angle) angles. The percentage of edge restenosis was higher for SES than for ZES (37.5% vs. 16.7%, P=0.017). Maximal angle at the proximal edge was 64.82°±33.46° for 26 stents with proximal edge restenosis compared with 31.84°±31.51° for 89 stents without proximal edge restenosis (P=0.001). The Δ angle was also significantly different between the 2 groups (14.81°±15.98° vs. 7.60°±8.86°, P=0.035). Similar findings were observed for distal edge restenosis. Both the maximal angle (39.09°±21.04° vs. 22.71°±22.83°, P=0.010) and Δ angle (20.23°±15.39° vs. 9.18°±9.66°, P=0.016) at the distal edge were significantly different between the 2 groups.

CONCLUSIONS

Physical stress determined by angulation at the stent edge segment and biomechanical properties of the DES can be considered as one of the plausible mechanisms for edge stent restenosis.

Genetic polymorphism of angiotensin converting enzyme and risk of coronary restenosis after percutaneous transluminal coronary angioplasties: evidence from 33 cohort studies

Background

In the past decade, a number of cohort studies studies have been carried out to investigate the relationship between the insertion/deletion polymorphism of the gene encoding angiotensin-converting enzyme and risk of restenosis after percutaneous transluminal coronary angioplasties in patients. However, these studies have yielded contradictory results. Genetic association studies addressing this issue are frequently hampered by insufficient power. We therefore performed a meta-analysis of the published studies to clarify this inconsistency and to establish a comprehensive picture of the relationship between ACE I/D polymorphism and post-PTCA restenosis risk.

Methods

Databases including Pubmed, EMBASE, ISI Web of Science, EBSCO, Cochrane Library databases and CNKI were searched to find relevant studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of association. The random-effects model was applied, addressing heterogeneity and publication bias.

Results

A total of 33 cohort studies involving 11,099 subjects were included. In a combined analysis, the OR for post-PTCA restenosis of the ACE DD genotype was 1.61 (95% CI: 1.27–2.04; P<10⁻⁵). In the subgroup analysis by intervention, significantly increased risks were also found in PTCA-stent and PTCA-balloon for the DD genotype of the polymorphism.

Conclusions

Our meta-analysis showed that the DD genotype of ACE I/D polymorphism was significantly associated with increased risk of restenosis, particularly for PTCA-stent.

Myocardial perfusion imaging after coronary revascularization: a clinical appraisal

Revascularization procedures, including percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG), are performed in many patients with coronary artery disease. Despite the effectiveness of these procedures, different follow-up strategies need to be considered for the management of patients after revascularization. Stress myocardial perfusion single-photon emission computed tomography (MPS) is a suitable imaging method for the evaluation of patients who have undergone PCI or CABG, and it has been used in the follow-up of such patients. Radionuclide imaging is included in the follow-up strategies after PCI and CABG in patients with symptoms, but guidelines warn against routine testing of all asymptomatic patients after revascularization. After PCI, in the absence of symptoms, radionuclide imaging is recommended and indicated as appropriate after incomplete or suboptimal revascularization and in specific asymptomatic patient subsets. On the other hand, the value of MPS late after CABG in risk stratification has been demonstrated even in the absence of symptoms. Thus, given the adverse outcome associated with silent ischaemia, it can be speculated that all patients regardless of clinical status should undergo stress testing late after revascularization. Larger prospective studies are needed to assess whether stress MPS will have an impact on the outcome in asymptomatic patients after revascularization.

Bioresorbable scaffolds in the treatment of coronary artery disease

Drug-eluting stents have reduced the risk of in-stent restenosis and have broadened the application in percutaneous coronary intervention in coronary artery disease. However, the concept of using a permanent metallic endovascular device to restore the patency of a stenotic artery has inherited pitfalls, namely the presence of a foreign body within the artery causing vascular inflammation, late complications such as restenosis and stent thrombosis, and impeding the restoration of the physiologic function of the stented segment. Bioresorbable scaffolds (BRS) were introduced to potentially overcome these limitations, as they provide temporary scaffolding and then disappear, liberating the treated vessel from its cage. Currently, several BRSs are available, undergoing evaluation either in clinical trials or in preclinical settings. The aim of this review is to present the new developments in BRS technology, describe the mechanisms involved in the resorption process, and discuss the potential future prospects of this innovative therapy.

First serial assessment at 6 months and 2 years of the second generation of absorb everolimus-eluting bioresorbable vascular scaffold: a multi-imaging modality study

BACKGROUND

Nonserial observations have shown this bioresorbable scaffold to have no signs of area reduction at 6 months and recovery of vasomotion at 1 year. Serial observations at 6 months and 2 years have to confirm the absence of late restenosis or unfavorable imaging outcomes.

METHODS AND RESULTS

The ABSORB trial is a multicenter single-arm trial assessing the safety and performance of an everolimus-eluting bioresorbable vascular scaffold. Forty-five patients underwent serial invasive imaging, such as quantitative coronary angiography, intravascular ultrasound, and optical coherence tomography at 6 and 24 months of follow-up. From 6 to 24 months, late luminal loss increased from 0.16±0.18 to 0.27±0.20 mm on quantitative coronary angiography, with an increase in neointima of 0.68±0.43 mm(2) on optical coherence tomography and 0.17±0.26 mm(2) on intravascular ultrasound. Struts still recognizable on optical coherence tomography at 2 years showed 99% of neointimal coverage with optical and ultrasonic signs of bioresorption accompanied by increase in mean scaffold area compared with baseline (0.54±1.09 mm(2) on intravascular ultrasound, P=0.003 and 0.77±1.33 m(2) on optical coherence tomography, P=0.016). Two-year major adverse cardiac event rate was 6.8% without any scaffold thrombosis.

CONCLUSIONS

This serial analysis of the second generation of the everolimus-eluting bioresorbable vascular scaffold confirmed, at medium term, the safety and efficacy of the new device.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00856856.

Krüppel-like factor 4 is induced by rapamycin and mediates the anti-proliferative effect of rapamycin in rat carotid arteries after balloon injury

BACKGROUND AND PURPOSE

The transcription factor, Krüppel-like factor 4 (KLF4), plays an important role in regulating the proliferation of vascular smooth muscle cells. This study aimed to examine the effect of rapamycin on the expression of KLF4 and the role of KLF4 in arterial neointimal formation.

EXPERIMENTAL APPROACH

Expression of KLF4 was monitored using real-time PCR and immunoblotting in cultured vascular smooth muscle cells. and in rat carotid arteries in vivo after balloon injury. Adenovirus-mediated overexpression and siRNA-mediated knockdown of KLF4 were used to examine the role of KLF4 in mediating the anti-proliferative role of rapamycin . KLF4-regulated genes were identified using cDNA microarray.

KEY RESULTS

Rapamycin induced the expression of KLF4 in vitro and in vivo. Overexpression of KLF4 inhibited cell proliferation and the activity of mammalian target of rapamycin (mTOR) and its downstream pathways, including 4EBP-1 and p70S6K in vascular smooth muscle cells and prevented the neointimal formation in the balloon-injured arteries. KLF4 up-regulated the expression of GADD45β, p57(kip2) and p27(kip1) . Furthermore, knockdown of KLF4 attenuated the anti-proliferative effect of rapamycin both in vitro and in vivo.

CONCLUSIONS AND IMPLICATIONS

KLF4 plays an important role in mediating the anti-proliferative effect of rapamycin in VSMCs and balloon-injured arteries. Thus, it is a potential target for the treatment of proliferative vascular disorders such as restenosis after angioplasty.

Long-term luminal change after drug-eluting stent implantation: serial angiographic follow-up study of the ZEST randomized trial

OBJECTIVE

To evaluate long-term patterns of luminal changes after implantation of different types of drug-eluting stents (DES), we analyzed the serial angiographic outcomes of patients implanted with zotarolimus-eluting stents (ZES), sirolimus-eluting stents (SES), or paclitaxel-eluting stents (PES).

BACKGROUND

Little is known regarding long-term luminal changes after DES implantation.

METHODS

As a subgroup analysis of the ZEST trial, we performed complete angiographic evaluation immediately after the procedure and at 9 months and 2 years in 111 patients with 165 lesions (36 patients with ZES, 40 with SES, and 35 with PES).

RESULTS

Baseline clinical, angiographic, and procedural characteristics were similar among the three groups. Quantitative angiographic analysis revealed significant decreases in minimal luminal diameter 9 months after stent implantation in the ZES (from 2.71 ± 0.49 to 2.21 ± 0.42 mm, P < 0.001), SES (from 2.79 ± 0.49 to 2.58 ± 0.57 mm, P < 0.001), and PES (from 2.66 ± 0.45 to 2.19 ± 0.52 mm, P < 0.001) groups. However, significant late improvements with different degree in luminal diameter were observed between 9 months and 2 years in the ZES (from 2.21 ± 0.42 to 2.39 ± 0.58 mm, P = 0.001), SES (from 2.58 ± 0.57 to 2.66 ± 0.60 mm, P = 0.039), and PES (from 2.19 ± 0.52 to 2.43 ± 0.52 mm, P < 0.001) groups.

CONCLUSION

Serial angiographic follow-up study revealed a biphasic luminal response after DES implantation, characterized by an early progression phase for the first 9 months and a late regression phase from 9 months to 2 years.

Everolimus-eluting ABSORB bioresorbable vascular scaffold: present and future perspectives

Everolimus-eluting ABSORB bioresorbable vascular scaffolds represent a novel approach that provides transient vessel support with drug-delivery capability without the long-term limitations of the metallic drug-eluting stents (DESs). The technology has the potential to overcome many of the safety concerns associated with metallic DESs and possibly even convey further clinical benefit. In particular the scaffold is designed for providing a short-term lumen support (up to 6-12 months) and for thereafter being completely bioresorbed, eliminating the permanent caging typical of the metallic DES. The first clinical studies testing this device in a small number of patients have shown very promising results with good clinical outcome up to 5 years' follow-up, highlighting important morphological and functional modifications at the scaffolded segment level, such as late lumen enlargement and recuperation of a normal vasoreactivity. A randomized trial, comparing ABSORB with the Xience Prime stent, will evaluate the efficacy and safety of this device in a wide population.

Evaluation of the second generation of a bioresorbable everolimus-eluting vascular scaffold for the treatment of de novo coronary artery stenosis: 12-month clinical and imaging outcomes

OBJECTIVES

The aim of this study was to demonstrate that the prevention of early scaffold area shrinkage of the ABSORB BVS (Rev.1.1, Abbott Vascular, Santa Clara, California) was sustained and not simply delayed by a few months.

BACKGROUND

With improved scaffold design and modified manufacturing process of its polymer, the second iteration of ABSORB (BVS 1.1) has improved performance to prevent a scaffold area reduction at 6 months.

METHODS

Fifty-six patients were enrolled and received 57 ABSORB scaffolds. Quantitative coronary angiography, intravascular ultrasound (IVUS), analysis of radiofrequency backscattering, echogenicity and optical coherence tomography (OCT) were performed at baseline and at 12-month follow-up.

RESULTS

Overall the scaffold area remained unchanged with IVUS as well as with OCT, whereas the radiofrequency backscattering and the echogenicity of the struts decreased by 16.8% (p < 0.001) and 20% (p < 0.001), respectively; more specifically, the strut core area on OCT decreased by 11.4% (p = 0.003). Despite the absence of scaffold area loss, pharmacological vasomotion was restored. On an intention-to-treat basis, the angiographic late lumen loss amounted to 0.27 ± 0.32 mm with an IVUS relative decrease in minimal lumen area of 1.94% (p = 0.12), without significant changes in mean lumen area. The OCT at follow-up showed that 96.69% of the struts were covered and that malapposition, initially observed in 18 scaffolds was only detected at follow-up in 4 scaffolds. Two patients experienced peri-procedural and iatrogenic myocardial infarction, respectively, whereas 2 underwent repeat intervention, resulting in the major adverse cardiac event rate of 7.1% (4 of 56).

CONCLUSIONS

The 12-month performance of the second-generation ABSORB bioresorbable everolimus-eluting scaffold justifies the conduct of a randomized trial against current best standards. (A Clinical Evaluation of the Bioabsorbable Everolimus Eluting Coronary Stent System [BVS EECSS] in the Treatment of Patients With de Novo Native Coronary Artery Lesions; NCT00856856).

Impact of small thrombus formation in restenotic bare-metal stent lesions associated with acute coronary syndrome: identification by optical coherence tomography

BACKGROUND

Although in-stent restenosis (ISR) after bare-metal stent (BMS) implantation is considered to be clinically benign, ISR is often associated with adverse complications, such as acute coronary syndrome (ACS). The frequency, type, and location of thrombi in ISR lesions and their clinical presentation have not yet been precisely validated.

METHODS

Thirty angiographic ISR lesions occurring within 3 to 8 months after stenting were evaluated by optical coherence tomography (OCT). A thrombus was defined as a mass protruding into the lumen with an irregular surface, and its type was divided into red or white. The maximum size of a thrombus and the longitudinal distance from the thrombus to the narrowest lumen were measured.

RESULTS

A thrombus was identified in 2 patients by angiography and in 10 patients by OCT (7% vs. 33%; P=0.01). OCT showed that 9 patients had white thrombus and another patient had both types of thrombi. ACS relevant to ISR was seen in 6 patients, and the frequency of ACS was significantly higher in patients with thrombus than in those without thrombus [50% (5/10) vs. 5% (1/20); P=0.003]. The maximum size of the thrombus was 412 ± 220 µm in height, 424 ± 251 µm in width, and the longitudinal distance between the thrombus and the minimum lumen area was 0.3 ± 0.7 mm.

CONCLUSIONS

One third of ISR lesions following BMS deployment dominantly contained a white thrombus, and half of them were associated with ACS. A small thrombus formation adjacent to the narrowest lumen in an ISR lesion may therefore contribute to the clinical presentation of ACS.

Targeted disruption of the prostaglandin E2 E-prostanoid 2 receptor exacerbates vascular neointimal formation in mice

OBJECTIVE

Restenosis after angioplasty remains a major clinical problem. Prostaglandin E(2) (PGE(2)) plays an important role in vascular homeostasis. The PGE(2) receptor E-prostanoid 2 (EP2) is involved in the proliferation and migration of various cell types. We aimed to determine the role of EP2 in the pathogenesis of neointimal formation after vascular injury.

METHODS AND RESULTS

Wire-mediated vascular injury was induced in the femoral arteries of male wild-type (EP2+/+) and EP2 gene-deficient (EP2-/-) mice. In EP2+/+ mice, EP2 mRNA expression was increased in injured vessels for at least 4 weeks after vascular injury. Neointimal hyperplasia was markedly accelerated in EP2-/- mice, which was associated with increased proliferation and migration of vascular smooth muscle cells (VSMCs) and increased cyclin D1 expression in the neointima layer. Platelet-derived growth factor-BB (PDGF-BB) treatment resulted in more significant cell proliferation and migration in VSMCs of EP2-/- mice than in those of EP2+/+ mice. Activation and overexpression of EP2 attenuated PDGF-BB-elicited cell proliferation and migration, induced G(1)→S-phase arrest and reduced PDGF-BB-stimulated extracellular signal-regulated kinase phosphorylation in EP2+/+ VSMCs.

CONCLUSIONS

These findings reveal a novel role of the EP2 receptor in neointimal hyperplasia after arterial injury. The EP2 receptor may represent a potential therapeutic target for restenosis after angioplasty.

Nitric oxide-dependent bone marrow progenitor mobilization by carbon monoxide enhances endothelial repair after vascular injury

BACKGROUND

Carbon monoxide (CO) has emerged as a vascular homeostatic molecule that prevents balloon angioplasty-induced stenosis via antiproliferative effects on vascular smooth muscle cells. The effects of CO on reendothelialization have not been evaluated.

METHODS AND RESULTS

Exposure to CO has diametrically opposite effects on endothelial cell (EC) and vascular smooth muscle cell proliferation in rodent models of carotid injury. In contrast to its effect of blocking vascular smooth muscle cell growth, CO administered as a gas or as a CO-releasing molecule enhances proliferation and motility of ECs in vitro by >50% versus air controls, and in vivo, it accelerates reendothelialization of the denuded artery by day 4 after injury versus day 6 in air-treated animals. CO enhanced EC proliferation via rapid activation of RhoA (Ras homolog gene family, member A), followed by downstream phosphorylation of Akt, endothelial nitric oxide (NO) synthase phosphorylation, and a 60% increase in NO generation by ECs. CO drives cell cycle progression through phosphorylation of retinoblastoma, which is dependent in part on endothelial NO synthase-generated NO. Similarly, endothelial repair in vivo requires NO-dependent mobilization of bone marrow-derived EC progenitors, and CO yielded a 4-fold increase in the number of mobilized green fluorescent protein-Tie2-positive endothelial progenitor cells versus controls, with a corresponding accelerated deposition of differentiated green fluorescent protein-Tie2-positive ECs at the site of injury. CO was ineffective in augmenting EC repair and the ensuing development of intimal hyperplasia in eNOS(-/-) mice.

CONCLUSIONS

Collectively, the present data demonstrate that CO accelerates EC proliferation and vessel repair in a manner dependent on NO generation and enhanced recruitment of bone marrow-derived endothelial progenitor cells.

Durability of antirestenotic efficacy in drug-eluting stents with and without permanent polymer

OBJECTIVES

We sought to assess changes in antirestenotic efficacy of drug-eluting stents (DES) by restudying subjects at 2 time points after coronary stenting (6 to 8 months and 2 years) and to compare differences in time courses of late luminal loss (LLL) between 3 different DES platforms in use at our institution.

BACKGROUND

DES therapy is associated with low levels of LLL at 6 to 8 months. The temporal course of neointimal formation after this time point remains unclear.

METHODS

This prospective, observational, systematic angiographic follow-up study was conducted at 2 centers in Munich, Germany. Patients underwent stenting with permanent-polymer rapamycin-eluting stents (RES), polymer-free RES, or permanent-polymer paclitaxel-eluting stents (PES). The primary end point was delayed LLL (the difference in in-stent LLL between 6 to 8 months and 2 years).

RESULTS

Of 2,588 patients undergoing stenting, 2,030 patients (78.4%) had 6- to 8-month angiographic follow-up and were enrolled in the study. Target lesion revascularization was performed in 259 patients; these patients were not considered for further angiographic analysis. Of 1,771 remaining patients, 1,331 had available 2-year reangiographic data (75.2%). Overall mean (SD) delayed LLL was 0.12 +/- 0.49 mm (0.17 +/- 0.50 mm, 0.01 +/- 0.42 mm, and 0.13 +/- 0.50 mm in permanent-polymer RES, polymer-free RES, and permanent-polymer PES groups, respectively [p < 0.001]). In multivariate analysis, only stent type (in favor of polymer-free RES) predicted delayed LLL.

CONCLUSIONS

Ongoing erosion of luminal caliber beyond 6 to 8 months after the index procedure is observed following DES implantation. Absence of permanent polymer from the DES platform seems to militate against this effect.

Very late changes in the dilated lesion following coronary balloon angioplasty: a 17 year serial quantitative angiographic study

AIMS

Limited data are available on the changes that occur at the dilated site many years after coronary balloon angioplasty. The development of bioabsorbable stents may increase the importance of understanding the long term changes that occur in an unscaffolded coronary artery following balloon-mediated injury.

METHODS AND RESULTS

This study evaluated, by serial quantitative angiography, the natural history of changes that occurred in the dilated segment between early (mean seven months), late (mean 4.5 years) and very late (mean 17 years) follow-up after balloon angioplasty. Of 127 consecutive patients (174 lesions) with successful coronary angioplasty, 125 underwent early, 84 late and 47 very late angiographic follow-up (75% of eligible survivors). The mean lesion diameter stenosis decreased from 36+/-11% at early to 26+/-15% at late follow-up (p<0.0001), and then increased again to 35+/-25% by very late follow-up (p=0.003). Although stenosis severity at early follow-up angiography predicted lesion regression at late follow-up, there was no significant correlation between late and very late follow-up lesion severity.

CONCLUSIONS

After coronary angioplasty, lesion regression at the dilated site from 7 months to 4.5 years is followed by slow lesion progression over the next 12 years.

A genome wide association analysis in the GENDER study

Percutaneous coronary intervention (PCI) has become an effective therapy to treat coronary artery diseases. However, one of the major drawbacks of PCI is the occurrence of restenosis in 8 to 40% of all treated patients. The GENetic Determinants of Restenosis (GENDER) project was designed to study the association between genetic polymorphisims and clinical restenosis. The discovery of genetic variants associated to the occurrence of restenosis after PCI may provide a more tailored therapy and may serve as rationale for new antirestenotic therapies. So far, several candidate gene approaches had already been performed in the GENDER samples but a Genome Wide Association Scan (GWAS) was still lacking. Here, we present preliminary results from the GWAS we are currently carrying out in the GENDER population. (Neth Heart J 2009;17:262-4.).

eNOS activation by physical forces: from short-term regulation of contraction to chronic remodeling of cardiovascular tissues

Nitric oxide production in response to flow-dependent shear forces applied on the surface of endothelial cells is a fundamental mechanism of regulation of vascular tone, peripheral resistance, and tissue perfusion. This implicates the concerted action of multiple upstream "mechanosensing" molecules reversibly assembled in signalosomes recruiting endothelial nitric oxide synthase (eNOS) in specific subcellular locales, e.g., plasmalemmal caveolae. Subsequent short- and long-term increases in activity and expression of eNOS translate this mechanical stimulus into enhanced NO production and bioactivity through a complex transcriptional and posttranslational regulation of the enzyme, including by shear-stress responsive transcription factors, oxidant stress-dependent regulation of transcript stability, eNOS regulatory phosphorylations, and protein-protein interactions. Notably, eNOS expressed in cardiac myocytes is amenable to a similar regulation in response to stretching of cardiac muscle cells and in part mediates the length-dependent increase in cardiac contraction force. In addition to short-term regulation of contractile tone, eNOS mediates key aspects of cardiac and vascular remodeling, e.g., by orchestrating the mobilization, recruitment, migration, and differentiation of cardiac and vascular progenitor cells, in part by regulating the stabilization and transcriptional activity of hypoxia inducible factor in normoxia and hypoxia. The continuum of the influence of eNOS in cardiovascular biology explains its growing implication in mechanosensitive aspects of integrated physiology, such as the control of blood pressure variability or the modulation of cardiac remodeling in situations of hemodynamic overload.

Paclitaxel-eluting versus bare-metal stents in acute ST elevation myocardial infarction (STEMI)

INTRODUCTION

Data comparing efficacy and safety of drug eluting stents (DES), particularly paclitaxel stent with bare metal stents (BMS) in the setting of acute ST elevation myocardial infarction (STEMI) is limited and inconclusive. The aim of our study is to compare the efficacy and safety of paclitaxel stent with bare metal stent in acute STEMI.

METHODS

A retrospective cohort study was performed on patients from our single community hospital who participated in the C-PORT trial from January 2003 to May 2005. One hundred forty-three patients treated exclusively with either BMS or paclitaxel DES were included (79 with paclitaxel DES and 64 with BMS) and were followed at 1, 3, and 6 months. The primary outcome was occurrence of major adverse cardiac events defined as cardiac death, STEMI or NSTEMI or the need for target vessel revascularization. Variables were compared using appropriate statistics and event free survival curves were estimated.

RESULTS

Baseline clinical characteristics in BMS and paclitaxel DES groups were well matched. No statistical difference between BMS and DES groups in the rate of cardiac death (6% vs. 9%, P = 0.56), STEMI or NSEMI (1.6% vs. 1.3% respectively, P = 0.88) and composite end point (13% vs. 10%, P = 0.65) was observed while a significant reduction in target vessel revascularization was seen in DES group (6% vs. 0% respectively, P = 0.02) was noticed.

CONCLUSION

In our patient group with acute STEMI, the use of paclitaxel DES did not show significant decrease in cumulative end points, cardiac mortality and recurrent STEMI or NSTEMI compared with BMS over a 6-month follow-up period. However, a significant reduction in revascularization of target vessel was seen.

Catheter-Based Treatment of Coronary Artery Disease

September 2007 marked the 30-year anniversary of the first human percutaneous coronary intervention, an index event that changed the course of modern-day cardiovascular care. Before that first procedure, adult invasive cardiology focused on diagnostic angiography as well as hemodynamic assessment of structural heart disease. Since that initial procedure, percutaneous coronary intervention has become the most frequently performed coronary revascularization procedure worldwide. Several factors have been responsible for this dramatic paradigm shift, the most prominent being identification of opportunities for technical improvement and the application of innovation and investigation in concert with colleagues, professional societies, and industry. These approaches will continue to be of paramount importance as new technologies are brought to bear on an increasingly broader group of patients with cardiovascular disease.

Impact of obstructive sleep apnea on the occurrence of restenosis after elective percutaneous coronary intervention in ischemic heart disease

Rationale

There is growing evidence that obstructive sleep apnea is associated with coronary artery disease. However, there are no data on the course of coronary stenosis after percutaneous coronary intervention in patients with obstructive sleep apnea.

Objectives

To determine whether sleep apnea is associated with increased late lumen loss and restenosis after percutaneous coronary intervention.

Methods

78 patients with coronary artery disease who underwent elective percutaneous coronary intervention were divided in 2 groups: 43 patients with an apnea hypopnea – Index < 10/h (group I) and 35 pt. with obstructive sleep apnea and an AHI > 10/h (group II). Late lumen loss, a marker of restenosis, was determined using quantitative coronary angiography after 6.9 ± 3.1 months.

Main results

Angiographic restenosis (>50% luminal diameter), was present in 6 (14%) of group I and in 9 (25%) of group II (p = 0.11). Late lumen loss was significant higher in pt. with an AHI > 10/h (0.7 ± 0.69 mm vs. 0.38 ± 0.37 mm, p = 0.01). Among these 35 patients, 21(60%) used their CPAP devices regularly. There was a marginally lower late lumen loss in treated patients, nevertheless, this difference did not reach statistical significance (0.57 ± 0.47 mm vs. 0.99 ± 0.86 mm, p = 0.08). There was no difference in late lumen loss between treated patients and the group I (p = 0.206).

Conclusion

In summary, patients with OSA and coronary artery disease have a higher degree of late lumen loss, which is a marker of restenosis and vessel remodeling after elective percutaneous intervention.

Update on drug-eluting stents for prevention of restenosis

Despite the success of coronary stent implantations in the last decade, in-stent restenosis due to neointimal hyperplasia remains a problem to overcome. Neointimal hyperplasia is a vascular response to stent injury and mainly consists of proliferation of smooth muscle cells and deposition of extracellular matrix. Recently, local drug delivery has been advocated as a potential strategy to prevent in-stent restenosis. Unprecedented results have been obtained in early clinical studies on sirolimus-eluting and paclitaxel-eluting stents. Trials using various pharmaceutical coatings on different coronary stents are ongoing. More types of drug-eluting stents are expected on the market in the near future. Meanwhile, the evaluation of drug-eluting stents is entering the second phase in which the safety and efficacy in more complex lesion subsets and different clinical presentations are being investigated. Results including cost-benefit analyses are expected to have a tremendous impact on the practice of interventional cardiology in the next decade.

Mouse strain differential neointimal response in vein grafts and wire-injured arteries

BACKGROUND

Neointimal development is seen clinically after both vein grafting and balloon catheterization, but may not represent the same pathology under these 2 conditions. This study compared the degree of neointimal hyperplasia after vein grafting or arterial-injury grafts in 2 strains of mice: C57Bl/6 and FVB.

METHODS AND RESULTS

Jugular vein branches were interpositioned as grafts in the femoral artery of syngenic-matched mice, with graft harvest at 30 days. Wire-injured carotid arteries were grafted to the carotid arteries of syngenic-matched mice, with graft harvest at 14 days. Histomorphometry revealed no strain differences in vein grafts in the extent of position-dependent neointimal thickening or lumen cross-sectional area. Both strains showed significantly thicker neointima and less lumen area at the proximal graft site (vs the mid-graft; p<0.05). In contrast, a significantly greater neointimal thickness was found in the wire-injured carotid grafts of FVB mice vs those of C57Bl/6 mice (p<0.05).

CONCLUSIONS

Neointimal formation shows a vessel-dependent, strain-dependent difference, with greater arterial neointimal thickening in FVB mice. These data suggest that different mechanisms operate for arterial-injury- vs vein-graft-associated neointimal development and that the difference has a genetic basis.

Circulating progenitor cells contribute to neointimal formation in nonirradiated chimeric mice

Recent evidence suggests that bone marrow-derived cells may contribute to repair and lesion formation following vascular injury. In most studies, bone marrow-derived cells were tracked by transplanting exogenous cells into bone marrow that had been compromised by irradiation. It remains to be determined whether endogenous circulating progenitors actually contribute to arterial remodeling under physiological conditions. Here, we established a parabiotic model in which two mice were conjoined subcutaneously without any vascular anastomosis. When wild-type mice were joined with transgenic mice that expressed green fluorescent protein (GFP) in all tissues, GFP-positive cells were detected not only in the peripheral blood but also in the bone marrow of the wild-type mice. The femoral arteries of the wild-type mice were mechanically injured by insertion of a large wire. At 4 wk, there was neointima hyperplasia that mainly consisted of alpha-smooth muscle actin-positive cells. GFP-positive cells were readily detected in the neointima (14.8+/-4.5%) and media (31.1+/-8.8%) of the injured artery. Some GFP-positive cells expressed alpha-smooth muscle actin or an endothelial cell marker. These results indicate that circulating progenitors contribute to re-endothelialization and neointimal formation after mechanical vascular injury even in nonirradiated mice.

Meta-analysis comparing clinical effectiveness of drug-eluting stents, bare metal stents and coronary artery bypass surgery

Objective  To compare clinical outcomes among patients receiving drug-eluting stents, bare metal stents, or coronary artery bypass grafting surgery (CABG) to treat coronary artery disease. Data sources  Randomised controlled trials were systematically selected from electronic database for head-to-head comparisons. The results from these head-to-head comparisons were used for an adjusted indirect comparison. Methods  Published randomised controlled trials were reviewed for outcome data in patients treated for coronary artery disease with drug-eluting stents, bare metal stents, or CABG. Head-to-head comparisons were conducted for drug-eluting stents versus bare metal stents and for CABG versus bare metal stents. Adjusted indirect comparison was used to compare drug-eluting stents and CABG. Mid-term clinical outcomes (range: 6-12 months) were investigated and included rates of mortality, myocardial infarction, thrombosis, target lesion revascularisation, target vessel revascularisation, restenosis and major adverse cardiac events. Results  Systematic literature search identified 23 randomised controlled trials (15 for drug-eluting stents vs. bare metal stents, 8 for CABG vs. bare metal stents). Head-to-head comparisons for both single and multiple vessel disease demonstrated that compared with bare metal stents, drug-eluting stents had better outcomes for target lesion revascularisation, target vessel revascularisation, restenosis and major adverse cardiac events. Except target lesion revascularisation, data were similarly favourable for CABG when compared with bare metal stents. Adjusted indirect comparison between drug-eluting stents and CABG in single vessel disease failed to detect significant differences in any of the measured outcomes. Multiple vessel disease data analysis demonstrated that target vessel revascularisation (odds ratio 3.41 [95% CI 2.29-5.08]) and major adverse cardiac events (1.89 [1.28-2.79]) were superior to drug-eluting stents in patients undergoing CABG. Conclusions  Drug-eluting stents and CABG were superior to bare metal stents in terms of target lesion revascularisation (drug-eluting stents only), target vessel revascularisation, restenosis and major adverse cardiac events. There was no difference in clinical outcomes when comparing CABG and drug-eluting stents in patients with single vessel disease, and CABG may be superior to drug-eluting stents for target vessel revascularisation and major adverse cardiac events in patients with multiple vessel disease. However, results may vary between subpopulations with different clinical or socioeconomic differences.

Remnant-like lipoprotein particle level and insulin resistance are associated with in-stent restenosis in patients with stable angina

BACKGROUND

The aim of this study was to evaluate the independent effect of serum remnant-like lipoprotein particle level and insulin resistance on in-stent restenosis in nondiabetic patients with stable angina.

METHODS

The study included 64 nondiabetic patients with stable angina who underwent successful coronary stenting. At the time of stenting, we evaluated the patients' lipid profiles including remnant-like lipoprotein particles cholesterol, plasma glucose and insulin levels, and insulin resistance by the homeostasis model assessment.

RESULTS

There was no significant difference in total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol levels between two patient groups with (n=15) and without (n=49) in-stent restenosis. Plasma remnant-like lipoprotein particles cholesterol level was significantly higher in patients with restenosis than in patients without restenosis (8.2+/-7.0 mg/dl vs. 4.5+/-2.6 mg/dl, P=0.006). Although plasma glucose level was similar between the two groups, insulin level and homeostasis model assessment were significantly higher in patients with restenosis, compared with those without restenosis (11.2+/-12.4 vs. 7.1+/-2.8, P=0.039; and 2.6+/-2.9 vs. 1.7+/-0.7, P=0.040, respectively). In multivariate logistic regression analysis, plasma remnant-like lipoprotein particles cholesterol level (>4.8 mg/dl; the 75th percentile of the distribution of remnant-like lipoprotein particles cholesterol level) was the independent predictor of in-stent restenosis (odds ratio: 8.15; confidence interval: 1.02-65.16; P=0.048).

CONCLUSIONS

Our findings suggest that high serum remnant-like lipoprotein particles cholesterol level, and not insulin resistance may be an independent risk factor on in-stent restenosis in nondiabetic patients with stable angina.

A quantitative estimate of bare-metal stenting compared with balloon angioplasty in patients with acute myocardial infarction: angiographic measures in relation to clinical outcome

We performed a systematic review of all randomised controlled trials (RCTs) from the pre-drug-eluting-stent era comparing bare-metal stenting (BMS) with balloon angioplasty in patients with acute myocardial infarction (MI) to examine coronary angiographic parameters of infarct-related vessel patency and to relate the angiographic measures to clinical outcome. The search was restricted to published RCTs in humans. 10 RCTs, (6192 patients) were analysed. Compared with balloon angioplasty, BMS was associated with reduced rates of reocclusion (6.7% vs 10.1%, OR 0.62, 95% CI 0.40 to 0.96, p = 0.03) and restenosis (23.9% vs 39.3%, OR 0.45, 95% CI 0.34 to 0.59, p<0.001), but not with reduced rates of subacute thrombosis (1.7% in both groups). BMS showed a reduction in target vessel revascularisation (TVR; 12.2% vs 19.2%, OR 0.50, 95% CI 0.37 to 0.69, p<0.001), but not in mortality (5.3% vs 5.1%) or reinfarction (3.9% vs 4%). The findings of this study support BMS placement in acute MI. The discrepancy between angiographic and clinical parameters has important implications for future studies investigating further technical improvements in mechanical reperfusion therapy.

Vascular remodeling: hemodynamic and biochemical mechanisms underlying Glagov's phenomenon

An important concept for vascular remodeling, termed Glagov's phenomenon, is that arteries remodel to maintain constant flow despite increases in atherosclerotic lesion mass. Although Glagov's phenomenon was originally described only for the case of arterial remodeling in response to growth of atherosclerotic plaques, experimental and clinical observations indicate that blood flow properties influence remodeling after angioplasty, hypertension, and flow diversion as well as atherosclerotic plaque progression. This review attempts to define Glagov's observation in terms of the physical parameters of blood in conduit arteries that must determine the remodeling response. Next we review experiments that have begun to identify specific molecules that influence vascular remodeling and therefore may serve as mediators for the phenomena. More comprehensive analyses of the specific molecular pathways in the vessels that determine constant flow may provide new therapeutic approaches to regulate vascular remodeling.