Intravascular ultrasound findings in the multicenter, randomized, double-blind RAVEL (RAndomized study with the sirolimus-eluting VElocity balloon-expandable stent in the treatment of patients with de novo native coronary artery Lesions) trial

Revolutionizing Cardiovascular Frontiers: A Dive Into Cutting-Edge Innovations in Coronary Stent Technology

Plain balloon angioplasty was the initial method used to enlarge the intracoronary lumen size. However, it was linked to acute coronary closure due to early vessel recoil. This led to the invention of coronary stents, which offer mechanical support to open and maintain the vascular lumen. Nevertheless, the metallic scaffold introduced other issues, such as thrombosis and restenosis caused by neointimal proliferation. To address these concerns, polymers were employed to cover the scaffold, acting as drug reservoirs and regulators for controlled drug release. The use of polymers prevents direct contact between blood and metallic scaffolds. Drugs within the stent were incorporated to inhibit proliferation and expedite endothelialization in the healing process. Despite these advancements, adverse effects still arise due to the inflammatory reaction caused by the polymer material. Consequently, resorbable polymers and scaffolds were later discovered, but they have limitations and are not universally applicable. Various scaffold designs, thicknesses, materials, polymer components, and drugs have their own advantages and complications. Each stent generation has been designed to address the shortcomings of the preceding generation, yet new challenges continue to emerge. Conflicting data regarding the long-term safety and efficacy of coronary stents, especially in the extended follow-up, further complicates the assessment.

Predicting Endothelium-Dependent Diastolic Function (FMD) and Its Correlation with the Degree of Coronary Artery Disease (CAD) and Plaque Vulnerability for Cardiovascular Events

Objective

This study aims to investigate the correlation between vascular endothelium-dependent diastolic function (FMD) and the degree of coronary artery disease (CAD), plaque vulnerability, and its predictive value for cardiovascular events.

Methods

Initially, patients (n=100) who were admitted from January 2020 to January 2021 and intended to undergo percutaneous coronary intervention (PCI) were selected. Further, FMD in all patients was determined before the procedure and divided into a high-FMD group (≥4.2%) and a low-FMD group (<4.2%). Further, the data of two groups, including general information, coronary artery lesions, and plaque fibrous cap, were compared. Finally, the relationship between FMD and the degree of coronary artery lesions and plaque vulnerability was analyzed.

Results

No significant differences were observed concerning general information, number of coronary arteries-associated branches, lesion type, involvement of the left main stem (LM), the proportion of chronic occluded lesions (CTO), and lipid pool angle between the low-FMD group and the high-FMD group (P > 0.05). Nevertheless, the degree of stenosis of the lesions in the low-FMD group was significantly higher than in the high-FMD group (P < 0.05). In addition, the thickness of the fibrous cap was considerably lower than that in the high-FMD group (P < 0.05). Moreover, the incidence rate of TCFA was significantly higher than the high-FMD group (P < 0.05). The correlation analysis showed that FMD was significantly negatively correlated with the degree of coronary artery lesion stenosis and TCFA (P < 0.05) and positively correlated with the fibrous cap thickness (P < 0.05).

Conclusion

Overall, a negative correlation between FMD and the degree of coronary stenosis, plaque vulnerability, and a high predictive value for post-PCI cardiovascular events suggested that FMD could be a critical diagnostic marker for CAD.

REabsorbable vs. DUrable Polymer Drug-Eluting Stents in All-Comer PatiEnts: the REDUCE registry

BACKGROUND

While the superiority of reabsorbable-polymer drug-eluting stents (RP-DES) over bare-metal stents and first-generation durable-polymer (DP)-DES has been largely established, their advantage compared with new-generation DP-DES is still controversial. This study aimed was to compare clinical outcomes of all-comer patients undergoing percutaneous coronary intervention (PCI) with new generation DP-DES or RP-DES implantation.

METHODS

We prospectively enrolled 679 consecutive patients treated with PCI with RP-DES or DP-DES. The primary endpoint was the 1-year incidence of major adverse clinical events (MACE), a composite of death, myocardial infarction (MI), and target vessel revascularization (TVR). Target lesion revascularization (TLR) and definite stent thrombosis were also recorded.

RESULTS

A total of 439 (64.6%) received RP-DES and 240 (36.4%) received DP-DES. No significant difference in the incidence of MACE (5.9 vs. 4.9%; hazard ratio, 1.23; 95% confidence interval (CI), 0.61-2.49; P = 0.569), death (1.8 vs. 1.7%; hazard ratio, 1.09; 95% CI, 0.33-3.64; P = 0.882), MI (2.3 vs. 2.1%; hazard ratio, 1.05; 95% CI, 0.36-3.08; P = 0.927), TVR (2.3 vs. 1.3%; hazard ratio, 1.70; 95% CI, 0.47-6.20; P = 0.418), TLR (1.4 vs. 0.4%; hazard ratio, 3.06; 95% CI, 0.37-25.40; P = 0.301), and definite stent thrombosis (0.5 vs. 0.4%; hazard ratio, 1.09; 95% CI, 0.10-12.10; P = 0.942) was observed between RP-DES and DP-DES patients at 1-year follow-up. These results were confirmed in a propensity score-matched cohort (n = 134 per group).

CONCLUSION

In our registry including a real-world population of all-comer patients undergoing PCI, RP-DES, or durable polymer-DES showed similar efficacy and safety at a 1-year follow-up.

Extract of Oxytropis pseudoglandulosa inhibits vascular smooth muscle cell proliferation and migration via suppression of ERK1/2 and Akt signaling pathways1

Excessive vascular smooth muscle cell (VSMC) proliferation and migration accelerate the development of occlusive vascular disease. Therefore, finding a means to control the aberrant proliferation and migration of VSMCs has own clinical significance. In the present study, we examined the feasibility of using extract from medicinal plant Oxytropis pseudoglandulosa (OG) to control pathologic proliferation and migration of VSMCs, which never have been tested. Our data indicate that the extract of OG significantly suppressed proliferation and migration of VSMCs without cytotoxic effect, suggesting the OG extract may be an alternative agent to effectively control the aberrant VSMC proliferation and migration without any serious adverse effect. These data suggest that the extract of OG may be a potent therapeutic agent for the treatment of occlusive vascular disease and warrant further studies to identify the major acting ingredient and to validate in vivo efficacy.

Compare Complication of Classic versus Patent Hemostasis in Transradial Coronary Angiography

BACKGROUND

Coronary artery disease (CAD) is multifactorial disease, in which thrombotic occlusion and calcification occur usually. New strategies have been made for diagnosis and treatment of CAD, such as transradial catheterization. Hemostasis could be done in two approaches: traditional and patent. Our aim is to find the best approach with lowest complication.

MATERIALS AND METHODS

In a comparative study, 120 patients were recruited and divided randomly into two subgroups, including traditional group (60 patients; 24 females, 36 males; mean age: 64.35 ± 10.56 years) and patent group (60 patients; 28 females, 32 males; mean age: 60.15 ± 8.92 years). All demographic data including age, gender, body mass index, and CAD-related risk factors (smoking, diabetes, hypertension) and technical data including the number of catheters, procedure duration, and hemostatic compression time and clinical outcomes (radial artery occlusion [RAO], hematoma, bleeding) were collected. Data were analyzed by SPSS version 16.

RESULTS

Our findings revealed that the incidence of RAO was significantly lower in patent groups compared with traditional group (P = 0.041). Furthermore, the difference incidence of RAO was higher in early occlusion compare with late one (P = 0.041). Moreover, there were significant relationship between some factors in patients of traditional group with occlusion (gender [P = 0.038], age [P = 0.031], diabetes mellitus [P = 0.043], hemostatic compression time [P = 0.036]) as well as in patent group (age [P = 0.009], hypertension [P = 0.035]).

CONCLUSION

Our findings showed that RAO, especially type early is significantly lower in patent method compared classic method; and patent hemostasis is the safest method and good alternative for classical method.

Revolution of Drug-Eluting Coronary Stents: An Analysis of Market Leaders

Percutaneous coronary intervention with drug-eluting stents (DES) is a well-established and widely-accepted treatment approach in patients with coronary artery disease. Although the underlying principle of DES remains constant for different stents available on the market, certain factors may offer variations with respect to deliverability (ease of placement), efficacy (preventing restenosis), and safety (thrombosis rates). These factors may include the type of drug (sirolimus, everolimus, biolimus, zotarolimus, novolimus, paclitaxel, docetaxel), type of stent platforms (stainless steel, platinum, cobalt-chromium, cobalt-nickel, platinum-chromium), type of polymers (permanent, biodegradable, polymer-free), thickness of stent struts (thick, thin, ultra-thin), type of coating (abluminal, conformal), and type of stent design (open-cell, closed-cell, combination of open-closed cell). In this context, we present a review on characteristic features of several of the most widely used coronary stents worldwide. Furthermore, the advancements of completely biodegradable stents are discussed. In addition, the future directions for the development of creating an ideal or perfect DES are debated.

Testosterone replacement attenuates intimal hyperplasia development in an androgen deficient model of vascular injury

BACKGROUND

Androgen deficiency (AD) is associated with increased risk of vascular disease. Dysfunctional remodeling of the vessel wall and atypical proliferative potential of vascular smooth muscle cells (VSMCs) are fundamental processes in the development of intimal hyperplasia (IH). We have demonstrated an inverse relationship between dihydrotestosterone (DHT) levels, matrix metalloproteinase activity, and VSMC migration and proliferation in vitro. Here, we investigated the role of AD and testosterone (TST) replacement in IH development in an animal model of vascular injury to elucidate mechanisms modulated by AD that could be playing a role in the development of vascular pathogenesis.

METHODS

Aged orchiectomized male rats underwent TST supplementation via controlled release pellet (0.5-35 mg). Young adult and middle-age adult intact (MI) and orchiectomized placebo (Plac) groups served as controls. All groups underwent balloon angioplasty of the left common carotid at a 14-d post-TST. Carotid tissue was collected at a 14-d post-balloon angioplasty and subjected to morphologic and immunohistochemical analyses. Human male VSMCs were treated with DHT (0-3000 nM) for 24 h then subjected to quantitative PCR for gene expression analyses and costained for F-actin and G-actin for visualization of cytoskeletal organization.

RESULTS

I:M ratio was increased in Plac, subphysiological, low-physiological, and high pharmacologic level TST animals compared with MI controls but was decreased with high-physiological TST supplementation. Injury-induced expression of previously defined matrix metalloproteinase remodeling enzymes was not significantly affected by TST status. Urotensin (UTS) receptor (UTSR) staining was low in injured vessels of all young adult intact, MI, and Plac controls but was significantly upregulated in all groups receiving exogenous TST supplementation, irrespective of dose. In vitro DHT exposure increased the expression of UTSR in VSMCs in a dose-dependent manner. However, this did not correlate with any change in proliferative markers. F:G actin staining revealed that DHT-induced cytoskeletal organization in a dose-dependent manner.

CONCLUSIONS

AD increased IH development in response to vascular injury, whereas physiological TST replacement attenuated this effect. AD-induced IH occurs independent of matrix remodeling mechanisms known to be heavily involved in vascular dysfunction, and AD alone does not affect the UTS and/or UTSR mechanism. Exogenous TST and/or DHT increases UTSR pathway signaling in vitro and in vivo. This modulation correlates to a shift in cytoskeletal organization and may exacerbate vasoconstrictive pathogenesis. While physiological TST replacement attenuates AD-modulated IH development, its UTS-mediated effect on vasotone may prove deleterious to overall vascular function.

Prognostic significance of endothelial dysfunction in patients undergoing percutaneous coronary intervention in the era of drug-eluting stents

Background

Endothelial function is a prognostic predictor in patients undergoing percutaneous coronary intervention (PCI). However, in an era with widespread use of drug-eluting stents, the clinical relevance of endothelial dysfunction on restenosis in patients undergoing PCI has not been fully evaluated.

Methods

This study included 80 patients with stable angina pectoris. Flow-mediated dilation (FMD) of the brachial artery was examined 1 week after PCI. Patients were retrospectively followed-up for an average of 21 months after PCI. The primary endpoints included cardiac death, nonfatal myocardial infarction, stroke, coronary revascularization, and critical limb ischemia.

Results

A drug-eluting stent was used in 58 patients and a cardiovascular event was recorded in 34 patients during follow-up. The incidence of all cardiovascular diseases was significantly greater in the low FMD (median FMD <4.2 %) than the high FMD (median FMD ≥4.2 %) group (60 % vs. 25 %, p <0.01). Furthermore, the incidence of coronary revascularization was significantly higher in the low than the high FMD group (p = 0.02), while the incidence of in-stent restenosis did not differ between the two groups. Cox regression analysis showed that low FMD was an independent predictor of cardiovascular events (hazard ratio: 2.77, 95 % confidence interval: 1.23 to 6.19, p = 0.01).

Conclusions

Impaired brachial artery FMD independently predicts long-term cardiovascular events after PCI in the era of drug-eluting stents.

Twelve Months Dual Antiplatelet Therapy after Drug-eluting Stents - Too Long, too Short or Just Right?

Dual Antiplatelet Therapy (DAPT) remains a cornerstone in the secondary prevention of coronary artery disease. Further, in contemporary practice, a period of DAPT is considered a mandatory requirement after intracoronary stents to prevent stent thrombosis (ST), a complication associated with heart attack and a mortality rate of up to 40 %. In current clinical practice, the default strategy in most centres is 12 months' DAPT followed by aspirin alone for life. However, the optimal duration of DAPT, particularly given the rapid iterative turnover of drug-eluting stents (DES) is the subject of discrepant evidence and clinical uncertainty. In particular, the 12-month regimen is based upon relatively weak evidence. A series of fairly small randomised trials, not powered to look specifically at ST as an endpoint, have recently indicated that there is no apparent disadvantage to shorter versus longer duration DAPT (including several trials of >12 months versus 12 months) when looking at various composite clinical endpoints. By contrast, the 9,961 patient DAPT trial, published in the New England Journal of Medicine at the end of 2014, demonstrated clinical outcome benefit, including a significantly lower rate of ST as a predefined primary endpoint, in DES patients randomised to 30 months' DAPT compared to stopping at 12 months. Here, the authors to assess the data, including the most recent meta-analyses, in an attempt to answer the question: DAPT after DES...12 months, longer or shorter?

Fully bioresorbable drug-eluting coronary scaffolds: A review

Following the development of stents, then drug-eluting stents (DES), bioresorbable scaffolds are proposed as a third evolution in coronary angioplasty, aiming to reduce the incidence of restenosis and stent thrombosis and to restore vascular physiology. At least 16 such devices are currently under development, but published clinical data were available for only three of them in September 2014. The first device is Abbott's BVS(®), a poly-L-lactic acid (PLLA)-based everolimus-eluting device, which has been tested in a registry and two non-randomized trials. Clinical results seem close to what is expected from a modern DES, but possibly with more post-procedural side-effects. Two randomized trials versus DES are underway. This device is already marketed in many European countries. The second device is Elixir's DESolve(®), a PLLA-based novolimus-eluting device, which has been evaluated in two single-arm trials. Results are not widely different from those expected from a DES. The third device is Biotronik's DREAMS(®), a metallic magnesium-based paclitaxel-eluting device, which has been assessed in an encouraging single-arm trial; its second version is currently undergoing evaluation in a single-arm trial. The available results suggest that the technological and clinical development of bioresorbable scaffolds is not yet complete: their possible clinical benefits are still unclear compared with third-generation DES; the impact of arterial physiology restoration has to be assessed over the long term; and their cost-effectiveness has to be established. From the perspective of a health technology assessment, there is no compelling reason to hasten the clinical use of these devices before the results of ongoing randomized controlled trials become available.

Increased mortality after a first myocardial infarction in human immunodeficiency virus-infected patients; a nested cohort study

AIMS

HIV infection may be associated with an increased recurrence rate of myocardial infarction. Our aim was to determine whether HIV infection is a risk factor for worse outcomes in patients with coronaray artery disease.

METHODS

We compared data aggregated from two ongoing cohorts: (i) the Acute Myocardial Infarction in Switzerland (AMIS) registry, which includes patients with acute myocardial infarction (AMI), and (ii) the Swiss HIV Cohort Study (SHCS), a prospective registry of HIV-positive (HIV+) patients. We included all patients who survived an incident AMI occurring on or after 1st January 2005. Our primary outcome measure was all-cause mortality at one year; secondary outcomes included AMI recurrence and cardiovascular-related hospitalisations. Comparisons used Cox and logistic regression analyses, respectively.

RESULTS

There were 133 HIV+, (SHCS) and 5,328 HIV-negative [HIV-] (AMIS) individuals with incident AMI. In the SHCS and AMIS registries, patients were predominantly male (72% and 85% male, respectively), with a median age of 51 years (interquartile range [IQR] 46-57) and 64 years (IQR 55-74), respectively. Nearly all (90%) of HIV+ individuals were on successful antiretroviral therapy. During the first year of follow-up, 5 (3.6%) HIV+ and 135 (2.5%) HIV- individuals died. At one year, HIV+ status after adjustment for age, sex, calendar year of AMI, smoking status, hypertension and diabetes was associated with a higher risk of death (HR 4.42, 95% CI 1.73-11.27). There were no significant differences in recurrent AMIs (4 [3.0%] HIV+ and 146 [3.0%] HIV- individuals, OR 1.16, 95% CI 0.41-3.27) or in hospitalization rates (OR 0.68 [95% CI 0.42-1.11]).

CONCLUSIONS

HIV infection was associated with a significantly increased risk of all-cause mortality one year after incident AMI.

An atypical presentation of an extremely late stent thrombosis after more than 7 years (2634 days) of DES implantation in a patient without obvious risk factors on regular dual antiplatelet therapy

Very late stent thrombosis is a rare complication of percutaneous coronary intervention in the era of dual antiplatelet therapy. The risk factors for stent thrombosis are drug default, age, diabetes, renal dysfunction, left ventricular dysfunction, smoking or procedure-related factors and complications. We are describing the case of a 55-year-old non-smoker patient without the conventional risk factors for stent thrombosis maintaining good compliance with dual antiplatelet (aspirin and clopidogrel) drugs in standard doses. The patient had a history of having received a Cypher stent more than 7 years (2634 days) ago in the left circumflex artery for the management of in-stent restenosis of a bare metal stent implanted previously. He was referred with acute stent thrombosis with an atypical presentation of non-ST elevation myocardial infarction having unexplainable spontaneous resolution of electrocardiographic changes. The patient was successfully managed with newer generation drug-eluting stents reimplantation. The presence of acute onset of symptoms and thrombus containing soft lesion as documented during intervention supported the diagnosis of acute stent thrombosis. To the best of our knowledge this case is one of the longest duration of presentation with acute stent thrombosis after stent implantation ever reported in literature and is also unique in its unusual mode of presentation.

Orbital atherectomy system in treating calcified coronary lesions: 3-Year follow-up in first human use study (ORBIT I trial)

BACKGROUND/PURPOSE

The ORBIT I trial evaluated the safety and performance of an orbital atherectomy system (OAS) in treating de novo calcified coronary lesions. Severely calcified coronary arteries pose ongoing treatment challenges. Stent placement in calcified lesions can result in stent under expansion, malapposition and procedural complications. OAS treatment may be recommended to facilitate coronary stent implantation in these difficult lesions.

MATERIALS/METHODS

Fifty patients with de novo calcified coronary lesions were enrolled in the ORBIT I trial. Patients were treated with the OAS followed by stent placement. Our institution treated 33/50 patients and continued follow-up for 3 years.

RESULTS

Average age was 54.4 years and 90.9% were males. Mean lesion length was 15.9mm. The average number of OAS devices used per patient was 1.3. Procedural success was achieved in 97% of patients. Angiographic complications were observed in five patients (two minor dissections, one major dissection and two perforations). The cumulative major adverse cardiac event (MACE) rate was 6.1% in-hospital, 9.1% at 30 days, 12.1% at 6 months, 15.2% at 2 years, and 18.2% at 3years. The MACE rate included two in-hospital non Q-wave myocardial infarctions (MI), one additional non Q-wave MI at 30 days leading to target lesion revascularization (TLR), and three cardiac deaths.

CONCLUSIONS

The ORBIT I trial suggests that OAS treatment may offer an effective method to modify calcified coronary lesion compliance to facilitate optimal stent placement in these difficult-to-treat patients with acceptable levels of safety up to 3 years post-index procedure.

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.

Electrophoretic coating of amphiphilic chitosan colloids on regulating cellular behaviour

In this communication, we report a facile nanotopographical control over a stainless steel surface via an electrophoretic deposition of colloidal amphiphilic chitosan for preferential growth, proliferation or migration of vascular smooth muscle cells (VSMCs) and human umbilical vein endothelial cells (HUVECs). Atomic force microscopy revealed that the colloidal surface exhibited a deposition time-dependent nanotopographical evolution, wherein two different nanotopographic textures indexed by 'kurtosis' (Rkur) value were easily designed, which were termed as 'sharp' (i.e. high peak-to-valley texture) surface and 'flat' (i.e. low peak-to-valley texture) surface. Cellular behaviour of VSMCs and HUVECs on both surfaces demonstrated topographically dependent morphogenesis, adherent responses and biochemical properties in comparison with bare stainless steel. The formation of a biofunctionalized surface upon a facile colloidal chitosan deposition envisions the potential application towards numerous biomedical devices, and this is especially promising for cardiovascular stents wherein a new surface with optimized texture can be designed and is expected to create an advantageous environment to stimulate HUVEC growth for improved healing performance.

Patient preferences for coronary artery bypass graft surgery or percutaneous intervention in multivessel coronary artery disease

OBJECTIVES

Determine if patients prefer multivessel percutaneous coronary intervention (mv-PCI) over coronary artery bypass graft surgery (CABG) for treatment of symptomatic multivessel coronary artery disease (mv-CAD) despite high 1-year risk.

BACKGROUND

Patient risk perception and preference for CABG or mv-PCI to treat medically refractory mv-CAD are poorly understood. We hypothesize that patients prefer mv-PCI instead of CABG even when quoted high mv-PCI risk.

METHODS

585 patients and 31 physicians were presented standardized questionnaires with a hypothetical scenario describing chest pain and medically refractory mv-CAD. CABG or mv-PCI was presented as treatment options. Risk scenarios included variable 1-year risks of death, stroke, and repeat procedures for mv-PCI and fixed risks for CABG. Participants indicated their preference of revascularization method based on the presented risks. We calculated the odds that patients or physicians would favor mv-PCI over CABG across a range of quoted risks of death, stroke, and repeat procedures.

RESULTS

For nearly all quoted risks, patients preferred mv-PCI over CABG, even when the risk of death was double the risk with CABG or the risk of repeat procedures was more than three times that for CABG (P < 0.0001). Compared to patients, physicians chose mv-PCI less often than CABG as the risk of death and repeat procedures increased (P < 0.001 and P = 0.004, respectively).

CONCLUSION

Patients favor mv-PCI over CABG to treat mv-CAD, even if 1-year risks of death and repeat procedures far exceed risk with CABG. Physicians are more influenced by actual risk and prefer mv-PCI less than patients despite similarly quoted 1-year risks.

Impact of frequency-domain optical coherence tomography guidance for optimal coronary stent implantation in comparison with intravascular ultrasound guidance

BACKGROUND

Frequency-domain optical coherence tomography (FD-OCT) is a novel, high resolution intravascular imaging modality. Intravascular ultrasound (IVUS) is a widely used conventional imaging modality for achieving optimal stent deployment. The aim of this study was to evaluate the impact of FD-OCT guidance for coronary stent implantation compared with IVUS guidance.

METHODS AND RESULTS

A total of 70 patients with de novo coronary artery lesions and either unstable or stable angina pectoris were enrolled in this randomized study (optical coherence tomography [OCT] group: n=35, IVUS group: n=35). In the OCT group, stent implantation was performed under FD-OCT guidance alone and final stent expansion was evaluated by IVUS. In the IVUS group, conventional IVUS guidance was used and final stent apposition was evaluated by FD-OCT. There were no significant differences regarding the procedural, fluoroscopy time, and contrast volume. Although device and clinical success rates also were similar, the visibility of vessel border was significantly lower in the OCT group (P<0.05). Minimum and mean stent area and focal and diffuse stent expansion were smaller (6.1±2.2 mm versus 7.1±2.1 mm, 7.5±2.5 versus 8.7±2.4 mm, 64.7±13.7% versus 80.3±13.4%, 84.2±15.8% versus 98.8±16.5%, P<0.05, respectively), and the frequency of significant residual reference segment stenosis at the proximal edge was higher in the OCT group (P<0.05). Incomplete apposed struts in both groups were similar (P=0.34).

CONCLUSIONS

FD-OCT guidance for stent implantation was associated with smaller stent expansion and more frequent significant residual reference segment stenosis compared with conventional IVUS guidance.

Coronary aneurysm occurring late after drug-eluting stent implantation

Drug-eluting stents may affect the normal healing process of the vessel wall and the remodeling process and may lead to late stent malapposition (LSM). The known incidence of this phenomen originates from short-term angiographic follow-up studies. We describe a case report of very late stent malapposition and marked positive vessel remodeling 3 years after sirolimus-eluting coronary stent implantation. Angiography performed one year after stent implantation was normal. Thus, the abnormalities developed sometime between years 1 and 3. The cause is unknown, but it is reasonable to suggest a local effect of the medication/polymer of the stent. LSM rate and aneurysmal formation is higher in DES than in BMS and may be associated with increased risk for late stent thrombosis. Currently, the risk of very late stent thrombosis after DES implantation is of major concern. As observed in this case report, LSM might occur and develop very late. This has significant consequences especially to the many asymptomatic patients with DES implanted many years ago and the recommendation of dual antiplatelet therapy. More studies with late and very late follow up are needed to better define this finding, its mechanism, how to avoid it, and how to treat it properly.

Paclitaxel-eluting stents reduce neointimal hyperplasia compared to bare metal stents in saphenous vein grafts: intravascular ultrasonography analysis of the SOS (Stenting of Saphenous Vein Grafts) trial

AIMS

To compare the intravascular ultrasonography (IVUS) findings between saphenous vein grafts (SVG) treated with paclitaxel-eluting stents (PES) vs. bare metal stents (BMS) in the Stenting Of Saphenous Vein Grafts (SOS) trial.

METHODS AND RESULTS

Of the 80 SOS trial patients, 38 had both baseline and follow-up IVUS examination and were included in this substudy: 17 patients received 28 BMS in 26 lesions and 21 patients received 30 PES in 28 lesions. Quantitative IVUS analysis was performed to determine the volume of in-stent neointimal hyperplasia (NIH) - defined as the difference between stent volume and lumen volume in the stented segments. Baseline characteristics were similar between patients who did and did not undergo baseline and follow-up IVUS. Patients receiving BMS and PES had similar stent and lumen volumes immediately after stenting. At 12-month follow-up, compared to BMS, PES-treated lesions had significantly less NIH volume (3.4 vs. 21.9 mm³, p<0.001) and neointima hyperplasia progression (1.6 vs. 17.1 mm³, p<0.001). No significant differences were seen in the 5 mm segment proximal and distal to the stent.

CONCLUSIONS

Compared to BMS, use of PES in SVG lesions is associated with significantly lower NIH formation, which may help explain the improved clinical outcomes with PES in these lesions.

Long-term effectiveness and safety of sirolimus drug-eluting stents

The root cause of coronary artery disease is atherosclerosis, ie, intraluminal narrowing (stenosis) of the arteries that supply blood to tissues of the heart. The introduction of the drug-eluting stent over the past decade has revolutionized the field of interventional cardiology. It is used extensively in clinical practice for the treatment of coronary artery disease. The first drug-eluting stent to receive US Food and Drug Administration approval was the sirolimus-eluting stent. Recently, two other stent analogs of sirolimus were approved, ie, the zotarolimus-eluting stent and the everolimus-eluting stent. However, concern has arisen in recent years about the long-term safety and efficacy of drug-eluting stents, due to the occurrence of late adverse clinical events, such as stent thrombosis. This review focuses on clinical studies that have been performed with the sirolimus-eluting stent or its analogs. We discuss the pharmacology, safety, and various therapeutic options that exist when choosing stents for coronary artery disease. Our aim is to provide a thorough review of the long-term efficacy and safety of sirolimus drug-eluting stents, and also to discuss currently approved and promising investigational drug-eluting stents, in an effort to provide insight into how these stents are currently evolving and generate further investigation in this area.

Delayed Coverage in Malapposed and Side-Branch Struts With Respect to Well-Apposed Struts in Drug-Eluting Stents

Background—

Pathology studies on fatal cases of very late stent thrombosis have described incomplete neointimal coverage as common substrate, in some cases appearing at side-branch struts. Intravascular ultrasound studies have described the association between incomplete stent apposition (ISA) and stent thrombosis, but the mechanism explaining this association remains unclear. Whether the neointimal coverage of nonapposed side-branch and ISA struts is delayed with respect to well-apposed struts is unknown.

Methods and Results—

Optical coherence tomography studies from 178 stents implanted in 99 patients from 2 randomized trials were analyzed at 9 to 13 months of follow-up. The sample included 38 sirolimus-eluting, 33 biolimus-eluting, 57 everolimus-eluting, and 50 zotarolimus-eluting stents. Optical coherence tomography coverage of nonapposed side-branch and ISA struts was compared with well-apposed struts of the same stent by statistical pooled analysis with a random-effects model. A total of 34 120 struts were analyzed. The risk ratio of delayed coverage was 9.00 (95% confidence interval, 6.58 to 12.32) for nonapposed side-branch versus well-apposed struts, 9.10 (95% confidence interval, 7.34 to 11.28) for ISA versus well-apposed struts, and 1.73 (95% confidence interval, 1.34 to 2.23) for ISA versus nonapposed side-branch struts. Heterogeneity of the effect was observed in the comparison of ISA versus well-apposed struts (H=1.27; I 2 =38.40) but not in the other comparisons.

Conclusions—

Coverage of ISA and nonapposed side-branch struts is delayed with respect to well-apposed struts in drug-eluting stents, as assessed by optical coherence tomography.

Clinical Trial Registration—

http://www.clinicaltrials.gov . Unique identifier: NCT00389220, NCT00617084.

Very Late Stent Thrombosis in a Drug-Eluting Stent due to Interruption of Anti-Platelet Agents in Patients With Acute Myocardial Infarction and Thrombocytosis

Stent thrombosis is a fatal complication in patients who have undergone percutaneous coronary intervention, and discontinuation of anti-platelet agent is a major risk factor of stent thrombosis. We report a rare case of very late stent thrombosis (VLST) following discontinuation of anti-platelet agents in a patient who experienced acute myocardial infarction and essential thrombocytosis. She had undergone implantation of a drug eluting stent (DES) and a bare metal stent (BMS) two and half years prior to her presentation. VLST developed in DES, not in BMS, following interruption of anti-platelet therapy.

IVUS-Guided Stent Implantation to Improve Outcome: A Promise Waiting to be Fulfilled

The use of intravascular ultrasound (IVUS) to improve acute angiographic results was already shown in the prestent era. Various studies demonstrated the efficacy of IVUS in balloon sizing and estimating the extent of positive remodeling. With the introduction of drug-eluting stents (DES) the rate of restenosis has been significantly reduced but a new concern, the risk of stent thrombosis, has emerged. The association of stent underexpansion with stent thrombosis was observed for bare metal stents (BMS) and DES. Until now, the criteria for IVUS optimization used in different studies have relied on distal reference or on mean reference vessel for stent or postdilatation balloon sizing. Furthermore, an important recent innovation not available in previous studies is the use of noncompliant balloons to perform high pressure post-dilatation. Universal and easily applicable IVUS criteria for optimization of stent implantation as well as randomized studies on IVUS-guided DES implantation are necessary to minimize stent malapposition and underexpansion, which in turn can positively influence the rates of stent restenosis and thrombosis.

Evaluation of neointimal coverage and apposition with various drug-eluting stents over 12 months after implantation by optical coherence tomography

BACKGROUND

Optical coherence tomography (OCT) is an imaging technology with high resolution which provides new opportunities for evaluating the vascular healing reaction after stent implantation. We used OCT to compare neointimal coverage and stent strut apposition with different types of drug-eluting stent (DES) at more than 12 months follow-up.

METHODS

Fifty five patients who accepted 72 DESs (19 sirolimus-eluting stents [SES, Cypher Select], 27 paclitaxel-eluting stents [PES, Taxus Liberte], 26 zotarolimus-eluting stents [ZES, Endeavor]) were enrolled in our study. OCT was performed at 12-18 months after stent implantation. The neointimal hyperplasia (NIH) thickness and stent strut apposition at 1-mm interval and the presence of thrombus in each stent were observed.

RESULTS

The average NIH thickness (0.1806 ± 0.1726 mm in SES vs. 0.2558 ± 0.2187 mm in PES vs. 0.2983 ± 0.2567 mm in ZES, p<0.001) and percentage of NIH area (17.21 ± 14.05% in SES vs. 23.09 ± 14.53% in PES vs. 28.73 ± 20.47% in ZES, p=0.002) were significantly greater in ZES than in other DESs. The prevalence of uncovered struts (8.96% in SES vs. 6.19% in PES vs. 2.98% in ZES, p<0.01) and malapposed struts (6.36% in SES vs. 2.32% in PES vs. 1.69% in ZES, p<0.01) was significantly lower in ZES than in other DESs. Thrombus was less frequently observed in ZES than in other DESs (SES 1.70% vs. PES 0.83% vs. ZES 0.17%, p<0.01).

CONCLUSIONS

Compared with SES and PES, ZES showed lower prevalence of uncovered struts and malapposed struts at more than 12 months follow-up.

Focus on the research utility of intravascular ultrasound - comparison with other invasive modalities

Intravascular ultrasound (IVUS) is an invasive modality which provides cross-sectional images of a coronary artery. In these images both the lumen and outer vessel wall can be identified and accurate estimations of their dimensions and of the plaque burden can be obtained. In addition, further processing of the IVUS backscatter signal helps in the characterization of the type of the plaque and thus it has been used to study the natural history of the atherosclerotic evolution. On the other hand its indigenous limitations do not allow IVUS to assess accurately stent struts coverage, existence of thrombus or exact site of plaque rupture and to identify some of the features associated with increased plaque vulnerability. In order this information to be obtained, other modalities such as optical coherence tomography, angioscopy, near infrared spectroscopy and intravascular magnetic resonance imaging have either been utilized or are under evaluation. The aim of this review article is to present the current utilities of IVUS in research and to discuss its advantages and disadvantages over the other imaging techniques.

Prevalence, predictors, and long-term prognosis of premature discontinuation of oral antiplatelet therapy after drug eluting stent implantation

To date, limited information is available on the long-term discontinuation rates of antiplatelet therapy after drug-eluting stent implantation. The aim of the present study was to determine the prevalence and predictors of premature discontinuation of oral antiplatelet therapy after drug-eluting stent implantation and to evaluate its effects on long-term prognosis. We studied 1,358 consecutive patients successfully treated with drug-eluting stents and discharged with dual oral antiplatelet therapy. Aspirin was to be maintained lifelong, and clopidogrel was prescribed for 12 months. The patients were followed for 36 months. The prevalence and predictors of aspirin and clopidogrel discontinuation were assessed. Major adverse cardiac events, defined as death, myocardial infarction, destabilizing symptoms leading to hospitalization, and nonfatal stroke, were recorded. Definite, probable, and possible stent thrombosis (ST) and major and minor bleeding were also determined. Of the 1,358 patients, 8.8% had discontinued one or both antiplatelet agents within the first 12 months ("early" discontinuation) and 4.8% had discontinued aspirin after 1 year ("late" discontinuation). Early discontinuation was predicted by in-hospital major bleeding, the use of oral anticoagulants at discharge, and the lack of a statin prescription. Previous stroke was the only independent predictor of late discontinuation. Patients with early discontinuation experienced a greater incidence of major adverse cardiac events (28.6% vs 13.7%, p <0.001) and ST (7.6% vs 3.4%, p = 0.038). All-cause mortality (13.4% vs 4.7%, p <0.001) and cardiovascular death (5% vs 1.2%, p = 0.007) were significantly more frequent among patients with early discontinuation. In patients with late discontinuation, a nonstatistically significant increase was seen in major adverse cardiac events (20% vs 13.3%, p = 0.128) and ST (6.2% vs 3.2%, p = 0.275). In conclusion, premature discontinuation of antiplatelet therapy is relatively common, especially within the first year, and strongly associated with increased cardiovascular events, including ST and death.