Appropriate use of drug-eluting stents: balancing the reduction in restenosis with the concern of late thrombosis

Myocardial Perfusion SPECT Imaging in Patients after Percutaneous Coronary Intervention

Coronary artery disease (CAD) is the most prevalent form of cardiovascular disease affecting about 13 million Americans, while more than one million percutaneous transluminal intervention (PCI) procedures are performed annually in the USA. The relative high occurrence of restenosis, despite stent implementation, seems to be the primary limitation of PCI. Over the last decades, single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI), has proven an invaluable tool for the diagnosis of CAD and patients’ risk stratification, providing useful information regarding the decision about revascularization and is well suited to assess patients after intervention. Information gained from post-intervention MPI is crucial to differentiate patients with angina from those with exo-cardiac chest pain syndromes, to assess peri-intervention myocardial damage, to predict-detect restenosis after PCI, to detect CAD progression in non-revascularized vessels, to evaluate the effects of intervention if required for occupational reasons and to evaluate patients’ long-term prognosis. On the other hand, chest pain and exercise electrocardiography are largely unhelpful in identifying patients at risk after PCI.

Although there are enough published data demonstrating the value of myocardial perfusion SPECT imaging in patients after PCI, there is still debate on whether or not these tests should be performed routinely.

The evolution of antiplatelet therapy in cardiovascular disease

The platelet--an anucleate cell--is the bedrock of thrombosis, both physiologically and pathologically. Antagonism of the P2Y(12) receptor for ADP is one of several pathways inhibiting the activation and aggregation of platelets, thereby attenuating coronary thrombosis in response to spontaneous plaque rupture or percutaneous revascularization. The addition of clopidogrel to a background of aspirin therapy was a revolutionary change in the management of ischemic coronary syndromes. Despite this paradigm shift, clopidogrel has certain limitations, including variability in platelet inhibitory effect, which is associated with adverse thrombotic events. In the evolution of antiplatelet treatment strategies, two new P2Y(12) receptor antagonists--prasugrel and ticagrelor--have been added to the armamentarium in the past few years. Both of these drugs confer greater platelet inhibition than clopidogrel. Nevertheless, more-potent platelet inhibition comes with an increased risk of hemorrhagic complications. Cangrelor and elinogrel are novel P2Y(12) inhibitors that show potential in the periprocedural setting with their rapid onset and offset of activity. Successes in P2Y(12) inhibitory therapies have reduced use of glycoprotein IIb/IIIa inhibitors, which block the final pathway leading to platelet aggregation and thrombosis. Newer therapies aimed at various molecular factors are under clinical investigation. Pharmacodynamic platelet function assays and pharmacogenetic testing to individualize and optimize antiplatelet therapy may find their way into clinical use, although much more study is needed.

Oral administration of the thrombin receptor antagonist E5555 (atopaxar) attenuates intimal thickening following balloon injury in rats

Thrombin is a powerful agonist for a variety of cellular responses including platelet aggregation and vascular smooth muscle cell (SMC) proliferation. These actions are mediated by a thrombin receptor known as protease-activated receptor-1 (PAR-1). Recently we discovered that 1-(3-tert-butyl-4-methoxy-5-morpholinophenyl)-2-(5,6-diethoxy-7-fluoro-1-imino-1,3-dihydro-2H-isoindol-2-yl)ethanone hydrobromide (E5555, atopaxar) is a potent and selective thrombin receptor antagonist. This study characterized the pharmacological effects of E5555 on SMC proliferation in vitro and in a rat model of intimal thickening after balloon injury in vivo. E5555 selectively inhibited rat aortic SMC proliferation induced by thrombin and thrombin receptor-activating peptide (TRAP) with half maximal inhibitory concentration (IC(50)) values of 0.16 and 0.038 μM, respectively. E5555 did not inhibit rat SMC proliferation induced by basic fibroblast growth factor (bFGF) and platelet-derived growth factor (PDGF) at concentrations up to 1μM. In addition, E5555 inhibited human aortic SMC proliferation induced by thrombin at concentrations of 0.3 and 3units/ml with IC(50) values of 0.028 and 0.079 μM, respectively, whereas it did not affect bFGF-induced proliferation at concentrations up to 1μM. Repeated oral administration of 30 mg/kg E5555 (once daily for 16 days) significantly reduced neointimal formation in the balloon-injured rat arterial model. These results suggested that a PAR-1 antagonist could be effective for treating restenosis following vascular intervention in addition to preventing thrombus formation. E5555 could thus have therapeutic potential for restenosis and chronic atherothrombotic disease.

Clinical evidence of interaction between clopidogrel and proton pump inhibitors

Clopidogrel is approved for reduction of atherothrombotic events in patients with cardiovascular (CV) and cerebrovascular disease. Dual antiplatelet therapy with aspirin and clopidogrel decreases the risk of major adverse cardiac events after acute coronary syndrome or percutaneous coronary intervention, compared with aspirin alone. Due to concern about gastrointestinal bleeding in patients who are receiving clopidogrel and aspirin therapy, current guidelines recommend combined use of a proton pump inhibitor (PPI) to decrease the risk of bleeding. Data from previous pharmacological studies have shown that PPIs, which are extensively metabolized by the cytochrome system, may decrease the ADP-induced platelet aggregation of clopidogrel. Results from retrospective cohort studies have shown a higher incidence of major CV events in patients receiving both clopidogrel and PPIs than in those without PPIs. However, other retrospective analyses of randomized clinical trials have not shown that the concomitant PPI administration is associated with increased CV events among clopidogrel users. These controversial results suggest that large specific studies are needed. This article reviews the metabolism of clopidogrel and PPIs, existing clinical data regarding the interaction between clopidogrel and PPIs, and tries to provide recommendations for health care professionals.

Polymeric coating of surface modified nitinol stent with POSS-nanocomposite polymer

Stent angioplasty is a successful treatment for arterial occlusion, particularly in coronary artery disease. The clinical communities were enthusiastic about the use of drug-eluting stents; however, these stents have a tendency to be a contributory factor towards late stage thrombosis, leading to mortality in a significant number of patients per year. This work presents an innovative approach in self-expanding coronary stents preparation. We developed a new nanocomposite polymer based on polyhedral oligomeric silsesquioxanes (POSS) and poly(carbonate-urea)urethane (PCU), which is an antithrombogenic and a non-biodegradable polymer with in situ endothelialization properties. The aim of this work is to coat a NiTi stent alloy with POSS-PCU. In prolonged applications in the human body, the corrosion of the NiTi alloy can result in the release of deleterious ions which leads to unwanted biological reactions. Coating the nitinol (NiTi) surface with POSS-PCU can enhance surface resistance and improve biocompatibility. Electrohydrodynamic spraying was used as the polymer deposition process and thus a few experiments were carried out to compare this process with casting. Prior to deposition the NiTi has been surface modified. The peel strength of the deposit was studied before and after degradation of the coating. It is shown that the surface modification enhances the peel strength by 300%. It is also indicated how the adhesion strength of the POSS-PCU coating changes post-exposure to physiological solutions comprised of hydrolytic, oxidative, peroxidative and biological media. This part of the study shows that the modified NiTi presents far greater resistance to decay in peel strength compared to the non-modified NiTi.

How safe and how good are drug-eluting stents?

Percutaneous transluminal coronary angioplasty revolutionized therapy for coronary artery disease. This early promise of a viable alternative to surgical treatment of coronary artery disease was thwarted by the high rates of angiographic restenosis. The advent of stenting reduced the rates of restenosis, although it was hindered by the new problem of in-stent restenosis. It was demonstrated that in-stent restenosis was the result of a new pathology in the form of neointimal hyperplasia, which was a maladaptive healing response to bare-metal stent implantation. Recently, the introduction of drug-eluting stents (DES) technology has offered a new solution to the problem of restenosis. Current evidence suggests that although DES have reduced restenosis rates, important concerns have been raised regarding increased stent thrombosis, myocardial infarction and death. The purpose of this article is to examine the efficacy and safety data of DES as highlighted in recent publications and to further discuss the biomolecular mechanisms of accelerated endothelization and stent thrombosis. In addition, we will examine some of the newer stent technologies available.

Underutilization of gastroprotection for at-risk patients undergoing percutaneous coronary intervention: Spain compared with the United States

BACKGROUND

Proton pump inhibitors (PPIs) are the preferred agents for the prevention of aspirin-associated upper gastrointestinal bleeding (UGIB). Data are limited to determine whether PPIs are being used to reduce UGIB risk.

AIM

To evaluate the implementation of PPI treatment to reduce the GI risk in two cardiology centres from Europe and the United States.

METHODS

A retrospective cross-sectional study was carried out at the University of Michigan and University Hospital-Zaragoza in 429 consecutive patients hospitalized for percutaneous coronary intervention (PCI) on dual antiplatelet therapy.

RESULTS

Admission for PPI co-therapy was similar (34% vs. 30%) in both centres. At discharge, the proportion of high-risk patients receiving PPI therapy in the Spanish centre (75.4%) was higher than their American peers (55.6%) (OR: 2.5; 95% CI; 1.3-4.7). No differences in PPI prescription rates were found among Spanish patients with/without GI risk factors. The opportunity to initiate PPI co-therapy in high-risk patients was missed in 81.8% (36/44) of those not on PPI at admission in US patients vs. 24.1% (19/79) (P < 0.0001) in Spanish patients.

CONCLUSIONS

There are important differences concerning PPI prescription and risk stratification in the two centres when managing PCI patients. Efforts to stratify risks and utilize appropriate strategies for UGIB prophylaxis in high-risk patients are warranted.

Acute coronary syndrome update for hospitalists

Acute coronary syndromes (ACSs)--unstable angina, non-ST-segment (ST, part of an electrocardiogram between the QRS complex and the T wave) or ST-segment elevation myocardial infarction (MI)--remain extremely common and clinically challenging. In addition to electrocardiography and biomarkers, formal risk stratification using risk scores has become an important part of the initial evaluation of patients with ACS. On the basis of the estimated risk of subsequent ischemic events, the optimal use and timing of cardiac catheterization and revascularization procedures can be determined. Additionally, antiplatelet and anticoagulant therapy can be instituted, with consideration given to both the ischemic and bleeding risks in an individual patient. A particular challenge in ACS management has been the rapid evolution of guidelines in response to new randomized clinical trial and registry data. Understanding and implementing the recommendations in these evidence-based guidelines are important parts of hospitalists' practice.

In vitro and in vivo performance of a dual drug-eluting stent (DDES)

This study reports on a dual drug-eluting stent (DDES) that has an anti-proliferative and an anti-thrombotic in a biodegradable polymer-coated onto a cobalt-chromium stent. The DDES was prepared by spray coating the bare metal stent with a biodegradable polymer loaded with sirolimus and triflusal, to treat against restenosis and thrombosis, respectively. The 2-layered dual-drug coated stent was characterized in vitro for surface properties before and after expansion, as well as for possible delamination by cross-sectioning the stent in vitro. The in vitro anti-platelet behavior of the triflusal-loaded films was investigated by using dynamic platelet adhesion measurements. Additionally, the in vitro degradation and release study of the films and the stents w/single sirolimus and dual sirolimus-triflusal in different formulations were examined. Finally, in vivo studies (in a porcine carotid artery model) were performed for acute thrombosis, inflammation and restenosis at 30 days. The in vitro results show DDES can sustain release both anti-proliferation drug (sirolimus) and anti-thrombosis drug (triflusal), two drugs were controlled in different rates to effectively reduce thrombosis and proliferation at the same time. In vivo results show a significant reduction in restenosis with dual-drug eluting stent compared with the controls (a bare metal stent, a sirolimus coated and a pure polymer-coated stent). The reduction in restenosis with a dual sirolimus-triflusal eluting stent is associated with an inhibition of inflammation, especially thrombus formation, suggesting that such dual-drug eluting stents have a role to play for the treatment of coronary artery disease.

Intravenous platelet blockade with cangrelor during PCI

BACKGROUND

Intravenous cangrelor, a rapid-acting, reversible adenosine diphosphate (ADP) receptor antagonist, might reduce ischemic events during percutaneous coronary intervention (PCI).

METHODS

In this double-blind, placebo-controlled study, we randomly assigned 5362 patients who had not been treated with clopidogrel to receive either cangrelor or placebo at the time of PCI, followed by 600 mg of clopidogrel. The primary end point was a composite of death, myocardial infarction, or ischemia-driven revascularization at 48 hours. Enrollment was stopped when an interim analysis concluded that the trial would be unlikely to show superiority for the primary end point.

RESULTS

The primary end point occurred in 185 of 2654 patients receiving cangrelor (7.0%) and in 210 of 2641 patients receiving placebo (8.0%) (odds ratio in the cangrelor group, 0.87; 95% confidence interval [CI], 0.71 to 1.07; P=0.17) (modified intention-to-treat population adjusted for missing data). In the cangrelor group, as compared with the placebo group, two prespecified secondary end points were significantly reduced at 48 hours: the rate of stent thrombosis, from 0.6% to 0.2% (odds ratio, 0.31; 95% CI, 0.11 to 0.85; P=0.02), and the rate of death from any cause, from 0.7% to 0.2% (odds ratio, 0.33; 95% CI, 0.13 to 0.83; P=0.02). There was no significant difference in the rate of blood transfusion (1.0% in the cangrelor group and 0.6% in the placebo group, P=0.13), though major bleeding on one scale was increased in the cangrelor group, from 3.5% to 5.5% (P<0.001), because of more groin hematomas.

CONCLUSIONS

The use of periprocedural cangrelor during PCI was not superior to placebo in reducing the primary end point. The prespecified secondary end points of stent thrombosis and death were lower in the cangrelor group, with no significant increase in the rate of transfusion. Further study of intravenous ADP blockade with cangrelor may be warranted. (ClinicalTrials.gov number, NCT00385138.)

Safety and efficacy of coronary drug-eluting stents in octogenarians

INTRODUCTION AND OBJECTIVES

The effectiveness of coronary drug-eluting stents has not been fully studied in very elderly patients who have clinical features that predispose them to side effects and long-term adverse events.

METHODS

The safety and efficacy of drug-eluting stents were studied in a historical cohort of consecutive octogenarian patients who underwent percutaneous coronary intervention.

RESULTS

Between 2002 and 2006, 176 octogenarian patients were treated using coronary stents: 90 with drug-eluting stents and 86 with bare-metal stents only. Patients treated using drug-eluting stents had a greater number of diseased vessels (2.28+/-0.85 vs. 1.87+/-0.87; P=.002), had more vessels treated (1.74+/-0.79 vs. 1.17+/-0.47; P< .0005), were more likely to have multivessel disease (79% vs. 59%; P=.005) and to undergo left main coronary artery treatment (20% vs. 1.0%; P< .0005), and had longer (26.6+/-6.7 mm vs. 16.6+/-4.9 mm; P< .0005) and smaller diameter (2.91+/-0.4 mm vs. 3.04+/-0.4 mm; P=.049) lesions. The median follow-up period was 26.3+/-12.9 months (in 98.3% of patients). After adjustment for other variables and for the likelihood of receiving a drug-eluting stent (i.e., the propensity score), there was no significant relationship between the type of coronary stent used and either mortality or the occurrence of adverse clinical events at 1 year of follow-up.

CONCLUSIONS

With careful clinical selection of patients, the use of drug-eluting stents in octogenarians with highly unfavorable angiographic characteristics can be as safe and effective as conventional stents for treating low-risk coronary lesions.

Differential regulation of vascular smooth muscle and endothelial cell proliferation in vitro and in vivo by cAMP/PKA-activated p85alphaPI3K

cAMP inhibits proliferation in most cell types, triggering different and sometimes opposing molecular pathways. p85alpha (phosphatidylinositol 3-kinase regulatory subunit) is phosphorylated by cAMP/PKA in certain cell lineages, but its effects on vascular smooth muscle cells (VSMCs) and endothelial cells (ECs) are unknown. In the present study, we evaluated 1) the role of p85alpha in the integration of cAMP/PKA-dependent signaling on the regulation of VSMC and EC growth in vitro; and 2) the effects of PKA-modified p85alpha on neointimal hyperplasia and endothelial healing after balloon injury in vivo. Plasmid constructs carrying wild-type and PKA-modified p85alpha were employed in VSMCs and ECs in vitro and after balloon injury in rat carotid arteries in vivo. cAMP/PKA reduced VSMC proliferation through p85alpha phosphorylation. Transfected PKA-activated p85alpha binds p21ras, reducing ERK1/2 activation and VSMC proliferation in vitro. In contrast, EC proliferation inhibition by cAMP is independent from PKA modification of p85alpha and ERK1/2 inhibition; indeed, PKA-activated p85alpha did not inhibit per se ERK1/2 activation and proliferation in ECs in vitro. Interestingly, cAMP reduced both VSMC and EC apoptotic death through p85alpha phosphorylation. Accordingly, PKA-activated p85alpha triggered Akt activation, reducing both VSMC and EC apoptosis in vitro. Finally, compared with controls, vascular gene transfer of PKA-activated p85alpha significantly reduced neointimal formation after balloon injury in rats, without inhibiting endothelial regeneration of the injured arterial segment. In conclusions, PKA-activated p85alpha integrates cAMP/PKA signaling differently in VSMCs and ECs. By reducing neointimal hyperplasia without inhibiting endothelial regeneration, it exerts a protective effect against restenosis after balloon injury.

The short-term effect on restenosis and thrombosis of a cobalt-chromium stent eluting two drugs in a porcine coronary artery model

The aim of this article was to study the effect of dual drug-eluting stent (DES) on both restenosis and thrombosis in a porcine coronary artery model. This study reports on the use of two drugs coated on the stent to simultaneously minimize both restenosis and thrombosis. The DES was prepared by spray coating a bare metal stent with a biodegradable polymer loaded with sirolimus and triflusal, to treat against restenosis and thrombosis, respectively. The two-layered dual drug-coated stent was characterized in vitro for surface properties before and after expansion, as well as for possible delamination by cross-sectioning the stent in vitro. In vivo animal studies (in a pig model) were then performed for acute thrombosis, inflammation, and restenosis. The results show a significant reduction in restenosis with a stent coated with both drugs compared with the controls (a bare metal stent, a sirolimus-coated, and a pure polymer-coated stent). The reduction in restenosis with a sirolimus/triflusal-eluting stent is associated with an inhibition of inflammation and thrombus formation, suggesting that such dual DES have a role to play for the treatment of coronary artery diseases.

Rapamycin promotes arterial thrombosis in vivo: implications for everolimus and zotarolimus eluting stents

AIMS

Drug-eluting stents (DES) may be associated with an increased risk for stent thrombosis when compared with bare-metal stents. In endothelial cells, rapamycin induces tissue factor (TF) by inhibiting the mammalian target of rapamycin (mTOR). However, the effect of mTOR inhibition on TF activity and thrombus formation in vivo has not yet been studied. Moreover, it is unclear whether second-generation DES substances everolimus and zotarolimus have an effect on endothelial TF expression.

METHODS AND RESULTS

In a mouse carotid artery photochemical injury model, rapamycin (182 +/- 27.5 microg/L) decreased time to thrombotic occlusion by 40%, increased TF activity, and abrogated p70S6K phosphorylation when compared with controls. In vitro, rapamycin, everolimus, and zotarolimus (each 10(-7) mol/l) enhanced TNF-alpha-induced TF expression by 2.2-, 1.7-, and 2.4-fold, respectively, which was paralleled by an increase in TF surface activity. Similar to rapamycin, everolimus and zotarolimus abrogated TNF-alpha-induced p70S6K phosphorylation under these conditions.

CONCLUSION

Rapamycin increases TF activity and promotes arterial thrombosis in vivo at concentrations relevant in patients undergoing DES implantation; this effect may increase the thrombogenicity of DES. Since everolimus and zotarolimus augment endothelial TF expression and activity in vitro in a similar manner as rapamycin, these findings may also be relevant for second generation DES.

ACE (I/D) polymorphism and response to treatment in coronary artery disease: a comprehensive database and meta-analysis involving study quality evaluation

BACKGROUND

The role of angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism in modifying the response to treatment modalities in coronary artery disease is controversial.

METHODS

PubMed was searched and a database of 58 studies with detailed information regarding ACE I/D polymorphism and response to treatment in coronary artery disease was created. Eligible studies were synthesized using meta-analysis methods, including cumulative meta-analysis. Heterogeneity and study quality issues were explored.

RESULTS

Forty studies involved invasive treatments (coronary angioplasty or coronary artery by-pass grafting) and 18 used conservative treatment options (including anti-hypertensive drugs, lipid lowering therapy and cardiac rehabilitation procedures). Clinical outcomes were investigated by 11 studies, while 47 studies focused on surrogate endpoints. The most studied outcome was the restenosis following coronary angioplasty (34 studies). Heterogeneity among studies (p < 0.01) was revealed and the risk of restenosis following balloon angioplasty was significant under an additive model: the random effects odds ratio was 1.42 (95% confidence interval:1.07-1.91). Cumulative meta-analysis showed a trend of association as information accumulates. The results were affected by population origin and study quality criteria. The meta-analyses for the risk of restenosis following stent angioplasty or after angioplasty and treatment with angiotensin-converting enzyme inhibitors produced non-significant results. The allele contrast random effects odds ratios with the 95% confidence intervals were 1.04(0.92-1.16) and 1.10(0.81-1.48), respectively. Regarding the effect of ACE I/D polymorphism on the response to treatment for the rest outcomes (coronary events, endothelial dysfunction, left ventricular remodeling, progression/regression of atherosclerosis), individual studies showed significance; however, results were discrepant and inconsistent.

CONCLUSION

In view of available evidence, genetic testing of ACE I/D polymorphism prior to clinical decision making is not currently justified. The relation between ACE genetic variation and response to treatment in CAD remains an unresolved issue. The results of long-term and properly designed prospective studies hold the promise for pharmacogenetically tailored therapy in CAD.

Noncardiac Surgery and Bleeding After Percutaneous Coronary Intervention

Background— The decision on whether to implant a drug-eluting or bare-metal stent during percutaneous coronary intervention (PCI) depends in part on the perceived likelihood of the patient developing late stent thrombosis. Noncardiac surgery and bleeding are associated with discontinuation of dual antiplatelet therapy and with increased stent thrombosis. We assessed the incidence of and predictors for subsequent noncardiac surgery and bleeding episodes in patients who had undergone PCI.

Methods and Results— Hospital discharge coding data were used to identify all adult patients undergoing public hospital PCI in New Zealand from 1996 to 2001. Hospital admissions during the ensuing 5 years were analyzed for noncardiac surgery and bleeding episodes. Eleven thousand one hundred fifty-one patients (age, 62�11 years; 30% women) underwent PCI, mainly for an acute coronary syndrome (73%). During the 5-year follow-up, 26% of the population underwent at least 1 noncardiac surgical procedure (23% orthopedic, 20% abdominal, 12% urologic, 10% vascular, 35% others) and 8.6% had at least 1 bleeding episode either requiring or occurring during hospitalization. Of those, half were gastrointestinal, and one quarter of bleeding events required blood transfusion. The main clinical predictors of noncardiac surgery were advanced age, previous noncardiac surgery, osteoarthritis, and peripheral vascular disease. A previous bleeding admission and age were the strongest predictors of subsequent bleeding.

Conclusions— Noncardiac surgery is required frequently after PCI, whereas bleeding is less common. Before implanting a drug-eluting or bare-metal stent, individual patient risk stratification by the interventional cardiologist should include assessment of whether there is an increased likelihood of needing noncardiac surgery or developing bleeding.

Comprehensive meta-analysis on drug-eluting stents versus bare-metal stents during extended follow-up

BACKGROUND

Several observational reports have documented both increased and decreased cardiac mortality or Q-wave myocardial infarction with drug-eluting stents compared with bare-metal stents.

METHODS

We sought to evaluate the safety and efficacy of drug-eluting stents compared with bare-metal stents early after intervention (<1 year) and late (>1 year) among a broad population of patients, using a meta-analysis of randomized clinical trials.

RESULTS

We identified 28 trials with a total of 10,727 patients and a mean follow-up of 29.6 months. For early outcomes (<1 year), all-cause mortality for drug-eluting stents versus bare-metal stents was 2.1% versus 2.4% (risk ratio [RR] 0.91, [95% confidence interval (CI), 0.70-1.18]; P=.47), non-Q-wave myocardial infarction was 3.3% versus 4.4% (RR 0.78 [95% CI, 0.61-1.00]; P=.055), target lesion revascularization was 5.8% versus 18.4% (RR 0.28 [95% CI, 0.21-0.38]; P <.001), and stent thrombosis was 1.1% versus 1.3% (RR 0.87 [95% CI, 0.60-1.26]; P=.47). For late outcomes (>1 year), all-cause mortality for drug-eluting stents versus bare-metal stents was 5.9% versus 5.7% (RR 1.03 [95% CI, 0.83-1.28]; P=.79), target lesion revascularization was 4.0% versus 3.3% (RR 1.22 [95% CI, 0.92-1.60]; P=.16), non-Q-wave myocardial infarction was 1.6% versus 1.2% (RR 1.36 [95% CI, 0.74-2.53]; P=.32) and stent thrombosis was 0.7% versus 0.1% (RR 4.57 [95% CI, 1.54-13.57]; P=.006).

CONCLUSIONS

There was no excess mortality with drug-eluting stents. Within 1 year, drug-eluting stents appear to be safe and efficacious with possibly decreased non-Q-wave myocardial infarction compared with bare-metal stents. After 1 year, drug-eluting stents still have similar mortality, despite increased stent thrombosis. The reduction in target lesion revascularization with drug-eluting stents mainly happens within 1 year, but is sustained thereafter.

Chronic kidney disease and dipstick proteinuria are risk factors for stent thrombosis in patients with myocardial infarction

BACKGROUND

Kidney failure (stage 5 chronic kidney disease [CKD]) is an independent risk factor for stent thrombosis (ST). Moderate (stage 3-4) CKD and proteinuria are both associated with adverse cardiovascular events, including worse outcomes after myocardial infarction (MI). Whether moderate CKD and proteinuria increase the risk of ST after MI is not known. This study evaluated the risk of ST associated with moderate CKD and dipstick proteinuria.

METHODS

We retrospectively analyzed clinical and laboratory data from 956 non-stage 5 CKD patients who were admitted with MI and received intracoronary stenting. Clinical follow-up was collected at 1 year for definite or probable ST, as well as for all-cause mortality, nonfatal MI or death, and target vessel revascularization or coronary artery bypass graft surgery.

RESULTS

After adjustment for multiple clinical and biochemical covariates, patients with both estimated glomerular filtration rate (GFR) of 15 to 59 mL min(-1) 1.73 m(-2) and > or =30 mg/dL dipstick proteinuria had increased cumulative incidence of ST (hazard rate [HR] 3.69, 95% CI 1.54-8.89), all-cause mortality (HR 2.68, 95% CI 1.34-5.37), and nonfatal MI or death (HR 3.20, 95% CI 1.77-5.81) at 1 year. In addition, estimated GFR of 15 to 59 mL min(-1) 1.73 m(-2) was a significant independent predictor of ST (HR 2.61, 95% CI 1.33-5.10). Dipstick proteinuria > or =30 mg/dL was associated with a trend toward increased risk for all outcomes.

CONCLUSIONS

In an acute MI population, moderate CKD was identified as a novel prognostic marker for ST. In addition, patients with both decreased GFR and proteinuria had higher incidences of all-cause mortality and nonfatal MI or death than patients with either condition alone.

Safety of drug-coated stents

BACKGROUND

Drug-coated (i.e., drug-eluting) stents (DES) are frequently used nowadays in the treatment of coronary artery disease given their superior antirestenotic effect and clear benefits in terms of reduction of repeat revascularizations and major adverse cardiac events. However, a number of safety concerns have been raised on DES.

OBJECTIVE

To appraise current data on the safety of DES.

METHODS

A thorough PubMed search was done for pertinent clinical reports on DES safety with the following string (updated December 2007): (drug(*) OR sirolimus OR paclitaxel) AND eluting(*) AND stent(*) AND (safety OR complication(*) OR thrombos(*) OR infarction) NOT (editorial[pt] OR review[pt]).

RESULTS/CONCLUSION

A total of 1077 citations were retrieved and appraised. The most relevant threats to DES safety were bleeding, difficulties in balloon deflation and retrieval, endothelial dysfunction and vasospasm, hypersensitivity, infection, late acquired malapposition and aneurysm formation, late restenosis, peri-procedural myocardial infarction, plaque prolapse, stent dislodgement or embolization, stent fracture, and stent thrombosis (with ensuing risk of death, myocardial infarction or arrhythmia). Of these, the most important and debated safety issue is the potentially increased risk in late stent thrombosis, which might offset the antirestenotic benefits of DES especially in patients at higher risk of thrombosis or who cannot comply with the recommended dual antiplatelet regimen. Nonetheless, further clinical studies are warranted to clarify whether these safety threats should be a concern for the large target population of patients with coronary artery disease most likely to benefit from DES implantation.