Effects of antiplatelet therapy with indobufen or aspirin-dipyridamole on graft patency one year after coronary artery bypass grafting

Safety and efficacy of aspirin and indobufen in the treatment of coronary heart disease: a systematic review and meta-analysis

Purpose

This meta-analysis aimed to compare the safety and efficacy of aspirin and indobufen in patients with coronary heart disease. The primary focus was on the incidence of cardiovascular events, bleeding events, and gastrointestinal reactions. Given the relatively limited research on indobufen, this study utilized aspirin as a control drug and employed meta-analysis to integrate existing clinical studies. The goal was to provide a reference for the clinical use of indobufen and to suggest directions for further largescale, multicenter prospective studies.

Methods

This review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We conducted a comprehensive search of the PubMed, EMBASE, WOS, and Cochrane Library databases to identify all relevant literature on indobufen. A total of nine trials met the inclusion criteria, encompassing seven randomized controlled trails (RCTs) and two retrospective studies. Categorical variables were analyzed using odds ratio and random effects models.

Results

The meta-analysis included nine trials, comprising seven RCTs and two retrospective studies. The pooled results indicated that indobufen significantly reduced the incidence of minor bleeding events, and gastrointestinal discomfort compared to aspirin. However, both drugs had similar effects on the incidence of recurrent angina pectoris, myocardial infarction and mortality due to coronary heart disease.

Conclusion

Indobufen was associated with fewer gastrointestinal reactions and a low risk of bleeding, making it a viable option for patients with high-risk factors for bleeding and gastric ulcers. Despite this, indobufen's short history and limited evidence base compared to aspirin highlight the need for further research. Aspirin remains widely available, cost-effective, and the preferred drug for the primary and secondary prevention of cardiovascular and cerebrovascular diseases. Indobufen or other antiplatelet agents should only be considered when aspirin is not tolerated or contraindicated. Further clinical trials are necessary to determine whether indobufen can replace aspirin.

Systematic Review Registration

https://www.crd.york.ac.uk/, identifier [CRD42024523477].

Preventive medication efficacy after 1-year follow-up for graft failure in coronary artery bypass surgery patients: Bayesian network meta-analysis

To compare preventive medications against graft failures in coronary artery bypass graft surgery (CABG) patients after a 1-year follow-up. Systematic review with Bayesian network meta-analysis and meta-regression analysis. We searched PubMed, Scopus, and Web of Science databases in February 2023 for randomized controlled trials, comparing preventive medications against graft failure in CABG patients. We included studies that reported outcomes at 1 year after surgery. Our primary outcome was graft failure After screening 11,898 studies, a total of 18 randomized trials were included. Acetylsalicylic acid (ASA) [odds ratios (OR) 0.51, 95% credibility interval (CrI) 0.28-0.95, meta-regression OR 0.54, 95% CrI 0.26-1.00], Clopidogrel + ASA (OR 0.27, 95% CrI 0.09-0.76, meta-regression OR 0.28, 95% CrI 0.09-0.85), dipyridamole + ASA (OR 0.50, 95% CrI 0.30-0.83, meta-regression OR 0.49, 95% CrI 0.26-0.90), ticagrelor (OR 0.40, 95% CrI 0.16-1.00, meta-regression OR 0.43, 95% CrI 0.15-1.2), and ticagrelor + ASA (OR 0.26, 95% CrI 0.10-0.62, meta-regression OR 0.28, 95% CrI 0.10-0.68) were superior to placebo in preventing graft failure. Rank probabilities suggested the highest likelihood to be the most efficacious for ticagrelor + ASA [surface under the cumulative ranking (SUCRA) 0.859] and clopidogrel + ASA (SUCRA 0.819). The 95% CrIs of ORs for mortality, bleeding, and major adverse cardio- and cerebrovascular events (MACE) were wide. A trend towards increased bleeding risk and decreased MACE risk was observed when any of the medication regimens were used when compared to placebo. Sensitivity analysis excluding studies with a high risk of bias yielded equivalent results. Of the reviewed medication regimens, dual antiplatelet therapy combining ASA with ticagrelor or clopidogrel was found to result in the lowest rate of graft failures.

Safety outcomes of anti-platelet therapy post coronary artery bypass graft surgery: A systematic review and network meta-analysis of randomized control trials

BACKGROUND

Antiplatelet therapy is used to decrease the risk of graft failure post coronary artery bypass graft surgery. We aimed to compare dual antiplatelet therapy (DAPT) with monotherapy along with a comparison of Aspirin, Ticagrelor, Aspirin+Ticagrelor (A+T) and Aspirin+Clopidogrel (A+C) to determine the major and minor bleeding risk, risk of postoperative myocardial infarction (MI), stroke, and all-cause mortality (ACM).

METHODS

Randomized Controlled Trials comparing the four groups were included. Odds ratio (OR) and Absolute Risk (AR) were employed to assess the mean and standard deviation (SD) with 95% confidence intervals (CI). The Bayesian random-effects model was used for statistical analysis. Risk difference and Cochran Q tests were used to calculate rank probability (RP) and heterogeneity, respectively.

RESULTS

We included 10 trials, consisting of 21 arms and 3926 patients. For the risk of major and minor bleed, A + T and Ticagrelor showed the lowest mean value of 0.040 (0.043) and 0.067 (0.073), respectively, and the highest RP of being the safest group. While a direct comparison between DAPT and monotherapy resulted in an OR of 0.57 [0.34, 0.95] for the risk of minor bleed. A + T was found to have the highest RP and the lowest mean value in terms of ACM, MI, and stroke.

CONCLUSION

No significant difference was found between monotherapy or dual-antiplatelet therapy for the major bleeding risk safety outcome, however DAPT was found to have a significantly higher rate of minor bleeding complications post-CABG. DAPT should be considered as the antiplatelet modality of choice post-CABG.

Antithrombotic strategies for preventing graft failure in coronary artery bypass graft

Coronary artery bypass graft (CABG) procedures face challenges related to graft failure, driven by factors such as acute thrombosis, neointimal hyperplasia, and atherosclerotic plaque formation. Despite extensive efforts over four decades, the optimal antithrombotic strategy to prevent graft occlusion while minimizing bleeding risks remains uncertain, relying heavily on expert opinions rather than definitive guidelines. To address this uncertainty, we conducted a review of randomized clinical trials and meta-analyses of antithrombotic therapy for patients with CABG. These studies examined various antithrombotic regimens in CABG such as single antiplatelet therapy (aspirin or P2Y12 inhibitors), dual antiplatelet therapy, and anticoagulation therapy. We evaluated outcomes including the patency of grafts, major adverse cardiovascular events, and bleeding complications and also explored future perspectives to enhance long-term outcomes for CABG patients. Early studies established aspirin as a key component of antithrombotic pharmacotherapy after CABG. Subsequent randomized controlled trials focused on adding a P2Y12 inhibitor (such as clopidogrel, ticagrelor, or prasugrel) to aspirin, yielding mixed results. This article aims to inform clinical decision-making and guide the selection of antithrombotic strategies after CABG.

Clopidogrel with indobufen or aspirin in minor ischemic stroke or high-risk transient ischemic attack: a randomized controlled clinical study

BACKGROUND

Ischemic stroke and transient ischemic attack (TIA) are the most prevalent cerebrovascular diseases. The conventional antiplatelet drugs are associated with an inherent bleeding risk, while indobufen is a new antiplatelet drug and has the similar mechanism of antiplatelet aggregation as aspirin with more safety profile. However, there have been no studies evaluating the combination therapy of indobufen and clopidogrel for antiplatelet therapy in cerebrovascular diseases.

OBJECTIVE

The CARMIA study aims to investigate the effectiveness and safety of a new dual antiplatelet therapy consisting of indobufen and clopidogrel comparing with the conventional dual antiplatelet therapy consisting of aspirin and clopidogrel in patients with minor ischemic stroke or high-risk TIA.

METHODS

An open-label randomized controlled clinical trial was conducted at a clinical center. We randomly assigned patients who had experienced a minor stroke or transient ischemic attack (TIA) within 72 h of onset, or within 1 month if they had intracranial stenosis (IS), to receive either indobufen 100 mg twice daily or aspirin 100 mg once daily for 21 days. For patients with IS, the treatment duration was extended to 3 months. All patients received a loading dose of 300 mg clopidogrel orally on the first day, followed by 75 mg once daily from the second day to 1 year. We collected prospective data using paper-based case report forms, and followed up on enrolled patients was conducted to assess the incidence of recurrent ischemic stroke or TIA, mRS score, NIHSS (National Institutes of Health Stroke Scale) score, and any bleeding events occurring within 3 month after onset.

RESULTS

We enrolled 202 patients diagnosed with ischemic stroke or transient ischemic attack. After applying the criteria, 182 patients were eligible for data analysis. Endpoint events (recurrence of ischemic stroke/TIA, myocardial infarction, or death) were observed in 6 patients (6.5%) receiving aspirin and clopidogrel, including 4 (4.3%) with stroke recurrence, 1 (1.1%) with TIA recurrence, and 1 (1%) with death. In contrast, no endpoint events were reported in the indobufen and clopidogrel group (P = 0.029). The group of patients receiving indobufen and clopidogrel exhibited significantly lower modified Rankin Scale (mRS) score. (scores range from 0 to 6, with higher scores indicating more severe disability) compared to the aspirin and clopidogrel group (common odds ratio 3.629, 95% CI 1.874-7.036, P < 0.0001). Although the improvement rate of NIHSS score in the indobufen and clopidogrel group was higher than that in the aspirin and clopidogrel group, the difference was not statistically significant (P > 0.05). Bleeding events were observed in 8 patients (8.6%) receiving aspirin and clopidogrel, including 4 (4.3%) with skin bleeding, 2 (2.2%) with gingival bleeding, 1 (1.1%) with gastrointestinal bleeding, and 1 (1.1%) with urinary system bleeding. On the other hand, only 1 patient (1.1%) in the indobufen and clopidogrel group experienced skin bleeding (P = 0.035).

CONCLUSION

The combination of indobufen and clopidogrel has shown non-inferior and potentially superior effectiveness and safety compared to aspirin combined with clopidogrel in patients with minor ischemic stroke and high-risk TIA in the CARMIA study (registered under chictr.org.cn with registration number ChiCTR2100043087 in 01/02/2021).

Liquid-like Oral Sustained-Release System Based on Acid-Sensitive in situ Hydrogel for Alleviate Gastrointestinal Side Effects of Indobufen

Commonly, most oral non-steroidal anti-inflammatory drugs (NSAIDs) have known gastric adverse reactions due to their long-term and high dose administration. In this study, a novel liquid sustained-release system based on multiple-unit in situ hydrogel beads was designed to address this issue. The system is composed of sodium alginate (SA), gellan gum (GG), zinc oxide (ZnO), and magnesium oxide (MgO). Furthermore, indobufen was loaded into the system to evaluate its gastric mucosal protection effect. This effect can be attributed to the topical antacid, pepsin inhibition, and sustained drug release properties of the system. It was proven that the stored solid gel system could undergo a "solid to liquid" transition after shaking. Once swallowed, the liquid gel could disperse well in the stomach as hydrogel beads. Then, the "liquid to solid" gelation occurred from the exterior to interior of each multiple-unit gel bead, triggered by the release of Zn2+ and Mg2+ from neutralization reactions. The formed gel demonstrated mild antacid effect that lasted for 3 hours and 66.3% pepsin inhibition in vivo. Moreover, the rats treated with the indobufen gel system showed a drug plasma concentration versus time curve with less fluctuation compared to the rats treated with the marketed preparation (YinDuo®) group. The gel system also exhibited an extended Tmax (6.50 hours) and reduced Cmax (52.87 μg/mL). Additionally, the gastric mucosal protection of the gel system was verified using three types of peptic gastric ulcer models. These findings suggested that this multiple-unit in situ gel could be a potential oral liquid sustained release delivery system for NSAIDs.

Reversible and Non-Competitive Inhibition of Cyclooxygenase by Indobufen for Efficient Antiplatelet Action and Relief of Gastrointestinal Irritation

Clinically, indobufen is widely used for the treatment of antiplatelet aggregation and anticoagulation. Prior studies have discovered that abnormal platelet function can be promptly restored to normal when the drug is stopped. Herein, through the study of the enzyme reaction kinetics, we demonstrated that the inhibitory effect of indobufen on cyclooxygenase-1 (COX-1) was reversible and non-competitive. Specifically, the cyclooxygenase inhibition experiment showed that the level of 6-keto-PGF1α in the gastric mucosa of the indobufen-treated groups was significantly higher than that of the aspirin group (###p < 0.001), indicating a higher level of PGI2 in and a better physiological state of the gastric mucosa. Moreover, the rat gastric ulcer index and mucosal section experiments further confirmed the relief of gastrointestinal irritation and the adverse reaction rate of the indobufen-treated group compared to those of the aspirin group. Furthermore, indobufen was verified to exert reversible inhibitory activity on the heme group of COX-1 and thus reversibly inhibit COX-1 activity. In general, compared with aspirin, the long-term oral administration of indobufen yields a lower risk of gastrointestinal symptoms, such as ulcers.

Antiplatelet therapy and coronary artery bypass grafting: a systematic review and network meta-analysis

OBJECTIVES

Acetylsalicylic acid (ASA) monotherapy is the standard of care after coronary artery bypass grafting (CABG), but the benefits of more intense antiplatelet therapy, specifically dual antiplatelet therapy (DAPT), require further exploration in CABG patients. We performed a network meta-analysis to compare the effects of various antiplatelet regimens on saphenous vein graft patency, mortality, major adverse cardiovascular events and bleeding among CABG patients.

METHODS

We searched Cochrane Central Register of Controlled Trials, Medical Literature Analysis and Retrieval Systems Online, Excerpta Medica Database, Cumulative Index to Nursing and Allied Health Literature, American College of Physicians Journal Club and conference proceedings for randomized controlled trials. Screening, data extraction, risk of bias assessment and Grading of Recommendations Assessment, Development and Evaluation were performed in duplicate. We conducted a random effect Bayesian network meta-analysis including both direct and indirect comparisons.

RESULTS

We included 43 randomized controlled trials studying 15 511 patients. DAPT with low-dose ASA and ticagrelor [odds ratio (OR) 2.53, 95% credible interval (CrI) 1.35–4.72; I2 = 55; low certainty] or clopidogrel (OR 1.56, 95% CrI 1.02–2.39; I2 = 55; very low certainty) improved saphenous vein graft patency when compared to low-dose ASA monotherapy. DAPT with low-dose ASA and ticagrelor was associated with lower mortality (OR 0.52, 95% CrI 0.30–0.87; I2 = 14; high certainty) and lower major adverse cardiovascular events (OR 0.63, 95% CrI 0.44–0.91; I2 = 0; high certainty) when compared to low-dose ASA monotherapy. Based on moderate certainty evidence, DAPT was associated with an increase in major bleeding.

CONCLUSIONS

Our results suggest that DAPT improves saphenous vein graft patency, mortality and major adverse cardiovascular event. As such, surgeons and physicians should consider re-initiating DAPT for acute coronary syndrome patients after their CABG, at the expense of an increased risk for major bleeding.

Clinical trial registration

International Prospective Register of Systematic Reviews ID Number CRD42019127695

Vein graft failure: from pathophysiology to clinical outcomes

Occlusive arterial disease is a leading cause of morbidity and mortality worldwide. Aside from balloon angioplasty, bypass graft surgery is the most commonly performed revascularization technique for occlusive arterial disease. Coronary artery bypass graft surgery is performed in patients with left main coronary artery disease and three-vessel coronary disease, whereas peripheral artery bypass graft surgery is used to treat patients with late-stage peripheral artery occlusive disease. The great saphenous veins are commonly used conduits for surgical revascularization; however, they are associated with a high failure rate. Therefore, preservation of vein graft patency is essential for long-term surgical success. With the exception of 'no-touch' techniques and lipid-lowering and antiplatelet (aspirin) therapy, no intervention has hitherto unequivocally proven to be clinically effective in preventing vein graft failure. In this Review, we describe both preclinical and clinical studies evaluating the pathophysiology underlying vein graft failure, and the latest therapeutic options to improve patency for both coronary and peripheral grafts.

Design, Synthesis, andIn VitroAntiplatelet Aggregation Activities of Ferulic Acid Derivatives

In order to discover new compounds with antiplatelet aggregation activities, some ferulic acid (FA) derivatives were designed and synthesized. Thein vitroantiplatelet aggregation activities of these compounds were assessed by turbidimetric test. The results showed that the target compound7fhad potent antiplatelet aggregation activity with its IC5027.6 μmol/L, and7fcan be regarded as a novel potent antiplatelet aggregation candidate.

Saphenous vein graft disease: review of pathophysiology, prevention, and treatment

Saphenous vein graft (SVG) disease after coronary artery bypass grafting (CABG) occurs in three phases: thrombosis, intimal hyperplasia, and atherosclerosis. Within the first month, thrombosis plays a major role. From month 1 to month 12, intimal hyperplasia occurs. Beyond 12 months, atherosclerosis becomes the primary cause for late graft failure. Endothelial damage has been shown to be the major underlying pathophysiology of SVG disease. Many factors contribute to endothelial damage from the moment the vein is harvested to when the vein is grafted into an arterial environment. To address this disease process, various therapeutic modalities, from surgical methods to medical treatment, have been evaluated. Surgically, the technical method of harvesting the vein has been shown to affect SVG patency. From a pharmacologic perspective, only two guideline class I recommended medications, aspirin and statins, have been shown to improve short- and long-term SVG patency after CABG. Despite these surgical and medical advances, SVG disease remains a significant problem with 1-year patency rates of 89% dropping to 61% after 10 years. This review discusses the pathogenesis of SVG disease, predictors of SVG failure, and current surgical and pharmacologic therapies to address SVG disease, including possible future treatment.

New antiplatelet agents

PURPOSE OF REVIEW

Cardiovascular events are still a major concern despite dual antiplatelet treatment with aspirin and clopidogrel. Moreover, recent developments that improved platelet inhibition were associated with increased bleeding complications, suggesting that personal dose adjustment might be needed. This review is dedicated to new developments in antiplatelet agents other than ADP P2Y12 receptor blockers, which are discussed in a separate article of this issue.

RECENT FINDINGS

The thrombin receptor protease activable receptor-1 antagonist SCH530348 and the thromboxane receptor antagonist terutroban are two promising agents that are now undergoing phase III clinical trials. Cilostazol, a phosphodiesterase III inhibitor, is currently tested in phase IV trials for several new indications. Despite previous disappointing results with oral GPIIbIIIa antagonists, new compounds with unique features are under development. In addition, targeting intracellular signaling pathways is a new area of research, with several attractive targets.

SUMMARY

Recent development of new antiplatelet agents, including inhibitors of thrombin receptor, thromboxane receptor, phosphodiesterase, glycoprotein VI, GPIIbIIIa and signaling pathways, may lead to a more effective and yet safe antiplatelet therapy with an improved clinical outcome.

Secondary prevention after coronary artery bypass grafting – what do we know?

There is insufficient knowledge about secondary prevention after coronary artery bypass grafting (CABG). Most of it is gathered from patients suffering from myocardial infarction and angina pectoris, only a minority of whom have undergone CABG. Whereas it seems clear that these patients should give up smoking and reduce low-density lipoprotein (LDL) cholesterol, there is uncertainty about the optimal antiplatelet regimen and antithrombotic treatment. There are some data indicating the benefit of behaviour modification. There is room for improvement and more knowledge when it comes to secondary prevention after CABG.

Antiplatelet drugs: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)

This article about currently available antiplatelet drugs is part of the Antithrombotic and Thrombolytic Therapy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). It describes the mechanism of action, pharmacokinetics, and pharmacodynamics of aspirin, reversible cyclooxygenase inhibitors, thienopyridines, and integrin alphaIIbbeta3 receptor antagonists. The relationships among dose, efficacy, and safety are thoroughly discussed, with a mechanistic overview of randomized clinical trials. The article does not provide specific management recommendations; however, it does highlight important practical aspects related to antiplatelet therapy, including the optimal dose of aspirin, the variable balance of benefits and hazards in different clinical settings, and the issue of interindividual variability in response to antiplatelet drugs.

The primary and secondary prevention of coronary artery disease: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)

The following chapter devoted to antithrombotic therapy for chronic coronary artery disease (CAD) is part of the Antithrombotic and Thrombolytic Therapy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Grade 1 recommendations are strong and indicate that the benefits do or do not outweigh risks, burden, and costs. Grade 2 suggests that individual patient values may lead to different choices (for a full understanding of the grading see the "Grades of Recommendation" chapter by Guyatt et al in this supplement, CHEST 2008; 133[suppl]:123S-131S). Among the key recommendations in this chapter are the following: for patients with non-ST-segment elevation (NSTE)-acute coronary syndrome (ACS) we recommend daily oral aspirin (75-100 mg) [Grade 1A]. For patients with an aspirin allergy, we recommend clopidogrel, 75 mg/d (Grade 1A). For patients who have received clopidogrel and are scheduled for coronary bypass surgery, we suggest discontinuing clopidogrel for 5 days prior to the scheduled surgery (Grade 2A). For patients after myocardial infarction, after ACS, and those with stable CAD and patients after percutaneous coronary intervention (PCI), we recommend daily aspirin (75-100 mg) as indefinite therapy (Grade 1A). We recommend clopidogrel in combination with aspirin for patients experiencing ST-segment elevation (STE) and NSTE-ACS (Grade 1A). For patients with contraindications to aspirin, we recommend clopidogrel as monotherapy (Grade 1A). For long-term treatment after PCI in patients who receive antithrombotic agents such as clopidogrel or warfarin, we recommend aspirin (75 to 100 mg/d) [Grade 1B]. For patients who undergo bare metal stent placement, we recommend the combination of aspirin and clopidogrel for at least 4 weeks (Grade 1A). We recommend that patients receiving drug-eluting stents (DES) receive aspirin (325 mg/d for 3 months followed by 75-100 mg/d) and clopidogrel 75 mg/d for a minimum of 12 months (Grade 2B). For primary prevention in patients with moderate risk for a coronary event, we recommend aspirin, 75-100 mg/d, over either no antithrombotic therapy or vitamin K antagonist (Grade 1A).

Postoperative analgesia with ketorolac is associated with decreased mortality after isolated coronary artery bypass graft surgery in patients already receiving aspirin: a propensity-matched study

OBJECTIVE

This study was designed to determine the effect of ketorolac on mortality after cardiac surgery.

DESIGN

A retrospective multivariable analysis with propensity matching and propensity scoring.

SETTING

A tertiary care university-affiliated medical center.

PARTICIPANT

Eleven hundred eighty-six patients undergoing isolated coronary artery bypass surgery.

MAIN RESULTS

Between January 1, 2002, and November 1, 2004, 168 patients undergoing isolated coronary artery bypass surgery received ketorolac, whereas 1,018 patients did not. There were 2 deaths (1%) in the ketorolac group compared with 104 (10%) in the nonketorolac group (p < 0.001). Within 90 days of surgery, there was 1 death (1%) in the ketorolac group compared with 51 (5%) in the nonketorolac group (p = 0.01). By Cox modeling, ketorolac use was associated with a 7-fold lower risk of death (p = 0.02). In the patients who survived at least 90 days, there was 1 death (1%) in the ketorolac group compared with 53 (5%) in the nonketorolac group (p = 0.01). By Cox modeling, ketorolac use was associated with a 2.4-fold lower risk of death (p = 0.03) in the late hazard period. In the propensity-matched groups, Kaplan-Meier survival was better in patients who received ketorolac (p = 0.02).

CONCLUSION

The use of ketorolac was associated with a statistically significant decrease in mortality at follow-up.

Cardioprotective Strategies to Improve Long-Term Outcomes Following Coronary Artery Bypass Surgery

BACKGROUND AND AIM

Cardioprotective strategies implemented to prevent ischemic events in patients at risk for cardiovascular disease have decreased morbidity and prolonged survival. In this review, we have used evidence-based medicine and number-needed-to-treat (NNT) analyses to determine which interventions are most beneficial in minimizing ischemic events and prolonging survival following coronary artery bypass graft (CABG) surgery.

METHODS

Therapeutic interventions available to minimize ischemic events in the post-CABG patient were analyzed using ACC/AHA Classifications and Level of Evidence Criteria. Based on these recommendations, NNT analyses were performed to determine the effectiveness of each intervention compared to the number of patients needed to be treated before a benefit was apparent.

RESULTS

The most beneficial intervention to improve mortality following CABG was the use of high tissue angiotensin-converting enzyme inhibitors, followed by statins and smoking cessation.

CONCLUSIONS

NNT analyses and evidence-based medicine recommendations provide surgeons with cardioprotective strategies to improve long-term outcomes following CABG surgery.

Upper gastrointestinal bleeding associated with antiplatelet drugs

BACKGROUND

The risk of major upper gastrointestinal bleeding associated with various antiplatelet drugs and the protection conferred by gastroprotective agents are not well defined.

AIM

To estimate the risk of upper gastrointestinal bleeding associated with the use of antiplatelet drugs and its prevention by gastroprotective agents.

METHODS

In a case-control study, we compared all cases of upper gastrointestinal bleeding from a gastric or duodenal lesion in patients over 18 years of age (2813 cases), with 7193 matched controls. Odds ratios of upper gastrointestinal bleeding for individual antiplatelet drugs with adjustment for potential confounders were estimated.

RESULTS

The individual risks of upper gastrointestinal bleeding were cardiovascular acetylsalicylic acid 4.0 (3.2-4.9), clopidogrel 2.3 (0.9-6.0), dipyridamole 0.9 (0.4-2.0), indobufen 3.8 (1.2-12.2), ticlopidine 3.1 (1.8-5.1) and triflusal 1.6 (0.9-2.7). Concomitant proton pump inhibitors decreased all risk estimates. For acetylsalicylic acid plus a proton pump inhibitor, the odds ratio was 1.1 (0.5-2.6). As a group, antiplatelet drugs accounted for 14.5% of all cases of upper gastrointestinal bleeding, i.e. 58 per million per year (334 per million per year among those older than 70 years).

CONCLUSIONS

The risk of upper gastrointestinal bleeding is substantially decreased by the concomitant use of proton pump inhibitors. The risk of acetylsalicylic acid plus a proton pump inhibitor seems lower than that of ticlopidine or clopidogrel.

One-Year Coronary Bypass Graft Patency

Background— Off-pump coronary bypass surgery has become a widely used technique during recent years. However, limited data are available with regard to 1-year patency of bypass grafts implanted on the beating heart in unselected consecutive bypass surgery candidates. The aim of this study was to compare 1-year angiographic patency of bypass grafts done on the beating heart (off pump) with those done classically (on pump).

Methods and Results— The PRAGUE-4 trial randomized 400 consecutive nonselected cardiac surgery candidates into group A (on pump; n=192) and group B (off pump; n=208). One-year follow-up coronary angiography was done in 255 patients. The arterial graft patency after 1 year was 91% in both groups. Saphenous graft patency was 59% (on pump) versus 49% (off pump; P =NS). Saphenous graft patency per patient was lower in the off-pump group: 0.7 patent anastomosis per patient versus 1.1 patent anastomosis in the on-pump group ( P <0.01). There were 46% on-pump patients with all grafts patent versus 52% off-pump patients ( P =NS). Grafts anastomosed distally to collateralized chronic total occlusions of native coronary arteries remained patent in 100% on the left anterior descending artery compared with 23% on other arteries ( P <0.0001).

Conclusions— The patency of arterial coronary bypass grafts done on the beating heart is excellent and equal to grafts done on pump. The off-pump procedure in the unselected patient population results in fewer patent saphenous grafts per patient.

Anticoagulants versus antiplatelet therapy for preventing stroke in patients with nonrheumatic atrial fibrillation and a history of stroke or transient ischemic attack

BACKGROUND

People with nonrheumatic atrial fibrillation (NRAF) who have had a transient ischemic attack (TIA) or minor ischemic stroke are at risk of recurrent stroke. Both warfarin and aspirin have been shown to reduce the recurrence of vascular events.

OBJECTIVES

The objective of this review was to compare the effect of anticoagulants with antiplatelet agents, for secondary prevention, in people with NRAF and previous cerebral ischemia.

SEARCH STRATEGY

We searched the Cochrane Stroke Group trials register (last searched 9 June 2003) and contacted trialists.

SELECTION CRITERIA

Randomised trials comparing oral anticoagulants with antiplatelet agents in patients with NRAF and a previous TIA or minor ischemic stroke.

DATA COLLECTION AND ANALYSIS

Both reviewers extracted and analysed data.

MAIN RESULTS

Two trial were identified. The European Atrial Fibrillation Trial (EAFT) involving 455 patients, who received either anticoagulants (International Normalised Ratio (INR) 2.5 to 4.0), or aspirin (300 mg/day). Patients joined the trial within three months of transient ischemic attack or minor stroke. The mean follow up was 2.3 years. In the Studio Italiano Fibrillazione Atriale (SIFA) trial, 916 patients with NRAF and a TIA or minor stroke within the previous 15 days were randomised to open label anticoagulants (INR 2.0 to 3.5) or indobufen (a reversible platelet cyclooxygenase inhibitor, 100 or 200 mg BID). The follow-up period was one year. The combined results show that anticoagulants were significantly more effective than antiplatelet therapy both for all vascular events (Peto odds ratio (Peto OR) 0.67, 95% confidence interval (CI) 0.50 to 0.91) and for recurrent stroke (Peto OR 0.49, 95% CI 0.33 to 0.72). Major extracranial bleeding complications occurred more often in patients on anticoagulants (Peto OR 5.16, 95% CI 2.08 to 12.83), but the absolute difference was small (2.8% per year versus 0.9% per year in EAFT and 0.9% per year versus 0% in SIFA). Warfarin did not cause a significant increase of intracranial bleeds.

REVIEWERS' CONCLUSIONS

The evidence from two trials suggests that anticoagulant therapy is superior to antiplatelet therapy for the prevention of stroke in people with NRAF and recent non-disabling stroke or TIA. The risk of extracranial bleeding was higher with anticoagulant therapy than with antiplatelet therapy.

Antithrombotic Therapy in Patients With Saphenous Vein and Internal Mammary Artery Bypass Grafts

This chapter about prevention of coronary artery bypass occlusion is part of the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). Among the key recommendations in this chapter are the following: For patients undergoing coronary artery bypass grafting (CABG), we recommend aspirin, 75 to 162 mg/d, starting 6 h after operation over preoperative aspirin (Grade 1A). In patients in whom postoperative bleeding prevents the administration of aspirin at 6 h after CABG, we recommend starting aspirin as soon as possible thereafter (Grade 1C). For patients undergoing CABG, we recommend against addition of dipyridamole to aspirin therapy (Grade 1A). For patients with coronary artery disease undergoing CABG who are allergic to aspirin, we recommend clopidogrel, 300 mg, as a loading dose 6 h after operation followed by 75 mg/d p.o. (Grade 1C+). In patients who undergo CABG for non-ST-segment elevation acute coronary syndrome (ACS), we recommend clopidogrel, 75 mg/d for 9 to 12 months following the procedure in addition to treatment with aspirin (Grade 1A). For patients who have received clopidogrel for ACS and are scheduled for CABG, we recommend discontinuing clopidogrel for 5 days prior to the scheduled surgery (Grade 2A). For patients undergoing CABG who have no other indication for vitamin K antagonists (VKAs), we suggest clinicians to not administer VKAs (Grade 2B). For patients undergoing CABG in whom oral anticoagulants are indicated, such as those with heart valve replacement, we suggest clinicians administer VKA in addition to aspirin (Grade 2C). For all patients with coronary artery disease who undergo internal mammary artery (IMA) bypass grafting, we recommend aspirin, 75 to 162 mg/d, indefinitely (Grade 1A). For all patients undergoing IMA bypass grafting without other indication for VKA, we suggest clinicians not use VKA (Grade 2C).

Platelet-Active Drugs: The Relationships Among Dose, Effectiveness, and Side Effects

This article discusses platelet active drugs as part of the Seventh American College of Chest Physicians Conference on Antithrombotic and Thrombolytic Therapy: Evidence-Based Guidelines. New data on antiplatelet agents include the following: (1) the role of aspirin in primary prevention has been the subject of recommendations based on the assessment of cardiovascular risk; (2) an increasing number of reports suggest a substantial interindividual variability in the response to antiplatelet agents, and various phenomena of "resistance" to the antiplatelet effects of aspirin and clopidogrel; (3) the benefit/risk profile of currently available glycoprotein IIb/IIIa antagonists is substantially uncertain for patients with acute coronary syndromes who are not routinely scheduled for early revascularization; (4) there is an expanding role for the combination of aspirin and clopidogrel in the long-term management of high-risk patients; and (5) the cardiovascular effects of selective and nonselective cyclooxygenase-2 inhibitors have been the subject of increasing attention.

Endoscopic Evaluation of the Effects of Indobufen and Aspirin in Healthy Volunteers

This is an outcomes pharmacodynamic study using Nonsteroidal antiinflammatory agents, particularly acetylsalicylic acid (ASA), have been shown useful in various cardiovascular disorders, but they can be a major cause of iatrogenic gastrointestinal injury. Newer NSAIDs such as indobufen, an inhibitor of platelet aggregation that acts by reversibly inhibiting the platelet cyclooxygenase enzyme, have proven to be as effective as the older NSAIDs and appear to have a better gastrointestinal tolerability profile. When the gastroduodenal tolerability of 10 days of oral treatment with indobufen or ASA was assessed in healthy adult volunteers using endoscopic evaluation and the modified score scale of Lanza, only 1 of 18 (6%) volunteers who received indobufen had an increased erosion score at the completion of therapy, compared with 6 of 18 volunteers who received ASA (33%). Overall, both drugs were well tolerated. These results suggest that indobufen has a lower incidence of gastrointestinal effects than other NSAIDs and should be useful in the management of patients with cardiovascular disease.

Comparison of the effects of ketoprofen on platelet function in the presence and absence of aspirin

PURPOSE

Although aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) exert inhibitory effects on platelets in vitro and in vivo, there are insufficient data to substantiate the use of NSAIDs alone as antiplatelet drugs in patients already taking aspirin. We therefore sought to determine whether aspirin, added to NSAID therapy, further suppresses platelet function.

SUBJECTS AND METHODS

We enrolled 25 healthy adult volunteers who were administered ketoprofen (extended-release capsules, 200 mg daily) for 1 week, followed by ketoprofen (200 mg daily) and aspirin (325 mg daily) or ketoprofen (200 mg daily) alone during the second week. Platelet aggregation, stimulated by epinephrine and arachidonic acid, and cyclooxygenase activity, measured by thromboxane B(2), were measured at baseline, on day 8, and on day 15.

RESULTS

On day 8, all subjects demonstrated abnormal platelet aggregation (>50% inhibition), which persisted at day 15 in both the aspirin and no aspirin groups. One week of ketoprofen treatment reduced thromboxane B(2) levels by 84% in the aspirin group and by 85% in the no aspirin group (P = 0.8), without any further inhibition measured on day 15.

CONCLUSION

Extended-release ketoprofen significantly inhibited platelet aggregation and thromboxane B(2) production in healthy volunteers. Addition of aspirin had no additional effect. Trials are warranted to determine whether these in vitro effects result in clinical antiplatelet activity in patients who require chronic treatment with NSAIDs, thereby avoiding the toxicity of NSAID/aspirin combination therapy.

Antiplatelet therapy in the elderly. Aspirin, ticlopidine-clopidogrel, and GPIIb/GPIIIa antagonists

Antiplatelet agents including aspirin, dipyridamole, the thienopyridines, and the GPIIb/IIIa antagonists have collectively demonstrated their ability to have a significant impact on the incidence of recurrent MIs, strokes, and other vascular ischemic events in the geriatric population. Low-dose aspirin also seems to be effective and safe for the primary prevention of ischemic heart disease in men considered at high risk. There is no evidence that the recommendations from these studies had increased relevance to younger adults, and the studies considering age as a variable found antiplatelet agents had either similar or increased benefit in older patients. In view of the relatively reduced adverse effects of these agents when compared with their potential therapeutic benefit, it is important that they be considered in all older patients for secondary prevention and in certain high-risk groups for primary prevention of cardiovascular morbidity and mortality.

Antiplatelet therapy. Aspirin, ticlopidine/clopidogrel, and anti-integrin agents

Aspirin is the most widely employed antithrombotic agent in use today and has a proven role in the prevention and acute management of atherosclerosis-associated arterial thrombotic events. More recently developed antiplatelet agents have been found to have specific prophylactic roles associated with percutaneous coronary intervention and other clinical settings. This article outlines pharmacologic considerations and current clinical knowledge relevant to the use of aspirin, ticlopidine, clopidogrel, and the GPIIbIIIa antagonists in the management of thrombotic disorders.

Antithrombotic therapy in patients with saphenous vein and internal mammary artery bypass grafts

Aspirin (325 and 900 mg/d) is effective for a period of 1 year in reducing the frequency of saphenous vein bypass graft occlusion when begun 1 day before operation or on the day of operation. Aspirin in combination with dipyridamole is not more effective than aspirin alone in the prevention of saphenous vein graft occlusion. Bleeding is higher among patients treated with aspirin (325 mg/d) than among controls if aspirin is started 1 day before operation. Bleeding in one trial was greater than controls if aspirin (300 mg/d) was started the day of operation, and in one trial there was no difference when aspirin (325 mg/d) was started the day of operation. Ticlopidine (500 mg/d), started 2 days after operation, was effective in maintaining graft patency. Oral anticoagulants were inconsistent in the maintenance of saphenous vein graft patency. The continued use of aspirin for 2 additional years after an initial year of aspirin therapy for the prevention of saphenous vein bypass graft occlusion showed no additional long-term benefit on graft patency at the end of the third year. Antithrombotic agents given to patients with internal mammary artery bypass grafts showed no benefit in comparison to placebo because patency on placebo was high.

Aortocoronary saphenous vein graft disease: pathogenesis, predisposition, and prevention

Aortocoronary saphenous vein graft disease, with its increasing clinical sequelae, presents an important and unresolved dilemma in cardiological practice. During the 1st month after bypass surgery, vein graft attrition results from thrombotic occlusion, while later the dominant process is atherosclerotic obstruction occurring on a foundation of neointimal hyperplasia. Although the risk factors predisposing to vein graft atherosclerosis are broadly similar to those recognized for native coronary disease, the pathogenic effects of these risk factors are amplified by inherent deficiencies of the vein as a conduit when transposed into the coronary arterial circulation. A multifaceted strategy aimed at prevention of vein graft disease is emerging, elements of which include: continued improvements in surgical technique; more effective antiplatelet drugs; increasingly intensive risk factor modification, in particular early and aggressive lipid-lowering drug therapy; and a number of evolving therapies, such as gene transfer and nitric oxide donor administration, which target vein graft disease at an early and fundamental level. At present, a key measure is to circumvent the problem of vein graft disease by preferential selection of arterial conduits, in particular the internal mammary arteries, for coronary bypass surgery whenever possible.

Differential suppression of thromboxane biosynthesis by indobufen and aspirin in patients with unstable angina

BACKGROUND

We have previously reported aspirin failure in suppressing enhanced thromboxane (TX) biosynthesis in a subset of episodes of platelet activation during the acute phase of unstable angina. The recent discovery of a second prostaglandin H synthase (PGHS-2), inducible in response to inflammatory or mitogenic stimuli, prompted us to reexamine TXA2 biosynthesis in unstable angina as modified by two cyclooxygenase inhibitors differentially affecting PGHS-2 despite a comparable impact on platelet PGHS-1.

METHODS AND RESULTS

We randomized 20 patients (15 men and 5 women aged 59+/-10 years) with unstable angina to short-term treatment with aspirin (320 mg/d) or indobufen (200 mg BID) and collected 6 to 18 consecutive urine samples. Urinary 11-dehydro-TXB2 was extracted and measured by a previously validated radioimmunoassay as a reflection of in vivo TXA2 biosynthesis. Metabolite excretion averaged 102 pg/mg creatinine (median value; n=76) in the aspirin group and 55 pg/mg creatinine (median value; n=99) in the indobufen group (P<.001). There were 16 samples (21%) with 11-dehydro-TXB2 excretion >200 pg/mg creatinine among patients treated with aspirin versus 6 such samples (6%) among those treated with indobufen (P<.001). In vitro and ex vivo studies in healthy subjects demonstrated the capacity of indobufen to largely suppress monocyte PGHS-2 activity at therapeutic plasma concentrations. In contrast, aspirin could only inhibit monocyte PGHS-2 transiently at very high concentrations.

CONCLUSIONS

We conclude that in unstable angina, episodes of aspirin-insensitive TXA2 biosynthesis may reflect extraplatelet sources, possibly expressing the inducible PGHS in response to a local inflammatory milieu, and a selective PGHS-2 inhibitor would be an ideal tool to test the clinical relevance of this novel pathway of arachidonic acid metabolism in this setting.

Indobufen versus warfarin in the secondary prevention of major vascular events in nonrheumatic atrial fibrillation. SIFA (Studio Italiano Fibrillazione Atriale) Investigators

BACKGROUND AND PURPOSE

The results of a large prospective randomized trial have shown the efficacy of oral anticoagulation in the secondary prevention of major vascular events in patients with nonrheumatic atrial fibrillation (NRAF); less well established is the role of antiplatelet agents. The present study compared the effects of indobufen, a reversible inhibitor of platelet cyclooxygenase, with those of warfarin in this setting.

METHODS

A total of 916 patients with NRAF and a recent (< or = 15 days) cerebral ischemic episode were admitted to this multicenter, randomized study, during which they were treated with either indobufen (100 or 200 mg BID) or warfarin (to obtain an international normalized ratio of 2.0 to 3.5) for 12 months. The two groups (462 on indobufen and 454 on warfarin) were well balanced in terms of their main baseline characteristics. The primary outcome of the study was the combined incidence of nonfatal stroke (including intracerebral bleeding), pulmonary or systemic embolism, nonfatal myocardial infarction, and vascular death.

RESULTS

At the end of follow-up, the incidence of primary outcome events was 10.6% in the indobufen group (95% confidence interval, 7.7% to 13.5%) and 9.0% in the warfarin group (95% confidence interval, 6.3% to 11.8%), with no statistically significant difference between treatments. The frequency of noncerebral major bleeding complications was low: only four cases (0.9%) of gastrointestinal bleeding were observed, all of them in the warfarin group.

CONCLUSIONS

We conclude that, within the limitations of its design, this study may help the medical community in devising appropriate antithrombotic strategies for NRAF patients for whom oral anticoagulants are contraindicated or do not represent a feasible approach to treatment.

Experimental models of accelerated atherosclerosis syndromes

The processes of angioplasty restenosis, vein graft failure, and transplant atherosclerosis, collectively termed 'syndromes of accelerated atherosclerosis', have been the focus of significant clinical and experimental research. Limitations of clinical studies have forced emphasis onto experimental animal models for the purpose of determining pathophysiology and evaluation of potential therapeutic strategies. However, the apparent failure of many in vivo animal models to predict interventional outcome in humans has raised doubt over their suitability as models of these pathophysiological states. Similar criticism has befallen the use of in vitro techniques for elucidating pathophysiology of the cellular elements. An awareness of the shortcomings of the various experimental models in use would therefore seem prerequisite both to a more critical evaluation of data generated from their use, and to the development of truly effective therapeutic strategies for humans.

Antiplatelet therapy

The major clinical indication for antiplatelet therapy has been the prevention of arterial thrombosis. Arterial thrombi are composed of predominantly platelets formed under conditions of elevated shear stress at sites of atherosclerotic vascular injury and disturbed blood flow. Aspirin, the prototype antiplatelet agent, has been in clinical use as an antithrombotic for almost a half century. However, clinical trials have exposed the limitations of aspirin, and there has been considerable recent progress in the development of more effective antiplatelet agents. These newer agents are rationally based on interrupting specific sites in the sequence of platelet activation. Inhibitors of the initial step of platelet adhesion remain experimental. Inhibitors of specific platelet agonist-receptor interactions include antithrombins, thromboxane A2 receptor antagonists, and adenosine diphosphate (ADP) receptor blockers including ticlopidine and clopidogrel. Inhibitors of arachidonic acid metabolism and thromboxane A2 include omega-3 fatty acids, aspirin and other nonsteroidal antiinflammatory drugs that inhibit cyclooxygenase, and thromboxane synthase inhibitors. The clinical efficacy of many of these agents may be limited by their actions, which are restricted to single, specific platelet receptors or metabolic pathways. Global interruption of the final step of platelet aggregation can be achieved with monoclonal antibodies and RGD (arginine-glycine-aspartic acid) analogs that block ligand binding to the platelet glycoprotein IIb/IIIa complex. Initial clinical trials with these novel agents have demonstrated superior efficacy in preventing reocclusion and restenosis following coronary angioplasty and atherectomy.