Improved aortocoronary bypass patency by low-dose aspirin (100 mg daily). Effects on platelet aggregation and thromboxane formation

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.

Graft thrombosis after coronary artery bypass surgery and current practice for prevention

Coronary artery bypass grafting (CABG) is the most frequently performed cardiac surgery worldwide. The reported incidence of graft failure ranges between 10% and 50%, depending upon the type of conduit used. Thrombosis is the predominant mechanism of early graft failure, occurring in both arterial and vein grafts. Significant advances have been made in the field of antithrombotic therapy since the introduction of aspirin, which is regarded as the cornerstone of antithrombotic therapy for prevention of graft thrombosis. Convincing evidence now exists that dual antiplatelet therapy (DAPT), consisting of aspirin and a potent oral P2Y12 inhibitor, effectively reduces the incidence of graft failure. However, this is achieved at the expense of an increase in clinically important bleeding, underscoring the importance of balancing thrombotic risk and bleeding risk when considering antithrombotic therapy after CABG. In contrast, anticoagulant therapy has proved ineffective at reducing the occurrence of graft thrombosis, pointing to platelet aggregation as the key driver of graft thrombosis. We provide a comprehensive review of current practice for prevention of graft thrombosis and discuss potential future concepts for antithrombotic therapy including P2Y12 inhibitor monotherapy and short-term DAPT.

Redefining the Roles of Aspirin across the Spectrum of Cardiovascular Disease Prevention

Even before its role in platelet inhibition was fully characterized in the 1980s, aspirin had been incorporated into the cardiovascular disease care algorithm. Early trials examining its use in unstable angina and acute myocardial infarction revealed evidence of its protective role in the secondary prevention of atherosclerotic cardiovascular disease (ASCVD). Large trials assessing use in the primary prevention setting and optimal dosing regimens were studied in the late 1990s and early 2000s. As a cornerstone of cardiovascular care, aspirin was incorporated into primary and secondary ASCVD prevention guidelines in the United States and mechanical heart valve guidelines. However, in recent years, with significant advances in medical and interventional ASCVD therapies, scrutiny has been placed on the bleeding profile of aspirin, and guidelines have adapted to new evidence. Updates in primary prevention guidelines reserve aspirin only for patients at higher ASCVD risk and low bleeding risk - though questions remain in ASCVD risk assessment as risk-enhancing factors have proven difficult to incorporate on a population level. New thoughts regarding aspirin use in secondary prevention - especially with the concomitant use of anticoagulants - have altered recommendations as additional data accrued. Finally, a recommendation for aspirin and vitamin K antagonists with mechanical heart valves has been modified. Despite aspirin losing a foothold in cardiovascular care, new evidence has strengthened claims for its use in women at high risk for preeclampsia.

Should nasogastric tube be used routinely in patients undergoing cardiac surgery? A narrative review

BACKGROUND AND AIM

Nasogastric tube (NGT) use has been common in the immediate postoperative period in surgical patients for decades. Potential advantages include the decompression of gastric contents and the early administration of time-sensitive medications. However, its routine use after cardiac surgery has not been established as a gold standard yet. The NGT use for prevention of postoperative nausea and vomiting has been a matter of debate in literature. Also, NGT use has also been associated with the incidence of some respiratory and gastrointestinal complications and it may be a source of significant pain and discomfort to patients. In this article, we review the current available literature regarding the use of NGT during and immediately after cardiac surgery, with particular emphasis on its potential role in enhanced postoperative recovery.

METHODS

We performed a database search in October 2021 using Embase, Cochrane Library, and Medline to identify studies that examined the use of NGT in patients that underwent cardiac surgery. Data and literature about NGT's impact on post-operative nausea and vomiting, early administration of medications, interference with imaging, post-operative complications, respiratory complications, gastrointestinal complications, pain and discomfort, and enhanced recovery after surgery were examined.

RESULTS

Three reports investigating the use of NGT to reduce post-operative nausea and vomiting were examined with sample sizes of 114, 104, and 202. The use of NGT did not significantly reduce the incidence of post-operative nausea and vomiting in 2/3 of the studies: a 2% nausea reduction with NGT (p < 0.05), a 7.7% nausea reduction with NGT (p = 0.6), and a 14% vomiting reduction with NGT (p = 0.007). The prevalence of pneumonia following NGT use has been shown to vary ranging from 4 to 95% with associated mortality rates of 17 to 62%.

CONCLUSION

Based on our findings, there is currently not sufficient evidence to support the routine use of NGT during cardiac surgery. Further research is needed to establish the role of NGT in this patient population.

2021 ACC/AHA/SCAI Guideline for Coronary Artery Revascularization: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The guideline for coronary artery revascularization replaces the 2011 coronary artery bypass graft surgery and the 2011 and 2015 percutaneous coronary intervention guidelines, providing a patient-centric approach to guide clinicians in the treatment of patients with significant coronary artery disease undergoing coronary revascularization as well as the supporting documentation to encourage their use.

METHODS

A comprehensive literature search was conducted from May 2019 to September 2019, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, CINHL Complete, and other relevant databases. Additional relevant studies, published through May 2021, were also considered.

STRUCTURE

Coronary artery disease remains a leading cause of morbidity and mortality globally. Coronary revascularization is an important therapeutic option when managing patients with coronary artery disease. The 2021 coronary artery revascularization guideline provides recommendations based on contemporary evidence for the treatment of these patients. The recommendations present an evidence-based approach to managing patients with coronary artery disease who are being considered for coronary revascularization, with the intent to improve quality of care and align with patients' interests.

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

Antithrombotic treatment after coronary artery bypass graft surgery: systematic review and network meta-analysis

OBJECTIVE

To assess the effects of different oral antithrombotic drugs that prevent saphenous vein graft failure in patients undergoing coronary artery bypass graft surgery.

DESIGN

Systematic review and network meta-analysis.

DATA SOURCES

Medline, Embase, Web of Science, CINAHL, and the Cochrane Library from inception to 25 January 2019. ELIGIBILITY CRITERIA: for selecting studies Randomised controlled trials of participants (aged ≥18) who received oral antithrombotic drugs (antiplatelets or anticoagulants) to prevent saphenous vein graft failure after coronary artery bypass graft surgery.

MAIN OUTCOME MEASURES

The primary efficacy endpoint was saphenous vein graft failure and the primary safety endpoint was major bleeding. Secondary endpoints were myocardial infarction and death.

RESULTS

This review identified 3266 citations, and 21 articles that related to 20 randomised controlled trials were included in the network meta-analysis. These 20 trials comprised 4803 participants and investigated nine different interventions (eight active and one placebo). Moderate certainty evidence supports the use of dual antiplatelet therapy with either aspirin plus ticagrelor (odds ratio 0.50, 95% confidence interval 0.31 to 0.79, number needed to treat 10) or aspirin plus clopidogrel (0.60, 0.42 to 0.86, 19) to reduce saphenous vein graft failure when compared with aspirin monotherapy. The study found no strong evidence of differences in major bleeding, myocardial infarction, and death among different antithrombotic therapies. The possibility of intransitivity could not be ruled out; however, between-trial heterogeneity and incoherence were low in all included analyses. Sensitivity analysis using per graft data did not change the effect estimates.

CONCLUSIONS

The results of this network meta-analysis suggest an important absolute benefit of adding ticagrelor or clopidogrel to aspirin to prevent saphenous vein graft failure after coronary artery bypass graft surgery. Dual antiplatelet therapy after surgery should be tailored to the patient by balancing the safety and efficacy profile of the drug intervention against important patient outcomes.

STUDY REGISTRATION

PROSPERO registration number CRD42017065678.

Network meta-analysis of antiplatelet therapy following coronary artery bypass grafting (CABG): none versus one versus two antiplatelet agents

Background

Numerous agents have been trialed following coronary artery bypass grafting (CABG) to maintain long-term graft patency. While clear evidence exists for the use of aspirin in maintaining graft patency, the role of dual-antiplatelet therapy in CABG patients is not as well established. This network meta-analysis aimed to compare the short-term post-CABG graft patency outcomes for patients with none, one or two antiplatelet agents.

Methods

Electronic databases were queried for randomized controlled trials comparing CABG graft patency rates at three months and beyond using various antiplatelet agents or placebo. Drug and graft patency data were compared using a mixed treatment comparison under a Bayesian hierarchical framework. A random-effects consistency model was applied. Direct and indirect comparisons were made between drugs and used to determine the relative efficacy for graft patency.

Results

The literature search identified 16 papers fulfilling the inclusion criteria, including a total of 3,133 patients with an average of 2.43 [95% confidence interval (CI): 2.20-2.66] grafts per patient. Graft types were incompletely reported, however, saphenous vein grafts (SVGs) were predominantly used [where specifically reported: 4,490 SVG, 1,226 internal mammary artery (IMA) grafts]. In all, five different agents and placebo in various regimens were compared by results of angiographic follow-up conducted at a mean of 10.4 months (95% CI: 9.28-11.5 months). Compared to placebo, aspirin alone [odds ratio (OR) 1.9; 95% credible interval (CrI): 1.3-2.8], aspirin + dipyridamole (OR 1.9; 95% CrI: 1.3-2.6), aspirin + clopidogrel (OR 2.9; 95% CrI: 1.5-5.7) and aspirin + ticagrelor (OR 3.8; 95% CrI: 1.2-13.0) significantly improved graft patency. When compared to aspirin monotherapy, aspirin + clopidogrel (OR 1.6; 95% CrI: 0.86-2.7) and aspirin + ticagrelor (OR 2.0; 95% CrI: 0.69-6.3) had OR that suggested a trend favoring patency compared to aspirin monotherapy, however, these results did not reach significance. Sub-group analysis of SVG graft patency was unable to reach significance (only eight studies with six treatment comparisons were evaluated). Secondary endpoints of death, bleeding, myocardial infarction and cerebrovascular accident were incompletely reported and were pooled but not compared between drug treatment arms.

Conclusions

Aspirin monotherapy and dual antiplatelet therapy (DAPT) provided significant all-graft patency benefit compared to placebo at three months and beyond. A trend existed for DAPT to improve graft patency compared to aspirin, although this did not reach statistical significance. Further randomized controlled studies comparing aspirin monotherapy to DAPT are required to determine the utility of DAPT in CABG patients for maintaining graft patency.

Effects of high- and low-dose aspirin on adaptive immunity and hypertension in the stroke-prone spontaneously hypertensive rat

Despite its well-known antithrombotic properties, the effect of aspirin on blood pressure (BP) and hypertension pathology is unclear. The hugely varying doses used clinically have contributed to this confusion, with high-dose aspirin still commonly used due to concerns about the efficacy of low-dose aspirin. Because prostaglandins have been shown to both promote and inhibit T-cell activation, we also explored the immunomodulatory properties of aspirin in hypertension. Although the common preclinical high dose of 100 mg/kg/d improved vascular dysfunction and cardiac hypertrophy, this effect was accompanied by indices of elevated adaptive immunity, renal T-cell infiltration, renal fibrosis, and BP elevation in stroke-prone spontaneously hypertensive rats and in angiotensin II-induced hypertensive mice. The cardioprotective effects of aspirin were conserved with a lower dose (10 mg/kg/d) while circumventing heightened adaptive immunity and elevated BP. We also show that low-dose aspirin improves renal fibrosis. Differential inhibition of the COX-2 isoform may underlie the disparate effects of the 2 doses. Our results demonstrate the efficacy of low-dose aspirin in treating a vast array of cardiovascular parameters and suggest modulation of adaptive immunity as a novel mechanism underlying adverse cardiovascular profiles associated with COX-2 inhibitors. Clinical studies should identify the dose of aspirin that achieves maximal cardioprotection with a new awareness that higher doses of aspirin could trigger undesired autoimmunity in hypertensive individuals. This work also warrants an evaluation of high-dose aspirin and COX-2 inhibitor therapy in sufferers of inflammatory conditions who are already at increased risk for cardiovascular disease.-Khan, S. I., Shihata, W. A., Andrews, K. L., Lee, M. K. S., Moore, X.-L., Jefferis, A.-M., Vinh, A., Gaspari, T., Dragoljevic, D., Jennings, G. L., Murphy, A. J., Chin-Dusting, J. P. F. Effects of high- and low-dose aspirin on adaptive immunity and hypertension in the stroke-prone spontaneously hypertensive rat.

Antithrombotic therapy in patients receiving saphenous vein coronary artery bypass grafts: a protocol for a systematic review and network meta-analysis

INTRODUCTION

The current evidence for the prevention of saphenous vein graft failure (SVGF) after coronary artery bypass graft (CABG) surgery consists of direct head-to-head comparison of treatments (including placebo) in randomised-controlled trials (RCTs) and observational studies. However, summarising the evidence using traditional pairwise meta-analyses does not allow the inclusion of data from treatments that have not been compared head to head. Exclusion of such comparisons could impact the precision of pooled estimates in a meta-analysis. Hence, to address the challenge of whether aspirin alone or in addition to another antithrombotic agent is a more effective regimen to improve SVG patency, a network meta-analysis (NMA) is necessary. The objectives of this study are to synthesise the available evidence on antithrombotic agents (or their combination) and estimate the treatment effects among direct and indirect treatment comparisons on SVGF and major adverse cardiovascular events, and to generate a treatment ranking according to their efficacy and safety outcomes.

METHODS

We will perform a systematic review of RCTs evaluating antithrombotic agents in patients undergoing CABG. A comprehensive English literature search will be conducted using electronic databases and grey literature resources to identify published and unpublished articles. Two individuals will independently and in duplicate screen potential studies, assess the eligibility of potential studies and extract data. Risk of bias and quality of evidence will also be evaluated independently and in duplicate. We will investigate the data to ensure its suitability for NMA, including adequacy of the outcome data and transitivity of treatment effects. We plan to estimate the pooled direct, indirect and the mixed effects for all antithrombotic agents using a NMA.

ETHICS AND DISSEMINATION

Due to the nature of the study, there are no ethical concerns nor informed consent required. We anticipate that this NMA will be the first to simultaneously assess the relative effects of multiple antithrombotic agents in patients undergoing CABG. The results of this NMA will inform clinicians, patients and guideline developers the best available evidence on comparative effects benefits of antithrombotic agents after CABG while considering the side effect profile to support future clinical decision-making. We will disseminate the results of our systematic review and NMA through a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42017065678.

Dual antiplatelet therapy for secondary prevention of coronary artery disease

Dual antiplatelet therapy (DAPT) combining aspirin and a P2Y₁₂ receptor inhibitor has been consistently shown to reduce recurrent major adverse cardiovascular events (MACE) in patients with acute coronary syndrome (ACS) or undergoing percutaneous coronary intervention (PCI) for stable coronary artery disease (CAD) compared with aspirin monotherapy, but at the expense of an increased risk of major bleeding. Nevertheless, the optimal duration of DAPT for secondary prevention of CAD remains uncertain, owing to the conflicting results of several large randomised trials. Among patients with stable CAD undergoing PCI with drug-eluting stents (DES), shorter durations of DAPT (3–6 months) were shown non-inferior to 12 or 24 months duration with respect to MACE, but reduced the rates of major bleeding. Contrariwise, prolonged DAPT durations (18–48 months) reduced the incidence of myocardial infarction and stent thrombosis, but at a cost of an increased risk of major bleeding and all-cause mortality. Until more evidence becomes available, the choice of optimal DAPT regimen and duration for patients with CAD requires a tailored approach based on the patient clinical presentation, baseline risk profile and management strategy. Future studies are however needed to identify patients who may derive benefit from shortened or extended DAPT courses for secondary prevention of CAD based on their individual ischaemic and bleeding risk. Based on limited evidence, 12 months duration of DAPT is currently recommended in patients with ACS irrespective of their management strategy, but large ongoing randomised trials are currently assessing the efficacy and safety of a short-term DAPT strategy (3–6 months) for patients with ACS undergoing PCI with newer generation DES. Finally, several ongoing, large-scale, randomised trials are challenging the current concept of DAPT by investigating P2Y₁₂ receptor inhibitors as single antiplatelet therapy and may potentially shift the paradigm of antiplatelet therapy after PCI in the near future. This article provides a contemporary state-of-the-art review of the current evidence on DAPT for secondary prevention of patients with CAD and its future perspectives.

Perioperative management of antiplatelet treatment in patients undergoing isolated coronary artery bypass grafting in Dutch cardiothoracic centres

BACKGROUND

International guidelines do not provide uniform recommendations regarding the use of antiplatelet treatment in the perioperative period in patients undergoing coronary artery bypass grafting (CABG).

METHODS

A questionnaire was sent to all 16 cardiothoracic centres in the Netherlands to determine which antiplatelet treatment is used in the perioperative setting. Furthermore, a single-centre prospective observational cohort study was performed which included all patients undergoing isolated CABG in July 2014.

RESULTS

Eleven centres responded to the survey. Acetylsalicylic acid monotherapy was discontinued before surgery in 6 centres. In patients with an acute coronary syndrome receiving dual antiplatelet therapy (DAPT), most centres discontinued the P2Y₁₂ inhibitor preoperatively. DAPT was restarted after surgery in 4 centres. However, 6 centres continued DAPT in patients who had undergone coronary stenting within one month of surgery. In patients with coronary stents, variation in the management of antiplatelet therapy increased in proportion to the interval between stenting and surgery. A total of 70 patients were included in the registry. Acetylsalicylic acid monotherapy was discontinued in 51% of patients and restarted in all patients. P2Y₁₂ inhibitor treatment was discontinued before surgery in 70% of patients and re-initiated after CABG in 29%.

CONCLUSIONS

Major differences were observed in the preoperative and postoperative management of antiplatelet treatment between different Dutch cardiothoracic centres and within a single centre. Part of this variation is probably due to lack of evidence and differences between the current guidelines; however, many of the strategies were not in accordance with any of these guidelines.

Low-Dose Aspirin and Sporadic Anovulation in the EAGeR Randomized Trial

CONTEXT

Among women with a single, recent pregnancy loss, daily preconception low-dose aspirin (LDA) increased the live birth rate with no effect on pregnancy loss. Ovulation is a potential mechanism underlying this effect.

OBJECTIVE

We estimated the effect of LDA on the per-cycle risk of anovulation among eumenorrheic women.

DESIGN

Multicenter, randomized, double-blind, placebo-controlled trial of daily LDA on reproductive outcomes. Preconception follow-up lasted 1 to 6 menstrual cycles (ClinicalTrials.gov, NCT00467363).

SETTING

Four US medical centers during 2007 to 2011.

PATIENTS OR OTHER PARTICIPANTS

Healthy women (n = 1214), age 18 to 40, were attempting pregnancy, had regular menstrual cycles (21 to 42 days), and had a history of 1 to 2 documented pregnancy losses, ≤2 live births, and no infertility. All participants completed at least 1 menstrual cycle of follow-up; none withdrew due to adverse events.

INTERVENTION

Aspirin (81 mg) daily for 1 to 6 menstrual cycles.

MAIN OUTCOME MEASURE

Per-cycle risk of anovulation, defined as the absence of both a positive spot-urine pregnancy test and a luteinizing hormone (LH) peak (2.5-fold increase in daily urinary LH). Hypothesis formulation preceded data collection.

RESULTS

Among 4340 cycles, LDA was not associated with anovulation (LDA: 13.4%, placebo: 11.1%; risk ratio = 1.16, 95% confidence interval, 0.88 to 1.52). Results were similar among women with a single, recent loss.

CONCLUSIONS

Daily LDA had no effect on anovulation among women with a history of 1 to 2 pregnancy losses. LDA may affect fertility via other pathways, and these warrant further study.

Clopidogrel use After Myocardial Revascularization: Prevalence, Predictors, and One-Year Survival Rate

Introduction

Antiplatelet therapy after coronary artery bypass graft (CABG) has been used. Little is known about the predictors and efficacy of clopidogrel in this scenario.

Objective

Identify predictors of clopidogrel following CABG.

Methods

We evaluated 5404 patients who underwent CABG between 2000 and 2009 at Duke University Medical Center. We excluded patients undergoing concomitant valve surgery, those who had postoperative bleeding or death before discharge. Postoperative clopidogrel was left to the discretion of the attending physician. Adjusted risk for 1-year mortality was compared between patients receiving and not receiving clopidogrel during hospitalization after undergoing CABG.

Results

At hospital discharge, 931 (17.2%) patients were receiving clopidogrel. Comparing patients not receiving clopidogrel at discharge, users had more comorbidities, including hyperlipidemia, hypertension, heart failure, peripheral arterial disease and cerebrovascular disease. Patients who received aspirin during hospitalization were less likely to receive clopidogrel at discharge (P≤0.0001). Clopidogrel was associated with similar 1-year mortality compared with those who did not use clopidogrel (4.4% vs. 4.5%, P=0.72). There was, however, an interaction between the use of cardiopulmonary bypass and clopidogrel, with lower 1-year mortality in patients undergoing off-pump CABG who received clopidogrel, but not those undergoing conventional CABG (2.6% vs 5.6%, P Interaction = 0.032).

Conclusion

Clopidogrel was used in nearly one-fifth of patients after CABG. Its use was not associated with lower mortality after 1 year in general, but lower mortality rate in those undergoing off-pump CABG. Randomized clinical trials are needed to determine the benefit of routine use of clopidogrel in CABG.

Reduced aspirin responsiveness as assessed by impedance aggregometry is not associated with adverse outcome after cardiac surgery in a small low-risk cohort

Reduced aspirin responsiveness (i.e. persistent high platelet reactivity in platelet function testing) might be associated with increased risk of myocardial ischemia and cardiac mortality in patients with coronary disease. However, the impact in patients undergoing coronary artery bypass grafting (CABG) is unclear. The aim of this prospective cohort study was to evaluate the predictive value of reduced aspirin responsiveness on cardiac and thromboembolic events in patients undergoing elective isolated CABG surgery with aspirin intake until at least two days before surgery. We included 304 patients in this prospective single-center cohort study. Impedance platelet aggregometry (Multiplate®) was performed directly before and on the first day after surgery. Reduced aspirin responsiveness was defined as area under the curve in ASPItest (AUCASPI) ≥300 U. The primary outcome was a composite of all-cause mortality and/or major adverse cardiac or thromboembolic events within 1 year. Reduced aspirin responsiveness was found in 13 and 24% of patients pre and postoperatively, respectively. There was no difference in the outcomes between patients with normal and reduced aspirin responsiveness in the preoperative measurement (log-rank test, p = 0.540). Multivariate analysis including logistic EuroSCORE I and postoperative troponin T levels did not show any association of reduced aspirin responsiveness with adverse outcome (hazard ratio, 0.576; (95% CI 0.128-2.585; p = 0.471). Similarly, postoperative reduced aspirin responsiveness was not associated with adverse events. To conclude, reduced aspirin responsiveness as evaluated by Multiplate® platelet function analyzer was not associated with increased incidence of major adverse cardiac and thromboembolic events and mortality after CABG surgery.

Relationship between postoperative clopidogrel use and subsequent angiographic and clinical outcomes following coronary artery bypass grafting

Dual antiplatelet therapy with both aspirin and clopidogrel is increasingly used after coronary artery bypass grafting (CABG); however, little is known about the safety or efficacy. We sought to determine the relationship between postoperative clopidogrel and clinical and angiographic outcomes following CABG. We evaluated 3,014 patients from PREVENT IV who underwent CABG at 107 US sites. Postoperative antiplatelet therapy was left to physician discretion. Risk-adjusted angiographic and clinical outcomes were compared in patients taking and not taking clopidogrel 30 days post-CABG. At 30 days, 633 (21%) patients were taking clopidogrel. Clopidogrel users were more likely to have peripheral vascular (15 vs. 11%) and cerebrovascular disease (17 vs. 11%), prior myocardial infarction (MI) (46 vs. 41%), and off-pump surgery (33 vs. 18%). Clopidogrel use was associated with statistically insignificant higher graft failure (adjusted odds ratio 1.3; 95% confidence interval [CI] [1.0, 1.7]; P = 0.05). At 5-year follow-up, clopidogrel use was associated with similar composite rates of death, MI, or revascularization (27 vs. 24%; adjusted hazard ratio 1.1; 95% CI [0.9, 1.4]; P = 0.38) compared with those not using clopidogrel. There was an interaction between use of cardiopulmonary bypass and clopidogrel with a trend toward lower 5-year clinical events with clopidogrel in patients undergoing off-pump CABG. In this observational analysis, clopidogrel use was not associated with better 5-year outcomes following CABG. There may be better outcomes with clopidogrel among patients having off-pump surgery. Adequately powered randomized clinical trials are needed to determine the role of dual antiplatelet therapy after CABG.

Role of surgical revascularization in diabetic patients with coronary artery disease

Diabetes is a well-known risk factor for morbidity and mortality associated with coronary artery disease. Currently, diabetics represent approximately a quarter of patients requiring coronary revascularization in the USA. The purpose of this article is to review and analyze the available data in surgical revascularization of diabetic patients with coronary artery disease. The review will also examine new developments in myocardial revascularization and assess their probable impact on the long-term outcome of diabetic patients.

The evaluation method for antiplatelet effect of acetylsalicylic acid

Reduced platelet aggregation by acetylsalicylic acid administration has been associated with adverse outcomes in patients with thrombotic diseases, thus it is important to determine aspirin resistance in those cases. The antiplatelet effect of acetylsalicylic acid is rarely measured, but it has many problems. The aim of this study was to find the evaluation method for antiplatelet effect after administration of acetylsalicylic acid. We developed a particle counting method based upon laser light scattering, and utilized the platelet aggregation agonists, collagen, at 0.25, 0.5 and 1.0 μg/mL, and adenosine diphosphate (ADP), at 0.5, 1.0 and 2.0 μM, to determine their effective concentrations. Seventeen healthy volunteers were administered acetylsalicylic acid at 162 mg/day, with platelet aggregation determined before and 20 min after administration. In all subjects, the rate of platelet aggregation induced by 1.0 μg/mL of collagen before taking acetylsalicylic acid was the highest value obtained, while 20 min after acetylsalicylic acid administration, aggregation induced by collagen at 1.0 μg/mL was significantly decreased as compared to before administration. As for the other concentrations of collagen and all those of ADP tested, platelet aggregation was either not significantly induced before taking acetylsalicylic acid or the rate of aggregation was not significantly decreased after taking acetylsalicylic acid. Our results indicate that collagen at 1.0 μg/mL is appropriate as a platelet aggregation agonist for evaluating the antiplatelet effect of acetylsalicylic acid. Thus, it is useful that the measurement is performed only once.

Dual anti-platelet therapy after coronary artery bypass grafting: is there any benefit? A systematic review and meta-analysis

BACKGROUND

Anti-platelet therapy is an important component of medical therapy post coronary artery bypass grafting (CABG). While aspirin administration is a Class I indication after CABG, the benefit of concomitant clopidogrel is a controversial issue.

METHODS

We searched OVID Medline, Cochrane, Scopus, and EMBASE for randomized control trials and observational studies comparing aspirin ± placebo to aspirin + clopidogrel after CABG.

RESULTS

Eleven articles (five randomized control trials and six observational studies) including 25,728 patients met inclusion criteria. Early saphenous vein graft occlusion was reduced with the use of dual anti-platelet therapy (risk ratio (RR) = 0.59, 95% CI 0.43-0.82, p = 0.02). In-hospital or 30-day mortality was lower with aspirin + clopidogrel (0.8%) compared to aspirin alone (1.9%) (p < 0.0001), while risk of angina or perioperative myocardial infarction was comparable (RR = 0.60, 95% CI 0.31-1.14, p = 0.12). Patients treated with aspirin + clopidogrel demonstrated a trend towards a higher incidence of major bleeding episodes as compared to patients treated with aspirin alone (RR = 1.17, 95% CI 1.00-1.37, p = 0.05). In a pooled analysis of studies involving off-pump CABG compared to aspirin alone, dual anti-platelet therapy reduced the risk of perioperative myocardial infarction and saphenous graft occlusion by 68% (47% to 71%) and 55% (2% to 79%) respectively.

CONCLUSION

Dual anti-platelet therapy after CABG improved early saphenous vein graft patency, but may increase the risk of bleeding. The use of dual anti-platelet therapy appears to be most beneficial in patients undergoing off-pump CABG. Prospective randomized studies are necessary to determine whether this beneficial effect of dual therapy is also achieved in patients undergoing on pump CABG.

Antiplatelet drugs: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

The article describes the mechanisms of action, pharmacokinetics, and pharmacodynamics of aspirin, dipyridamole, cilostazol, the thienopyridines, and the glycoprotein IIb/IIIa antagonists. The relationships among dose, efficacy, and safety are discussed along with a mechanistic overview of results of randomized clinical trials. The article does not provide specific management recommendations but highlights important practical aspects of antiplatelet therapy, including optimal dosing, the variable balance between benefits and risks when antiplatelet therapies are used alone or in combination with other antiplatelet drugs in different clinical settings, and the implications of persistently high platelet reactivity despite such treatment.

Relationship between vein graft failure and subsequent clinical outcomes after coronary artery bypass surgery

BACKGROUND

Vein graft failure (VGF) is common after coronary artery bypass graft surgery, but its relationship with long-term clinical outcomes is unknown. In this retrospective analysis, we examined the relationship between VGF, assessed by coronary angiography 12 to 18 months after coronary artery bypass graft surgery, and subsequent clinical outcomes.

METHODS AND RESULTS

Using the Project of Ex Vivo Vein Graft Engineering via Transfection IV (PREVENT IV) trial database, we studied data from 1829 patients who underwent coronary artery bypass graft surgery and had an angiogram performed up to 18 months after surgery. The main outcome measure was death, myocardial infarction, and repeat revascularization through 4 years after angiography. VGF occurred in 787 of 1829 patients (43%). Clinical follow-up was completed in 97% of patients with angiographic follow-up. The composite of death, myocardial infarction, or revascularization occurred more frequently among patients who had any VGF compared with those who had none (adjusted hazard ratio, 1.58; 95% confidence interval, 1.21-2.06; P=0.008). This was due mainly to more frequent revascularization with no differences in death (adjusted hazard ratio, 1.04; 95% confidence interval, 0.71-1.52; P=0.85) or death or myocardial infarction (adjusted hazard ratio, 1.08; 95% confidence interval, 0.77-1.53; P=0.65).

CONCLUSIONS

VGF is common after coronary artery bypass graft surgery and is associated with repeat revascularization but not with death and/or myocardial infarction. Further investigations are needed to evaluate therapies and strategies for decreasing VGF to improve outcomes in patients undergoing coronary artery bypass graft surgery.

Colonic mucosal lesions associated with low-dose aspirin: a case control study

OBJECTIVE

Low-dose aspirin (LDA) is widely used because it reduces the risk of vascular events in patients with atherosclerosis. Recently, there has been a substantial increase in prescriptions for LDA. We analyzed the risk of colonic mucosal lesions associated with the long-term use of LDA.

MATERIAL AND METHODS

Among Japanese patients who underwent a colonoscopy between January 2004 and December 2006, 199 colitis cases and 5764 non-colitis controls were identified after excluding 749 patients based on study criteria. The history of LDA use was compared between the cases and controls and the multivariate (age-, sex- and underlying diseases-) adjusted odds ratio (OR) was estimated using a multiple logistic regression model.

RESULTS

The adjusted OR for colonic mucosal lesions associated with LDA use versus non-use was 1.45 [95% confidence interval (CI), 0.87-2.42; p = 0.152]. In terms of gender differences, the OR for LDA-induced colitis in females was significantly increased at 2.55 (95% CI, 1.31-4.94; p = 0.006) but was not significantly increased in males at 0.70 (95% CI, 0.34-1.45; p = 0.334).

CONCLUSIONS

In females, LDA increased the risk of colonic mucosal lesions, suggesting that LDA may contribute to the pathogenesis of colonic ulceration or colitis. Therefore, it is essential that prescribing physicians be aware of the risk of LDA-induced colonic lesions.

[Antiplatelet agents and proton pump inhibitors. How can the risk-benefit balance be optimized in patients at risk for cardiovascular disease and gastrointestinal bleeding?]

Antiplatelet agents are routinely used in both primary and secondary prevention of cardiovascular events. The development of new antiplatelet agents and the strong growth of interventional cardiology have led to this therapy being more widely prescribed and for longer periods. The most important secondary effect is the rise in the incidence of hemorrhagic complications, the most prevalent being gastrointestinal bleeding. In this context, the balance between the cardiovascular benefits and bleeding risk of these agents must be optimized. This review provides specific management recommendations and highlights important practical aspects related to antiplatelet therapy, including the interaction between clopidogrel and proton pump inhibitors. The benefits and hazards in distinct clinical settings are outlined within the context of optimizing the balance between the cardiovascular benefits and bleeding risk of antiplatelet therapy.

Colonic mucosal lesions associated with long-term or short-term administration of nonsteroidal anti-inflammatory drugs

AIM

The effects of short- or long-term administration of nonsteroidal anti-inflammatory drugs (NSAIDs) on the colon have not been well characterized. We assessed the risk of developing colonic mucosal lesions according to the duration of exposure to NSAIDs: short-term and/or long-term use.

METHOD

A case-controlled study was performed by reviewing medical records for endoscopic findings, underlying disease, pre-endoscopic symptoms, category of NSAIDs used and duration of use. The patients underwent colonoscopy between January and October 2004, and 75 colitis cases and 1801 non-colitis controls were identified. The prevalence of NSAID use was compared between the cases and controls. The age- and sex- adjusted odds ratios (OR) were estimated using multiple logistic regression models.

RESULTS

NSAIDs had been used in colitis cases and non-colitis controls for over six months in 20.0% and 12.7%, and for one week in 4.0% and 2.1%. Overall 76.0% and 85.2% had not received NSAIDs. The adjusted OR (95% confidence interval) for colonic mucosal lesions with short- and long term NSAID administration combined vs. non-use was 2.04 (1.16-3.61). When determined separately for short- and long-term NSAID users, the adjusted ORs were 1.48 (0.42-5.25) and 2.21 (1.19-4.11), compared to non-users. These values signify a trend toward an increased frequency of colonic mucosal lesions with longer use of NSAIDs (P=0.011 for trend).

CONCLUSION

Long-term use of NSAIDs increased the risk of colonic mucosal lesions, suggesting that NSAIDs may contribute to the pathogenesis of colonic ulcer or colitis.

Prevention of the renarrowing of coronary arteries using drug-eluting stents in the perioperative period: an update

The management of patients scheduled for surgery with a coronary stent, and receiving 1 or more antiplatelet drugs, has many controversies. The premature discontinuation of antiplatelet drugs substantially increases the risk of stent thrombosis (ST), myocardial infarction, and cardiac death, and surgery under an altered platelet function could also lead to an increased risk of bleeding in the perioperative period. Because of the conflict in the recommendations, this article reviews the current antiplatelet protocols after positioning a coronary stent, the evidence of increased risk of ST associated with the withdrawal of antiplatelet drugs and increased bleeding risk associated with its maintenance, the different perioperative antiplatelet protocols when patients are scheduled for surgery or need an urgent operation, and the therapeutic options if excessive bleeding occurs.

Clinical features of gastroduodenal ulcer in Japanese patients taking low-dose aspirin

BACKGROUND AND AIM

The risks of peptic ulcer complications increase in association with low-dose aspirin (LDA) use. The endoscopic findings and clinical features of gastroduodenal ulcer have not been thoroughly investigated in patients taking LDA.

METHOD

We classified 1,041 gastroduodenal ulcer patients into three groups [patients taking LDA (group A), patients taking nonaspirin nonsteroidal anti-inflammatory drug (NSAID) (group N), and patients taking neither aspirin nor nonaspirin NSAID (group C)] and 241 bleeding gastroduodenal ulcer patients into three corresponding groups (groups a, n, and c). We investigated the clinical features, endoscopic characteristics, and endoscopic treatment of the hemorrhagic lesion in the gastroduodenal ulcer patients taking LDA and compared them with those of the other groups.

RESULTS

The frequency of bleeding events such as hematemesis, melena, and anemia was significantly higher in group A and N than in group C. The percentage of ulcers located in the antrum was higher in group A and N than in group C, and also higher in group a and n than in group c. The percentage of ulcers located in the body, fundus, and cardia was significantly higher in the bleeding patients than in all gastroduodenal ulcer patients. The percentage of cases that required additional endoscopic treatment in group a was higher than in group c. Duration of hospitalization of group a was significantly longer than that of group c.

CONCLUSION

These results indicate that it is very important to prevent LDA-induced gastroduodenal ulcer complications, including bleeding.