Dual Antiplatelet Therapy with Clopidogrel and Aspirin Versus Aspirin Monotherapy in Patients Undergoing Coronary Artery Bypass Graft Surgery

Antiplatelet therapy after coronary artery bypass surgery: five year follow-up of randomised DACAB trial

OBJECTIVE

To assess the effect of different antiplatelet strategies on clinical outcomes after coronary artery bypass grafting.

DESIGN

Five year follow-up of randomised Different Antiplatelet Therapy Strategy After Coronary Artery Bypass Grafting (DACAB) trial.

SETTING

Six tertiary hospitals in China; enrolment between July 2014 and November 2015; completion of five year follow-up from August 2019 to June 2021.

PARTICIPANTS

500 patients aged 18-80 years (including 91 (18.2%) women) who had elective coronary artery bypass grafting surgery and completed the DACAB trial.

INTERVENTIONS

Patients were randomised 1:1:1 to ticagrelor 90 mg twice daily plus aspirin 100 mg once daily (dual antiplatelet therapy; n=168), ticagrelor monotherapy 90 mg twice daily (n=166), or aspirin monotherapy 100 mg once daily (n=166) for one year after surgery. After the first year, antiplatelet therapy was prescribed according to standard of care by treating physicians.

MAIN OUTCOME MEASURES

The primary outcome was major adverse cardiovascular events (a composite of all cause death, myocardial infarction, stroke, and coronary revascularisation), analysed using the intention-to-treat principle. Time-to-event analysis was used to compare the risk between treatment groups. Multiple post hoc sensitivity analyses examined the robustness of the findings.

RESULTS

Follow-up at five years for major adverse cardiovascular events was completed for 477 (95.4%) of 500 patients; 148 patients had major adverse cardiovascular events, including 39 in the dual antiplatelet therapy group, 54 in the ticagrelor monotherapy group, and 55 in the aspirin monotherapy group. Risk of major adverse cardiovascular events at five years was significantly lower with dual antiplatelet therapy versus aspirin monotherapy (22.6% v 29.9%; hazard ratio 0.65, 95% confidence interval 0.43 to 0.99; P=0.04) and versus ticagrelor monotherapy (22.6% v 32.9%; 0.66, 0.44 to 1.00; P=0.05). Results were consistent in all sensitivity analyses.

CONCLUSIONS

Treatment with ticagrelor dual antiplatelet therapy for one year after surgery reduced the risk of major adverse cardiovascular events at five years after coronary artery bypass grafting compared with aspirin monotherapy or ticagrelor monotherapy.

TRIAL REGISTRATION

NCT03987373ClinicalTrials.gov NCT03987373.

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.

Dual-Antiplatelet Therapy After Coronary Artery Bypass Grafting: A Survey of UK Cardiac Surgeons

OBJECTIVE

Antiplatelet therapy after coronary artery bypass grafting (CABG) is important in postoperative medical management. Although cardiac surgeons are well-versed in the guidelines regarding discontinuation of dual-antiplatelet therapy (DAPT; aspirin and a P2Y12 antagonist) before CABG to minimize bleeding risk, there is considerable variability in DAPT dosing after CABG. The objective of this study was to explore the current trends in DAPT after CABG in the UK to improve understanding of the existing practice.

DESIGN

This study used an online survey with 9 questions about the use of DAPT after CABG. An invitation to participate was sent to all adult cardiac surgeons currently in practice in the UK and the Republic of Ireland.

SETTING

The study was conducted in the UK and the Republic of Ireland.

PARTICIPANTS

Participants in this study were adult cardiac surgeons currently in practice in the UK and the Republic of Ireland.

INTERVENTIONS

There were no interventions in this study.

MEASUREMENTS AND MAIN RESULTS

Responses were received from across the UK (85.4% UK; 4% each from Scotland and Northern Ireland, 1.3% from Wales) and 5.3% from the Republic of Ireland. Fifty-seven percent of the respondents performed between 50 and 100 CABGs per year. Ninety-one percent of the respondents prescribe DAPT postoperatively, but the choice of which patients receive it varied. Most responding surgeons used DAPT for selective patient cohorts, such as those with acute coronary syndrome (51%), diffuse coronary artery disease (42%), perioperative myocardial infarction (36%), coronary endarterectomy (31%), or when bypassing a stented coronary artery (23%). Thirty-eight percent of the respondents began all their patients with CABGs on DAPT. The most preferred P2Y12 antagonist was clopidogrel, used by 75% of respondents and introduced on day 1 after surgical revascularization (71%). The routine duration for DAPT is 12 months, which 78% of the respondents preferred. The main reason for not starting DAPT in those surveyed was the bleeding risk associated with DAPT (72%).

CONCLUSIONS

The survey uncovered variation in the use of DAPT after CABG. However, DAPT remains the preferred strategy after CABG in the UK. The study highlighted the need to develop standardized protocols for DAPT after CABG.

External stenting for saphenous vein grafts in coronary artery bypass grafting: A meta-analysis

OBJECTIVES

Autologous saphenous vein grafts (SVGs) are the most commonly used bypass conduits in coronary artery bypass grafting (CABG) with multivessel coronary artery disease. Although external support devices for SVGs have shown promising outcomes, the overall efficacy and safety remains controversial. We aimed to evaluate external stenting for SVGs in CABG versus non-stented SVGs.

METHODS

MEDLINE, EMBASE, Cochrane Library and clinicaltrails.gov were searched for randomized controlled trials (RCTs) to evaluate external-stented SVGs versus non-stented SVGs in CABG up to 31 August 2022. The risk ratio and mean difference with 95% confidence interval were analysed. The primary efficacy outcomes included intimal hyperplasia area and thickness. The secondary efficacy outcomes were graft failure (≥50% stenosis) and lumen diameter uniformity.

RESULTS

We pooled 438 patients from three RCTs. The external stented SVGs group showed significant reductions in intimal hyperplasia area (MD: -0.78, p < 0.001, I2  = 0%) and thickness (MD: -0.06, p < 0.001, I2  = 0%) compared to the non-stented SVGs group. Meanwhile, external support devices improved lumen uniformity with Fitzgibbon I classification (risk ratio (RR):1.1595, p = 0.05, I2  = 0%). SVG failure rates were not increased in the external stented SVGs group during the short follow-up period (RR: 1.14, p = 0.38, I2  = 0%). Furthermore, the incidences of mortality and major cardiac and cerebrovascular events were consistent with previous reports.

CONCLUSIONS

External support devices for SVGs significantly reduced the intimal hyperplasia area and thickness, and improved the lumen uniformity, assessed with the Fitzgibbon I classification. Meanwhile, they did not increase the overall SVG failure rate.

Acute Coronary Syndromes Among Patients with Prior Coronary Artery Bypass Surgery

PURPOSE OF REVIEW

Acute coronary syndromes (ACS) often occur in individuals with prior coronary artery bypass graft surgery (CABG). Our goal was to describe the prevalence, clinical characteristics, prognosis, and treatment strategies in this group of patients.

RECENT FINDINGS

Studies demonstrate that both acute and long-term major adverse cardiovascular outcomes are increased in patients with ACS and prior CABG compared to those without CABG. Much of this risk is attributed to the greater comorbid conditions present in patients with prior CABG. Data regarding optimal management of ACS in patients with prior CABG are limited, but most observational studies favor an early invasive approach for treatment. Native vessel percutaneous coronary intervention (PCI), if feasible, is generally preferred to bypass graft PCI. Patients with ACS and prior CABG represent a high-risk group of individuals, and implementing optimal preventive and treatment strategies are critically important to reduce the risk.

Coagulation and Transfusion Updates From 2021

2021 and the COVID 19 pandemic have brought unprecedented blood shortages worldwide. These deficits have propelled national efforts to reduce blood usage, including limiting elective services and accelerating Patient Blood Management (PBM) initiatives. A host of research dedicated to blood usage and management within cardiac surgery has continued to emerge. The intent of this review is to highlight this past year's research pertaining to PBM and COVID-19-related coagulation changes.

Safety Comparison of Monotherapy Aspirin to Dual Antiplatelet Therapy Following Coronary Artery Bypass Surgery

Background

Dual antiplatelet therapy (DAPT) is recommended over single antiplatelet therapy (SAPT) in patients following coronary artery bypass grafting (CABG). The compilation of evidence has focused on the efficacy of DAPT to limit risk of graft occlusion, however the safety, especially in the on-pump CABG population, is less well described. The aim of this study was to assess the safety of DAPT versus SAPT after on-pump CABG.

Methods

This was a single-center, retrospective cohort analysis of adult patients following isolated on-pump CABG between January 2012 and December 2019 not on oral anticoagulation at discharge. The primary endpoint was occurrence of a composite bleeding event identified by pre-specified ICD codes. Secondary endpoints consisted of 30-day and 1-year mortalities along with individual bleeding components.

Results

Of the 2341 patients included 1250 patients were in the SAPT arm and 1091 patients in the DAPT arm. The study populations differed by age, prior MI, PAD, and CHF status/stage. Bleeding events occurred in a total of 70 patients (3.0%), with 36 patients (2.9%) in the SAPT arm and 34 patients (3.1%) in the DAPT arm (P = .74). 30-day (SAPT 0.7% vs DAPT 0.4%) and 1-year (SAPT 3.3% vs DAPT 2.3%) mortality were not significantly different between groups. The most frequent bleed event was in the gastrointestinal tract.

Conclusion

In this study, DAPT was not associated with an increase in composite bleeding compared to SAPT. This study could reduce the barrier to prescribing of DAPT given previous efficacy data.