Randomized trial of fondaparinux versus heparin to prevent graft failure after coronary artery bypass grafting: the Fonda CABG study

Different antithrombotic strategies after coronary artery bypass grafting to prevent adverse events: a retrospective analysis

OBJECTIVE

Coronary artery bypass grafting (CABG) is associated with antithrombotic therapy in terms of postoperative adverse events; however, it is still unknown whether the early use of such drugs after CABG is safe and effective. In this study, we aim to evaluate the relationship between different postoperative antithrombotic strategies and in-hospital adverse events in patients undergoing isolated coronary artery bypass grafting surgery.

METHODS

This was a single-center, retrospective cohort analysis of patients undergoing isolated CABG due to coronary artery disease (CAD) between 2001 and 2012. Data were extracted from the Medical Information Mart for Intensive Care III database. The patients involved were divided into the ASA (aspirin 81 mg per day only) or DAPT (aspirin plus clopidogrel 75 mg per day) group according to the antiplatelet strategy. Patients were also stratified into subgroups based on the type of anticoagulation. The in-hospital risk of bleeding and adverse events was investigated and compared between groups. Propensity score matching (PSM) was performed to reduce the potential effects of a selection bias.

RESULTS

A total of 3274 patients were included in this study, with 2358 in the ASA group and 889 in the DAPT group. Following the PSM, no significant difference was seen in the risk of major bleeding between the two groups according to the PLATO, TIMI or GUSTO criteria. There was no difference in the postoperative mortality. In subgroup analysis, patients given anticoagulant therapy had an increased incidence of bleeding-related events. Multivariable analysis revealed that postoperative anticoagulant therapy and the early use of heparin, but not DAPT, were independent predictors of bleeding-related events.

CONCLUSIONS

Postoperative DAPT was not associated with an increased occurrence of bleeding-related events in patients undergoing isolated CABG and appears to be a safe antiplatelet therapy. The addition of anticoagulants to antiplatelet therapy increased the risk of bleeding and should be considered cautiously in clinical practice.

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.

Clinical Decision Pathway for the Use of Fondaparinux in the Management of Acute Coronary Syndrome (ACS) in Hospitals with and Without Catheter Laboratories: An Expert Opinion from India

The current recommendations by Indian experts who are focused on the challenges in the management of patients with acute coronary syndrome (ACS) in rural areas, due to limited catheterization (CATH) lab facilities and interventional cardiologist coverage across the country, are described. 120 cardiologist experts drafted recommendations during ten advisory board meetings conducted from April to May 2022. Experts framed statements based on experience, collective clinical judgment from practical experience, and available scientific evidence regarding ACS. The consensus positioned fondaparinux as highly useful in non-CATH-lab-based hospitals for patients diagnosed with non-ST elevation acute coronary syndrome (NSTE-ACS) and ST elevation acute coronary syndrome (STE-ACS) patients who cannot be shifted to percutaneous coronary intervention (PCI)-capable centres, or for patients who are thrombolysed at peripheral centres.

Anticoagulation and antiplatelet therapy post coronary artery bypass surgery

BACKGROUND

Coronary artery bypass grafting (CABG) is the gold standard treatment for patients with multivessel coronary heart disease. Although its use has proven long-term survival benefits, there is a relative degree of graft failure which increases morbidity and mortality rates.

DISCUSSION

This review discusses clinical outcomes following antiplatelet and anticoagulant therapy after CABG. There is wide variation of evidence about the use of clopidogrel or ticagrelor to aspirin postoperatively in relation to improving graft patency rates or clinical outcomes over the use of aspirin alone. These dual therapies may have significant protective effects in patients undergoing off-pump CABG. Recent studies suggest that superior outcomes may be attained by combining prasugrel with aspirin. Further research is needed to evaluate this, as well as compare the effectiveness of different dual antiplatelet regimens. There is weak evidence for post-CABG anticoagulation, with warfarin and rivaroxaban providing no protection against graft failure but decreasing long-term major adverse cardiac events. Anticoagulation seems to be indicated only in post-CABG patients at high risk of future ischemic events.

CONCLUSION

The use of dual anti-platelet therapy post coronary artery bypass surgery needs further research. Potentially, selective patient groups will benefit more from the addition of thienopyridine antiplatelets or anticoagulants to aspirin after CABG.

A randomized study of the safety and efficacy of fondaparinux versus placebo in the prevention of venous thromboembolism after coronary artery bypass graft surgery

Venous thromboembolism (VTE) after coronary artery bypass graft (CABG) surgery may increase the postoperative morbidity and mortality. Therefore, we examined the current postoperative need for prophylactic antithrombotic therapy after CABG surgery.

METHODS

This randomized, placebo-controlled, double-blind study was designed to compare the safety and efficacy of fondaparinux versus placebo in the prevention of VTE after CABG surgery. Between March 2010 and January 2013, 78 patients free from preoperative deep vein thrombosis (DVT) were enrolled, of whom 37 were randomly assigned to placebo and 41 to treatment with fondaparinux. The primary study end point was a composite, up to day 11, of (a) cumulative incidence of all VTE events, defined as symptomatic and asymptomatic DVT, and fatal and nonfatal pulmonary embolisms (efficacy end point), and (b) cumulative incidence of major hemorrhages (safety end point).

RESULTS

A single asymptomatic DVT of a lower extremity was detected by duplex ultrasound at the time of discharge from the hospital in the placebo-treated group, and a single major postoperative hemorrhage occurred in the fondaparinux-treated group.

CONCLUSIONS

The incidence of postprocedural asymptomatic DVT in this sample of patients undergoing CABG surgery was low. The overall incidence of DVT in the control and investigational treatment groups was similar. Our results showed no benefit of prophylactic postoperative fondaparinux in this population. These findings are congruent with other published studies and provide additional support for recent recommendations not to routinely use anticoagulant prophylaxis after cardiac surgery.

Saphenous vein graft failure after coronary artery bypass surgery: pathophysiology, management, and future directions

OBJECTIVE

To review our current understanding of the epidemiology and pathogenesis of vein graft failure (VGF), give an overview of current preventive and interventional measures, and explore strategies that may improve vein graft patency.

BACKGROUND

VGF and progression of native coronary artery disease limit the long-term efficacy of coronary artery bypass graft surgery.

METHODS

We reviewed the published literature on the pathophysiology, prevention, and/or treatment of VGF by searching the MEDLINE (January 1, 1966-January 1, 2012), EMBASE (January 1, 1980-January 1, 2012), and Cochrane (January 1, 1995-January 1, 2012) databases. In addition, we reviewed references from the selected articles for studies not identified in the initial search. Basic science and clinical studies were included; non-English language publications were excluded.

RESULTS

Acute thrombosis, neointimal hyperplasia, and accelerated atherosclerosis are the 3 mechanisms that lead to VGF. Preventive measures include matching and quality assessment of conduit and target vessel, lipid-lowering drugs, antithrombotic therapy, and cessation of smoking. Treatment of VGF includes medical therapy, percutaneous intervention, and redo coronary artery bypass graft surgery. In patients undergoing graft intervention, the use of drug-eluting stents, antiplatelet agents, and embolic protection devices may improve clinical outcomes.

CONCLUSIONS

Despite advances in management, VGF remains one of the leading causes of poor in-hospital and long-term outcomes after coronary artery bypass graft surgery. New developments in VGF prevention such as gene therapy, external graft support, fully tissue-engineered grafts, hybrid grafts, and synthetic conduits are promising but unproven. Future efforts to reduce VGF require a multidisciplinary approach with a primary focus on prevention.

Anti-PF4/heparin antibodies and venous graft occlusion in postcoronary artery bypass surgery patients randomized to postoperative unfractionated heparin or fondaparinux thromboprophylaxis

BACKGROUND

Anti-PF4/heparin antibodies are frequently generated after coronary artery bypass grafting (CABG) surgery, with platelet-activating IgG implicated in heparin-induced thrombocytopenia (HIT). It is controversial whether non-platelet-activating antibodies are associated with thrombosis.

OBJECTIVES

To determine in post-CABG patients whether thromboprophylaxis using fondaparinux vs. unfractionated heparin (UFH) reduces the frequency of anti-PF4/heparin antibodies, and whether anti-PF4/heparin antibodies are associated with early graft occlusion.

METHODS/PATIENTS

In a pre-planned secondary analysis of a randomized control trial (RCT) comparing fondaparinux vs. UFH thromboprophylaxis post-CABG, we determined the frequency of anti-PF4/heparin antibody formation by solid-phase enzyme-immunoassay (EIA) and of platelet-activating antibodies by serotonin-release assay (SRA); the SRA and fluid-phase EIA were used to assess fondaparinux cross-reactivity. We also examined whether anti-PF4/heparin antibodies were associated with early arterial or venous graft occlusion (6-week CT angiography).

RESULTS

We found no significant difference in the frequency of antibody formation between patients who received fondaparinux vs. UFH (65.3% vs. 46.0%; P = 0.069), and no significant fondaparinux cross-reactivity. Venous graft occlusion(s) occurred in 6/26 patients who formed 'strong' IgG antibodies (≥ 1.0 optical density [OD] units and ≥ 2× baseline) vs. 3/66 who did not (P = 0.0139). In both unadjusted and adjusted analyses, strong postoperative (but not pre-operative) anti-PF4/heparin IgG responses were associated with a markedly increased risk of early venous (but not arterial) graft occlusion (adjusted OR, 9.25 [95% CI, 1.73, 49.43]; P = 0.0093); notably, none of the three SRA-positive patients developed a venous graft occlusion.

CONCLUSIONS

Fondaparinux vs. UFH thromboprophylaxis postCABG does not reduce anti-PF4/heparin antibody formation. Non-platelet-activating anti-PF4/heparin IgG antibodies generated post operatively are associated with early venous graft occlusion.

Prehospitalization antiplatelet therapy and outcomes after saphenous vein graft intervention

Antiplatelet therapy is recommended after coronary artery bypass grafting, because it improves saphenous vein graft (SVG) patency and clinical outcomes. We investigated the association between prehospital antiplatelet regimens and outcomes after SVG intervention. Patients who underwent SVG intervention from 2003 to 2008 were divided into 3 groups: (1) no antiplatelet therapy, (2) the use of aspirin or clopidogrel, and (3) the use of dual antiplatelet therapy (DAPT) at admission. Clinical follow-up examinations were performed at 30 days and 1 year. The primary outcome was the composite of all-cause mortality, myocardial infarction, the need for revascularization, and stroke at 30 days. The relation between antiplatelet therapy and outcomes was adjusted for factors associated with the outcomes. A total of 225 patients underwent SVG intervention, 87% were men, and the mean age was 70 years. Of the 225 patients, 21 (9.4%) were not receiving antiplatelet therapy, 102 (45.3%) were receiving aspirin/clopidogrel, and 102 (45.3%) were receiving DAPT. The patients without antiplatelet therapy were more frequently women, had presented earlier after coronary artery bypass grafting, and were less frequently taking other cardiac-related medications. The patients taking aspirin or DAPT were more often smokers and had a greater peripheral vascular burden. The incidence of the 30-day and 1-year primary outcomes was greater in patients without preadmission antiplatelet use (38.1% vs 14.9% and 13.9%, overall p = 0.01; 52.4% vs 29.5% and 28.3%, overall p = 0.03). After adjustment, antiplatelet use remained associated with the primary outcome. In conclusion, prehospital use of antiplatelet therapy was associated with a lower occurrence of major adverse cardiac events after SVG intervention. We did not find that DAPT improved outcomes compared to single antiplatelet therapy.

'No-touch' saphenous vein harvesting improves graft performance in patients undergoing coronary artery bypass surgery: a journey from bedside to bench

The saphenous vein is the most commonly used conduit in patients undergoing coronary artery bypass surgery yet its patency is inferior to the internal thoracic artery. Vascular damage inflicted to the vein when using conventional harvesting techniques affects its structure. Endothelial denudation is associated with early vein graft failure while damage of the outermost vessel layers has adverse long-term effects on graft performance. While many in vitro and in vivo experimental studies aimed at improving vein graft patency have been performed to date no significant 'bench to bedside' advances have been made. Among experimental strategies employed is the use of pharmacological agents, gene targeting and external stents. A 'no-touch' technique, where the saphenous vein is removed with minimal trauma and normal architecture preserved, produces a superior graft with long term patency comparable to the internal thoracic artery. Interestingly, many experimental studies are aimed at repairing or replacing those regions of the saphenous vein damaged when harvesting conventionally. 'No-touch' harvesting is superior in coronary artery bypass patients with long-term data published 5years ago. Here we describe a 'bedside to bench' situation where the mechanisms underlying the improved performance of 'no touch' saphenous vein grafts in patients have been studied in the laboratory.