Outcomes of patients with acute coronary syndromes who are treated with bivalirudin during percutaneous coronary intervention: an analysis from the Randomized Evaluation in PCI Linking Angiomax to Reduced Clinical Events (REPLACE-2) trial

Antiplatelet agents for chronic kidney disease

BACKGROUND

Antiplatelet agents are widely used to prevent cardiovascular events. The risks and benefits of antiplatelet agents may be different in people with chronic kidney disease (CKD) for whom occlusive atherosclerotic events are less prevalent, and bleeding hazards might be increased. This is an update of a review first published in 2013.

OBJECTIVES

To evaluate the benefits and harms of antiplatelet agents in people with any form of CKD, including those with CKD not receiving renal replacement therapy, patients receiving any form of dialysis, and kidney transplant recipients.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 13 July 2021 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

We selected randomised controlled trials of any antiplatelet agents versus placebo or no treatment, or direct head-to-head antiplatelet agent studies in people with CKD. Studies were included if they enrolled participants with CKD, or included people in broader at-risk populations in which data for subgroups with CKD could be disaggregated.

DATA COLLECTION AND ANALYSIS

Four authors independently extracted data from primary study reports and any available supplementary information for study population, interventions, outcomes, and risks of bias. Risk ratios (RR) and 95% confidence intervals (CI) were calculated from numbers of events and numbers of participants at risk which were extracted from each included study. The reported RRs were extracted where crude event rates were not provided. Data were pooled using the random-effects model. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We included 113 studies, enrolling 51,959 participants; 90 studies (40,597 CKD participants) compared an antiplatelet agent with placebo or no treatment, and 29 studies (11,805 CKD participants) directly compared one antiplatelet agent with another. Fifty-six new studies were added to this 2021 update. Seven studies originally excluded from the 2013 review were included, although they had a follow-up lower than two months. Random sequence generation and allocation concealment were at low risk of bias in 16 and 22 studies, respectively. Sixty-four studies reported low-risk methods for blinding of participants and investigators; outcome assessment was blinded in 41 studies. Forty-one studies were at low risk of attrition bias, 50 studies were at low risk of selective reporting bias, and 57 studies were at low risk of other potential sources of bias. Compared to placebo or no treatment, antiplatelet agents probably reduces myocardial infarction (18 studies, 15,289 participants: RR 0.88, 95% CI 0.79 to 0.99, I² = 0%; moderate certainty). Antiplatelet agents has uncertain effects on fatal or nonfatal stroke (12 studies, 10.382 participants: RR 1.01, 95% CI 0.64 to 1.59, I² = 37%; very low certainty) and may have little or no effect on death from any cause (35 studies, 18,241 participants: RR 0.94, 95 % CI 0.84 to 1.06, I² = 14%; low certainty). Antiplatelet therapy probably increases major bleeding in people with CKD and those treated with haemodialysis (HD) (29 studies, 16,194 participants: RR 1.35, 95% CI 1.10 to 1.65, I² = 12%; moderate certainty). In addition, antiplatelet therapy may increase minor bleeding in people with CKD and those treated with HD (21 studies, 13,218 participants: RR 1.55, 95% CI 1.27 to 1.90, I² = 58%; low certainty). Antiplatelet treatment may reduce early dialysis vascular access thrombosis (8 studies, 1525 participants) RR 0.52, 95% CI 0.38 to 0.70; low certainty). Antiplatelet agents may reduce doubling of serum creatinine in CKD (3 studies, 217 participants: RR 0.39, 95% CI 0.17 to 0.86, I² = 8%; low certainty). The treatment effects of antiplatelet agents on stroke, cardiovascular death, kidney failure, kidney transplant graft loss, transplant rejection, creatinine clearance, proteinuria, dialysis access failure, loss of primary unassisted patency, failure to attain suitability for dialysis, need of intervention and cardiovascular hospitalisation were uncertain. Limited data were available for direct head-to-head comparisons of antiplatelet drugs, including prasugrel, ticagrelor, different doses of clopidogrel, abciximab, defibrotide, sarpogrelate and beraprost.

AUTHORS' CONCLUSIONS

Antiplatelet agents probably reduced myocardial infarction and increased major bleeding, but do not appear to reduce all-cause and cardiovascular death among people with CKD and those treated with dialysis. The treatment effects of antiplatelet agents compared with each other are uncertain.

Clinical review: bleeding - a notable complication of treatment in patients with acute coronary syndromes: incidence, predictors, classification, impact on prognosis, and management

This article focuses on the incidence, predictors, classification, impact on prognosis, and management of bleeding associated with the treatment of acute coronary syndrome. The issue of bleeding complications is related to the continual improvement of ischemic heart disease treatment, which involves mainly (a) the widespread use of coronary angiography, (b) developments in percutaneous coronary interventions, and (c) the introduction of new antithrombotics. Bleeding has become an important health and economic problem and has an incidence of 2.0% to 17%. Bleeding significantly influences both the short- and long-term prognoses. If a group of patients at higher risk of bleeding complications can be identified according to known risk factors and a risk scoring system can be developed, we may focus more on preventive measures that should help us to reduce the incidence of bleeding.

Sex-related effectiveness of bivalirudin versus abciximab and heparin in non-ST-segment elevation myocardial infarction

BACKGROUND

Female sex independently predicts bleeding risk after percutaneous coronary intervention (PCI). Bivalirudin is safer than abciximab plus heparin in patients with non-ST-segment elevation myocardial infarction (NSTEMI). Thus, a greater benefit of bivalirudin in women would be expected.

METHODS

We performed a sex-based analysis of the patients with NSTEMI (n = 1,721, 399 women) enrolled in the ISAR-REACT 4 trial and randomized to receive bivalirudin or abciximab plus heparin. Main outcome was a 30-day composite of death, large recurrent myocardial infarction, urgent target vessel revascularization, or major bleeding. Secondary outcome was 1-year composite of death, myocardial infarction, or target vessel revascularization.

RESULTS

No difference in the main outcome was observed in groups with bivalirudin or abciximab plus heparin: 12.6% versus 15.5% (hazard ratio [HR] 0.81, 95% CI 0.48-1.37) among women and 10.6% versus 9.5% (HR 1.12, 95% CI 0.77-1.64) among men. Major bleeding occurred in 4.5% in the bivalirudin group versus 7.5% in the abciximab plus heparin group (HR 0.60, 95% CI 0.26-1.39) among women and 2.0% versus 3.8% (HR 0.52, 0.27-1.02) among men. At 1 year, the secondary outcome was observed in 24.1% in the bivalirudin group versus 28.7% in the abciximab plus heparin group among women, HR of 0.80 (95% CI 0.55-1.17), and in 20.6% and 19.0%, respectively, HR of 1.10 (95% CI 0.86-1.40) among men.

CONCLUSION

Despite a higher peri-PCI bleeding risk in women, bivalirudin is as effective as and safer than abciximab plus heparin in women and men with NSTEMI undergoing PCI.

Abciximab and heparin versus bivalirudin for non-ST-elevation myocardial infarction

BACKGROUND

The combination of glycoprotein IIb/IIIa inhibitors and heparin has not been compared with bivalirudin in studies specifically involving patients with non-ST-segment elevation myocardial infarction undergoing percutaneous coronary intervention (PCI). We compared the two treatments in this patient population.

METHODS

Immediately before PCI, we randomly assigned, in a double-blind manner, 1721 patients with acute non-ST-segment elevation myocardial infarction to receive abciximab plus unfractionated heparin (861 patients) or bivalirudin (860 patients). The study tested the hypothesis that abciximab and heparin would be superior to bivalirudin with respect to the primary composite end point of death, large recurrent myocardial infarction, urgent target-vessel revascularization, or major bleeding within 30 days. Secondary end points included the composite of death, any recurrent myocardial infarction, or urgent target-vessel revascularization (efficacy end point) and major bleeding (safety end point) within 30 days.

RESULTS

The primary end point occurred in 10.9% of the patients in the abciximab group (94 patients) and in 11.0% in the bivalirudin group (95 patients) (relative risk with abciximab, 0.99; 95% confidence interval [CI], 0.74 to 1.32; P=0.94). Death, any recurrent myocardial infarction, or urgent target-vessel revascularization occurred in 12.8% of the patients in the abciximab group (110 patients) and in 13.4% in the bivalirudin group (115 patients) (relative risk, 0.96; 95% CI, 0.74 to 1.25; P=0.76). Major bleeding occurred in 4.6% of the patients in the abciximab group (40 patients) as compared with 2.6% in the bivalirudin group (22 patients) (relative risk, 1.84; 95% CI, 1.10 to 3.07; P=0.02).

CONCLUSIONS

Abciximab and unfractionated heparin, as compared with bivalirudin, failed to reduce the rate of the primary end point and increased the risk of bleeding among patients with non-ST-segment elevation myocardial infarction who were undergoing PCI. (Funded by Nycomed Pharma and others; ISAR-REACT 4 ClinicalTrials.gov number, NCT00373451.).

The use and limitations of unfractionated heparin

Despite the development of newer anticoagulants, unfractionated heparin remains an indispensible agent in the treatment of thrombotic disorders. Heparin exerts its major effect via antithrombin, converting antithrombin to a more efficient inhibitor of circulating thrombin (factor IIa), factor Xa, factor IXa, factor XIIa, and kallikrein. However, due to the multiple anticoagulant mechanisms of heparin, differential molecular weight-based clearance, issues of heparin resistance, and patient-specific characteristics (age, weight, gender, and tobacco), attaining therapeutic anticoagulation is complicated. As a result, a minority of patients in major clinical trials achieve an activated partial thromboplastin time within the target window in an appropriate time-frame despite the use of weight-based titration nomograms. The resultant under- or over-therapeutic anticoagulation is associated with increased risks of ischemic and bleeding complications, suggesting the importance of maintaining heparin anticoagulation within a relatively narrow therapeutic range. In this review we discuss the mechanisms of heparin action, clinical ramifications of incorrect dosing in major trials, and attempts to improve the achievement of therapeutic anticoagulation.

Magnitude and consequences of missing the acute infarct-related circumflex artery

Emergent reperfusion strategies are integral to providing optimal patient outcomes in the setting of acute coronary artery occlusion. ST-segment elevation on the surface 12-lead electrocardiogram, although specific as a surrogate marker, is insensitive to acute posterior circulation coronary artery occlusion. Studies of non-ST-segment elevation acute coronary syndrome consistently identify patients who have epicardial vessel occlusion at the time of initial angiography, which is usually delayed for hours or days after the initial presentation. In addition, studies of ST-segment elevation myocardial infarction often divulge a disparity in identification of the infarct-related artery, with an underrepresentation of the left circumflex artery. Taken together, it is likely that many patients with left circumflex artery occlusion are "missed" during the early phases of myocardial infarction due to the electrocardiographically silent nature of the posterior territory, resulting in delayed myocardial salvage and worse cardiovascular outcomes. In this review, we report on the magnitude of missed left circumflex infarction and the consequences of this delay in diagnosis. We review the electrocardiographic findings of left circumflex occlusion and discuss strategies to enhance early identification. Heightened awareness of this clinical scenario and the available methods to avoid missing this elusive diagnosis are imperative in our quest to further improve the outcomes of patients with acute myocardial infarction.

The use of adjunctive anticoagulants in patients with acute coronary syndrome transitioning to percutaneous coronary intervention

Patients presenting to the Emergency Department (ED) need to be quickly diagnosed, risk-stratified, and treated accordingly. Anticoagulants used in the ED should be easy to use and suitable for all patients with acute coronary syndromes, regardless of treatment strategy. In patients with ST-segment myocardial infarction, current guidelines recommend unfractionated heparin regardless of reperfusion strategy or low-molecular-weight heparin (LMWH) as an alternative in patients undergoing percutaneous coronary intervention (PCI). The LMWH enoxaparin is approved for ST-segment elevation myocardial infarction patients managed medically or undergoing PCI. The recently updated American College of Cardiology/American Heart Association guidelines for patients with unstable angina or non-ST-segment elevation myocardial infarction recommend unfractionated heparin or the LMWH enoxaparin (class IA recommendation), or the factor Xa inhibitor fondaparinux or the direct thrombin inhibitor bivalirudin (class IB recommendation) for patients managed invasively. This review discusses each of these anticoagulant options in the context of patients transitioning to PCI.

Implementing Consultant Recommendations in Percutaneous Coronary Interventions: Look before you Leap

Purpose

To determine if hospital consultant recommendations were clinically applicable to the cardiac catheterization laboratory and to compare medication usage in percutaneous coronary intervention (PCI) to those goals.

Methods

The medical records of 96 adults on whom PCI had been performed over a 6-month period were reviewed retrospectively. Only PCIs that included intracoronary stent placement were considered. The primary end point was to determine if abciximab usage was 15% or less in all PCI cases. Secondary end points evaluated the use of abciximab, eptifibatide, and bivalirudin based on the acuity of the clinical syndrome.

Results

Abciximab, eptifibatide, and bivalirudin monotherapy were used in 16.7%, 40.6%, and 42.7% of all cases, respectively. The total consumption of abciximab exceeded the primary end point by 1.7%. Eptifibatide usage was 71% of all glycoprotein (GP) IIb/IIIa inhibitors, less than the 85% target proposed by the hospital consultants. Bivalirudin monotherapy surpassed eptifibatide as the antithrombotic of choice across all PCI cases. The use of provisional GP IIb/IIIa inhibitors in conjunction with bivalirudin was 8.3%, more than the 5% target specified by the consultants. Emergent PCIs comprised 41% of all cases sampled.

Conclusion

This 6-month retrospective survey demonstrated that the use of abciximab exceeded the percentage recommended by consultants. However, given the large percentage of emergent PCIs during the time period and the literature supporting the use of abciximab in emergent PCIs, a change in GP IIb/IIIa inhibitor usage patterns was not considered necessary.

Effectiveness and safety of reduced-dose enoxaparin in non-ST-segment elevation acute coronary syndrome followed by antiplatelet therapy alone for percutaneous coronary intervention

Adjunctive pharmacotherapy for stabilizing patients with acute coronary syndrome/non-ST-segment elevation myocardial infarction (ACS/NSTEMI) and for subsequent percutaneous coronary intervention (PCI) includes a combination of anticoagulant and antiplatelet agents. However, all anticoagulants have been shown to paradoxically activate platelets and induce other prothrombotic activities, increase bleeding, and/or cause thrombocytopenia. A single-center experience of 1,400 consecutive patients presenting with ACS/NSTEMI managed using decreased-dose anticoagulation (enoxaparin) and dual-antiplatelet therapy (aspirin and clopidogrel) followed by triple-antiplatelet therapy (aspirin, clopidogrel, and eptifibatide) alone, without additional anticoagulation, during subsequent PCI was retrospectively analyzed. Patients received a median of 3 doses of enoxaparin at a mean dose of 0.51 mg/kg. The final dose was administered 10.8 hours (mean) before PCI. Medical management "failed" in 8 patients (0.6%), and each required emergency PCI. The overall technical success rate was 99.8%. One major adverse clinical event (0.1%) occurred within 24 hours after PCI. Non-Q-wave myocardial infarction occurred in 1.8% of patients, major and minor bleeding complications, in 0.1% and 2.1%, respectively, and thrombocytopenia in 1.3%. Five additional major adverse clinical events (0.4%) occurred within 30 days after PCI, none involving target vessel thrombosis. In conclusion, for patients with ACS/NSTEMI, reduced-dose enoxaparin combined with dual-antiplatelet therapy followed by triple-antiplatelet therapy alone (without additional anticoagulation) during subsequent PCI appears safe and may prove efficacious.

Comparison of baseline characteristics, treatment patterns, and in-hospital outcomes of Asian versus non-Asian white Americans with non-ST-segment elevation acute coronary syndromes from the CRUSADE quality improvement initiative

It has been suggested that Asians may respond differently to antithrombotic therapy, but contemporary management and outcomes of non-ST-segment elevation (NSTE) acute coronary syndromes (ACSs) in Asian patients have not been well characterized. Using data from the CRUSADE initiative, we compared baseline characteristics, treatment patterns, and in-hospital outcomes between 1,071 Asian and 72,513 non-Asian white patients hospitalized with NSTE ACS. Asian patients were more likely to have hypertension, diabetes, and renal insufficiency compared with non-Asian whites. Body mass index was lower in Asian patients (24.9 vs 27.8 kg/m(2), p <0.0001). Use of acute medical therapies, cardiac catheterization, and percutaneous or surgical revascularization did not significantly differ between Asian and white groups after adjustment for patient and hospital characteristics. In-hospital mortality (5.0% vs 4.4%, adjusted odds ratio [OR] 1.24, 95% confidence interval [CI] 0.88 to 1.73) and reinfarction rates (2.0% vs 2.3%. adjusted OR 0.94, 95% CI 0.65 to 1.38) were also similar. In contrast, rates of major bleeding (13.4% vs 9.4%, p <0.0001) and red blood cell transfusion (9.6% vs 6.6%, p = 0.0005) were significantly higher in the Asian population and this higher bleeding risk persisted after adjustment for bleeding risk factors and body mass index; adjusted ORs were 1.32 (95% CI 1.08 to 1.62) and 1.32 (95% CI 1.01 to 1.72), respectively. In conclusion, despite similar treatment, Asian patients with NSTE ACS have significantly higher bleeding risk even after adjustment for risk factors and body mass index. Further investigation is needed to explore the potential for ethnic variability in antithrombotic susceptibility.

New anticoagulant options for ST-elevation myocardial infarction and unstable angina pectoris/non-ST-elevation myocardial infarction

In addition to antiplatelet therapy with aspirin, anticoagulation therapy with unfractionated heparin decreases the risk of myocardial infarction and death in patients with acute coronary syndromes. However, unfractionated heparin has pharmacologic limitations that limit efficacy and safety. Enoxaparin, fondaparinux, and bivalirudin are new anticoagulant therapy options with either superior efficacy or better safety than unfractionated heparin. Compared with unfractionated heparin, enoxaparin and fondaparinux are easier to administer, do not require monitoring, and facilitate longer treatment duration. Bivalirudin offers advantages for patients undergoing early percutaneous revascularization. Careful attention to dosing and excellent vascular access site management after cardiac catheterization are required to decrease the risk of bleeding and blood transfusion, which have been associated with increased mortality risk.

Antithrombotic strategies in non-ST elevation acute coronary syndromes: focus on bivalirudin

Acute coronary syndromes (ACS) are a common presentation of coronary artery disease, accounting for more than one million hospital admissions in the US annually. Owing to high rates of mortality and reinfarction, ACS represent a major public health concern. The following review discusses the pathogenesis of ACS and optimal approaches for the management of patients with ACS, with special focus on new antithrombotic strategies, including the direct thrombin inhibitor bivalirudin. Bivalirudin has several notable mechanistic advantages compared with unfractionated heparin, including activity against clot-bound thrombin, inhibition of thrombin-induced platelet activation, short plasma half-life in patients with normal or mildly impaired renal function (25 minutes), and linear pharmacokinetics less affected by plasma proteins and renal insufficiency. These properties provide a more predictable inhibition of coagulant activity than unfractionated heparin, with less degree of inter-patient variability in anticoagulation response. The findings from the several clinical trials assessing safety and efficacy of bivalirudin are analyzed in detail, including the recent randomized controlled Acute Catheterization and Urgent Intervention Triage Strategy (ACUITY) trial. Based on the results of the ACUITY trial, a newer streamlined strategy for the invasive treatment of moderate- and high-risk patients with ACS is discussed.

Anticoagulant therapy in acute coronary syndromes

Thrombus formation on a disrupted atherosclerotic coronary artery plaque is the usual event that precipitates acute coronary syndromes (ACS). Anticoagulation therapy with unfractionated heparin, in addition to antiplatelet therapy with aspirin, decreases the risk of myocardial infarction and death with ACS. However, unfractionated heparin has pharmacological limitations that limit efficacy and safety. Low-molecular-weight heparins (enoxaparin), direct thrombin inhibitors (bivalirudin) and Factor Xa inhibitors (fondaparinux) are new anticoagulant therapy options with either superior efficacy or improved safety over unfractionated heparin. Compared with unfractionated heparin, enoxaparin and fondaparinux are easier to administer, do not require monitoring and facilitate longer treatment duration. Bivalirudin offers advantages for patients undergoing percutaneous revascularization. Careful attention to dosing and excellent vascular access site management are required to decrease the risk of bleeding and blood transfusion, which have been associated with increased mortality risk.