Provisional glycoprotein IIb/IIIa blockade in a randomized investigation of bivalirudin versus heparin plus planned glycoprotein IIb/IIIa inhibition during percutaneous coronary intervention: predictors and outcome in the Randomized Evaluation in Percutaneous coronary intervention 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.

A meta-analysis and cost-minimization analysis of bivalirudin versus heparin in high-risk patients for percutaneous coronary intervention

This meta‐analysis was performed to compare the safety, efficacy, and pharmacoeconomic of bivalirudin versus heparin in high‐risk patients for percutaneous coronary interventions (PCI). Earlier meta‐analysis comparing bivalirudin and heparin during PCI demonstrated that bivalirudin caused less bleeding with more stent thrombosis. However, little data were available on the safety of bivalirudin versus heparin in high‐risk patients for PCI. Thus, we performed a meta‐analysis to evaluate the efficacy and safety in the “high‐risk” patients. A systematic search of electronic databases was conducted up to July 30, 2020. The Cochrane Risk of Bias assessment tool was used to assess the quality of included studies. The primary outcomes were all‐cause death and major adverse cardiac events (MACE); secondary outcomes were major and minor bleeding, followed by a cost‐minimization analysis comparing bivalirudin and heparin using a local drug and medical costs reported in China. Subgroup analysis was based on the type of disease of the high‐risk population. Finally, a total of 10 randomized controlled trials involved 42,699 patients were collected. The Cochrane Risk of Bias Tool was employed to appraise the research quality. No significant difference was noted between bivalirudin and heparin regarding all‐cause death and MACE. However, subgroup analysis showed that bivalirudin caused less major bleeding in female (OR:0.65, 95% CI:0.53–0.79), diabetes (OR:0.55, 95%CI:0.42–0.73), and CKD (OR:0.59, 95%CI:0.63–1.65). The scatterers of the included literature were approximately symmetrical, and no research was outside the funnel plot. Additionally, cost‐minimization analysis showed that heparin was likely to represent a cost‐effective option compared with bivalirudin in China, with potential savings of 2129.53 Chinese Yuan (CNY) per patient for one PCI. Overall, the meta‐analysis showed that although bivalirudin appeared to have a lower risk of major bleeding rate, the overall effectiveness and safety between the two groups showed no significant difference in high‐risk patients for PCI. But the results of the cost‐minimization analysis showed that heparin could be a potential cost‐saving drug than bivalirudin in patients for PCI in China.

Safety and efficacy of bivalirudin with glycoprotein IIb/IIIa for high-risk percutaneous coronary intervention

AIMS

The aim of the study was to assess the safety and efficacy of bivalirudin + glycoprotein (Gp) IIb/IIIa inhibitor as compared to unfractionated heparin (UFH) + Gp IIb/IIIa inhibitor in high risk patients undergoing elective percutaneous coronary intervention (PCI). The primary end point was time to sheath removal and ambulation where as peri-procedure myocardial damage, access site bleeding and major adverse cardiac events (MACE) rates were secondary end points.

METHODS

One hundred and one high risk patients undergoing elective PCI were randomly assigned to either bivalirudin + GpIIb/IIIa inhibitor or UFH + Gp IIb/IIIa inhibitor. PCI was performed by standard technique and activated clotting time was monitored immediately on arrival to recovery area and every 60 min thereafter. Sheath were pulled out once ACT was below 150 seconds and patients were mobilized 6hrs after sheath were removed. Peri-procedure myocardial damage was assessed by serial Trop I levels.

RESULTS

Patient assigned to bivalirudin + tirofiban has significantly reduced time to sheath removal and ambulation as compared to those who received UFH + tirofiban (p < 0.0001) although peak Act did not differ in the groups. Peak Trop I levels were significantly lower in bivalirudin + tirofiban group (p = 0.023) and peri-procedure Trop I elevation occurred in significantly lower number of patients treated with bivalirudin + tirofiban (p = 0.029).

CONCLUSIONS

The combination of bivalirudin + tirofiban was safe and effective as compared to UFH + tirofiban in high risk patients undergoing elective PCI.

Threshold haemoglobin levels and the prognosis of stable coronary disease: two new cohorts and a systematic review and meta-analysis

BACKGROUND

Low haemoglobin concentration has been associated with adverse prognosis in patients with angina and myocardial infarction (MI), but the strength and shape of the association and the presence of any threshold has not been precisely evaluated.

METHODS AND FINDINGS

A retrospective cohort study was carried out using the UK General Practice Research Database. 20,131 people with a new diagnosis of stable angina and no previous acute coronary syndrome, and 14,171 people with first MI who survived for at least 7 days were followed up for a mean of 3.2 years. Using semi-parametric Cox regression and multiple adjustment, there was evidence of threshold haemoglobin values below which mortality increased in a graded continuous fashion. For men with MI, the threshold value was 13.5 g/dl (95% confidence interval [CI] 13.2-13.9); the 29.5% of patients with haemoglobin below this threshold had an associated hazard ratio for mortality of 2.00 (95% CI 1.76-2.29) compared to those with haemoglobin values in the lowest risk range. Women tended to have lower threshold haemoglobin values (e.g, for MI 12.8 g/dl; 95% CI 12.1-13.5) but the shape and strength of association did not differ between the genders, nor between patients with angina and MI. We did a systematic review and meta-analysis that identified ten previously published studies, reporting a total of only 1,127 endpoints, but none evaluated thresholds of risk.

CONCLUSIONS

There is an association between low haemoglobin concentration and increased mortality. A large proportion of patients with coronary disease have haemoglobin concentrations below the thresholds of risk defined here. Intervention trials would clarify whether increasing the haemoglobin concentration reduces mortality.

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.

Bleeding risk and outcomes of Bivalirudin versus Glycoprotein IIb/IIIa inhibitors with targeted low-dose unfractionated Heparin in patients having percutaneous coronary intervention for either stable or unstable angina pectoris

For patients undergoing elective percutaneous coronary intervention (PCI), procedural anticoagulation with bivalirudin was previously shown to significantly reduce bleeding complications at the cost of a modest increase in ischemic events compared with unfractionated heparin (UFH) and glycoprotein IIb/IIIa inhibitors (GPIs). However, the excess bleeding in patients treated with UFH and GPIs may have been caused by excessively high UFH doses and increased activated clotting times. This study sought to determine the bleeding risk of targeted low-dose UFH with GPIs compared with bivalirudin in patients undergoing elective PCI. Of 1,205 patients undergoing elective PCI, 602 underwent PCI with adjunctive UFH and GPIs with the UFH dose targeted to an activated clotting time of approximately 250 seconds, and 603 patients matched for baseline characteristics underwent PCI with bivalirudin. Outcomes were analyzed for major bleeding (hematocrit decrease >15%, gastrointestinal bleed, or major hematoma) and 6-month major adverse cardiac events (death, myocardial infarction, and target-lesion revascularization). The maximum activated clotting time achieved was 261.7 +/- 61.6 seconds in the UFH/GPI group and 355.4 +/- 66.6 in the bivalirudin group (p <0.001). In-hospital major bleeding rates were similar between groups (1.8% UFH/GPI vs 1.7% bivalirudin; p = 0.83), as were transfusion requirements (1.2% UFH/GPI vs 0.5% bivalirudin; p = 0.61). The 6-month major adverse cardiac event rate was also similar between groups (9.5% UFH/GPI vs 9.0% bivalirudin; p = 0.81). In conclusion, there were no significant differences in major bleeding and 6-month major adverse cardiac events for patients undergoing elective PCI treated with targeted low-dose UFH and GPIs compared with those treated with bivalirudin.

Beyond the platelet count: heparin antibodies as independent risk predictors

A major potential side effect of heparin is immunogenicity, eliciting antibody development to a protein complex comprised of platelet factor 4 and heparin. Nevertheless, the clinical implications of heparin antibody positive patients remain broad, ranging from no apparent clinical consequences to life-threatening arterial and venous thromboemboli. The "Iceberg Model" has been proposed to depict this spectrum, with a relatively large population of antibody-positive patients forming the base of the iceberg, a smaller population of thrombocytopenic patients in the middle and a limited number of patients with thrombocytopenia and thrombosis comprising the apex. An underlying assumption of this model is that thrombosis occurs only in settings of relative or absolute thrombocytopenia. However, several recent studies suggest that antibody formation to platelet factor 4/heparin complexes, even in the absence of thrombocytopenia, may be associated with thrombotic events. In this review, we summarize these data, consider potential mechanisms for thrombosis, and suggest recommendations for testing and management of antibody-positive patients.

AlphaIIbbeta3 priming and clustering by orally active and intravenous integrin antagonists

BACKGROUND

Drugs that block platelet-platelet and platelet-fibrin interactions via the alpha(IIb)beta(3) (glycoprotein IIb/IIIa) receptor are used daily in patients undergoing percutaneous coronary interventions. Along with expected increases in spontaneous bleeding, clinical trials have revealed a surprising increase in thrombosis when these drugs are used without other anticoagulants. A better understanding of their mechanisms can minimize these risks.

OBJECTIVES

This study tested the hypothesis that interventions designed to block fibrinogen binding inevitably leave the alpha(IIb)beta(3) receptor in an activated state. It compared the effects on platelet function and alpha(IIb)beta(3) conformation of the orally active compounds orbofiban and roxifiban, the i.v. agents eptifibatide and tirofiban, and echistatin, an arginine-glycine-aspartate (RGD) disintegrin.

METHODS

The integrin antagonist concentrations required to saturate platelets and to block platelet-platelet and platelet-fibrin interactions were determined by flow cytometry, aggregometry, and clot-based adhesion assays, respectively. Analytical ultracentrifugation measured each antagonist's effects on the solution structure of alpha(IIb)beta(3). Fluorescence anisotropy provided equilibrium and kinetic data for integrin:antagonist interactions.

RESULTS

Both orally active drugs bound more tightly and inhibited platelet aggregation and adhesion to fibrin more effectively than echistatin. Analytical ultracentrifugation yielded this order for perturbing alpha(IIb)beta(3) conformation (priming) and promoting oligomerization (clustering): echistatin > eptifibatide > orbofiban > tirofiban > roxifiban. Roxifiban was also most effective at disrupting the rapidly forming/slowly dissociating alpha(IIb)beta(3):echistatin complex.

CONCLUSIONS

Our results suggest that the same molecular mechanisms that enable glycoprotein IIb/IIIa inhibitors to bind tightly to the alpha(IIb)beta(3) receptor and block fibrinogen binding contribute to their ability to perturb the resting integrin's conformation, thus limiting the safety and efficacy of both oral and i.v. integrin antagonists.