Antithrombotic therapy during percutaneous coronary intervention: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy

Anticoagulant Effect of Standard Dose Heparin During Peripheral Endovascular Intervention

BACKGROUND

The objective of this clinical study was to investigate the anticoagulant effect of standard fixed dose of heparin during endovascular intervention in the lower extremity arteries.

METHODS

A prospective clinical pilot study was completed with retrospective quality review of patients between 2015 and 2017 (n = 61). Patients undergoing elective endovascular intervention for arterial insufficiency in the lower extremities were enrolled. A standard fixed intra-arterial dose of 5000 IU of unfractionated heparin (UFH) was administered during the procedure without adjustment for weight or monitoring. Activated clotting time (ACT) was measured before and ten minutes after heparin administration and at the end of the procedure. The primary study end point was the level of heparin anticoagulation after standard perioperative administration.

RESULTS

Mean age was 74 ± 9 years, 48% women. Mean weight was 74 ± 15 kg, and mean BMI, 25.6 ± 4.7 kg/m². The endovascular interventions were performed at the iliac arteries 19.7% (12/61), at the femoral popliteal segment 50.8 % (31/61), below the knee arteries 6.6% (4/61), and at multiple levels 13% (8/61). The perioperative mean ACT increased from baseline 155 ± 43 s (n = 31) to ten minutes after heparin administration 290 ± 70 s (n = 60) (P < 0.01) and was at the end of the procedure 276 ± 73 s (n = 59). Perioperative ACT ten minutes after heparin administration: 5.0% (3/60) of the patients had ACT <200 s, 25.0% (15/60) had ACT 200-250 s, 48.3% (29/60) ACT 251-349, and 21.7% (13/60) ACT ≥350 s. At the end of the procedure, 17.2 % (10/58) of the patients had ACT <200, 24.1 % (14/58) had ACT 200-250 s, 37.9% (22/58) ACT 251-349, and 20.7 % (12/58) ACT ≥350 s. The mean dose of heparin per kg body weight was 70 ± 15 IU/kg. There was a significant difference between the ACT groups when analyzing heparin dose per kg body weight: 54 ± 14 IU/kg for patients with ACT <200, 69 ± 13 IU/kg with ACT 200-250 s, 68 ± 13 IU/kg with ACT 251-349, and 81 ± 18 IU/kg with ACT >350 (P = 0.0095). The same pattern was seen for heparin dose per BMI and DuBois. In univariate logistic regression analysis, ACT ≥350 s was associated with lower body weight (OR 0.92; 95% CI 0.87-0.98; P = 0.008), lower BMI (OR 0.80; 95% CI 0.67-0.96; P = 0.014), and lower body surface area DuBois (OR 0.53; 95% 0.32-0.85; P = 0.009). In multivariable regression, the ACT association with body weight remained (OR 0.92; 95% 0.87-0.98; P = 0.008). There were no perioperative or immediate postoperative bleeding complications requiring blood transfusion or surgical intervention in this study cohort.

CONCLUSIONS

The standard heparin dosing of 5000 IU during endovascular intervention for arterial insufficiency in the lower extremities helps achieve ACT >200 s in almost all patients, but most patients were outside recommended target interval. To provide a more consistent and predictable heparinization, a weight-based bolus dose of 70 IU heparin/kg is recommended.

Risk factors associated with bleeding after multi antithrombotic therapy during implantation of cardiac implantable electronic devices

Previous studies showed that continuous anticoagulation or single antiplatelet therapy during implantations of cardiac implantable electronic devices (CIED) was relatively safe. However, the safety of continuous multi antithrombotic therapy (AT) in patients undergoing CIED interventions has not been clearly defined. We sought to evaluate the safety of this therapy during CIED implantations. A total of 300 consecutive patients (mean 69 years old, 171 males) with CIED implantations were enrolled in this study. The patients were divided into 6 groups [No-AT, oral anticoagulant therapy (OAT), single antiplatelet therapy (SAPT), OAT and SAPT, dual antiplatelet therapy (DAPT), triple AT (TAT)], and the perioperative complications were evaluated. Clinically significant pocket hematomas (PH) were defined as PH needing surgical intervention, prolonged hospitalizations, interruption of AT, or blood product transfusions. There were 129, 89, 49, 20, 10, and 3 patients in No-AT, OAT, SAPT, OAT + SAPT, DAPT, and TAT groups, respectively. The occurrence of clinically significant PH and thromboembolism did not differ among 6 groups (p = 0.145 and p = 0.795, respectively). However, high HAS-BLED score and valvular heart disease (VHD) were associated with clinically significant PH (p = 0.014 and p = 0.015, respectively). Continuous multi AT may be tolerated, but patients with high HAS-BLED score or VHD would require a careful attention during CIED implantations.

Anticoagulation Monitoring

Optimal management of anticoagulant therapy requires an understanding of the laboratory tests often employed to guide therapy. The activated partial thromboplastin time (aPTT) can detect abnormalities in the intrinsic and common clotting pathways. Despite numerous limitations in the aPTT test, it remains the gold standard for monitoring unfractionated heparin and direct thrombin inhibitor therapy. The aPTT can be performed in the central laboratory or at the bedside (point of care [POC] testing). The activated clotting time (ACT) is a POC test that is routinely employed to monitor high-dose heparin during invasive and surgical procedures. The ACT therapeutic range will depend on the specific procedure or surgery being performed. Heparin levels are becoming more routinely available and are used to establish the aPTT therapeutic range for heparin therapy as well as for direct monitoring of heparin and low-molecular-weight heparin therapy. The international normalized ratio (INR) is the gold standard for monitoring warfarin patients. The target INR depends on the indication for anticoagulation. POC monitoring for warfarin is becoming increasingly used. Clinicians should have a thorough understanding of the benefits as well as the limitations of warfarin POC monitoring.

Incorporating linked healthcare claims to improve confounding control in a study of in-hospital medication use

INTRODUCTION

The Premier Perspective hospital billing database provides a promising data source for studies of inpatient medication use. However, in-hospital recording of confounders is limited, and incorporating linked healthcare claims data available for a subset of the cohort may improve confounding control. We investigated methods capable of adjusting for confounders measured in a subset, including complete case analysis, multiple imputation of missing data, and propensity score (PS) calibration.

METHODS

Methods were implemented in an example study of adults in Premier undergoing percutaneous coronary intervention (PCI) in 2004-2008 and exposed to either bivalirudin or heparin. In a subset of patients enrolled in UnitedHealth for at least 90 days before hospitalization, additional confounders were assessed from healthcare claims, including comorbidities, prior medication use, and service use intensity. Diagnostics for each method were evaluated, and methods were compared with respect to the estimates and confidence intervals of treatment effects on repeat PCI, bleeding, and in-hospital death.

RESULTS

Of 210,268 patients in the hospital-based cohort, 3240 (1.5 %) had linked healthcare claims. This subset was younger and healthier than the overall study population. The linked subset was too small for complete case evaluation of two of the three outcomes of interest. Multiple imputation and PS calibration did not meaningfully impact treatment effect estimates and associated confidence intervals.

CONCLUSIONS

Despite more than 98 % missingness on 24 variables, PS calibration and multiple imputation incorporated confounders from healthcare claims without major increases in estimate uncertainty. Additional research is needed to determine the relative bias of these methods.

Combination of factor Xa inhibition and antiplatelet therapy after stenting in patients with iliofemoral post-thrombotic venous obstruction

OBJECTIVES

Studies addressing optimal postprocedural pharmacological management after endovascular stenting of iliofemoral post-thrombotic venous obstruction are lacking. We report our early clinical experience with a combination of rivaroxaban and clopidogrel in patients after iliofemoral post-thrombotic venous obstruction stenting.

METHODS

Demographic, procedural, and follow-up data of nine patients (seven women; mean age of 32 ± 11 years) undergoing 10 procedures for iliofemoral post-thrombotic venous obstruction performed between August 2012 and January 2014 were retrospectively reviewed. After endovascular intervention, all patients were administered 20 mg rivaroxaban once daily (s.i.d.) and 75 mg clopidogrel s.i.d. or every second day depending on the individual drug responsiveness for at least six months. The adenosine diphosphate-induced platelet aggregation (platelet aggregation, in aggregation units × min) was assessed on a Multiplate analyzer. Patency was verified venographically at procedure end and was evaluated with duplex ultrasound in regular follow-ups.

RESULTS

Iliofemoral venous flow was successfully re-established by percutaneous endovascular angioplasty and stent implantation in nine left-sided and one bilateral iliofemoral post-thrombotic venous obstruction. Under dual treatment strategy of rivaroxaban and clopidogrel with platelet aggregation control (median (range): 285 aggregation units × min (192; 402)), none of the patients experienced restenosis or stent thrombosis, respectively. After a median follow-up of 14 months (range: 6-26 months), the primary patency rate was 100% and no in-stent restenosis, stent occlusion or relevant minor or major bleeding occurred.

CONCLUSION

Combined factor Xa inhibition and tailored antiplatelet therapy after stenting of iliofemoral post-thrombotic venous obstruction were safe and performed favorably in terms of vessel patency.

Initial Experience With the Absorb Bioresorbable Vascular Scaffold Below the Knee

Purpose: To investigate a new bioresorbable vascular scaffold for the treatment of focal tibial and distal popliteal lesions. Methods: Tibial and distal popliteal angioplasty was performed in 15 limbs of 14 patients (9 men; median age 82 years) with critical limb ischemia (CLI, n=7) or severe claudication. The 18 lesions (mean length 22.2±14.0 mm) were implanted with 22 everolimus-eluting bioresorbable scaffolds (Absorb). Clinical and ultrasound follow-up was performed at 1, 3, 6, and 12 months to detect restenosis and evaluate safety, midterm restenosis rate, and clinical improvement. Results: Immediate technical success was 100%, although a single limb suffered 2 scaffold thromboses on the first day; it was salvaged with repeat endovascular intervention. All patients were available for surveillance examinations during a follow-up of 6.1±3.9 months; no patient died. Of the 15 limbs in the analysis, clinical improvement was present in 12 (4 of 7 CLI patients); there was no amputation, bypass surgery, or evidence of binary restenosis on follow-up sonographic examination. Conclusion: Midterm follow-up for this small pilot sample demonstrates acceptable safety and patency results, together with freedom from all major adverse limb events, using the Absorb bioresorbable vascular scaffold below the knee.

Monitoring and Reversal of Anticoagulation and Antiplatelets

Since percutaneous transluminal coronary angioplasty was first described and the breakthrough studies of the role of stents were reported, the evolution in anticoagulation and antiplatelet therapy used during percutaneous coronary intervention (PCI) has reduced periprocedural ischemic events and stent thrombosis. Although greater combinations and doses of anticoagulation with antiplatelets seem to provide the best protection against thrombogenic and embolic events, there is a significant trade-off with a higher risk of major and minor bleeding episodes. This review article expands on each of the commonly used antiplatelet and anticoagulants used at time of PCI, focusing on drug monitoring and reversal.

Early application of an intra-aortic balloon pump in patients with ST-segment elevation acute myocardial infarction scheduled for elective percutaneous coronary intervention

OBJECTIVE

This study evaluated the effect of early application of intra-aortic balloon pump (IABP) counterpulsation in patients with ST-segment elevation acute myocardial infarction (STEMI), scheduled for elective percutaneous coronary intervention (PCI).

METHODS

Patients who had experienced STEMI for 12-72 h received (IABP group) or did not receive (control group) IABP counterpulsation for 3-5 days before PCI.

RESULTS

One hundred patients were included. Frequencies of infarct-related artery thrombolysis in acute myocardial infarction (TIMI) flow rate classes 0, I and II in the IABP group (11.5, 1.9 and 7.7%, respectively) were significantly lower than in the control group (29.1, 14.6 and 22.9%, respectively) before PCI. After PCI, the frequency of TIMI class III flow rate in the IABP group (96.2%) was significantly higher than that in the control group (81.3%). Four weeks after PCI, the left ventricular ejection fraction (LVEF) was significantly higher, and the incidence of major cardiac events was significantly lower, in the IABP group compared with the control group.

CONCLUSIONS

Early use of IABP counterpulsation in STEMI patients scheduled for PCI was effective, with a favourable safety profile. IABP counterpulsation reduced the incidence of major adverse cardiac events and improved LVEF. However, IABP devices must be used at an early stage, to obtain optimal results.

Utility of optical coherence tomography to assess a hazy intracoronary image after percutaneous coronary intervention

Although its use in daily practice is not common, optical coherence tomography (OCT) is a powerful research tool in invasive cardiology. This report describes a hazy angiography image after percutaneous coronary intervention that has been assessed using OCT. Based on the results of the OCT, the patient underwent an elective coronary angioplasty with standard anticoagulation. After implantation of the stent, an intracoronary hazy image was seen on angiography. The use of OCT permitted a correct diagnosis and a successful treatment. This paper provides a discussion of the advantages and disadvantages of OCT, and a comparison with intravascular ultrasound.

Stenting in Acute STEMI Intervention

Stenting in acute myocardial infarction (AMI) has the benefits of achieving acute optimal angiographic results and correcting residual dissection to decrease the incidence of restenosis and reocclusion. Studies have shown that percutaneous transluminal coronary angioplasty for primary treatment after AMI is superior to thrombolytic therapy regarding the restoration of normal coronary blood flow. Coronary stenting improves initial success rates, decreases the incidence of abrupt closure, and is associated with a reduced rate of restenosis. In the presence of thrombus-containing lesions, coronary stenting constitutes an effective therapeutic strategy, either after failure of initial angioplasty or electively as the primary procedure.

Aspirin and platelet adenosine diphosphate receptor antagonists in acute coronary syndromes and percutaneous coronary intervention: role in therapy and strategies to overcome resistance

Platelet activation and aggregation are key components in the cascade of events causing thrombosis following plaque rupture. Antiplatelet therapy is essential in the treatment of patients with acute coronary syndromes (ACS) and for those requiring percutaneous coronary intervention (PCI). Aspirin (acetylsalicylic acid) is a well established antiplatelet therapy and is mandated for secondary prevention of cardiovascular events following ACS. In patients with ACS, the addition of clopidogrel to aspirin is more effective than aspirin alone. For patients undergoing PCI, dual antiplatelet therapy with aspirin and clopidogrel is warranted. Aspirin should be continued indefinitely after PCI. Pretreatment of patients with clopidogrel prior to PCI lowers the incidence of cardiovascular events, yet the optimum timing of drug administration and dose are still being investigated, as is the duration of therapy following PCI. Late-stent thrombosis with drug-eluting stents has pushed the recommendation for duration of clopidogrel therapy up to 1 year and perhaps beyond, in patients without risks for bleeding. The concepts of aspirin and clopidogrel resistance are important clinical questions. No uniform definition exists for aspirin or clopidogrel resistance. Measurements of resistance are often highly variable and do not necessarily correlate with clinical resistance. Noncompliance remains the most prominent mode of resistance. Screening of selected patient populations for resistance or pharmacologic intervention of those patients termed 'resistant' warrants further study.

The REG1 anticoagulation system: a novel actively controlled factor IX inhibitor using RNA aptamer technology for treatment of acute coronary syndrome

Antithrombotic agents including anticoagulants and antiplatelets are the cornerstone of treatment of acute coronary syndromes. Currently available anticoagulants have several important limitations including unpredictable pharmacodynamics, immunogenicity, and difficulty in reversibility. A potent anticoagulant that has predictable efficacy, is easily reversible should the clinical need arise, and reduces ischemic events without an increase in bleeding risk would overcome many of the current limitations. Inhibition of factor IX in the coagulation cascade has shown promise as a target for development of a novel anticoagulant with a favorable bleeding risk. Aptamers are small oligonucleotides that can be developed to inhibit specific protein targets with high affinity and used as active drugs. Because aptamers are made of oligonucleotide sequences, they provide the code for their own complement (reversal agent) that can be developed and used to inhibit their function. The REG1 anticoagulation system is a novel, aptamer-based, factor IXa inhibitor that is being developed for use in patients undergoing percutaneous coronary intervention and the treatment of acute coronary syndrome.

Antiplatelet resistance and thromboembolic complications in neurointerventional procedures

Antiplatelet resistance is emerging as a significant factor in effective secondary stroke prevention. Prevalence of aspirin and clopidogrel resistance is dependent upon laboratory test and remains contentious. Large studies in cardiovascular disease populations have demonstrated worse ischemic outcomes in patients with antiplatelet resistance, particularly in patients with coronary stents. Thromboembolism is a complication of neurointerventional procedures that leads to stroke. Stroke rates related to aneurysm coiling range from 2 to 10% and may be higher when considering silent ischemia. Stroke associated with carotid stenting is a major cause of morbidity. Antiplatelet use in the periprocedure setting varies among different centers. No guidelines exist for use of antiplatelet regimens in neurointerventional procedures. Incidence of stroke in patients post procedure may be partly explained by resistance to antiplatelet agents. Further research is required to establish the incidence of stroke in patients with antiplatelet resistance undergoing neurointerventional procedures.

Antithrombotic therapy in cardiac embolism

Anticoagulation is indicated in most cardioembolic ischemic strokes for secondary prevention. In many cardiac conditions, anticoagulation is also indication for primary stroke prevention, mainly when associated to vascular risk factors. Anticoagulation should be started as soon as possible, as it is safe even in moderate acute strokes. The efficacy of early anticoagulation after cardioembolic stroke in relation to outcome has not been assessed adequately, but there is evidence from animal models and clinical studies that anticoagulation with unfractionated heparin is associated with a better outcome mediated in part by its anti-inflammatory properties.

Hypercoagulable state after off-pump coronary artery bypass grafting: evidence, mechanisms and implications

During the past decade, there has been a dramatic resurgence in the adoption of off-pump technology in coronary artery bypass surgery. This has inspired remarkable advances in the techniques of localized tissue stabilization and a greater understanding of the physiology of beating-heart mobilization and exposure. An avalanche of reports in the literature has demonstrated the early safety and efficacy of the procedure. However, despite abundant evidence validating the safety and efficacy of off-pump coronary artery bypass surgery, considerable controversy still persists regarding the long-term outcomes of this approach to myocardial revascularization. One area of concern, and even greater uncertainty, surrounds the issue of the existence of a hypercoagulable state after off-pump coronary artery bypass surgery. This article evaluates the current best evidence available from randomized controlled trials to assess the impact of off-pump coronary artery bypass surgery on coagulation, fibrinolysis and platelet activation, discusses the issue of hypercoagulability with emphasis on the mechanisms responsible for this actual or potential hypercoagulability, and explores the implications of this issue for clinical practice.

Perioperative management of antiplatelet-drugs in cardiac surgery

The management of coronary patients scheduled for a coronary artery bypass grafting (CABG), who are receiving one or more antiplatelet drugs, is plenty of controversies. It has been shown that withdrawal of antiplatelet drugs is associated with an increased risk of a thrombotic event, but surgery under an altered platelet function also means an increased risk of bleeding in the perioperative period. Because of the conflict recommendations, this review article tries to evaluate the outcome of different perioperative antiplatelet protocols in patients with coronary artery disease undergoing CABG.

Looking back into the future: desirudin in acute coronary syndromes and coronary stenting

Although percutaneous coronary intervention (PCI) is a highly effective modality for the management of acute coronary syndromes, it can potentiate the existing prothrombotic state around lesion areas and lead to ischaemic complications. Adjunctive pharmacologic treatment with heparin reduces the risk of ischaemic events, but the utility of heparin is limited by its unpredictable pharmacodynamic effects and its inability to modulate fibrin-bound thrombin. Additionally, a potential risk of heparin-induced thrombocytopenia is associated with heparin use. Direct thrombin inhibitors (DTIs) have emerged as potential alternatives to heparin in patients undergoing PCI. Bivalirudin is a DTI indicated for use in PCI. Results from various studies have suggested clinical benefit associated with the use of bivalirudin, driven primarily by the reduction in bleeding risks compared with the standard treatment regimens. Of concern, however, is a significant increase in acute stent thrombosis with bivalirudin monotherapy compared with heparin plus GPIIb/IIIa inhibitors following primary PCI for ST-segment elevation myocardial infarction (STEMI). Desirudin is a highly potent DTI with greater binding affinity than bivalirudin for thrombin. This report provides a comparative overview of the pharmacology and clinical utility of desirudin and bivalirudin in the setting of PCI.

Radiolabeled Cyclic RGD Peptides as Radiotracers for Imaging Tumors and Thrombosis by SPECT

The integrin family is a group of transmembrane glycoprotein comprised of 19 α- and 8 β-subunits that are expressed in 25 different α/β heterodimeric combinations on the cell surface. Integrins play critical roles in many physiological processes, including cell attachment, proliferation, bone remodeling, and wound healing. Integrins also contribute to pathological events such as thrombosis, atherosclerosis, tumor invasion, angiogenesis and metastasis, infection by pathogenic microorganisms, and immune dysfunction. Among 25 members of the integrin family, the α(v)β(3) is studied most extensively for its role of tumor growth, progression and angiogenesis. In contrast, the α(IIb)β(3 )is expressed exclusively on platelets, facilitates the intercellular bidirectional signaling ("inside-out" and "outside-in") and allows the aggregation of platelets during vascular injury. The α(IIb)β(3) plays an important role in thrombosis by its activation and binding to fibrinogen especially in arterial thrombosis due to the high blood flow rate. In the resting state, the α(IIb)β(3) on platelets does not bind to fibrinogen; on activation, the conformation of platelet is altered and the binding sites of α(IIb)β(3 )are exposed for fibrinogen to crosslink platelets. Over the last two decades, integrins have been proposed as the molecular targets for diagnosis and therapy of cancer, thrombosis and other diseases. Several excellent review articles have appeared recently to cover a broad range of topics related to the integrin-targeted radiotracers and their nuclear medicine applications in tumor imaging by single photon emission computed tomography (SPECT) or a positron-emitting radionuclide for positron emission tomography (PET). This review will focus on recent developments of α(v)β(3)-targeted radiotracers for imaging tumors and the use of α(IIb)β(3)-targeted radiotracers for thrombosis imaging, and discuss different approaches to maximize the targeting capability of cyclic RGD peptides and improve the radiotracer excretion kinetics from non-cancerous organs. Improvement of target uptake and target-to-background ratios is critically important for target-specific radiotracers.

Fondaparinux with UnfracTionated heparin dUring Revascularization in Acute coronary syndromes (FUTURA/OASIS 8): a randomized trial of intravenous unfractionated heparin during percutaneous coronary intervention in patients with non-ST-segment elevation acute coronary syndromes initially treated with fondaparinux

BACKGROUND

There is uncertainty regarding the optimal adjunctive unfractionated heparin (UFH) regimen for percutaneous coronary intervention (PCI) in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) treated with fondaparinux.

OBJECTIVE

The aim of this study is to evaluate the safety of 2 dose regimens of adjunctive intravenous UFH during PCI in high-risk patients with NSTE-ACS initially treated with fondaparinux and referred for early coronary angiography.

DESIGN

This is an international prospective cohort study of approximately 4,000 high-risk patients presenting to hospital with unstable angina or non-ST-segment elevation myocardial infarction, treated with fondaparinux as initial medical therapy, and referred for early coronary angiography with a view to revascularization. Within this cohort, 2,000 patients undergoing PCI will be eligible for enrollment into a double-blind international randomized parallel-group trial evaluating standard activated clotting time (ACT)-guided doses of intravenous UFH versus a non-ACT-guided weight-adjusted low dose. The standard regimen uses an 85-U/kg bolus of UFH if there is no platelet glycoprotein IIb/IIIa (GpIIb-IIIa) inhibitor or 60 U/kg if GpIIb-IIIa inhibitor use is planned, with additional bolus guided by blinded ACT measurements. The low-dose regimen uses a 50 U/kg UFH bolus, irrespective of planned GpIIb-IIIa use. The primary outcome is the composite of peri-PCI major bleeding, minor bleeding, or major vascular access site complications. The assessment of net clinical benefit is a key secondary outcome: it addresses the composite of peri-PCI major bleeding with death, myocardial infarction, or target vessel revascularization at day 30.

CONCLUSION

FUTURA/OASIS 8 will help define the optimal UFH regimen as adjunct to PCI in high-risk NSTE-ACS patients treated with fondaparinux.

Evaluation of a new heparin agent in percutaneous coronary intervention: results of the phase 2 evaluation of M118 IN pErcutaNeous Coronary intErvention (EMINENCE) Trial

BACKGROUND

Factor Xa and factor IIa (thrombin) play roles in thrombotic complications after percutaneous coronary intervention. M118 is a novel low-molecular-weight heparin that has been rationally designed to capture the desired attributes of unfractionated heparin (UFH) and low-molecular-weight heparin: Potent activity against factor Xa and IIa, predictable pharmacokinetics after both intravenous and subcutaneous administration, ability to be monitored by use of point-of-care coagulation assays, and reversibility with protamine sulfate. We performed a phase 2 randomized trial to evaluate the safety and feasibility of M118 in the setting of elective percutaneous coronary intervention.

METHODS AND RESULTS

Overall, 503 patients undergoing elective percutaneous coronary intervention at 43 centers in the United States and Canada were randomized in an open-label fashion to 1 of 4 arms: UFH 70 U/kg, M118 50 IU/kg IV, M118 75 IU/kg IV, or M118 100 IU/kg IV. The primary outcome was the composite of death, myocardial infarction, repeat revascularization, stroke, thrombocytopenia, catheter thrombus, bailout use of glycoprotein IIb/IIIa inhibitor, or any bleeding through 30 days. The primary end point occurred in 31.1% of patients randomized to UFH and in 22.7%, 28.3%, and 30.1% of patients randomized to M118 50, 75, and 100 IU/kg, respectively. The primary analysis comparing the rates of the primary end points between the pooled M118 groups versus UFH demonstrated that M118 was noninferior to UFH at preventing percutaneous coronary intervention-related complications (28.4% pooled M118 arms versus 31.1% UFH). The adverse event profiles of M118 and UFH were comparable.

CONCLUSIONS

This phase 2 randomized trial demonstrates that M118 is well tolerated and feasible to use as an anticoagulant in patients undergoing elective percutaneous coronary intervention and forms the basis for further investigation of this agent in ischemic heart disease.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00543400.

To continue or discontinue aspirin in the perioperative period: a randomized, controlled clinical trial

BACKGROUND

Major adverse cardiac events (MACEs) are a common cause of death after non-cardiac surgery. Despite evidence for the benefit of aspirin for secondary prevention, it is often discontinued in the perioperative period due to the risk of bleeding.

METHODS

We conducted a randomized, double-blind, placebo-controlled trial in order to compare the effect of low-dose aspirin with that of placebo on myocardial damage, cardiovascular, and bleeding complications in high-risk patients undergoing non-cardiac surgery. Aspirin (75 mg) or placebo was given 7 days before surgery and continued until the third postoperative day. Patients were followed up for 30 days after surgery.

RESULTS

A total of 220 patients were enrolled, 109 patients received aspirin and 111 received placebo. Four patients (3.7%) in the aspirin group and 10 patients (9.0%) in the placebo group had elevated troponin T levels in the postoperative period (P=0.10). Twelve patients (5.4%) had an MACE during the first 30 postoperative days. Two of these patients (1.8%) were in the aspirin group and 10 patients (9.0%) were in the placebo group (P=0.02). Treatment with aspirin resulted in a 7.2% absolute risk reduction [95% confidence interval (CI), 1.3-13%] for postoperative MACE. The relative risk reduction was 80% (95% CI, 9.2-95%). Numbers needed to treat were 14 (95% CI, 7.6-78). No significant differences in bleeding complications were seen between the two groups.

CONCLUSIONS

In high-risk patients undergoing non-cardiac surgery, perioperative aspirin reduced the risk of MACE without increasing bleeding complications. However, the study was not powered to evaluate bleeding complications.

Impact of anticoagulant therapy with dual antiplatelet therapy on prognosis after treatment with drug-eluting coronary stents

BACKGROUND

Although combination therapy for various cardiac conditions with dual antiplatelet therapy (aspirin and thienopyridine derivatives) and warfarin sodium has become increasingly popular, the safety and effectiveness of this aggressive treatment regimen remain unknown.

METHODS AND RESULTS

We retrospectively enrolled and analyzed 575 consecutive patients who had been implanted with drug-eluting coronary stents. The primary and secondary endpoints were major bleeding complications and major adverse cardiovascular events (MACE), respectively. At the time of discharge, 525 patients (91.3%) were prescribed with dual antiplatelet therapy, and 50 (8.7%) of them received dual antiplatelet plus anticoagulant therapy (triple therapy). The patients treated with triple therapy had a greater prevalence of comorbid conditions, including left ventricular systolic dysfunction and multi-vessel coronary disease compared to those on the dual antiplatelet regimen. During a median follow-up of 459 days, 14 (2.7%) patients receiving dual, and 9 (18.0%) receiving triple therapy reached the primary endpoint (p<0.001). These results show that warfarin use was associated with an increased risk of subsequent major bleeding. On the other hand, the incidence of MACE did not differ between the two groups (p=0.108 by the log-rank test). Multivariate analysis showed that renal impairment was an independent predictor of the risk of subsequent major bleeding in the triple therapy group.

CONCLUSIONS

Triple therapy increased the hemorrhagic complications in patients after percutaneous coronary intervention with drug-eluting stents, especially in patients with impaired renal function. Great caution should be taken with patients who necessitate the addition of anticoagulation therapy with warfarin to dual antiplatelet therapy.

Platelet inhibition with cangrelor in patients undergoing PCI

BACKGROUND

Cangrelor, a nonthienopyridine adenosine triphosphate analogue, is an intravenous blocker of the adenosine diphosphate receptor P2Y(12). This agent might have a role in the treatment of patients who require rapid, predictable, and profound but reversible platelet inhibition.

METHODS

We performed a large-scale international trial comparing cangrelor with 600 mg of oral clopidogrel administered before percutaneous coronary intervention (PCI) in patients with acute coronary syndromes. The primary efficacy end point was a composite of death from any cause, myocardial infarction, or ischemia-driven revascularization at 48 hours.

RESULTS

We enrolled 8877 patients, and 8716 underwent PCI. At 48 hours, cangrelor was not superior to clopidogrel with respect to the primary composite end point, which occurred in 7.5% of patients in the cangrelor group and 7.1% of patients in the clopidogrel group (odds ratio, 1.05; 95% confidence interval [CI], 0.88 to 1.24; P=0.59). Likewise, cangrelor was not superior at 30 days. The rate of major bleeding (according to Acute Catheterization and Urgent Intervention Triage Strategy criteria) was higher with cangrelor, a difference that approached statistical significance (3.6% vs. 2.9%; odds ratio, 1.26; 95% CI, 0.99 to 1.60; P=0.06), but this was not the case with major bleeding (according to the Thrombolysis in Myocardial Infarction criteria) or severe or life-threatening bleeding (according to Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries criteria). A secondary exploratory end point of death from any cause, Q-wave myocardial infarction, or ischemia-driven revascularization showed a trend toward a reduction with cangrelor, but it was not significant (0.6% vs. 0.9%; odds ratio, 0.67; 95% CI, 0.39 to 1.14; P=0.14).

CONCLUSIONS

Cangrelor, when administered intravenously 30 minutes before PCI and continued for 2 hours after PCI, was not superior to an oral loading dose of 600 mg of clopidogrel, administered 30 minutes before PCI, in reducing the composite end point of death from any cause, myocardial infarction, or ischemia-driven revascularization at 48 hours. (ClinicalTrials.gov number, NCT00305162.)

[Radial access and management of patients with long-term oral anticoagulation for cardiac catheterization]

Patients with long-term oral anticoagulation are exposed to high bleeding risk and should be managed with care for invasive procedure. Angioplasty is assumed to increase bleeding and access site complications and it is often recommended to temporarily interrupt anticoagulation therapy. Moreover, due to the lack of recommendations, antithrombotic regimen adopted after stenting represents a substantial challenge for the physician who must balance the risk of ischemic and bleeding events. Nevertheless, approaches as uninterrupted therapeutic oral anticoagulation, transradial approach and a best knowledge of ischemic risk, haemorrhage risk and restenosis risk can limit long term complication. Herein, we review the currently available data assessing angioplasty and long-term antithrombotic therapy for stented patients with long-term oral anticoagulation and we propose a potential treatment paradigm to improve long-term prognosis.