Low-molecular-weight heparin vs. unfractionated heparin in percutaneous coronary intervention: A combined analysis

Safety and Efficacy of Enoxaparin During Low-Risk Elective Percutaneous Coronary Intervention

Intravenous unfractionated heparin (UFH) is the most frequently used anticoagulant for percutaneous coronary intervention (PCI). Intravenous enoxaparin, a low-molecular-weight heparin, has superior pharmacokinetic and pharmacodynamic properties compared with UFH. Multiple trials have shown enoxaparin to be safe and effective in PCI. However, there has not been a contemporary study evaluating its safety and efficacy. To assess its efficacy and safety, intravenous enoxaparin during PCI through radial artery access was evaluated in PCI patients from January 2015 to December 2019. Outcomes included procedural success, all-cause mortality, ischemic complications, and bleeding complications from the time of the procedure until hospital discharge. A total of 1019 consecutive eligible patients were identified. Median age was 63 years, and 70% were men. The indication for PCI was stable and unstable angina in two-thirds of cases (77%). Few patients had myocardial infarction (MI) (2.2%) as the indication for intervention. The procedure was successful in 98.2% of cases. There were no deaths. Procedural MI occurred in 0.3% of patients. Acute stent thrombosis occurred in 0.4%. Urgent revascularization and stroke occurred in 0.1% each. Small wrist hematomas occurred in 0.3% and all were managed conservatively. There was one radial artery pseudoaneurysm. There were no cases of major bleeding. In conclusion, this single-center study showed that intravenous enoxaparin is a reasonable alternative anticoagulant for use in low-risk and elective non-MI PCI through radial artery access.

Comparison of Managing Factor Xa Inhibitor to Unfractionated Heparin Transitions by aPTT Versus a Treatment Guideline Utilizing Heparin Anti-Xa Levels

BACKGROUND

There are inadequate data on the optimal strategy for transitioning factor Xa inhibitors (FXai; apixaban, rivaroxaban) to unfractionated heparin (UFH) infusions.

OBJECTIVE

In patients transitioning from an FXai to an UFH infusion, this study compared the safety and efficacy of monitoring UFH infusions using an activated partial thromboplastin time (aPTT) titration scale versus utilizing an UFH-calibrated anti-Xa titration scale aided by a novel institutional guideline.

METHODS

A retrospective cohort analysis was conducted on adult patients transitioning from an FXai to an UFH infusion at 2 medical centers from June 1, 2018, to November 1, 2020. One institution utilized aPTT while the other institution primarily used UFH-calibrated anti-Xa. The primary endpoint was a composite of death, major bleeding, or new thrombosis during the hospitalization with a planned noninferiority analysis. Secondary outcomes were also collected including the amount and duration of UFH administered between cohorts.

RESULTS

The incidence rate of the primary composite endpoint was 6.3% in the anti-Xa group and 11% in the aPTT group (P < 0.001 for noninferiority, P = 0.138 for superiority) meeting noninferiority criteria. No statistical differences were seen in new thrombosis, major bleeding, or any bleeding.

CONCLUSION AND RELEVANCE

This represents the first report of a comparison between aPTT versus anti-Xa monitoring in relation to clinical outcomes for patients transitioning from an FXai to an UFH infusion. A transition guideline primarily utilizing an UFH-calibrated anti-Xa assay appears to be a safe alternative to aPTT monitoring and can aid facilities in the management of patients during these complex transitions.

Biomarkers of Thrombosis in ST-Segment Elevation Myocardial Infarction: A Substudy of the ATOLL Trial Comparing Enoxaparin Versus Unfractionated Heparin

BACKGROUND

The aim was to compare the peri-procedural biomarkers of coagulation and platelet activation in patients randomly allocated to intravenous enoxaparin or unfractionated heparin (UFH) in the ATOLL randomized trial (NCT00718471).

METHODS AND RESULTS

A total of 129 patients (n = 58 enoxaparin and n = 71 UFH) admitted for ST-segment elevation myocardial infarction (STEMI) treated by percutaneous coronary intervention (PCI) were included in this substudy of the ATOLL trial. Activated partial thromboplastin time ratio, anti-Xa activity, von Willebrand factor antigen, prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin complex (TAT), tissue factor pathway inhibitor and soluble CD40 ligand were measured at sheath insertion (T1) and at the end of the PCI (T2) and correlated with 1-month clinical outcomes. Target anticoagulation levels at T2 were more readily achieved in patients receiving enoxaparin compared to those receiving UFH (80.3 vs 18.2%, p < 0.0001). Increased levels of F1 + 2 and TAT measured at T2 were associated with the incidence of the composite ischemic endpoint (p = 0.04 and p = 0.03) and all-cause mortality (p < 0.0001 and p = 0.002). Release of F1 + 2 between T1 and T2 also predicted the composite ischemic endpoint (312 ± 513 vs 37 ± 292, p = 0.04) and net clinical outcome (185 ± 405 vs 3.2 ± 278, p = 0.03).

CONCLUSIONS

During primary PCI, enoxaparin achieved therapeutic levels more frequently than UFH. Higher level of thrombin generation measured at the end of the PCI procedure was associated with more frequent ischemic events.

Parenteral anticoagulants in heart disease: Current status and perspectives (Section II)

Anticoagulants are a mainstay of cardiovascular therapy, and parenteral anticoagulants have widespread use in cardiology, especially in acute situations. Parenteral anticoagulants include unfractionated heparin, low-molecular-weight heparins, the synthetic pentasaccharides fondaparinux, idraparinux and idrabiotaparinux, and parenteral direct thrombin inhibitors. The several shortcomings of unfractionated heparin and of low-molecular-weight heparins have prompted the development of the other newer agents. Here we review the mechanisms of action, pharmacological properties and side effects of parenteral anticoagulants used in the management of coronary heart disease treated with or without percutaneous coronary interventions, cardioversion for atrial fibrillation, and prosthetic heart valves and valve repair. Using an evidence-based approach, we describe the results of completed clinical trials, highlight ongoing research with currently available agents, and recommend therapeutic options for specific heart diseases.

Safety and efficacy of periprocedural anticoagulation with enoxaparin in patients undergoing peripheral endovascular revascularization

BACKGROUND

Periprocedural anticoagulation is primarily used in endovascular procedures to prevent acute reocclusion of the target vessel, but periprocedural anticoagulation might also have an impact on long-term outcome. Consecutive bleeding events are feared complications. Despite changes in peripheral endovascular revascularizations (EVRs), the periprocedural management has remained unchanged for years. Unfractionated heparin is still the treatment of choice during and immediately after EVR.

MATERIALS AND METHODS

We performed a prospective, single-center, open-label phase III study comparing 2 different regimes of enoxaparin peri-interventional to peripheral EVR stratified into low- and high-risk groups according to the acute and long-term reocclusion risk due to their vessel morphology. In both groups, 0.5 mg/kg of enoxaparin as a bolus was administered intravenously 10 to 15 minutes before the start of the procedure. In the low-risk group, 40 mg of enoxaparin were administered once daily for 7 days; whereas in the high-risk group, 1 mg/kg of enoxaparin was administered subcutaneously (sc) 2 times a day for 48 hours after the procedure and afterward 40 mg of enoxaparin was administered sc once daily for 5 days.

RESULTS

For the analysis of the per protocol population, 44 patients remained in the low-risk group and 140 in the high-risk group. Concerning the primary safety end point, a total of 25 (13.59%) bleeding events occurred until day 30; 5 (11.36%) of them in the low-risk group and 20 (14.29%) in the high-risk group (P = .809 for low vs high risk). None of the bleeding events observed were major according to Thrombolysis In Myocardial Infarction criteria. Concerning our primary efficacy end point, none of the patients showed an acute reocclusion classified as a significant decrease in ankle-brachial index (ABI) or elevated peak systolic velocity ratio confirmed by duplex sonography until day 30. Concerning the second end point of prevention of chronic reobstruction, at day 180 ABI has decreased in the low-risk group from mean 0.94 at day 30 to mean 0.89 and from 1.28 at day 30 to 0.85 after 6 months in the high-risk group. No significant reobstruction was found in the low-risk group, whereas 5 significant reobstruction events were objectified in the high-risk group, all of them in the femoropopliteal arterial segment at day 180.

CONCLUSION

We conclude that low-molecular-weight heparin either in a low-dose or high-dose regime during a peripheral EVR is safe concerning bleeding complications and acute reobstructions. The long-term follow-up showed no significant difference between our high- and low-risk groups concerning reobstruction. The periprocedural anticoagulation seems to have no influence on the long-term patency rate after peripheral EVR.

Comparison of enoxaparin and unfractionated heparin in endovascular interventions for the treatment of peripheral arterial occlusive disease: a randomized controlled trial

BACKGROUND

Although unfractionated heparin (UFH) is an effective antithrombotic agent in endovascular interventions for the treatment of peripheral occlusive arterial disease (PAOD), it produces a highly variable anticoagulant response. Intravenous (i.v.) enoxaparin might be an effective and safe alternative.

PATIENTS AND METHODS

In a prospective, open-label, randomized, single-center trial, 210 patients with PAOD (Fontaine stage IIb to IV) were randomly assigned in a 1 (UFH): 2 (enoxaparin) fashion to receive an i.v. bolus of 60 units UFH per kg body weight or 0.5 mg enoxaparin per kg body weight, respectively, before endovascular intervention. The primary composite endpoint assessed the clinical performance of enoxaparin by comparing the peri-interventional rate of thromboembolia/occlusion (efficacy) of endovascularly reconstructed areas, of bleeding according to the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO) criteria (safety) and of any necessary re-intervention for any percutaneous transluminal angioplasty (PTA)-related bleeding. The secondary endpoint evaluated anti-factor (F)Xa levels during intervention.

RESULTS

The primary composite endpoint showed a better performance of enoxaparin (10.5% vs. 2.5% absolute difference - 8.0%; P < 0.05). The concomitant use of acetylsalicylic acid (ASA) significantly (P < 0.05) increased the risk of a complication in the UFH group, but not in the enoxaparin group. Within 15 min, anti-Xa levels were reached by 63.7% of patients treated with enoxaparin and only by 39.1% with UFH.

CONCLUSION

Enoxaparin has a better performance than UFH in endovascular interventions for the treatment of PAOD. In patients with concomitant use of ASA, the risk of complications with UFH increases significantly compared with enoxaparin.

Role of enoxaparin resistance in recurrent chest pain in the intensive care unit

To investigate the relationship between anticoagulation treatment and drug resistance in chest pain, levels of factor Xa residual activity were determined in patients seen in intensive care with recurrent chest pain and compared with levels in patients who had no ischaemic events during hospitalization. A total of 122 patients aged 18 - 75 years who were admitted to hospital with acute coronary syndrome and treated with enoxaparin were included. Of these, 62 patients had recurrent chest pain while hospitalized (group A) and 60 patients had an uneventful follow-up period (group B). Patients requiring primary percutaneous transluminal coronary angioplasty and/or treatment with glycoprotein IIb/IIIa inhibitors, and those with renal failure, a high risk of bleeding or receiving anti-inflammatory drugs were excluded from the study. Median levels (+/- interquartile range) of factor Xa residual activity were significantly higher in group A compared with group B (0.68 +/- 0.29 IU/ml versus 0.34 +/- 0.33 IU/ml). It is concluded that enoxaparin resistance, resulting in high levels of factor Xa residual activity, should be considered in patients with recurrent ischaemia.

Efficacy of enoxaparin, certoparin and dalteparin in preventing cardiac catheter thrombosis: an in vitro approach

Owing to its beneficial pharmacological profile, the low-molecular-weight heparin (LMWH) enoxaparin is increasingly being taken as an alternative to UFH in the treatment of ACS with an early invasive strategy and in elective percutaneous coronary interventions (PCI). Insufficient anticoagulation increases the risk of catheter thrombus formation during PCI. The aim of the present study was to test in vitro the hypotheses that (i) inhibiting thrombin or thrombin generation by administering LMWH is a critical intervention in preventing catheter thrombus formation and (ii) other LMWH such as certoparin or dalteparin are as effective as enoxaparin. Blood pre-treated with the anticoagulants of interest was continuously circulated through a guiding catheter by using a roller pump for a maximum experimental period of 60 min or until the catheter became occluded. Overall thrombus weight, anti-Xa activity and electron microscopic features such as deposits of platelets, erythrocytes and fibrin on the catheter surface were quantified as endpoints. All LMWH tested significantly reduced catheter thrombus generation comparable to UFH treatment whereas there was no difference between the specific LMWH with respect to catheter thrombus formation or deposition of platelets, erythrocytes and fibrin. Thrombus generation was found to negatively correlate with anti-Xa activity. The additional use of eptifibatide did not affect thrombus formation. These data suggest that modulating plasmatic coagulation by employing LMWH is critical for preventing catheter thrombus formation and at the same time offer a potential for administering LMWH other than enoxaparin, such as certoparin or dalteparin, in the setting of PCI.

[Enoxaparin vs. non-fractionated heparin in primary angioplasty of acute myocardial infarction]

OBJECTIVE

The objective of this study is to compare the effectiveness of intravenous enoxaparin (ENX) and Non-fractionated Heparin (NFH) in primary angioplasty (PA) of acute myocardial infarction (PA-AMI).

DESIGN

A prospective, observational study.

PATIENTS AND METHODS

A total of 191 patients admitted at the hospital with the diagnosis of Acute Myocardial Infarction (AMI) and treated with primary angioplasty were included. ENX was used in 91 patients (47.6%) and NFH in 100 patients (52.4%). Choice of treatment was based on the operator's opinion. Patients with cardiogenic shock were excluded. The first group received an intravenous bolus of ENX (0.75-1 mg/Kg) and the second one NFH (70-100 u/Kg), depending on whether it was associated with abciximab or not. In-hospital follow-up was performed, evaluating mortality and bleeding complications of both treatments.

RESULTS

In-hospital mortality was 1.1% for the ENX group and 3.3% for NFH one. No significant differences were found in the number of bleeding complications with ENX (4.4%) and NFH (9.0%). There was one subacute thrombosis of stent for the ENX group and 3 thrombosis in the NFH-treated group. No significant differences were found in size of infarction measure with troponin I level (63.1 for ENX and 54.8 for the NFH) or in the left ventricle ejection fraction on hospital discharge (51% for ENX and 49.4% for the NFH).

CONCLUSIONS

Primary angioplasty can be safely sued with the intravenous administration of ENX, no significant differences being found between both treatments in mortality and bleeding complications.

Interactions between heparins, glycoprotein IIb/IIIa antagonists, and coronary intervention. The Global Registry of Acute Coronary Events (GRACE)

OBJECTIVES

The purpose of this study is to evaluate hospital mortality and major bleeding rates among patients receiving low molecular weight heparin (LMWH), unfractionated heparin (UFH), or both, and to investigate whether concomitant glycoprotein (GP) IIb/IIIa antagonists and coronary intervention affect patterns of use and outcomes with different heparins.

BACKGROUND

With widespread use of glycoprotein (GP) IIb/IIIa inhibitors and invasive treatments, patients with high-risk acute coronary syndrome (ACS) may have a greater bleeding risk and may not gain additional benefit from LMWHs. The purpose of this study is to evaluate hospital mortality and major bleeding rates among patients receiving LMWH, UFH, or both, and to investigate whether concomitant GP IIb/IIIa antagonists and coronary intervention affect patterns of use and outcomes with different heparins.

METHODS

Data were analyzed from 28,445 patients with ACS; 21,287 had non-ST-segment elevation myocardial infarction or unstable angina and received LMWH or UFH.

RESULTS

Fifty-one percent of patients received LMWH, 32% UFH, and 17% both. The lowest inhospital mortality and bleeding rates occurred with LMWH (2.7% and 1.8% vs UFH, 4.1% and 2.7%; all P < .0001). After multivariable analysis, LMWH was associated with lower inhospital mortality rates in patients not treated with GP IIb/IIIa antagonists, irrespective of whether they had a percutaneous coronary intervention (PCI) (odds ratio 0.77, 95% confidence interval 0.63-0.94 without PCI vs odds ratio 0.45, 95% confidence interval 0.21-0.98 with PCI). Excess bleeding occurred with PCI in LMWH-treated patients. Patients older than 75 years who received GP IIb/IIIa antagonists and any antithrombotic but not PCI had an increased risk of major bleeding (LMWH 14%, UFH 8.3%).

CONCLUSIONS

In patients with non-ST-elevation ACS without GP IIb/IIIa antagonists, LMWH was associated with a lower mortality rate and more bleeding episodes in PCI-treated patients than UFH; no differences occurred with GP IIb/IIIa antagonists. Elderly patients managed medically with GP IIb/IIIa antagonists and either heparin had a very high major bleeding risk.

Percutaneous Coronary Intervention in Patients Receiving Enoxaparin or Unfractionated Heparin After Fibrinolytic Therapy for ST-Segment Elevation Myocardial Infarction in the ExTRACT-TIMI 25 Trial

OBJECTIVES

We sought to evaluate whether enoxaparin (ENOX) is superior to unfractionated heparin (UFH) as adjunctive therapy for patients with ST-segment elevation myocardial infarction (STEMI) who receive fibrinolytic therapy and subsequently undergo percutaneous coronary intervention (PCI) by analyzing data from the ExTRACT-TIMI 25 (Enoxaparin and Thrombolysis Reperfusion for Acute Myocardial Infarction Treatment-Thrombolysis In Myocardial Infarction 25) trial.

BACKGROUND

Limited data are available on the use of ENOX compared with UFH as adjunctive therapy in STEMI patients treated with fibrinolytic therapy and subsequent PCI.

METHODS

A total of 20,479 STEMI patients who received fibrinolytic therapy were randomized to a strategy of ENOX throughout index hospitalization or UFH for at least 48 h, with blinded study drug to continue if PCI was performed. The primary end point of death or recurrent MI through 30 days was compared for ENOX versus UFH among the patients who underwent subsequent PCI (n = 4,676).

RESULTS

After initial fibrinolysis, fewer patients underwent PCI through 30 days in the ENOX versus the UFH group (22.8% vs. 24.2%; p = 0.027). Among patients who underwent PCI by 30 days, the primary end point occurred in 10.7% of ENOX and 13.8% of UFH patients (0.77 relative risk; p < 0.001). There were no differences in major bleeding for ENOX versus UFH (1.4% vs. 1.6%; p = NS). Results were similar when PCI was carried out in patients receiving blinded study drug during PCI (n = 2,178).

CONCLUSION

Among patients treated with fibrinolytic therapy for STEMI who underwent subsequent PCI, ENOX administration was associated with a reduced risk of death or recurrent MI without difference in the risk of major bleeding. The strategy of ENOX support for fibrinolytic therapy followed by PCI is superior to UFH and provides a seamless transition from the medical management to the interventional management phase of STEMI without the need for introducing a second anticoagulant in the cardiac catheterization laboratory.

Comparison of access-related bleeding complications in women versus men undergoing percutaneous coronary catheterization using the radial versus femoral artery

Women constitute a high-risk population for bleeding, which is a major prognostic predictor after percutaneous coronary catheterization procedures. We prospectively followed 3,261 consecutive percutaneous coronary procedures performed by radial artery catheterization (RAC) or femoral artery catheterization (FAC). The primary study objective was to determine the relative incidences of in-hospital major and minor puncture-related hemorrhages. Secondary objectives were to (1) identify predictors of major bleeds and (2) estimate how often a second, alternative access site is required for catheterization. In women, no major bleeding occurred after 299 RAC procedures performed, whereas 25 major bleeding episodes occurred after 601 FAC procedures (p = 0.0008). Women who underwent RAC also had a significantly lower incidence of minor hemorrhages than women who underwent FAC (19 of 299, 6.4%, vs 237 of 601, 39.4%, respectively, p = 0.00001). On multivariate analysis, independent predictors of major bleeding were FAC (odds ratio [OR] 27.4, 95% confidence interval [CI] 3.8 to 199.9), use of glycoprotein IIb/IIIa inhibitors (OR 5.6, 95% CI 2.7 to 11.9), female gender (OR 4.5, 95% CI 2.2 to 9.0), age >70 years (OR 2.4, 95% CI 1.2 to 4.8), and an acute coronary syndrome setting (OR 2.4, 95% CI 1.1 to 5.0). Women who underwent RAC were more likely to require a second access site than men (14% vs 1.7%), but operators less selective in RAC use successfully completed the procedure by radial approach in >90% of patients. In conclusion, extensive RAC was more effective at preventing access-related bleeding complications in women than FAC.

Pharmacological antithrombotic adjuncts to percutaneous coronary intervention

Stent thrombosis is the major cause of early adverse events during percutaneous coronary intervention. Its incidence has fallen considerably in recent years, principally due to the introduction of effective antithrombotic therapies. The selection of an appropriate antithrombotic regimen is critical in achieving a balance between reducing ischaemic events and minimising bleeding complications in patients undergoing percutaneous coronary intervention. In this article, evidence for the role of antiplatelet and anticoagulant therapies is discussed, including the thienopyridines, glycoprotein IIb/IIIa receptor antagonists, direct thrombin inhibitors and pentasaccharides.

Enoxaparin versus unfractionated heparin in elective percutaneous coronary intervention

BACKGROUND

Despite its limitations, unfractionated heparin has been the standard anticoagulant used during percutaneous coronary intervention (PCI). Several small studies have suggested that intravenous enoxaparin may be a safe and effective alternative. Our primary aim was to assess the safety of enoxaparin as compared with that of unfractionated heparin in elective PCI.

METHODS

In this prospective, open-label, multicenter, randomized trial, we randomly assigned 3528 patients with PCI to receive enoxaparin (0.5 or 0.75 mg per kilogram of body weight) or unfractionated heparin adjusted for activated clotting time, stratified according to the use or nonuse of glycoprotein IIb/IIIa inhibitors. The primary end point was the incidence of major or minor bleeding that was not related to coronary-artery bypass grafting. The main secondary end point was the percentage of patients in whom the target anticoagulation levels were reached.

RESULTS

Enoxaparin at a dose of 0.5 mg per kilogram was associated with a significant reduction in the rate of non-CABG-related bleeding in the first 48 hours, as compared with unfractionated heparin (5.9% vs. 8.5%; absolute difference, -2.6; 95% confidence interval [CI], -4.7 to -0.6; P=0.01), but the higher enoxaparin dose was not (6.5% vs. 8.5%; absolute difference, -2.0; 95% CI, -4.0 to 0.0; P=0.051). The incidence of major bleeding was significantly reduced in both enoxaparin groups, as compared with the unfractionated heparin group. Target anticoagulation levels were reached in significantly more patients who received enoxaparin (0.5-mg-per-kilogram dose, 79%; 0.75-mg-per-kilogram dose, 92%) than who received unfractionated heparin (20%, P<0.001).

CONCLUSIONS

In elective PCI, a single intravenous bolus of 0.5 mg of enoxaparin per kilogram is associated with reduced rates of bleeding, and a dose of 0.75 mg per kilogram yields rates similar to those for unfractionated heparin, with more predictable anticoagulation levels. The trial was not large enough to provide a definitive comparison of efficacy in the prevention of ischemic events. (ClinicalTrials.gov number, NCT00077844 [ClinicalTrials.gov].).

Cardiac events after low osmolar ionic or isosmolar nonionic contrast media utilization in the current era of coronary angioplasty

OBJECTIVES

Our study aimed to compare the isosmolar nonionic dimer iodixanol and the low osmolar ionic agent ioxaglate in the current era of percutaneous coronary intervention (PCI), using clopidogrel, enoxaparine, direct stenting, and drug eluting stent.

BACKGROUND

Previous studies have suggested an association between thrombus-related events and type of contrast media.

METHODS

Our prospective single-center study included 498 consecutive patients who were assigned to receive either iodixanol (n = 231) or ioxaglate (n = 267). The primary endpoint was the cumulative rate of in-hospital major adverse clinical events (MACE). A secondary endpoint was the rate of angiographic or procedural complications.

RESULTS

Clinical and angiographic baseline characteristics and procedural data were similar in the 2 groups. A peak anti-Xa > 0.5 IU/ml was obtained in 97% in both groups. Glycoprotein IIb/IIIa inhibitors were used in 42% of patients. Coronary stenting was performed in 91% of patients, with direct stenting in 70%, and drug-eluting stent in 28% of patients. In-hospital MACE was more frequent in patients receiving iodixanol compared with those receiving ioxaglate (4.8% vs. 0.3%, P < 0.005). This difference was mainly related to the appearance of a large thrombus during PCI (6% with iodixanol vs. 0.3% with ioxaglate, P < 0.0001). In multivariate analysis, independent predictors of in-hospital MACE were use of iodixanol (P < 0.01), the higher number of stent used (P < 0.008), bifurcation/ostial lesion (P < 0.01), and balloon dilation before stenting (p < 0.001).

CONCLUSIONS

In our study reflecting the current era of PCI, thrombus-related events are more frequent with the isosmolar nonionic dimer iodixanol than with the low osmolar ionic agent ioxaglate.

Argatroban, a direct thrombin inhibitor for heparin-induced thrombocytopaenia: present and future perspectives

Heparin remains the most commonly used anticoagulant in the treatment of patients with acute vascular syndromes, including myocardial infarction, unstable angina and ischaemic stroke. However, heparin therapy is not always associated with a significant improvement of clinical outcomes, is linked with enhanced bleeding risk and can occasionally provoke the development of heparin-induced thrombocytopaenia, the most devastating complication of conventional therapy with unfractioned heparin. Understanding the key role of thrombin in clot formation and platelet activation has stimulated the development of a new class of drugs - direct thrombin inhibitors. The direct thrombin inhibitor argatroban has been known for decades. Similar to the unfractioned heparin, argatroban requires intravenous administration and activated partial prothrombin time-dependent dose adjustment; however, this pharmacological agent has a relatively short half-life that broadens its safety margins, as well as its low antigenic potential due to the small molecular weight of the compound. The efficacy of argatroban has been demonstrated among patients with acute coronary syndromes and stroke. However, this drug is currently approved by the FDA only for the treatment of patients with heparin-induced thrombocytopaenia. Indeed, in such patients, argatroban significantly improves clinical outcomes, and is associated with reduced mortality. Further clinical studies are needed to present more clinical evidence necessary to broad the indication spectrum of this agent.

Drug Insight: bleeding after percutaneous coronary intervention-risks, measures and impact of anticoagulant treatment options

In Europe, the use of interventional cardiology, including percutaneous coronary intervention (PCI), is increasing rapidly. The use of anticoagulation agents in PCI procedures is essential, but despite technical improvements, a significant associated bleeding risk still exists: more than 5% of patients are estimated to require transfusion, and around a further 13% experience minor bleeding. The methods used to detect and measure blood loss following PCI, however, vary widely between institutions and clinical trials. The risk of bleeding is influenced by therapeutic options and patient-specific characteristics, such as age, anemia and previous exposure to anticoagulants. Bleeding is associated with death, and also with less severe conditions such as thrombocytopenia, anemia, and hematoma, which have major impacts on patients' welfare and length of hospital stay, and on hospital budgets. Unfractionated heparin is the most widely used anticoagulant during PCI. Heparin, antiplatelet agents and other anticoagulants, however, have limitations that make it difficult to achieve a level of anticoagulation that prevents ischemic events without promoting bleeding. The use of low-molecular-weight heparin and the addition of glycoprotein IIb/IIIa inhibitors offer improved outcomes, but safer and more effective therapeutic agents are still required. New anticoagulants, including direct thrombin inhibitors such as bivalirudin, show similar levels of efficacy to heparin plus glycoprotein IIb/IIIa inhibitors, but with fewer hemorrhagic complications, and might advance clinical practice. This review evaluates the impact of PCI-related bleeding on patients' outcomes and hospital resources, examines methods for the detection and measurement of bleeding, and appraises the therapeutic options--particularly the newer agents--available to minimize hemorrhagic complications.