Early increase of von Willebrand factor predicts adverse outcome in unstable coronary artery disease: beneficial effects of enoxaparin. French Investigators of the ESSENCE Trial

Investigation of the effect of Interleukin-1 receptor antagonist (IL-1ra) on markers of inflammation in non-ST elevation acute coronary syndromes (The MRC-ILA-HEART Study)

Background

Acute Coronary Syndromes account for 15% of deaths in the UK, and patients remain at significant risk of re-admission for future complications and death. Pathologically the underlying process of atherosclerosis is driven by inflammatory mechanisms, which are activated in ACS patients. Previous studies have investigated the role of inflammatory markers in this process, including interleukin 1 (IL-1) and C Reactive Protein (CRP). Pre-clinical studies indicate that IL-1 may be a primary driver of ACS and that the naturally occurring interleukin-1 receptor antagonist (IL-1ra) may inhibit the atherosclerotic process. This study will investigate the effects of IL-1ra on inflammatory markers in man.

Methods/design

Three centres in the UK are planning to recruit 186 Non-ST elevation myocardial infarction patients to receive either interleukin-1 receptor antagonist (Anakinra) or matching placebo. Patients will receive a daily subcutaneous injection of either study drug or placebo over a 14 day period. The primary outcome is area under the curve of high sensitivity C-Reactive Protein (CRP) over the first 7 days.

Discussion

The MRC-ILA-HEART Study is a proof of concept clinical trial investigating the effects of IL-1ra upon markers of inflammation in patients with Non-ST elevation myocardial infarction. It is hoped this will provide new and exciting information in relation to an "anti-inflammatory" strategy for patients with acute coronary syndrome.

Trial registration

ISRCTN89369318

Evolution of anticoagulant and antiplatelet therapy: benefits and risks of contemporary pharmacologic agents and their implications for myonecrosis and bleeding in percutaneous coronary intervention

Periprocedural myonecrosis, as evidenced by elevated creatine kinase-myocardial bound (CK-MB) levels, occurs in up to 25% of patients undergoing percutaneous coronary intervention (PCI) and has been linked with an increased risk of adverse short- and long-term clinical outcomes. Such myonecrosis arises from three main pathophysiological mechanisms: procedure-related complications, lesion-specific characteristics (e.g., large thrombus burden, plaque volume), and patient-specific characteristics (e.g., genetic predisposition, arterial inflammation). Periprocedural myonecrosis has not been definitively identified as the cause of postprocedural ischemic events, although agents that reduce or prevent thrombosis--including aspirin, thienopyridines, heparin, low-molecular-weight heparins, glycoprotein IIb/IIIa inhibitors, and direct thrombin inhibitors--have been shown to reduce the incidence of ischemic outcomes in this population, as have agents that reduce inflammation (aspirin, statins). At the same time, antithrombotic agents are known to increase the risk of bleeding and the use of transfusions, which have likewise been associated with worse outcomes in these patients. Thus, optimal management of patients undergoing PCI represents a balance between minimizing the risk of ischemic outcomes and simultaneously minimizing the risk of major bleeding. It may be that patients who have only minor, untreated postprocedural elevations in CK-MB level (with no clinical or angiographic signs of ischemia) might have a better prognosis than patients who have normal CK-MB levels but who suffer major bleeding complications.

Acute Type B Aortic Dissection: Does Aortic Arch Involvement Affect Management and Outcomes?: Insights From the International Registry of Acute Aortic Dissection (IRAD)

BACKGROUND

Stanford Type B acute aortic dissection (TB-AAD) spares the ascending aorta and is optimally managed with medical therapy in the absence of complications. However, the treatment of TB-AAD with aortic arch involvement (AAI) remains an unresolved issue.

METHODS AND RESULTS

We examined 498 patients with TB-AAD enrolled in the International Registry of Acute Aortic Dissection (IRAD) between 1996 and 2003. Kaplan-Meier mortality curves were constructed and multivariate regression models were performed to identify independent predictors of AAI and to evaluate whether AAI was an independent predictor of follow-up mortality. We found that 371 (74.5%) patients with TB-AAD did not have AAI versus 127 (25.5%) with AAI. Independent predictors of AAI were a history of previous aortic surgery (OR 3.4; 95% CI, 1.6 to 7.6; P=0.002), absence of back pain (OR 1.6; 95% CI, 1.1 to 2.5; P=0.05), and any pulse deficit (1.9; 95% CI, 1.1 to 3.3, P=0.03). Mortality for patients without AAI was 9.4%+/-4.3% and 21.0%+/-6.9% at 1 and 3 years versus 9.2%+/-7.7% and 19.9%+/-11.1% with AAI, respectively (mean follow-up overall, 2.3 years, log rank P=0.82). AAI was not an independent predictor of long-term mortality.

CONCLUSIONS

Patients with TB-AAD and aortic arch involvement do not differ with regards to mortality at 3 years. Whether or not AAI involvement impacts other measures of morbidity such as freedom from operation or endovascular intervention deserves further study.

Serial changes in von Willebrand factor-cleaving protease (ADAMTS13) and prognosis after acute myocardial infarction

Von Willebrand factor (VWF), a cofactor in platelet adhesion and aggregation, increases hemostasis and thrombosis. Recently, a metalloprotease that cleaves VWF multimers has been identified, namely ADAMTS13. The aim of this study was to investigate the relation between serial changes in plasma VWF and ADAMTS13 and the prognosis after acute myocardial infarction (AMI). We measured serial changes of plasma VWF and ADAMTS13 antigen levels in 92 patients with AMI and 40 control subjects. VWF levels were significantly higher in patients with AMI compared with controls (p <0.01) on admission, peaked 3 days after admission, and remained high for 14 days. In contrast, on admission, ADAMTS13 levels were significantly lower in patients with AMI compared with controls (p <0.0001), with minimum antigen levels reached after 3 days, and remained lower for 14 days. The ratio of VWF/ADAMTS13 antigen levels was higher in patients with AMI compared with controls throughout the time course. Cox hazards analysis revealed that the early increase of VWF and VWF/ADAMTS13 ratio levels and the early decrease of ADAMTS13 levels were significant predictors of future thrombotic events during the 1-year follow-up period. Kaplan-Meier analysis demonstrated that patients with major decreases of ADAMTS13 levels and high increases of VWF/ADAMTS13 levels had significantly greater probabilities for development of thrombotic events (p = 0.0104 and 0.0209, respectively). In conclusion, these findings suggest that monitoring the changes of VWF and ADAMTS13 antigen levels in the early phase might be valuable for predicting and preventing thrombosis during 1-year follow-up in patients with AMI.

von Willebrand factor in CHD and stroke: Relationships and therapeutic implications

Atherosclerotic cardiovascular disease (CVD), which includes coronary heart disease (CHD) and stroke, is now the most common cause of death in the middle aged and elderly in all parts of the world except subSaharan Africa. The direct cause of death is frequently an acute thrombotic arterial occlusion. Because atherosclerosis is a diffuse disease, patients with CHD also have a high risk of ischemic stroke. The hemostatic process is a needed defense mechanism to control hemorrhage after injury but at same time, if overactive, may have the potential to precipitate diseases such as myocardial infarction or stroke in the setting of atherosclerosis. In approximately 1% of all patients with ischemic stroke, and in up to 4% of young adults with stroke, the major precipitant of brain ischemia is a hematologic disorder or coagulopathy that predisposes to thrombosis. von Willebrand factor (vWF) plays an important role in platelet adhesion to subendothelial structures and in the intrinsic pathway of coagulation. It is regarded as an indirect measure of endothelial dysfunction. Deficiency of vWF in von Willebrand's disease is well established. However, much less is known regarding the pathophysiologic implications of an elevated level of vWF, particularly in relation to CVD and cerebrovascular disease. The importance of vWF in the pathogenesis of this disease is poorly defined and information is limited and inconsistent. Elevated levels of vWF have been variably linked with risk of CHD; causal criteria are not fully met. Relationships with stroke risk are even less well established. Measurement of vWF adds little to risk prediction after considering the major risk factors--age, sex, smoking, raised blood cholesterol, and hypertension. vWF may have a greater role in predicting outcome in subjects with acute coronary syndromes (ACS), stroke, and perhaps atrial fibrillation. Investigation of the use of vWF level to guide treatment of ACS or stroke is ongoing; however, there is no compelling evidence to date.

Critical appraisal of C-reactive protein throughout the spectrum of cardiovascular disease

Clinicians involved in the care of patients with cardiovascular conditions have recently been confronted with an important body of literature linking inflammation and cardiovascular disease. Indeed, the level of systemic inflammation as measured by circulating levels of C-reactive protein (CRP) has been linked to prognosis in patients with atherosclerotic disease, congestive heart failure, atrial fibrillation, myocarditis, aortic valve disease and heart transplantation. In addition, a number of basic science reports suggest an active role for CRP in the pathophysiology of cardiovascular diseases. This article explores the potential role of CRP in disease initiation, progression, and clinical manifestations and reviews its role in the prediction of future events in clinical practice. Therapeutic interventions to decrease circulating levels of CRP are also reviewed.

Enoxaparin reduces H2O2-induced activation of human endothelial cells by a mechanism involving cell adhesion molecules and nuclear transcription factors

There are data that document the anti-inflammatory effect of enoxaparin (EP) and its possible antioxidant potential. This study was designed to search for the antioxidant mechanism(s) of EP directly on endothelial cells exposed to an oxidant stimulus. For this purpose cultured human endothelial cells were exposed to nontoxic concentrations of hydrogen peroxide in the presence or absence of EP, and the adhesion of monocytes, the expression of cell adhesion molecules and transcription factors possibly involved in the process were tested. Adhesion assays, ELISA and Western blot analysis revealed that EP reduced monocyte adhesion, ICAM-1 and P-selectin expression, decreased the nuclear levels of c-Jun and p65 proteins, and diminished the phosphorylation of c-Jun protein, MAPK p38 and JNK. Together, the data demonstrate the antioxidant effect of EP and the involvement of ICAM-1, P-selectin, MAPK p38, JNK and the transcription factors NF-kappaB and AP-1 in the mechanism of action of this drug.

Redefining Risk in Acute Coronary Syndromes Using Molecular Medicine

Acute coronary syndromes represent a complex phenotype involving the interplay of many elements. The risk of developing an acute coronary syndrome and related complications has been defined by variables such as age, diabetes, smoking history, serum creatine phosphokinase, or electrocardiographic findings. However, in the past 5 years the wide-scale acceptance of a protein--troponin--has changed the diagnostic profile. With advances in molecular medicine, this protein is a segue to a panel of molecular assays that will improve screening and tailored intervention. We expound upon some of these factors and the potential they may carry in changing clinical medicine.

Determinants of In-Hospital Death and Rupture in Patients With a Stanford B Aortic Dissection

BACKGROUND

In Stanford B acute aortic dissection (AAD), medical treatment is the choice of therapy in the acute phase, however, a portion of patients experience complications caused by serious clinical outcomes including aortic rupture and abdominal visceral ischemia. The objective of this study was to determine the predictors of in-hospital events in an Asian cohort of Stanford type B AAD.

METHODS AND RESULTS

Hospital records were queried to identify patients that met following criteria: (1) AAD presenting within 14 days of symptom onset; and (2) computed tomography (CT) confirmation of a dissected descending aorta not involving the ascending aorta. An in-hospital event was defined as death, rupture/impending rupture, or organ malperfusion. Patient characteristics, inflammatory markers, and CT findings were obtained from clinical case records and retrospectively analyzed. Two hundred and twenty patients with Stanford B AAD were identified. In-hospital events occurred in 15 patients (there were 8 deaths, and 5 patients need to undergo emergent surgery because of impending rupture or rupture, and 4 patients experienced organ malperfusion). In univariate logistic regression analysis, the non-thrombosed type (odds ratio (OR) 3.88, 95% confidence interval (CI) 1.20-12.61, p=0.02) and maximum aortic diameter measured by an initial CT (each having a 5 mm increment: OR 1.61, 95% CI 1.20-2.15, p=0.001) were significant predictors of in-hospital events. In multiple logistic regression analysis, the only significant predictor was maximum aortic diameter measured by an initial CT (each having a 5 mm increment: OR 1.41, 95% CI 1.04-1.92, p=0.03).

CONCLUSION

The results identified a large maximum aortic diameter as the independent predictor of in-hospital events in Stanford type B AAD. The non-thrombosed type might also help differentiate high-risk patients.

Long-term survival in patients presenting with type B acute aortic dissection: insights from the International Registry of Acute Aortic Dissection

BACKGROUND

Follow-up survival studies in patients with acute type B aortic dissection have been restricted to a small number of patients in single centers. We used data from a contemporary registry of acute type B aortic dissection to better understand factors associated with adverse long-term survival.

METHODS AND RESULTS

We examined 242 consecutive patients discharged alive with acute type B aortic dissection enrolled in the International Registry of Acute Aortic Dissection (IRAD) between 1996 and 2003. Kaplan-Meier survival curves were constructed, and Cox proportional hazards analysis was performed to identify independent predictors of follow-up mortality. Three-year survival for patients treated medically, surgically, or with endovascular therapy was 77.6+/-6.6%, 82.8+/-18.9%, and 76.2+/-25.2%, respectively (median follow-up 2.3 years, log-rank P=0.61). Independent predictors of follow-up mortality included female gender (hazard ratio [HR],1.99; 95% confidence interval [CI], 1.07 to 3.71; P=0.03), a history of prior aortic aneurysm (HR, 2.17; 95% CI, 1.03 to 4.59; P=0.04), a history of atherosclerosis (HR, 2.48; 95% CI, 1.32 to 4.66; P<0.01), in-hospital renal failure (HR, 2.55; 95% CI, 1.15 to 5.63; P=0.02), pleural effusion on chest radiograph (HR, 2.56; 95% CI, 1.18 to 5.58; P=0.02), and in-hospital hypotension/shock (HR, 12.5; 95% CI, 3.24 to 48.21; P<0.01).

CONCLUSIONS

Contemporary follow-up mortality in patients who survive to hospital discharge with acute type B aortic dissection is high, approaching 1 in every 4 patients at 3 years. Current treatment and follow-up surveillance require further study to better understand and optimize care for patients with this complex disease.

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].).

Predischarge C-reactive protein and 1-year outcome after acute coronary syndromes

PURPOSE

To investigate the relationship between high-sensitivity C-reactive protein and cardiovascular events following acute coronary syndrome.

METHODS

This nationwide, cross-sectional, prospective study involved 439 patients with an acute coronary syndrome who presented to the hospital within 24 hours of symptom onset. Patients with a concomitant inflammatory process were excluded. Predischarge C-reactive protein samples were measured using a high-sensitivity method in a core laboratory. The outcome was the composite of death, acute myocardial infarction, stroke/transient ischemic attack, urgent hospitalization for unstable angina, and urgent revascularization within 1 year.

RESULTS

At 1 year, event rates were 10.2% for the lowest, 8.2% for the middle, and 11.0% for the highest C-reactive protein tertiles (P = .75) with similar event-free survival (P = .70). The hazard ratio (HR) for event rates between the highest and lowest tertiles was 1.10 (95% confidence interval [CI]: 0.54 to 2.20) There was marked overlap of C-reactive protein values between patients with and without events (median [interquartile range]: 8.39 [3.27 to 32.63] vs 9.55 [4.07 to 24.02], respectively; P = .91). C-reactive protein was not an independent predictor of 1-year events (HR for highest tertile: 1.19; 95% CI: 0.58 to 2.43; P = .64) and performed poorly on receiver operating characteristic curve analysis (C statistic = 0.51).

CONCLUSION

Predischarge high-sensitivity C-reactive protein level is a poor predictor of cardiovascular events at 1 year after acute coronary syndrome.

Inter-relationships of indices of endothelial damage/dysfunction [circulating endothelial cells, von Willebrand factor and flow-mediated dilatation] to tissue factor and interleukin-6 in acute coronary syndromes

BACKGROUND

Increased circulating endothelial cells (CECs, reflecting endothelial damage) in acute coronary syndromes (ACS) has been reported. However, the inter-relationships of indices of endothelial damage/injury with development of vascular (dys)function, plasma levels of tissue factor (TF, an index of coagulation) and interleukin-6 (IL-6, a pro-inflammatory cytokine) have not been investigated in ACS. We hypothesized that increased CECs can be related to impaired flow-mediated vasodilatation (FMD, an index of endothelial dysfunction) and elevated plasma von Willebrand factor (vWf, also marking endothelial damage/dysfunction), TF and IL-6 in patients with ACS.

METHODS

We studied 120 patients with ACS (80 acute myocardial infarction and 40 unstable angina; 86 male, age 65+/-12 years) and 40 matched patients with stable CAD and 40 healthy controls (HC) in a cross-sectional analysis. Plasma vWf, TF and IL-6 levels were measured by ELISA. CECs were quantified using epifluorescence microscope after immunomagnetic separation with CD146. Brachial artery FMD was assessed in a subset of 39 ACS patients.

RESULTS

ACS patients had significantly higher CECs, vWf, TF and IL-6 levels, but lower FMD, when compared to stable CAD and HC (all p<0.001) and all were inter-correlated significantly. In ACS, CECs was strongly correlated with FMD (r=-0.64, p<0.001) and TF (r=0.7, p<0.001). In stable CAD, significant correlations were again found between many indices, but on multivariate analysis, IL-6 and vWf were both independently related to FMD.

CONCLUSIONS

Increased CECs in ACS patients are closely associated with endothelial damage/dysfunction (vWf and FMD), coagulation (TF) and inflammation (IL-6). These inter-relationships support the concept of a central role of endothelial damage/injury in the activation of vascular and coagulation abnormalities in ACS.

Long-Term Survival in Patients Presenting With Type A Acute Aortic Dissection

Background— Earlier studies evaluating long-term survival in type A acute aortic dissection (TA-AAD) have been restricted to a small number of patients in single center experiences. We used data from a contemporary, multi-center international registry of TA-AAD patients to better understand factors associated with long-term survival.

Methods and Results— We examined 303 consecutive patients with TA-AAD enrolled in the International Registry of Acute Aortic Dissection (IRAD) between 1996 and 2003. We included patients who were discharged alive and had documented clinical follow-up data. Kaplan-Meier survival curves were constructed to depict cumulative survival in patients from date of hospital discharge. Stepwise Cox proportional hazards analysis was performed to identify independent predictors of follow-up mortality. We found that 273 (90.1%) patients had been managed surgically and 30 (9.9%) were managed medically. Patients who were dead at follow-up were more likely to be older (63.9 versus 58.4 years, P =0.007) and to have had previous cardiac surgery (23.9% versus 10.6%, P =0.01). Survival for patients treated with surgery was 96.1%±2.4% and 90.5%±3.9% at 1 and 3 years versus 88.6%±12.2% and 68.7%±19.8% without surgery (mean follow-up overall, 2.8 years, log rank P =0.009). Multivariate analysis identified a history of atherosclerosis (relative risk (RR), 2.17; 95% confidence interval [CI], 1.08 to 4.37; P =0.03) and previous cardiac surgery (RR, 2.54; 95% CI, 1.16 to 5.57; P =0.02) as significant, independent predictors of follow-up mortality.

Conclusions— Contemporary 1- and 3-year survival in patients with TA-AAD treated surgically are excellent. Independent predictors of survival during the follow-up period do not appear to be influenced by in-hospital risks but rather preexisting comorbidities.

Procoagulant factors and the risk of myocardial infarction in young women

OBJECTIVES

We investigated whether elevated levels of factor VIII, IX and XI is associated with myocardial infarction (MI) in young women. In addition, we studied ABO blood group, von Willebrand factor (VWF) and C-reactive protein (CRP).

METHODS AND RESULTS

We compared 200 women with MI before age 49 years with 626 controls from a population-based case-control study. Mean levels of factor VIII activity (VIII), von Willebrand factor antigen (VWF), factor IX activity (IX) were higher in patients (133, 134 and 132 IU/dL) than in controls (111, 107 and 120 IU/dL, respectively). Mean levels of factor XI (XI) were equal in patients (114 IU/dL) and controls (113 IU/dL). The odds ratio (OR) for MI for blood group non-O vs. O was 1.6 [95% confidence interval (CI) 1.1-2.3]. The OR adjusted for age, index year and area of residence for the highest quartile >150 IU/dL of factor VIII was 2.7 (95% CI 1.6-4.6), of VWF 4.7 (95% CI 2.3-9.7), of factor IX 2.6 (95% CI 1.3-5.4) and of factor XI 0.9 (95% CI 0.5-1.4), all compared with the lowest quartile <100 IU/dL.

CONCLUSIONS

Non-O blood group, high VWF, factor VIII and factor IX levels are associated with an increased risk of MI in young women, while high factor XI levels are not.

Integrating Soluble Biomarkers and Imaging Technologies in the Identification of Vulnerable Atherosclerotic Patients

The clinical utility of a biomarker depends on its ability to identify high-risk individuals to optimally manage the patient. A new biomarker would be of clinical value if it is accurate and reliable, provides good sensitivity and specificity, and is available for widespread application. Data are accumulating on the potential clinical utility of integrating imaging technologies and circulating biomarkers for the identification of vulnerable (high-risk) cardiovascular patients. A multi-biomarker strategy consisting of markers of inflammation, hemostasis and thrombosis, proteolysis and oxidative stress, combined with new imaging modalities (optical coherence tomography, virtual histology plus IVUS, PET) can increase our ability to identify such thombosis-prone patients. In an ideal scenario, cardiovascular biomarkers and imaging combined will provide a better diagnostic tool to identify high-risk individuals and also more efficient methods for effective therapies to reduce such cardiovascular risk. However, additional studies are required in order to show that this approach can contribute to improved diagnostic and therapeutic of atherosclerotic disease.

Differential regulation of endothelial exocytosis of P-selectin and von Willebrand factor by protease-activated receptors and cAMP

Thrombin-mediated endothelial-cell release of von Willebrand factor (VWF) and P-selectin functionally links protease-activated receptors (PARs) to thrombosis and inflammation. VWF release can be stimulated by both Ca2+ and cAMP, and, although both VWF and P-selectin are found in Weibel-Palade bodies (WPBs), we found that their release could be differentially regulated. In these studies, human umbilical vein endothelial cells stimulated with cAMP or PAR2-AP led to a delayed release of VWF and significantly less P-selectin release compared with histamine, thrombin, or PAR1-AP. Dose-response studies revealed that PAR2-AP was significantly less efficacious in promoting the release of P-selectin compared with VWF. PAR2-AP-induced robust stimulation of intracellular Ca2+ coupled with a significantly greater inhibitory effect of calcium chelation on release of VWF compared with cell-surface expression of P-selectin, suggests an additional Ca2+-independent pathway involved in release of P-selectin. PAR2-AP failed to increase global cAMP levels; however, inhibition of protein kinase A led to a significant attenuation of PAR2-AP-mediated release of VWF. Confocal microscopy studies revealed that PAR2 and forskolin caused preferential release of a population of Weibel-Palade bodies (WPBs) consisting of only VWF. Thus, WPBs are pharmacologically and morphologically heterogeneous, and distinct granule populations are susceptible to differential regulation.

Time course of release of inflammatory markers after coronary stenting: comparison between bare metal stent and sirolimus-eluting stent

BACKGROUND

High levels of release of inflammatory markers after coronary angioplasty are predictors of late restenosis. Sirolimus-eluting stent reduces the risk of restenosis.

AIM OF THE STUDY

To compare the release of inflammatory markers after coronary angioplasty with sirolimus-eluting stent and bare metal stent.

METHODS

Sixteen patients with a proximal left anterior descending coronery artery stenosis were randomly assigned to receive either bare metal stent (n = 8) or sirolimus-eluting stent (n = 8). We measured simultaneously aortic and coronary sinus concentrations of the von Willebrand factor antigen, tumor necrosis factor-alpha and interleukin-6 before, immediately and after 2 h after stenting. High-sensitivity C-reactive protein and troponin-I circulating levels were measured before and 6 and 24 h after coronary angioplasty.

RESULTS

Before stenting, all values were similar in both groups. The coronary sinus change of the von Willebrand factor antigen level between baseline and 2 h after stenting was + 20.1 +/- 26.9% in the bare metal stent group and -5.7 +/- 23.02% in the sirolimus-eluting stent group (P < 0.05). We observed a significant increase in the von Willebrand factor antigen (from 132.8+/-58.8 to 169 +/- 40.7%, P < 0.05) systemic concentrations 24 h after stenting in the bare metal stent group but not in the sirolimus-eluting stent group (from 140.6+/-84% to 136 +/- 39.5%), P = NS).

CONCLUSION

The present study shows that a difference in the release of inflammatory markers can be detected after coronary stenting with bare metal stent or sirolimus-eluting stent. The lower release of the von Willebrand factor antigen in the coronary sinus 2 h after the procedure and the lower systemic concentrations of the von Willebrand factor antigen 24 h after stenting in the sirolimus-eluting stent group are likely to reflect a reduced production of the von Willebrand factor antigen at the site of the vascular injury.

Influence of prolonged dalteparin treatment on coagulation, fibrinolysis and inflammation in unstable coronary artery disease

BACKGROUND

Unstable coronary artery disease (CAD) is a multi-factorial disease involving thrombotic and inflammatory processes. Short-term low molecular weight (LMW) heparin treatment reduces coagulation activity and clinical events. We investigated the influence of prolonged treatment on coagulation, fibrinolysis and inflammation.

METHODS AND RESULTS

Serial blood samples were obtained from 555 of 2,267 unstable CAD patients in the FRISC II study. Patients were treated with the LMW heparin dalteparin 120 IU kg(-1) s.c. twice daily for 5-7 days and randomized to placebo (n=285) or gender and weight-adjusted doses of dalteparin (5,000 or 7,500 IU) twice daily (n=270) for 3 months. Dalteparin persistently depressed coagulation activity with, when compared with placebo, lower median levels of factor VIIa (63 IU mL(-1) vs. 84 IU mL(-1)), prothrombin fragment 1 + 2 (0.86 nmol L(-1) vs. 1.09 nmol L(-1)) and D-dimer (21 microg L(-1) vs. 43 microug L(-1)) after 3 months, all P<0.01. Reactivation of coagulation activity was observed after cessation of both short-term and prolonged dalteparin treatment. Higher levels of tPA/PAI-1 complex (11.7 microg L(-1) vs. 6.5 microg L(-1), P<0.001) and von Willebrand factor (162% vs. 136%, P<0.001) were found during prolonged dalteparin treatment. Interleukin-6, C-reactive protein and fibrinogen levels were unaffected by dalteparin treatment.

CONCLUSIONS

Three months dalteparin treatment resulted in a sustained and pronounced reduction of coagulation activity, which corresponds to the observed reduction in death and myocardial infarction during the initial 6 weeks in the FRISC II study. The persistently elevated levels of tPA/PAI-1 complex and von Willebrand factor might reflect effects on platelets and endothelial cells and thus contribute to the gradually decreased efficacy by prolonged dalteparin treatment in unstable CAD.

Enoxaparin versus tinzaparin in non-ST-segment elevation acute coronary syndromes: results of the enoxaparin versus tinzaparin (EVET) trial at 6 months

BACKGROUND

We have previously reported significant benefits of using enoxaparin, compared to tinzaparin, in the 7- and 30-day incidence of the composite triple end point of death, myocardial infarction (MI), or recurrent angina in patients with non-ST-segment elevation acute coronary syndromes (NSTACS). In the present study, we aimed to determine whether the observed benefits of enoxaparin were maintained beyond the early phase and report the results of the 6-m follow-up of patients in the EVET study.

METHODS

We recruited 438 patients with NSTACS. All patients received oral aspirin and were randomized to also receive enoxaparin, 100 IU/kg subcutaneously twice daily (equivalent to 1 mg/kg twice daily; n = 220), or tinzaparin, 175 IU/kg subcutaneously once daily (n = 218), for up to 7 days.

RESULTS

At 6 m, the incidence of the composite triple end point of death, MI, or recurrent angina was lower among patients receiving enoxaparin compared to those receiving tinzaparin (25.5% vs 44.0%, P < .001). A lower incidence of the secondary composite end point of death or MI was also found in the enoxaparin group compared to tinzaparin group (2.7% vs 6.9%, P = .046). The need for revascularization procedures was also lower in the enoxaparin group compared to tinzaparin group (23.2% vs 37.2%, P = .002).

CONCLUSIONS

In patients with NSTACS, enoxaparin significantly reduced the rates of recurrent ischemic events and therapeutic procedures in the short term, with sustained benefit at 6 m compared to tinzaparin.

Clinical use of enoxaparin in the management of non-ST segment elevation acute coronary syndromes

Enoxaparin (Lovenox; Roule-Poulenc Rorer, Inc.), a low molecular weight heparin (LMWH), is commonly used in the management of non-ST-segment elevation acute coronary syndromes (NSTE ACS) based on clinical trial outcomes. It is one of a group of glycosaminoglycan compounds that accelerate the inactivation of factor Xa by inducing a conformational change in antithrombin. In contrast to unfractionated heparin (UFH), LMWH have greater bioavailability, a more predictable anticoagulant response, longer half-life and a higher proportion of anti-factor Xa to anti-factor IIa activity. As a consequence, laboratory monitoring of the anticoagulant effect is typically unnecessary. Antithrombin therapy with LMWH or UFH has the highest-level recommendation (IA) in the 2002 professional guidelines for the management of unstable angina and non-ST-elevation myocardial infarction, where enoxaparin has a IIA recommendation over UFH unless early coronary artery bypass surgery is planned. In a recent systematic overview of > 20,000 patients with NSTE ACS from six clinical trials, including conservative and invasively managed patients, enoxaparin provided a statistically significant reduction in 30-day death or nonfatal myocardial infarction (MI) compared with UFH with no significant excess in transfusions, or major bleeding. These data support the role of enoxaparin as an anti-coagulant in patients with NSTE ACS.

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

This meta-analysis assessed the rates of the efficacy and safety endpoints with intravenous low-molecular-weight heparin (LMWH) compared with unfractionated heparin (UFH) in patients undergoing percutaneous coronary intervention (PCI). Subcutaneous LMWH has compared favorably with UFH, but limited experience exists with intravenous LMWH for immediate anticoagulation in PCI. The meta-analysis included data from eight randomized trials in which patients received LMWH (n = 1,037) or UFH (n = 978) during PCI. Seven additional nonrandomized studies/registries were analyzed to assess the efficacy and safety of LMWH during PCI. Efficacy endpoints were ischemic events (usually a composite of death, myocardial infarction, and urgent revascularization) and the safety endpoint was bleeding (major, minor, or all bleeding). In the randomized studies, LMWH was comparable with UFH in terms of efficacy (6.2% vs. 7.5%) and major bleeding (0.9% vs. 1.8%). The analysis of pooled data, randomized or not, suggests potential improved efficacy (5.8% vs. 7.6%) and reduced major bleeding (0.6% vs. 1.8%) with LMWH (n = 3,787) compared with UFH (n = 978). During PCI, intravenous LMWH without coagulation monitoring has the potential to be at least as safe and efficacious as intravenous UFH. Further studies of LMWHs in PCI are therefore required.

Independent association of von Willebrand factor with surrogate markers of atherosclerosis in middle-aged asymptomatic subjects

Von Willebrand factor (VWF) is considered a reliable marker of endothelial damage. Plasma levels of VWF were measured in 857 middle-aged subjects (80.4% men) free of clinically overt atherosclerotic disease, in relation to cardiovascular risk factors, carotid intima-media thickness (IMT) and microalbuminuria, two established surrogate markers of atherosclerosis. There was linear trend for the increase of VWF, carotid IMT (p < 0.001) and microalbuminuria (p = 0.018). The association between VEF and both markers remained statistically significant after adjusting for cardiovascular risk factors and inflammatory markers (p < 0.01). In conclusion, VWF was independently associated with both structural and functional surrogates of atherosclerosis in asymptomatic subjects, thus representing a systemic biomarker of subclinical atherosclerosis.

A part le fibrinogène, les facteurs/marqueurs d’hémostase ont-ils aussi une place pour évaluer le risque d’accident cardiovasculaire ischémique ?

Most cardiovascular events result from a thrombotic complication of atherosclerotic lesions. In arterial vessels such as the coronary bed, an interrelationship of haemostatic, coagulation and fibrinolytic factors is implicated. While it can be demonstrated that fibrinogen is a risk factor/marker, the role of other factors is not well established. Under arterial flow conditions, platelets are predominantly involved in the thrombotic reaction. Yet, apart from a large increase in the platelet count, the involvement of platelet parameters in cardiovascular risk is not clearly evident. The lack of definitive platelet markers is at least partly due to the difficulty of studying platelet function ex vivo. Several polymorphisms of platelet glycoproteins carrying a moderate increase in risk have been reported, but only in younger patients. One potentially important factor for coagulation is the fibrin structure, which is dependent on fibrinogen, the rate of thrombin generation, the activity of factor XIII and the interrelationship of the cells concerned, all of which act on its sensitivity to thrombosis. Coagulation factors largely affect the rate of thrombin generation. The activity of the fibrinolytic system (and principally any deficiency) has a role in the cardiovascular risk. General markers of cardiovascular risk such as D-dimers are potentially useful, but they increase with thrombin generation and are decreased by a deficiency in fibrinolysis. Furthermore, possibly because they are not indicative of the fibrin structure, they are poorly correlated with clinical events. The poor significance of the available haemostatic, coagulation and/or fibrinolytic parameters is probably due to their lack of representativeness, since haemostatic, coagulation and fibrinolytic systems are all involved in the thrombotic response (and some in atherogenesis itself). Atherogenesis is a multifactorial process and numerous moderate risk factors act in association. Better predictability of the haemostatic tests would probably result from both the design of more representative tests and the evaluation of multiple parameters, and would lead to the definition of a risk score. Technological advances will make this possible.

Association of endothelin-1 with transient myocardial ischemia in patients with unstable angina pectoris

In this study we assessed whether serum endothelin-1 levels were associated with indexes of disease severity in unstable angina, including troponin I, C-reactive protein, and transient myocardial ischemia. Endothelin-1 levels were higher in patients who had transient myocardial ischemia and in those who had 3-vessel disease on angiography but were not significantly correlated with levels of C-reactive protein and troponin I.

A potential pharmacogenomic strategy for anticoagulant treatment in non-ST elevation acute coronary syndromes: the role of interleukin-1 receptor antagonist genotype

OBJECTIVES

Our aim was to determine a pharmacogenomic approach to heparin use in non-ST elevation acute coronary syndromes, specifically the impact of interleukin (IL)-1 receptor antagonist polymorphisms upon von Willebrand factor (vWF) responses to unfractionated heparin (UFH) and low molecular weight heparin (LMWH).

BACKGROUND

In acute coronary syndromes (ACS), identification of specific biological or genetic targets to direct pharmacological treatment remains a challenge. vWF has been shown to predict future cardiovascular risk and the response to anticoagulant treatments during non-ST elevation ACS. IL-1 receptor antagonist (IL-1RN) polymorphisms predict the change in vWF between 24 and 48 h (Delta vWF) during non-ST elevation ACS.

METHODS

We genotyped at the IL-1 locus, 67 patients with non-ST elevation ACS who received either LMWH or UFH, and measured vWF levels at 24 and 48 h.

RESULTS

LMWH was superior to UFH in reducing the rise in vWF between 24 and 48 h in the cohort as a whole. However, when patients were stratified by IL-1RN genotype, LMWH was superior to UFH in reducing Delta vWF only in allele *2 carriers (0.51 iU mL(-1) vs. 1.37, P < 0.01), but not in non-carriers (- 0.03 iU mL(-1) vs. 0.15, P = NS).

CONCLUSION

IL-1RN genotype may be a useful marker to identify patients that benefit from LMWH in non-ST elevation ACS.

Predictors of the rise in vWF after ST elevation myocardial infarction: implications for treatment strategies and clinical outcome

AIMS

Prior studies suggest that acute coronary syndromes (ACSs) are associated with endothelial activation and that this is of prognostic significance. We hypothesized that endothelial activation, as measured by a rise in von Willebrand Factor (DeltavWF), was influenced by the thrombolysis in myocardial infarction flow grade (TFG), the corrected TIMI frame count (CTFC) and the choice of anticoagulant therapy after fibrinolysis in ST elevation myocardial infarction (STEMI).

METHODS AND RESULTS

Data were drawn from the enoxaparin and tenecteplase tissue plasminogen activator (TNK-tpa) with or without GPIIb/IIIa inhibitor as the reperfusion strategy in the STEMI trial (ENTIRE-TIMI 23). Three hundred and fourteen patients had serial measurements of vWF (baseline and 48-72 h) and angiographic data available. TFG<3 (P=0.0042) or CTFC>/=40 at 60 min (P=0.0035) were associated with a higher DeltavWF. DeltavWF >/=75th percentile was associated with a higher incidence of death or myocardial infarction (MI) at 30 days, compared with <75th percentile (11.2 vs. 4.1%, P=0.027). Enoxaparin independently reduced the DeltavWF (P=0.019) and also the composite of death or MI (OR 0.33, 95% CI 0.12-0.91, P=0.03) compared with unfractionated heparin.

CONCLUSION

In STEMI treated by fibrinolysis, coronary flow at 60 min and choice of adjunctive anticoagulant appear to be independent determinants of DeltavWF. Enoxaparin is independently associated with a reduction in DeltavWF and a reduction in death or MI. The clinical benefits of enoxaparin as an adjunctive treatment in STEMI may be mediated in part by a reduction in vWF release.

Circulating endothelial cells, von Willebrand factor, interleukin-6, and prognosis in patients with acute coronary syndromes

Markers of inflammation (eg, interleukin-6 [IL-6]), and endothelial perturbation (von Willebrand factor [VWF], circulating endothelial cells [CECs]) are altered in acute coronary syndromes (ACS). We hypothesized that CECs and IL-6 levels during the first 48 hours of ACS would predict 30-day and 1-year major cardiovascular end points (MACE). A total of 156 patients with ACS were included. Blood was drawn on admission (baseline) and 48 hours later for plasma VWF, IL-6 (both enzyme-linked immunosorbent assay [ELISA]), and CECs (CD146 immunomagnetic separation). CEC phenotyping was performed by indirect immunoperoxidase staining. At 30 days, 48 patients had a MACE, a predicted by baseline and 48-hour CECs and IL-6 levels, 48-hour VWF levels, and by the “admission–48 hour change” (Δ) in CECs, VWF, and IL-6 (all P = .002). On multivariate analysis, 48-hour CECs (P &lt; .001) were the strongest predictor of MACE, followed by ΔIL-6 (P = .01) and ΔVWF (P = .048); 48-hour CECs were the only predictor of death (P = .007). At 1 year, 65 patients had MACE, predicted by 48-hour CECs and ΔIL-6 levels (P &lt; .001); age (P = .046) and 48-hour CECs (P &lt; .001) were the only predictors of death. CECs stained 93% positive for endothelial nitric oxide synthase (eNOS) but were less than 1% positive for CD34, CD36, and CD45 and less than 3% for CD31. Like raised VWF, abnormal CECs and IL-6 levels during the first 48 hours of ACS were strongly associated with 30-day MACE. CECs at 48 hours were the only independent predictor of both death and MACE at 30 days and 1 year, indicating the crucial role of endothelial/vascular damage in ACS pathophysiology.

[Treatment of deep vein thrombosis. When to use which substance?]

Current antithrombotic therapy of deep vein thrombosis (DVT) consists of an initial course of heparin, followed by the secondary prevention with oral anticoagulation (OAC). Low molecular weight heparin has several advantages over unfractionated heparin, however, renal insufficiency has to be observed to avoid accumulation. The synthetic pentasaccharide Fondaparinux is a factor Xa inhibitor, that will shortly be available for the initial treatment of DVT. Oral anticoagulation with vitamin K antagonists (VKA) is highly effective, the standard target INR is 2.0-3.0. For a first episode of DVT the duration of OAC usually is six months, but has to be adjusted according to the estimated risk for recurrence. Because of the narrow therapeutic window of VKA, low molecular weight heparins are increasingly being used for secondary prevention in patients with an increased risk for bleeding, mostly in 1/2-therapeutic dose. At present, several new antithrombotic agents are being studied and may become available shortly for DVT treatment.

Enoxaparin--a low molecular weight heparin, restores the altered vascular reactivity of resistance arteries in aged and aged-diabetic hamsters

We questioned whether the low molecular weight heparin enoxaparin acts upon the altered vascular reactivity of the resistance arteries in normal biological aging and in aging associated with diabetes. Experiments were performed on isolated resistance arteries of young (4 months old), aged (16 months old), and aged-diabetic hamsters (16 months old and 5 months since streptozotocin injection), and the reactivity was assessed by the myograph technique. The results showed that enoxaparin (60 microg/ml) had favorable effects on the vascular reactivity in aged and aged-diabetic conditions, i.e., diminished the contractility of the arterial wall to 10(-8)-10(-6) M noradrenaline (NA) and to K(+), and potentiated the impeded endothelium-dependent relaxation to 10(-8)-10(-4) M acetylcholine (ACh). The effect was more pronounced compared to that produced by unfractionated heparin (UFH). These pharmacological effects supplement the anticoagulant properties of enoxaparin and may be of relevance for improving perfusion/circulation in the microvasculature of aged and of aged-diabetic persons.

Pharmacodynamic and pharmacokinetic properties of enoxaparin : implications for clinical practice

Enoxaparin is a low-molecular-weight heparin (LMWH) that differs substantially from unfractionated heparin (UFH) in its pharmacodynamic and pharmacokinetic properties. Some of the pharmacodynamic features of enoxaparin that distinguish it from UFH are a higher ratio of anti-Xa to anti-IIa activity, more consistent release of tissue factor pathway inhibitor, weaker interactions with platelets and less inhibition of bone formation. Enoxaparin has a higher and more consistent bioavailability after subcutaneous administration than UFH, a longer plasma half-life and is less strongly bound to plasma proteins. These properties mean that enoxaparin provides a more reliable anticoagulant effect without the need for laboratory monitoring, and also offers the convenience of once-daily administration. Clinical studies have confirmed that these pharmacological advantages translate into improved outcomes. There are important pharmacokinetic and pharmacodynamic differences between enoxaparin, other LMWHs and UFH, and therefore these molecules cannot be regarded as interchangeable.

Variable inhibition of high-shear-induced platelet plug formation by eptifibatide and tirofiban under conditions of platelet activation and high von Willebrand release: a randomized, placebo-controlled, clinical trial

BACKGROUND

Glycoprotein (GP) IIb/IIIa antagonists have become a mainstay for the treatment of acute coronary syndromes. Yet, they have rarely been evaluated under relevant pathophysiologic conditions, for example, high shear rates in the presence of physiologic calcium concentrations. We compared the efficacy of eptifibatide and tirofiban versus placebo on high shear-induced platelet plug formation in a model in which healthy subjects exhibit von Willebrand factor concentrations and platelet activation comparable to patients with acute coronary syndromes.

METHODS

Thirty male volunteers received 2 ng/kg endotoxin and standard doses of eptifibatide, tirofiban, or placebo over a period of 5 hours in a randomized, double-blinded, placebo-controlled, double-dummy parallel-group trial. Platelet inhibition was measured with the Platelet Function Analyzer-100 (PFA-100) and the Ultegra method.

RESULTS

Although bolus infusion of both GPIIb/IIIa antagonists inhibited high shear-induced platelet plug formation, continuous infusion of eptifibatide prolonged closure times more effectively than did tirofiban (P <.008). Interestingly, tirofiban had only placebo-like effects on platelet plug formation after 2 hours. However, when additional drug was exogenously added, closure time values were maximally prolonged in all cases.

CONCLUSIONS

Standard doses, particularly of tirofiban, have limited impact on high shear-induced platelet plug formation at physiologic Ca(2+) concentrations.

Improved survival of surgery for acute type a aortic dissection

OBJECTIVES

In the past decade, progress in cardiovascular technology has been incorporated into the surgical treatment of acute type A dissection resulting in remarkable improvement. Factors in this progress encompass rapid noninvasive diagnosis, intraoperative introduction of aprotinine, surgical glue, sealed grafts, and refined surgical technique. The objective of this study is to identify which factors contributed to the improvement of the surgical outcome of acute type A dissections.

METHODS

Between January 1989 and February 2001, 78 consecutive patients had emergency surgeries for acute type A dissection. The initial 31 patients (group I) received preoperative angiography, when possible. Since 1996, the next 47 patients (group II) have received noninvasive rapid diagnosis with hemostatic surgical management. This included aggressive proximal resection and judicious use of gelatin resorcine formol glue and felt strips. Between the two groups, in-hospital mortality and morbidity, incidence of neurological complications, late survival and cardiovascular events were compared. Risk factors for in-hospital death were investigated with univariate and multivariate analysis.

RESULTS

The in-hospital mortality was significantly improved in group II (4.3%) compared with group I (29.0%). Overall mortality was 14.1%. Multivariate analysis revealed preoperative limb ischemia and delayed timing of operation (> 3 hours after arrival) as independent risk factors for in-hospital death. Late survival at 5 years was 61.5+/-7.5%. Between the two groups there was no significant difference in late survival or cardiovascular events.

CONCLUSIONS

Immediate surgical intervention, using rapid noninvasive diagnosis with hemostatic management, substantially improves the surgical outcome of acute aortic dissection.

Descending thoracic aortic diseases: stent-graft repair

PURPOSE

To evaluate endovascular treatment of descending thoracic aorta with commercially available self-expanding stent-grafts.

MATERIALS AND METHODS

Seventy patients with aortic dissection, intramural hemorrhage, degenerative and posttraumatic aneurysm, penetrating atherosclerotic ulcer, and pseudoaneurysm underwent endovascular treatment. Eleven patients had impending rupture and were treated on an emergency basis. Stent-grafts were customized or selected on the basis of spiral computed tomographic (CT) or magnetic resonance (MR) imaging measurements. Preprocedure diagnostic angiography was performed in patients with aortic dissection and in other selected patients. All procedures were performed in an operating room and monitored with digital subtraction angiography (DSA) and transesophageal echocardiography (TEE). Follow-up was at 1, 3, 6, and 12 months after treatment and yearly thereafter.

RESULTS

Stent positioning was technically successful in 68 cases. At DSA and TEE, complete aneurysm or false-lumen exclusion was achieved in 66 (97%) cases. No intraoperative mortality or complications occurred. In-hospital complications included transient monoparesis (one patient) and extension of dissection into ascending aorta (one patient) that was repaired surgically. Early endoleak was observed in five (7%) patients: In three (type 2), endoleak resolved spontaneously; in one (type 1), it was persistent; and in one (type 1), treatment was converted to surgery. At long term, one (1%) patient died of aortic rupture; another, of respiratory insufficiency. Five (7%) late endoleak (type 1, one caused by migration of the stent) cases were observed. In three (4%), endovascular treatment was successful; in two (3%), surgery was performed. In one patient with persistent postimplantation syndrome, treatment was converted to surgery after successful aneurysm sealing. Procedure failure (ie, aortic disease-related mortality or conversion to surgery) occurred in six (9%) patients.

CONCLUSION

Endovascular stent-graft repair is less invasive in patients with chronic and acute descending thoracic aortic aneurysm and dissection.

The use of low molecular weight heparin to predict clinical outcome in patients with unstable angina that had undergone percutaneous coronary intervention

BACKGROUND

Antithrombotic therapy with heparin reduces the rate of ischemic events in patients with acute coronary syndrome. Low-molecular-weight heparin, given subcutaneously twice daily, has a more predictable anticoagulant effect than standard unfractionated heparin. Moreover, it is easier to administer and does not require monitoring.

METHODS

We prospectively analyzed 180 patients with unstable angina who had undergone percutaneous coronary intervention (PCI) between 1999 and 2001 at Chonnam National University Hospital and had received either 120 U/kg of dalteparin (Fragmin), administered subcutaneously twice daily (Group I; n = 90, 61.8 +/- 8.9 years, male 67.8%), or had received continuous intravenous unfractionated heparin (Group II; n = 90, 62.6 +/- 9.7 years, male 70.0%). During hospitalization and at 6 month after PCI, major adverse cardiac events such as acute myocardial infarction, target vessel revascularization, death, and restenosis were examined.

RESULTS

During hospitalization, the incidence of acute myocardial infarction, target vessel revascularization and death were not different between the two groups. At follow-up coronary angiography 6 months after PCI, the incidence of restenosis was lower in group I than in group II (Group I; 26/90, 28.8% vs. Group II; 32/90, 35.6%, p = 0.041) and the incidence of target vessel revascularization was lower in group I than in group II (Group I; 21/90, 23.3% vs. Group II; 27/90, 30.0%, p = 0.039). No difference was found in the rates of major and minor hemorrhages, ischemic strokes or thrombocytopenia between two groups. By multivariate analysis, the factors related to restenosis were lesion length, postprocedural minimal luminal diameter, CRP on admission, diabetes mellitus, the type of heparin, and stent use.

CONCLUSION

Dalteparin, a low molecular weight heparin, is superior to standard unfractionated heparin in terms of reducing the restenosis rate and target vessel revascularization without increasing bleeding complications.

Safety and efficacy of unfractionated heparin versus enoxaparin in patients who are obese and patients with severe renal impairment: analysis from the ESSENCE and TIMI 11B studies

BACKGROUND

The advantages of enoxaparin over unfractionated heparin (UFH) for the treatment of patients with non-ST-segment elevation acute coronary syndromes are well established. However, no data are available about the safety and efficacy in patients who are obese and patients with severe renal impairment.

METHODS

A retrospective analysis of treatment effects was performed on patients who were obese and patients with severe renal impairment from the Efficacy Safety Subcutaenous Enoxaparin in Non-Q-wave Coronary Events (ESSENCE) and Thrombolysis in Myocardial Infarction (TIMI) 11B trials, in which patients were treated with enoxaparin or UFH. The primary composite end point was death, myocardial infarction (MI), and urgent revascularization (UR), and the secondary end points were major and any hemorrhage.

RESULTS

When compared with UFH, enoxaparin reduced the rate of the primary end point in patients who were obese (14.3% vs 18.0%, P =.05), patients who were not obese (16.1% vs 19.2%, P <.01), and patients without severe renal impairment (15.7% vs 18.4%, P <.01). There was no significant difference in major bleeding between enoxaparin and UFH in any of the 4 subgroups. There were no differences in either the primary end point (17.6% vs 16.2%, P =.39) or major hemorrhage (1.3% vs 0.8%, P =.12) in patients who were obese receiving either UFH or enoxaparin compared with patients who were not obese. Patients with severe renal impairment tended toward a higher rate of the primary end point (25.9% vs 17%, P =.09) and experienced more major hemorrhages (6.6% vs 1.1%, P <.0001).

CONCLUSIONS

Enoxaparin reduced the rate of the combined end point of death/MI/UR in the subgroups of patients who were obese, patients who were not obese, and patients without renal insufficiency. Obesity did not impact clinical outcomes in the combined analysis of ESSENCE and TIMI 11B. Patients with severe renal impairment have a higher risk of clinical events and major and any hemorrhages than patients without severe renal impairment, whether they are treated with UFH or enoxaparin.

Prothrombotic and antithrombotic pathways in acute coronary syndromes

The acute coronary syndromes arise from procoagulant changes in complex plaques, which trigger both platelet activation and coagulation pathways. These 2 pathways intersect at a number of points that form positive-feedback loops to sustain and accelerate thrombus formation. In normal hemostasis and with a healthy endothelium, intravascular thrombosis is prevented, and vascular patency is protected by the fibrinolytic system and a number of antithrombotic factors, such as antithrombin, thrombomodulin, and tissue factor pathway inhibitor. However, atherosclerosis is characterized by a hypercoagulable state, and the fibrinolytic balance is skewed toward occlusive thrombus formation at critical sites on vulnerable plaques. This review focuses on cellular and humoral mechanisms and the antithrombotic strategies that are important during the acute phase of an ischemic coronary syndrome, both in patients managed conservatively and in patients scheduled for an interventional procedure. These strategies include fibrinolytic therapy, antiplatelet therapies (aspirin, clopidogrel, glycoprotein IIb/IIIa receptor inhibitors), and low-molecular-weight heparin.

Effect of site of venous protamine administration, previously alleged risk factors, and preoperative use of aspirin on acute protamine-induced pulmonary vasoconstriction

OBJECTIVE

To determine whether the incidence of protamine-induced pulmonary vasoconstriction (PIPV) is influenced by central venous versus peripheral venous infusion of protamine and whether aspirin ingestion within a week of surgery would decrease the incidence of PIPV.

DESIGN

Single-institution, prospective, observational, randomized trial.

SETTING

University teaching hospital.

PARTICIPANTS

One thousand four hundred ninety-seven consecutive patients undergoing cardiopulmonary bypass procedures.

INTERVENTION

Protamine neutralization of heparin by infusion pump via either central venous or peripheral venous route.

MEASUREMENTS AND MAIN RESULTS

Five previously suspected risk factors (valve surgery, prior protamine exposure, history of pulmonary hypertension, fish allergy, and vasectomy), aspirin ingestion within 7 days of surgery, and demographic information were recorded. PIPV was defined as an abrupt increase in mean PA pressure of 7 mmHg or more with associated right ventricular dysfunction as assessed by observation of the right ventricle in the field and regional wall motion abnormality by transesophageal echocardiogram and hypotension (systolic blood pressure < or = 90 mmHg). Data were collected via continuous strip chart recording. A total of 10 patients (0.6%) developed PIPV during protamine infusion. The incidents were similar with respect to the site of venous administration. Prior exposure to protamine was associated with a greater incidence of PIPV (odds ratio 6.9; p < 0.01). Other previously suspected risk factors did not achieve statistical significance. None of the 766 patients who ingested aspirin experienced PIPV as opposed to 10 of the 731 patients who did not ingest aspirin (odds ratio 0.08; p < 0.001).

CONCLUSIONS

Although the site of venous protamine administration does not influence incidence of PIPV, aspirin ingestion within 1 week of surgery may decrease it. These data also confirmed other studies suggesting that previous protamine administration predisposes to this protamine reaction.

Comparison of effects on markers of blood cell activation of enoxaparin, dalteparin, and unfractionated heparin in patients with unstable angina pectoris or non-ST-segment elevation acute myocardial infarction (the ARMADA study)

The low-molecular-weight heparins (LMWHs) enoxaparin and dalteparin have shown superior and equivalent efficacy, respectively, over unfractionated heparin (UFH) in patients with unstable angina pectoris (UAP) or non-ST-segment elevation myocardial infarction (NSTEMI). This study aimed to identify markers of blood cell activation that are independent predictors of outcomes at 1 month and to compare the effects of enoxaparin, dalteparin, and UFH on any such markers. In this multicenter, prospective, open-label study, 141 patients with UAP or NSTEMI were randomized to treatment for 48 to 120 hours with enoxaparin (n = 46), dalteparin (n = 48), or UFH (n = 47). Blood samples were taken at the time of randomization and after > or =48 hours of treatment but before catheterization. Multivariate analysis identified increased plasma levels of von Willebrand factor (vWF) and decreased platelet levels of glycoprotein Ib/IX complexes as independent predictors of 1-month adverse outcome (a composite of death, myocardial infarction, and recurrent ischemia). vWF release was strongly related to and may have been released by inflammation as measured by C-reactive protein. Both LMWHs reduced the release of vWF in plasma (as well as C-reactive protein) compared with UFH. Enoxaparin had a more favorable effect on glycoprotein Ib/IX complexes than either dalteparin or UFH. The incidence of the composite clinical efficacy end point was: 13% (enoxaparin), 19% (dalteparin), and 28% (UFH). vWF and its receptor glycoprotein Ib/IX play a key role in acute coronary syndromes. vWF is linked to inflammation and, like glycoprotein Ib/IX, is affected more favorably by the LWMHs than by UFH.

A guide to therapeutic decision-making in patients with non-ST-segment elevation acute coronary syndromes

Recent clinical trial evidence supports an inflammatory etiology in acute ischemic heart disease. When a segment of coronary artery becomes inflamed, important cytokines, such as tissue factor, are released, facilitating thrombosis. Serum inflammatory markers are elevated in most acute coronary syndrome patients at presentation. Mortality risk has been shown to be associated with increased levels of high-sensitivity C-reactive protein (CRP), interleukin 6, and serum vascular cell adhesion molecule. Platelets, which are rich in inflammatory mediators (CD40 and its ligand thrombospondin, and phospholipase A2), also supply important triggers for the inflammatory cascade. In addition, more than 35 platelet-associated messenger ribonucleic acid mediators involved in arterial injury and inflammation have been found. The use of biomarkers of inflammation, such as CRP, and of the sequelae of embolization, such as troponin, provide a window into the underlying pathophysiology of acute ischemic heart disease. New agents from three distinct drug classes have recently flooded the therapeutic armamentarium. Decision-making is further complicated by the choice of an invasive (aggressive) or a medical (conservative) strategy of management with respect to coronary revascularization. For patients at highest risk, aspirin, beta-blockers, nitrates, and a statin should be given, and clopidogrel, enoxaparin, a glycoprotein (GP) IIb/IIIa inhibitor, plus an invasive strategy should be considered. For intermediate- and low-risk patients, a "sliding-scale" approach may be best. Decisions about the three classes of antithrombotics--low-molecular-weight heparins, GP IIb/IIIa inhibitors, and thienopyridines--along with whether to adopt an early invasive strategy, should be made on an individual basis.

Use of low-molecular-weight heparins in the management of acute coronary artery syndromes and percutaneous coronary intervention

CONTEXT

Low-molecular-weight heparins (LMWHs) possess several potential pharmacological advantages over unfractionated heparin as an antithrombotic agent.

OBJECTIVE

To systematically summarize the clinical data on the efficacy and safety of LMWHs compared with unfractionated heparin across the spectrum of acute coronary syndromes (ACSs), and as an adjunct to percutaneous coronary intervention (PCI).

DATA SOURCES

We searched MEDLINE for articles from 1990 to 2002 using the index terms heparin, enoxaparin, dalteparin, nadroparin, tinzaparin, low molecular weight heparin, myocardial infarction, unstable angina, coronary angiography, coronary angioplasty, thrombolytic therapy, reperfusion, and drug therapy, combination. Additional data sources included bibliographies of articles identified on MEDLINE, inquiry of experts and pharmaceutical companies, and data presented at recent national and international cardiology conferences.

STUDY SELECTION

We selected for review randomized trials comparing LMWHs against either unfractionated heparin or placebo for treatment of ACS, as well as trials and registries examining clinical outcomes, pharmacokinetics, and/or phamacodynamics of LMWHs in the setting of PCI. Of 39 studies identified, 31 fulfilled criteria for analysis.

DATA EXTRACTION

Data quality was determined by publication in the peer-reviewed literature or presentation at an official cardiology society-sponsored meeting.

DATA SYNTHESIS

The LMWHs are recommended by the American Heart Association and the American College of Cardiology for treatment of unstable angina/non-ST-elevation myocardial infarction. Clinical trials have demonstrated similar safety with LMWHs compared with unfractionated heparin in the setting of PCI and in conjunction with glycoprotein IIb/IIIa inhibitors. Finally, LMWHs show promise as an antithrombotic agent for the treatment of ST-elevation myocardial infarction.

CONCLUSIONS

The LMWHs could potentially replace unfractionated heparin as the antithrombotic agent of choice across the spectrum of ACSs. In addition, they show promise as a safe and efficacious antithrombotic agent for PCI. However, further study is warranted to define the benefit of LMWHs in certain high-risk subgroups before their use can be universally recommended.

The contribution of genetic factors to thrombotic and bleeding outcomes in coronary patients randomised to IIb/IIIa antagonists

Genetic variants are risk factors for coronary disease, but their role in recurrent events and in response to treatment is less clear. We genotyped genetic variants implicated in primary coronary disease in 924 Caucasians with acute coronary syndromes participating in the OPUS-TIMI16 trial of the GPIIb/IIIa antagonist orbofiban. These were the platelet glycoprotein (GP) receptors GPIIIa, GPIa, GPIbalpha; platelet ligands beta-fibrinogen and von Willebrand Factor (vWF); interleukins (IL) IL-1RN, and IL-6; adhesion proteins E-selectin and P-selectin; and metalloproteinase MMP-9. Cox modelling of all genetic variants demonstrated no significant impact on the composite endpoint (P = 0.88), which included myocardial infarction (MI), death, recurrent ischemia, urgent revascularisation and stroke, but a significant impact on recurrent myocardial infarction alone (chi(2) = 20.4, 10 df, P = 0.04). There was a significant interaction of the polymorphisms with orbofiban treatment influencing bleeding outcomes (P = 0.004). Thus, genetic polymorphisms may be associated with subsequent myocardial infarction, and may also be associated with treatment-associated bleeding among coronary patients.