The risk of iatrogenic bleeding in acute coronary syndromes and long-term mortality

Reduced nicotinamide adenine dinucleotide phosphate inhibits rat platelet aggregation and p38 phosphorylation

Previous studies found that reduced nicotinamide adenine dinucleotide phosphate (NADPH) protected neurons against ischemia/reperfusion-induced injury. In addition to ROS reduction and ATP increment, preliminary data suggested that NADPH inhibited ADP and thrombin-induced platelet aggregation. As the effect of NADPH on platelet function was not reported by other investigators, the actions of NADPH on platelet function and mechanisms of actions were investigated in the present study. In vitro studies, the effects of different concentrations of NADPH on platelet aggregation induced by ADP (10 μM), thrombin (0.05 U/mL) or AA (50 μM) were determined. The results showed that NADPH could inhibit platelet aggregation induced by ADP, thrombin or AA in a concentration dependent manner. When the inhibitory effects of NAD⁺, NADH, NADP⁺ and NADPH on platelet aggregation were compared, NADPH demonstrated the relatively best effect on platelet aggregation. In vivo studies, the effects of NADPH on platelet aggregation, tail bleeding time, coagulation response and ferric chloride-induced thrombosis were determined in mice or rats. The maximum aggregation rate of platelets of rats injected with NADPH (5 mg/kg) was lower than platelets from control rats. NADPH transiently prolonged tail bleeding time in mice at 30 min after the injection of NADPH (7.5 mg/kg), while aspirin (15 mg/kg) significantly prolonged the tail bleeding time in mice at all time points examined. NADPH (5 mg/kg), as well as aspirin (10 mg/kg), had no effect on coagulation response in rats. Using a FeCl₃-induced abdominal aorta injury thrombosis model, administration of NADPH (5 mg/kg) significantly delayed the onset of vessel occlusion, while aspirin (10 mg/kg) almost completely prevented the vessel occlusion. With microscopic examination the thrombi in injured vessel sections of rats received NADPH were much smaller and less dense than that of rats received vehicle treatment. ADP induced an increase in phosphorylation of p38 and the effect was markedly inhibited by the p38 inhibitor SB203580. Similarly, NADPH also inhibited ADP-induced phosphorylation of p38. Similar to NADPH, SB203580 robustly inhibited ADP- and thrombin-induced platelet aggregation. In addition, NADPH also reduced ADP-induced increases in ROS in platelets. The current results demonstrated that NADPH inhibited platelet aggregation, oxidative stress and p38 phosphorylation, suggesting that NADPH might be a novel compound for management of high risk of cardiovascular disease.

Incidence and predictors of bleeding among Egyptian patients presenting with acute coronary syndrome: Using CRUSADE risk score

Background

Early invasive strategies; in management of acute coronary syndrome; has led to improvement of patient outcomes. However, these invasive therapies have their own risks, namely bleeding and blood transfusion.

The aim of this study was to determine the incidence of bleeding, its location and severity among the study population, to correlate between the patients' characteristics and the risk profile of the patients based upon the CRUSADE risk score and increased bleeding events, and lastly; to identify the predictors of increased bleeding risk among Egyptian patients who presented with acute coronary syndrome.

Methods

The study had included eight hundred and twenty-three patients referred to coronary care unit (CCU), to (Ain Shams University hospital, Specialized Ain Shams hospital, and 6th October insurance hospital) with diagnosis of Acute Coronary Syndrome “ACS” within a period from 1/2014 till 7/2014, and they were followed up for additional three months following discharge with assessment of their bleeding risk and risk scores.

Results

More bleeding events had been witnessed among the study population who were older, diabetics, had renal impairment, had peripheral vascular disease, had congestive heart failure picture at presentation; more among female sex category and more among patients receiving GPIIbIIIa antagonists. Those bleeding events had been experienced during hospital stay.

Conclusion

Risk of bleeding can be evaluated using a simple risk score in both STEMI & NSTEMI patients, and across anti-coagulant strategies, providing important prognostic information. Variability in the rates of bleeding is likely based on differences in baseline characteristics, comorbidities, and invasive treatment strategies rather than specific anti-coagulation regimens. Patients at highest risk of bleeding are also at highest risk of ischaemia and thrombotic complications. Thus higher risk patients need a more careful treatment approach to maximize the efficacy of therapy and to reduce thrombotic risk while reducing the bleeding risk.

Subarachnoid hemorrhage mimicking leakage of contrast media after coronary angiography

We report a patient who developed subarachnoid hemorrhage (SAH) just after coronary angiography (CAG) with non-ionic contrast media (CM) and minimal dose of heparin. The 55-year-old man had a history of acute ST elevation myocardial infarction that had been treated with primary percutaneous coronary intervention and was admitted for a follow-up CAG. The CAG was performed by the transradial approach, using 1000 U of unfractionated heparin for the luminal coating and 70 mL of iodixanol. At the end of CAG, he complained of nausea and rapidly became stuporous. Brain CT showed a diffusely increased Hounsfield unit (HU) in the cisternal space, similar to leakage of CM. The maximal HU was 65 in the cisternal space. No vascular malformations were detected on cerebral angiography. The patient partially recovered his mental status and motor weakness after 2 days. Two weeks later, subacute SAH was evident on magnetic resonance imaging. The patient was discharged after 28 days.

Frequency and impact of bleeding in elective coronary stent clinical trials--utility of three commonly used definitions

BACKGROUND

Bleeding events are common after percutaneous coronary intervention (PCI) and have been shown to increase mortality in studies of acute coronary syndrome (ACS) and anti-thrombotic therapy. Despite this evidence, bleeding has not been included as a traditional major endpoint in clinical trials of low-risk populations enrolled in PCI clinical trials. Thus, the impact of specific bleeding definitions has not been evaluated fully among these patients.

METHODS AND RESULTS

Using patient-level pooled data from sirolimus and zotarolimus drug-eluting stent clinical trials, we identified bleeding events using three common definitions of bleeding, ACUITY, TIMI, and GUSTO, and assessed the impact on mortality and MI at 12 months after PCI. The GUSTO, ACUITY, and TIMI classifications identified bleeding rates of 2.3%, 1.9%, and 2.1%, respectively. The GUSTO criteria classified all 118 suspected bleeding events. There were 22 (18.6%) and 8 (6.8%) suspected bleeding events that did not meet ACUITY and TIMI criteria, respectively. The combined endpoint of all-cause death or myocardial infarction (MI) at 12 months was significantly higher for patients with a bleeding event compared with those who did not bleed [hazard ratio 1.95 (95% CI 1.06-3.60)].

CONCLUSION

There is a substantial variability in the utility and inclusiveness of three widely used bleeding definitions in identifying clinically significant bleeding events in clinical trials of low risk patients undergoing PCI with DES. Patients with bleeding after elective PCI have an increased one-year risk of death or MI compared to those patients who do not bleed.

Arterial thrombosis--insidious, unpredictable and deadly

The formation of blood clots--thrombosis--at sites of atherosclerotic plaque rupture is a major clinical problem despite ongoing improvements in antithrombotic therapy. Progress in identifying the pathogenic mechanisms regulating arterial thrombosis has led to the development of newer therapeutics, and there is general anticipation that these treatments will have greater efficacy and improved safety. However, major advances in this field require the identification of specific risk factors for arterial thrombosis in affected individuals and a rethink of the 'one size fits all' approach to antithrombotic therapy.

A critical appraisal of bleeding events reported in venous thromboembolism prevention trials of patients undergoing hip and knee arthroplasty

BACKGROUND

Anticoagulants are effective for the prevention of venous thromboembolism (VTE) but cause bleeding. Interpretation of the risks and benefits of new anticoagulant regimens for VTE prevention is complicated by a lack of standardized definitions and reporting of bleeding. We reviewed the reporting of bleeding in randomized controlled trials of new anticoagulants compared with standard doses of enoxaparin in hip and knee arthroplasty, and examined the possible impact of differences in the definition of major bleeding on interpretation of the trial results.

METHODS

Electronic searches identified 16 phase III trials published between 2001 and 2010 involving 41,265 patients comparing one of five new anticoagulants with a common comparator, enoxaparin.

RESULTS

Major bleeding rates in patients treated with enoxaparin ranged from 0.1% to 3.1% in hip arthroplasty trials and from 0.2% to 1.4% in knee arthroplasty trials. In studies that excluded surgical-site bleeding from the definition, major bleeding rates were about 10-fold lower than in those which included surgical-site bleeding. Within the individual trials, the choice of bleeding definition and the methods of assessment of bleeding influenced the conclusions regarding the risk of bleeding with new anticoagulant regimens relative to enoxaparin. Eight of the 16 studies demonstrated a ≥ 40% relative risk differences in major bleeding between treatment groups but the difference was statistically significant in only two of these trials.

CONCLUSION

Randomized VTE prevention trials report markedly different rates of major bleeding despite similar patient populations and doses and durations of anticoagulant prophylaxis and were underpowered to detect modest differences in patient-important bleeding events. Standardization of bleeding definitions and reporting seems desirable.

Hematomas of at least 5 cm and outcomes in patients undergoing elective percutaneous coronary intervention: insights from the SafeTy and Efficacy of Enoxaparin in PCI patients, an internationaL randomized Evaluation (STEEPLE) trial

BACKGROUND

Major bleeding significantly impacts outcomes in patients undergoing percutaneous coronary intervention (PCI). No uniform definitions exist for major and minor bleeding. Hematomas > or =5 cm at the femoral puncture site are considered major bleeding events in some trials and minor in others. Limited information is available on the incidence and clinical relevance of hematomas > or =5 cm in PCI patients.

METHODS

Data from the STEEPLE trial in patients undergoing elective PCI were used to assess the impact of hematomas > or =5 cm on ischemic outcomes (mortality, nonfatal myocardial infarction, or urgent target vessel revascularization) up to day 30 and all-cause 1-year mortality. Hematoma data were available for 3,342 of 3,528 patients in STEEPLE. Patients with (n = 103) and without (n = 3,239) hematomas > or =5 cm were evenly distributed across treatment groups.

RESULTS

No differences were observed in 30-day ischemic outcomes between patients with and without hematomas (5.8% vs 5.9%, respectively; P = .96). No transfusions were observed in patients with hematomas as compared with patients without hematomas (0% and 0.4%, respectively; P = .52). A greater reduction in hemoglobin was observed (pre- vs post-PCI) in patients with hematomas as compared with patients without hematomas (-0.84 vs -0.35 g/L, P < or = .001). No significant difference in all-cause 1-year mortality was observed between patients with and without hematomas (0.0% vs 1.7%, P = .98).

CONCLUSIONS

After PCI, hematomas > or =5 cm had no effect on 30-day ischemic events or 1-year mortality. Although there is no agreed classification for large hematomas, the lack of a relationship between hematomas > or =5 cm and clinical outcome after PCI justifies the classification of these hematomas as minor bleeds in STEEPLE.

Practical prescribing of intravenous unfractionated heparin

Intravenous unfractionated heparin is sometimes poorly managed in NHS hospitals. This article investigates why this is so and reviews the evidence for optimal unfractionated heparin prescribing, using it to make some suggestions as to how doctors can improve this.

New antithrombotic drugs

Thrombosis, both venous and arterial, is a major cause of morbidity and mortality worldwide. Consequently, there is an ongoing search for new antithrombotic drugs, particularly novel antiplatelet agents and anticoagulants. A better understanding of the biochemical pathways involved in platelet activation and coagulation and of the links between these systems and the impact of thrombosis on inflammation has led to the identification of new targets for antithrombotic drugs. This paper focuses on these new targets and new antiplatelet drugs and anticoagulants and describes the major advances in the continuing search for more potent antithrombotic drugs that have limited effects on hemostasis.