Management strategies for a better outcome in unstable coronary artery disease

Systemic Inflammatory Response Syndrome Predicts Mortality in Acute Coronary Syndrome without Congestive Heart Failure

INTRODUCTION

High levels of inflammatory biochemical markers are associated with an increased risk among patients with acute coronary syndrome (ACS). The objective of the current study was to evaluate the prognostic significance of the systemic inflammatory response syndrome (SIRS) among ACS patients with no clinical or radiological evidence of congestive heart failure (CHF).

METHODS

Consecutive patients with ACS and no clinical or radiological evidence of CHF in the emergency department (ED) were included in the study. The endpoint was hospital mortality. Categorical variables were compared by calculating proportions with 95% confidence intervals (CIs) and by using the Fisher Exact test. Continuous variables were compared by using the Wilcoxon Rank Sum test. The association of the variables with hospital mortality was assessed by using the logistic regression analysis.

RESULTS

The study included 196 patients (60 years; female 32.6 %). Six patients (3.1 %) died in hospital and 22 patients (11.2 %) had SIRS on admission to the ED. The following variables were predictors of hospital mortality: age with an odds ratio (OR) of 1.1 (95% CI, 1-1.2) for each one additional year (p <0.01), systolic arterial pressure with an OR 0.9 (95% CI, 0.9-1), diastolic arterial pressure with an OR 0.9 (95% CI, 0.8-1) for each one additional mmHg (p < 0.01), respiratory rate with an OR 1.5 (95% CI, 1.2-1.9) for each one additional breath per minute (p < 0.01), and SIRS with an OR 9 (95% CI, 1.7-47.8) (p 0.02). Because of the small number of events, it was not possible to assess the independence of these risk factors.

CONCLUSION

SIRS was a marker of increased risk of hospital mortality among patients with ACS and no clinical or radiological evidence of CHF.

Management of patients with type 2 diabetes after acute coronary syndromes

Acute coronary syndromes are associated with a high risk for subsequent major cardiovascular events and with a risk for mortality that remains substantially increased for many months following the acute phase. Patients with type 2 diabetes mellitus are especially vulnerable and encounter excessive long-term mortality. Effective management of patients with type 2 diabetes following acute coronary syndromes requires aggressive multidisciplinary efforts for reduction of several risk factors, including meticulous control of blood glucose. The evidence for different medication and treatment strategies capable of improving the outcomes is reviewed and the currently available recommendations are summarised.

A combination of troponin T and 12-lead electrocardiography: a valuable tool for early prediction of long-term mortality in patients with chest pain without ST-segment elevation

BACKGROUND

Electrocardiography (ECG) obtained on admission and a troponin T (tn-T) level measured early after admission are simple and accessible methods for predicting outcome in patients with suspected unstable angina or myocardial infarction without persistent ST-elevations. However, there are few studies about the combination of these 2 methods as a means of predicting long-term outcome.

METHODS

ECG was obtained on admission, and a tn-T level was analyzed on admission and after 6 hours in 710 consecutive patients admitted because of chest pain and no ST-elevations. Patients were observed for a median time of 40 months for death.

RESULTS

ST-segment depressions > or =0.05 mV were present in 266 patients (37%). These patients had a 9.7-fold increased risk of death, compared with patients with normal ECG results. Isolated T-Wave inversions or pathological signs other than ST-T changes were present in 196 patients (28%), who had a 4.5-fold increased risk of death compared with patients who had normal ECG results. At 6 hours after admission, 169 patients (24%) had at least 1 sample of tn-T > or =0.10 microg/L, which resulted in an 3.7-fold increased risk of death. In a multivariate analysis, both ECG on admission and tn-T level came out as independent predictors of outcome. When these methods were combined, patients could be divided into low- (tn-T level <0.10 microg/L and no ST-segment depression), intermediate- (tn-T level > or =0.10 microg/L or ST-segment depression), and high-risk groups (tn-T level > or =0.10 microg/L and ST-segment depression).

CONCLUSIONS

ECG and tn-T level are valuable tools to quickly risk stratify patients with chest pain. The combination of these methods is superior to either one alone.

Influence of patient characteristics and renal function on factor Xa inhibition pharmacokinetics and pharmacodynamics after enoxaparin administration in non-ST-segment elevation acute coronary syndromes

BACKGROUND

The current standard of care for patients with non-ST-segment elevation acute coronary syndromes (ACS) includes antithrombotic therapy with aspirin and heparin. Although emerging data suggest that low-molecular weight preparations offer distinct advantages over unfractionated heparin, limited information on patient-related factors that may influence dosing, safety, and efficacy is available.

PURPOSE

The purpose of our study was the determination of the impact of patient age, sex, body weight, and renal function on factor Xa inhibition pharmacokinetics and pharmacodynamics after enoxaparin administration in patients with ACS.

METHODS AND RESULTS

Patients enrolled in the TIMI 11A trial received a full complement of antiischemic therapy, aspirin, and enoxaparin (30 mg intravenously, followed by weight-adjusted doses of either 1 mg/kg or 1.25 mg/kg subcutaneously every 12 hours). Before and after the third and last doses, blood samples were obtained from 445 patients for measurement of anti-Xa activity. The mean apparent clearance, distribution volume, and plasma half-life were 0.733 L/h, 5.24 L, and 5 hours, respectively. Among a wide range of clinical and laboratory covariates, creatinine clearance emerged as the most influential factor on apparent clearance, area under the curve, and anti-Xa activity. Patients with marked renal impairment (creatinine clearance <40 mL/min) had higher trough and peak anti-Xa activity compared with those with normal renal function and were more likely to have major hemorrhagic events.

CONCLUSION

The pharmacokinetic and pharmacodynamic profiles after enoxaparin administration are consistent across a broad range of patients with ACS. Dose adjustments or anti-Xa coagulation monitoring or both will be necessary rarely in routine clinical practice, with the exception of patients with severe renal insufficiency.

Current management of unstable angina: lessons from the TACTICS-TIMI 18 trial

Patients presenting with unstable angina pectoris or non-Q-wave myocardial infarction (MI), if treated inadequately, are at a high risk of MI and subsequent mortality. The use of intravenous small molecule glycoprotein IIb/IIIa inhibitors along with standard therapeutic management options improves outcome. Since the publication of the Thrombolysis in Myocardial Ischemia IIIB, Veterans Affairs Non-Q-Wave Infarction Strategies In-Hospital (VANQWISH) and Fragmin and Fast Revascularization during InStability in Coronary artery disease II (FRISC II) studies, there is great debate about the advantages of following an early 'invasive' treatment option with coronary angiography and revascularization after initial medical therapy compared with the 'conservative' approach, where angiography is reserved for those who remain symptomatic. The Treat angina with Aggrastat and determine Cost of Therapy with an Invasive or Conservative Strategy--Thrombolysis in Myocardial Infarction 18 (TACTICS-TIMI 18) study has helped to resolve some of the controversies since it was designed with more current medical (early and routine use of tirofiban) and revascularization (use of stents during percutaneous coronary interventions) options as part of the invasive treatment protocol. This study indicated that an early invasive strategy in risk stratified patients combined with early use of tirofiban with standard medical therapy significantly improves outcome and appears well tolerated.

Diagnosis and risk stratification in patients with acute coronary syndromes according to ESC guidelines

Diagnosis and risk stratification of patients with acute coronary syndromes remain extremely important in order to avoid unnecessary hospitalizations on the one hand, and to improve prognosis of these patients on the other. For diagnosis of acute coronary syndromes, an ECG should be obtained at rest, troponin T and I should be measured on admission and again 6 to 12 h later, and myoglobin or CK-MB should be determined in patients with recent syndromes and those with recurring ischemia. Risk should be assessed upon admission and repeatedly during the hospital stay. Early risk indicators are: age, male sex, previous manifestation of coronary artery disease, history of left ventricular dysfunction or congestive heart failure and ongoing chest pain, as well as ST depression, transient ST segment elevation, and elevated levels of troponin T or I. Longer term risk assessment in unstable coronary artery disease includes rest and stress echocardiography, exercise ECG, thallium scintigraphy, as well as coronary angiography and left ventriculography. Markers of high long-term risk are old age, prior history of myocardial infarction, diabetes, elevated levels of C-reactive protein, and the extent of coronary artery disease and left ventricular dysfunction.

Cardiac markers and risk stratification: an integrated approach

Risk stratification of patients with acute coronary syndromes (ACS) is pivotal for correct allocation of health resources and for maximizing the benefit of available treatment modalities. However, clinical and electrocardiographic indicators of high risk lack sufficient sensitivity for the detection of major cardiac events. The complementary information provided by the measurement of different biomarkers is believed to be very useful. Specifically, elevations of cardiac troponin I (cTnI) and T (cTnT) are strongly associated with a high-risk profile both at short- and long-term. This has been definitely demonstrated in many studies as well as in cumulative meta-analysis. The role of different biomarkers, such as those reflecting activation of hemostasis and the presence of inflammation, is however less defined. At the moment, no study has prospectively evaluated these biomarkers in the whole spectrum of unselected patients with ACS. It is also unclear whether these biomarkers add independent prognostic value to the clinical and electrocardiographic indicators of adverse outcome and whether they offer additional information when compared to each other. The Early Prognostic Value of Biochemical Markers of Myocardial Damage, Activation of Hemostatic Mechanism and Inflammation in Acute Ischemic Syndromes (EMAI) study has been prospectively designed to solve these issues. In this study, we have evaluated the prognostic value of cTnI and cTnT, D-dimer, prothrombin fragment 1+2 (F1+2), thrombin-antithrombin complex (TAT) and C-reactive protein (CRP) in patients with ACS at the time of admission. We have enrolled in 31 Italian Coronary Care Units 1971 patients with rest anginal pain within 12 h from admission and electrocardiographic evidence of myocardial ischemia. Of these, 730 patients resulted to have ST-segment elevation myocardial infarction eligible for a reperfusion strategy and 1241, an acute coronary syndrome without persisting ST-segment elevation. Primary outcome measure of the study is the composite of death and non-fatal MI within 30 days from admission, which has occurred in 8.9% of the study population.

Unstable angina pectoris and non-Q-wave myocardial infarction

Unstable angina pectoris and non-Q-wave myocardial infarction are clinical syndromes that share many pathophysiologic and clinical features. In the spectrum of coronary artery disease, these syndromes lie between chronic stable angina and Q-wave myocardial infarction. Although both conditions are associated with significant morbidity and mortality, patients presenting with these syndromes can be further risk stratified into higher and lower risk based on a number of readily available clinical features and biochemical parameters. Such risk stratification can allow for more tailored treatment and better resource allocation. Although routine early coronary angiography and revascularization has not been shown to be superior to conservative management, certain high-risk patients may benefit from a more aggressive strategy. Medical therapy with the use of antiplatelet, anticoagulant, and antiischemic agents remains the cornerstone of emergent treatment for patients presenting with these syndromes. The recent demonstration of a reduction in both morbidity and mortality with the glycoprotein IIb/IIIa antagonists has further expanded the armamentarium of available agents. Following initial stabilization, risk stratification with stress testing can help identify patients with a large residual ischemic burden who may benefit from coronary angiography with revascularization if feasible.

Dalteparin: an update of its pharmacological properties and clinical efficacy in the prophylaxis and treatment of thromboembolic disease

Dalteparin is a low molecular weight heparin (LMWH) with a mean molecular weight of 5000. Compared with unfractionated heparin (UFH), the drug has markedly improved bioavailability and increased plasma elimination half-life, and exerts a greater inhibitory effect on plasma activity of coagulation factor Xa relative to its effects on other coagulation parameters. Dalteparin also has less lipolytic activity than UFH. Dalteparin 2500U once daily subcutaneously is of similar antithrombotic efficacy to UFH 5000IU twice daily, and 2 studies have shown superiority over UFH 2 or 3 times daily of dalteparin 5000U once daily in patients requiring surgical thromboprophylaxis. After total hip arthroplasty, dalteparin was superior to adjusted-dosage warfarin and was of greater thromboprophylactic efficacy when given for 35 than for 7 days. Intravenous or subcutaneous dalteparin is as effective as intravenous UFH when given once or twice daily in the initial management of established deep vein thrombosis (DVT). The drug is also effective in long term home treatment. Dalteparin has been shown to be effective in combination with aspirin in the management of unstable coronary artery disease (CAD), with composite end-point data from 1 study suggesting benefit for up to 3 months. Current data indicate potential of the drug in the management of acute myocardial infarction (MI). Dalteparin is also of similar efficacy to UFH, with a single bolus dose being sufficient in some patients, in the prevention of clotting in haemodialysis and haemofiltration circuits. Pharmacoeconomic data indicate that overall costs relative to UFH from a hospital perspective can be reduced through the use of dalteparin in patients receiving treatment for venous thromboembolism. Dalteparin has also been shown to be cost effective when used for surgical thromboprophylaxis. Overall, rates of haemorrhagic complications in patients receiving dalteparin are low and are similar to those seen with UFH.

CONCLUSIONS

Dalteparin is effective and well tolerated when given subcutaneously once daily in the prophylaxis and treatment of thromboembolic disease. The simplicity of the administration regimens used and the lack of necessity for laboratory monitoring facilitate home or outpatient treatment and appear to translate into cost advantages from a hospital perspective over UFH or warfarin. Dalteparin also maintains the patency of haemodialysis and haemofiltration circuits, with beneficial effects on blood lipid profiles and the potential for prophylaxis with a single bolus injection in some patients. Data are also accumulating to show dalteparin to be an effective and easily administered alternative to UFH in patients with CAD.

Low molecular weight heparin in unstable coronary artery disease

Since the recognition that any thrombosis overlying a ruptured atherosclerotic plaque is a central component of the pathogenesis of unstable coronary artery disease (CAD), a number of antithrombotic treatment strategies have been investigated in randomised clinical trials. Aspirin reduces the occurrence of symptomatic and silent ischaemia, myocardial infarction (MI) and death in patients with unstable CAD, both in the acute phase and during continued long-term treatment and is now considered routine therapy. The addition of unfractionated heparin infusion further reduces cardiac events during the treatment period, but is not associated with any sustained benefits during long-term follow-up. Low molecular weight heparins (LMWHs) are completely absorbed by the sc. route. A predictable anticoagulant effect is maintained by sc. injections every 12 - 24 h without laboratory monitoring. The FRISC trial demonstrated that, in conjunction with aspirin, the LMWH dalteparin reduced death and MI by more than 50% in the acute phase. Four similar trials have directly compared LMWH with unfractionated heparin and demonstrated at least the same efficacy in the acute phase, treated between three and eight days. The LMWH enoxaparin was more effective at reducing death or MI than unfractionated heparin infusion during the three days of treatment, an effect which lasted up to 12 months. Prolonged out-patient treatment beyond the acute phase has been evaluated in four trials. It was demonstrated, in two of these trials, that continuing twice-daily injections of dalteparin further reduced the risk of death, MI and need for revascularisation at least during the initial six weeks of treatment. This effect was confined, however, to patients with signs of myocardial damage, i.e., elevation of troponin, at admission. During prolonged out-patient treatment, there is an increased risk of severe bleeding due to the combination of LMWH with aspirin. Based on successful results, the LMWHs, having the convenience of treatment and the option for continuation in an out-patient setting, should replace unfractionated heparin as the routine treatment in unstable CAD. If an early invasive procedure is considered, the LMWH therapy should be continued until the intervention as a 'bridge-to-revascularisation'. New antiplatelet agents are also emerging as additional useful tools for treating these patients, thus it is urgent to evaluate the comibination of these new therapies with the LMWHs.

Guidelines for the diagnosis and management of unstable angina and non-Q-wave myocardial infarction: proposed revisions. International Cardiology Forum

BACKGROUND

In 1994, the United States Agency for Health Care Policy and Research issued clinical practice guidelines for the diagnosis and management of unstable angina and non-Q-wave myocardial infarction. In the past 5 years, rapid progress has been made in the management of patients with unstable coronary syndromes, yet current guidelines do not necessarily reflect these advances.

METHODS AND RESULTS

An international forum of cardiology investigators reviewed existing guidelines and discussed areas in which the diagnosis and treatment of unstable angina and non-Q-wave myocardial infarction should be modified. It was agreed that there is sufficient evidence to recommend the following changes: (1) use of serum cardiac markers should be expanded to include troponin I and T levels as diagnostic and prognostic tools; (2) low-molecular-weight heparins should replace unfractionated heparin as antithrombotic agents; (3) new classes of antiplatelet agents are recommended in addition to aspirin; and (4) the use of cholesterol-lowering drugs is appropriate in the long-term management of these patients.

CONCLUSIONS

Evidence from clinical trials within the last 5 years requires that significant changes be made to existing guidelines for the diagnosis and management of unstable angina and non-Q-wave myocardial infarction. The recommendations detailed should be considered in the creation and implementation of updated guidelines.

Targeting treatment for optimal outcome

Rapid assessment of patients presenting with acute chest pain is essential, in order to distinguish between those who have a life-threatening condition, such as myocardial infarction or unstable angina, and the substantial proportion who do not have an acute coronary syndrome. It is thus of vital importance that reliable techniques are available to facilitate rapid risk stratification, as an aid to both clinical diagnosis and management strategy decisions. Assessments based on clinical findings, electrocardiographic monitoring, symptom-limited exercise testing, and biochemical marker measurements, used either singly or in various combinations, can fulfill this role. The present paper reviews some of the recent data that demonstrate the value of these techniques. Very few studies allow conclusions to be drawn about optimal treatment strategies in relation to groups stratified according to prognostic markers, and the question of whether intense medical treatment or early invasive intervention is most beneficial is one that clinical trials have yet to address adequately. In the recently completed Fragmin and Fast Revascularization during InStability in Coronary artery disease (FRISC II) study, comparisons were made of clinical outcomes achieved with early invasive versus noninvasive (i.e., medical) management strategies, and with short-term versus prolonged anticoagulation with dalteparin sodium (Fragmin), in patients with unstable coronary artery disease. All study participants underwent symptom-limited exercise testing and provided blood sample for measurements of biochemical markers; continuous electrocardiography monitoring and echocardiography were also performed in a high proportion of patients. Data from the FRISC II trial thus shed further light on the issue of risk stratification and its use to determine optimal treatment strategies.