The electrocardiogram predicts one-year outcome of patients with unstable angina and non-Q wave myocardial infarction: results of the TIMI III Registry ECG Ancillary Study. Thrombolysis in Myocardial Ischemia

Prognostic value of clinical variables at presentation in patients with non-ST-segment elevation acute coronary syndromes: results of the Proyecto de Estudio del Pronóstico de la Angina (PEPA)

Patients with suspected non-ST-segment elevation acute coronary syndromes (NSTEACS) constitute a heterogeneous population with variable outcomes. Risk stratification in this population of patients is difficult due to the complexity in patient risk profile. We conducted this study to characterize the value of clinical and electrocardiographic variables for risk stratification in an unselected population of consecutive patients with NSTEACS on admission. Thirty-five clinical and electrocardiographic variables at presentation in the emergency room of 18 hospitals were prospectively analyzed in 4,115 patients with NSTEACS and related with the outcomes at 90 days. We also developed a risk score using the variables found to be independent predictors of ischemic events to facilitate risk stratification. Cardiovascular mortality was 4.3% and the rate for the outcome of either cardiovascular death or nonfatal myocardial infarction was 6.9%. The only independent predictors of mortality were age, diabetes, peripheral vascular disease, postinfarction angina, Killip class > or = 2, ST-segment depression, and elevation of cardiac markers. A risk profile using the variables found to be independent predictors of events was calculated for cardiovascular mortality and for the combination of either death or nonfatal myocardial infarction. Event rates increased significantly in all subgroups of patients based on the number of independent risk factors as the risk score increased. Using these factors, 90-day mortality ranged from as low as 0.4% in patients with no risk factors to 21.1% for those with more than 4 risk factors. In conclusion, simple clinical and electrocardiographic data obtained at hospital admission allow an accurate risk stratification of patients with NSTEACS. In the PEPA registry, simple variables easy to obtain at admission appear to be a valuable tool in discerning between patients at very low and very high risk according to the cluster of factors for each patient. The risk score developed was obtained from an unselected population, representative of the whole spectrum of patients with NSTEACS, allowing identification of patients at different risks for adverse outcomes, and, therefore, permitting optimization of therapy.

Benefit of clopidogrel in patients with acute coronary syndromes without ST-segment elevation in various risk groups

BACKGROUND

The Clopidogrel in Unstable angina to prevent Recurrent Events (CURE) trial demonstrated that clopidogrel, given early and continued long term, was superior to placebo in patients with non-ST-elevation acute coronary syndromes receiving aspirin. The purpose of the present analysis was to estimate the treatment effect Zof clopidogrel in patients who were stratified according to their risk of future cardiovascular events.

METHODS AND RESULTS

Patients (n=12 562) who presented within 24 hours after the onset of symptoms were randomized to receive clopidogrel (300 mg followed by 75 mg daily) or placebo in addition to aspirin for 3 to 12 months. Treatment effect was analyzed in various risk groups according to the Thrombolysis in Myocardial Infarction (TIMI) risk score. The TIMI risk model was validated in the CURE population (C statistic, 0.634). The primary composite outcome of cardiovascular death, myocardial infarction, or stroke increased proportionally with increasing risk according to the TIMI risk score. The impact of clopidogrel versus placebo on the rate of the primary outcome was as follows: low-risk group (TIMI score 0 to 2), 4.1% versus 5.7% (relative risk [RR], 0.71; 95% confidence interval [CI], 0.52 to 0.97; P< 0.04), intermediate-risk group (TIMI score 3 to 4), 9.8% versus 11.4% (RR, 0.85; 95% CI, 0.74 to 0.98; P<0.03), and high-risk group (TIMI score 5 to 7), 15.9% versus 20.7% (RR, 0.73; 95% CI, 0.60 to 0.90; P<0.004). There was no evidence of statistical heterogeneity among the groups.

CONCLUSIONS

The benefit of clopidogrel demonstrated in the CURE trial is consistent in low-, intermediate-, and high-risk patients with acute coronary syndromes (as stratified by TIMI risk score), thus supporting its use in all patients with documented non-ST elevation acute coronary syndromes.

Prognosis in the thrombolysis in myocardial ischemia III registry according to the Braunwald unstable angina pectoris classification

The unstable angina pectoris (UAP) classification proposed by Braunwald in 1989, although often used, has never been validated in a large, prospective multicenter study in which all subgroups of patients were included. Patients with UAP or non-ST-elevation myocardial infarction (NSTEMI) were enrolled in the Thrombolysis In Myocardial Ischemia III Registry and classified according to the Braunwald classification for UAP. Clinical end points were compared at 6 weeks and 1 year. Of 3,318 patients, those with primary UAP had lower rates of recurrent myocardial infarction (MI) or death when compared with patients with secondary UAP and post-MI UAP at 6 weeks (4.1% vs 6.4% vs 13.4%, respectively; p <0.001) and 1 year (9.7% vs 16.7% vs 19.7%; p <0.001). Recurrent ischemia at 6 weeks followed the same gradient (13.2% vs 18.5% vs 20.8%; p <0.001). Patients with secondary UAP had similar extent of disease at angiography as primary UAP. Patients with nonresting UAP had lower rates of death or MI than patients with UAP at rest (3.0% vs 5.6%, p = 0.011 at 6 weeks, and 8.2% vs 12.5%, p = 0.004 at 1 year). Patients with ST-segment deviation and those who had received prior antianginal medical treatment also had worse outcomes. Thus, the Braunwald classification of UAP predicts prognosis with secondary UAP, post-MI UAP, and patients with pain at rest who have a higher risk for death or recurrent cardiac events. Given their high risk for adverse events, patients with secondary UAP should be treated aggressively.

Release of cardiac troponin I after temporally graded acute coronary ischaemia with electrocardiographic ST depression

BACKGROUND

Elevation of cardiac biochemical markers and ST segment depression in the electrocardiogram have important roles in the risk stratification of unstable coronary syndromes. We assessed graded duration of acute coronary ischaemia with ST depression versus release of cardiac troponin I (cTnI) and conventional cardiac markers in 15 ischaemic pigs and 11 controls.

METHODS

Coronary ischaemia was induced via percutaneous technique by semiinflating an angioplasty balloon in the left circumflex artery. Blood velocity monitored by Doppler was reduced until ST depression > or =0.1 mV was obtained. Among 26 pigs, six controls had jugular vein sheath introduced only, five controls jugular vein and bilateral femoral sheaths, and 15 pigs were divided into three equal groups (n=5) in which ischaemia was maintained for 10, 20 and 30 min, respectively.

RESULTS

Mean blood flow velocity (cm/s) at baseline was 16.3+/-6.5 and was reduced to 4.1+/-3.2 (25% of normal, range 20-29%) during ischaemia. cTnI (microg/l) did not increase in controls but increased from 0.05 to 0.52 (P<0.05) and 0.76 (P<0.05) with 10 and 20 min of ischaemia, and to 30.77 (P<0.05) with 30 min of ischaemia. A rise of myoglobin and conventional cardiac enzymes did not distinguish controls with arterial cut-down from the ischaemia groups.

CONCLUSION

Release of cTnI depends on the duration of ST depression ischaemia. The critical time for a major release seems to be between 20 and 30 min. Thus, very early intervention in patients with prolonged ST depression ischemia should be focused on in future clinical trials.

Changing the diagnostic criteria for myocardial infarction in patients with a suspected heart attack affects the measurement of 30 day mortality but not long term survival

OBJECTIVES

To explore the effects of alternative methods of defining myocardial infarction on the numbers and survival patterns of patients identified as having sustained a confirmed myocardial infarct.

DESIGN

An inclusive historical cohort of patients admitted with a suspected heart attack. Patients were recoded from raw clinical data (collected at the index admission) to the epidemiological definitions of myocardial infarction used by the Nottingham heart attack register (NHAR), the World Health Organization (MONICA), and the UK heart attack study.

SETTING

Single health district.

PATIENTS

The NHAR identified all patients admitted in 1992 with suspected myocardial infarction.

OUTCOME MEASURES

Survival at 30 days and four year postdischarge.

RESULTS

2739 patients were identified, of whom 90% survived to discharge. Recoding increased the numbers of patients defined as having confirmed myocardial infarction from 26% under the original NHAR classification to 69%, depending on the classification system used. In confirmed myocardial infarction, subsequent 30 day survival from admission varied from 77-86% depending on the classification system; four year survival after discharge was not affected. The distribution of important prognostic variables differed significantly between groups of patients with confirmed myocardial infarction defined by different systems. Patients with suspected but unconfirmed myocardial infarction under all classification systems had a worse postdischarge mortality.

CONCLUSIONS

The classification system used had a substantial effect on the numbers of patients identified as having had a myocardial infarct, and on the 30 day survival. There were significant numbers of patients with more atypical presentations, not labelled as myocardial infarction, who did badly following discharge. More research is needed on these patients.

[Prognostic factors in unstable angina with dynamic electrocardiographic changes. Value of fibrinogen]

INTRODUCTION AND OBJECTIVES

The prognosis of unstable angina varies between series depending on the inclusion criteria and management protocol used. The aim of this study was to analyze in-hospital events and their predictors in a homogeneous single-center series of patients with unstable angina.

MATERIAL AND METHODS

A total of 246 patients with the following inclusion criteria were studied: 1) resting anginal pain, 2) transient electrocardiographic changes during anginal pain, 3) normal CK-MB levels and 4) exclusion of postinfarction angina. All patients were treated with aspirin and enoxaparin (1 mg/kg/12 h). Coronary angiography was performed in the case of recurrent angina or ischemia in Bruce I-II stage during the predischarge effort stress test. The variables recorded were risk factors, history of ischemic heart disease, history of coronary surgery, ECG upon admission, and fibrinogen.

RESULTS

During the hospital stay the following events were recorded: 36% recurrent angina, 58% cardiac catheterization, and 5,7% major events (infarction or death). Multivariate analysis found recurrent angina to be more frequent in patients with a history of coronary bypass surgery (p = 0.004. OR = 22; CI 95%, 3-182), ST-segment changes (p = 0.01. OR = 4.7, CI 95%; 1.4-15.9) and higher fibrinogen (p = 0.002. OR = 1,4, CI 95%; 1.1-1.7). Fibrinogen was the only variable related to cardiac catheterization (p = 0,009. OR = 1.3. CI 95%, 1.1-1.6) and major events (p = 0.001. OR = 2.0. CI 95%, 1.4-3.1).

CONCLUSIONS

1) Unstable angina with electrocardiographic changes was associated to a high rate of in-hospital events. 2) Fibrinogen was related to any event, and previous by-pass surgery and ST changes were related to recurrent angina.

[Prognostic value of fibrinogen in patients admitted with suspected unstable angina and non-q-wave myocardial infarction]

INTRODUCTION AND OBJECTIVE

In recent years, the relation between biological markers of inflammation and prognosis in patients suffering from acute coronary syndromes has been investigated. The aim of this study was to evaluate the association between baseline fibrinogen concentrations and the development of clinical events in patients admitted with suspicion of unstable angina and non-Q-wave myocardial infarction.

MATERIAL AND METHOD

Levels of fibrinogen at enrollment were analyzed in 325 consecutive patients with acute coronary syndromes. Fibrinogen values were divided into tertiles and the incidence of clinical events was evaluated at each level. The combination of death and/or myocardial infarction was the main endpoint.

RESULTS

Fibrinogen levels were significantly higher in patients who subsequently had myocardial infarction, cardiac death, or both during follow up. The probabilities of death and/or myocardial infarction were 6%, 13%, and 29% (p < 0.0001), respectively, in patients grouped by fibrinogen tertiles (304, 305-374 and 375 mg/dl). Multivariate predictors of combined events were age, previous angina, ST-segment depression in the admission ECG, and fibrinogen into tertiles. The adjusted hazard ratio (95% CI) for patients in the upper tertile was 4.8 (1.6-14; p = 0.004).

CONCLUSIONS

High fibrinogen levels were related to a less favorable long-term or short-term outcome in patients admitted for suspicion of unstable angina and non-Q-wave myocardial infarction. This association persists after adjustment for other classical risk factors such as age, prior angina, and ST-segment depression in the ECG.

[2002 Update of the Guidelines of the Spanish Society of Cardiology for Unstable Angina/Without ST-Segment Elevation Myocardial Infarction]

Since the Spanish Society of Cardiology Clinical Practice Guidelines on Unstable Angina/Non-Q-Wave Myocardial Infarction were released in 1999, the conclusions of several studies that have been published make it advisable to update current clinical recommendations. The main findings are related to the developing role of Chest Pain Units in the management and early risk stratification of acute coronary syndromes in the emergency department; new information concerning the efficacy of glycoprotein IIb/IIIa inhibitors, clopidogrel and low-molecular-weight heparins in the pharmacological treatment of acute coronary syndromes without ST-segment elevation; and the role of early invasive strategy in improving the prognosis of these patients. The published evidence is reviewed and the corresponding clinical recommendations for the management of acute coronary syndromes without persistent ST-segment elevation are updated.

Critical pathways for management of patients with acute coronary syndromes: an assessment by the National Heart Attack Alert Program

BACKGROUND

The use of critical pathways for a variety of clinical conditions has grown rapidly in recent years, particularly pathways for patients with acute coronary syndromes (ACS). However, no systematic review exists regarding the value of critical pathways in this setting.

METHODS

The National Heart Attack Alert Program established a Working Group to review the utility of critical pathways on quality of care and outcomes for patients with ACS. A literature search of MEDLINE, cardiology textbooks, and cited references in any article identified was conducted regarding the use of critical pathways for patients with ACS.

RESULTS

Several areas for improving the care of patients with ACS through the application of critical pathways were identified: increasing the use of guideline-recommended medications, targeting use of cardiac procedures and other cardiac testing, and reducing the length of stay in hospitals and intensive care units. Initial studies have shown promising results in improving quality of care and reducing costs. No large studies designed to demonstrate an improvement in mortality or morbidity were identified in this literature review.

CONCLUSIONS

Critical pathways offer the potential to improve the care of patients with ACS while reducing the cost of care. Their use should improve the process and cost-effectiveness of care, but further research in this field is needed to determine whether these changes in the process of care will translate into improved clinical outcomes.

The prognostic and therapeutic implications of increased troponin T levels and ST depression in unstable coronary artery disease: the FRISC II invasive troponin T electrocardiogram substudy

BACKGROUND

In unstable coronary artery disease, both increased troponin T level and occurrence of ST-segment depression are associated with a worse prognosis. In the Fast Revascularisation in InStability in Coronary disease trial II invasive study, we evaluated whether the troponin T level, alone and combined with ST depression, identified more severe coronary artery disease or a greater efficacy of an early invasive strategy.

METHODS

In the study, 2457 patients with unstable coronary artery disease were randomized to early invasive or noninvasive strategy. Troponin T value and admission electrocardiogram results were available in 2286 patients.

RESULTS

In the noninvasive cohort, death or myocardial infarction occurred in 16.6% with troponin T level > or =0.03 microg/L versus 8.5% with troponin T level < 0.03 microg/L (P <.001). In the invasive group, 49% of patients with both ST depression and troponin T level > or =0.03 microg/L had 3-vessel or left main disease compared with 17% if neither finding was present (P <.001). The invasive strategy reduced death/myocardial infarction at 12 months in the cohort with both ST depression and troponin T level > or =0.03 microg/L from 22.1% to 13.2% (risk ratio, 0.60; 95% confidence interval, 0.43 to 0.82; P =.001). In the cohort with either ST depression or troponin T level > or =0.03 microg/L or neither of these findings, the absolute gain of the invasive strategy was smaller and more uncertain.

CONCLUSION

Patients with unstable coronary artery disease with the combination of troponin T level > or =0.03 microg/L and ST depression have a poor prognosis and, in half of the cases, 3-vessel or left main disease. In these patients, an early invasive strategy will substantially reduce death/myocardial infarction.

Interventional therapy of the acute coronary syndromes

The acute coronary syndromes (ACS) have in common rupture of a vulnerable plaque, leading to exposure of the subendothelial surface and plaque core. The resultant thrombosis leads to a variable degree of flow occlusion, the extent of which differentiates the three syndromes and their treatment by percutaneous coronary intervention (PCI). The guiding principle in the decision when to use PCI in the ACS is that the more time critical and high risk the clinical situation, the more likely it is that PCI will improve ultimate outcome. The use of risk stratification by clinical variables can lead to better triage of patients with non-ST-elevation myocardial infarction (MI) and unstable angina between PCI and medical management. Patients presenting with symptoms suggestive of prolonged ischemia should have an electrocardiogram searching for ST changes, a targeted physical, and blood drawn for rapid assay of cardiac enzymes. In the event that ST elevations suggest infarction, while medical therapy is initiated, emergency cardiac catheterization can be organized. PCI in ACS requires adjunctive antiplatelet and antithrombin therapy, and, in general, coronary stenting is advisable. Among patients with non-ST-elevation MI or unstable angina who can be medically stabilized, the presence of high clinical risk scores would favor early coronary angiography. In their absence, medical therapy can be pursued, unless recurrent ischemia occurs. When the patient's condition is stable, evaluation by stress testing can be used to guide further decisions.

The reperfusion era. Strategies for establishing or maintaining coronary patency

Only 3 decades ago, controversy existed over the origin of the thrombus that occluded coronary arteries during myocardial infarction (MI). Then, the acute clinical angiographic studies of DeWood butterssed new pathological and experimental evidence that the thrombus was the proximate cause of MI and unstable angina. The remaining years of the 20th century saw an explosion of knowledge delineating a spectrum of related disorders now collectively called acute coronary syndromes (ACS). The clinician managing patients is confronted with an array of evidence as more than 75,000 patients worldwide have been randomized to clinical trials in ACS. This article reviews key pathophysiological concepts, presents an initial strategy for triage of patients, and summarizes evidence-based medicine guiding therapy for acute coronary lesions.

"Hot" unstable angina--is it worse than subacute unstable angina? Results from the GUARANTEE Registry

BACKGROUND AND METHODS

Because time to presentation to the hospital affects time to treatment and is known to be important in acute myocardial infarction, we evaluated this variable in patients with unstable angina/non-ST segment elevation myocardial infarction (UA/NSTEMI). Among 2909 consecutive patients with UA/NSTEMI admitted to 35 hospitals in 6 geographic regions of the United States, we compared patients with acute (onset of pain <12 hours before admission) and subacute (onset >12 hours) unstable angina.

RESULTS

Patients with "hot" (acute) unstable angina presented more often to the emergency department and were subsequently admitted more often to an intensive care unit. Hospital administration of medications did not differ between the two groups, with the exception of heparin, which was paradoxically used more often in subacute patients (p<0.001). All cardiac invasive procedures were undertaken less often in the acute patients (catheterization, 41.4% vs. 58.7%, p=0.001; percutaneous coronary intervention, 11.3% vs. 21.1%, p=0.001; coronary artery bypass grafting, 5.6% vs. 12.0%, p=0.001). A greater percentage of acute patients were found to have no significant coronary artery disease at cardiac catheterization (20.1% vs. 15.0%, p=0.006). Mortality did not differ between the two groups; however, the composite endpoint of death and MI favored the acute patients (1.3% vs. 2.2%, p=0.032).

CONCLUSIONS

Contrary to our initial hypothesis, "hot" UA patients tended to be at lower risk than patients with subacute presentation, highlighting the fact that patients with UA/NSTEMI remain at high risk even after the initial 12-hour period.

Enoxaparin in unstable angina/non-ST-segment elevation myocardial infarction: treatment benefits in prespecified subgroups

BACKGROUND

Two large-scale phase III clinical trials, the Efficacy and Safety of Subcutaneous Enoxaparin in Non-Q-wave Coronary Events (ESSENCE) trial and the Thrombolysis in Myocardial Infarction (TIMI) 11B study, have shown the low-molecular-weight heparin, enoxaparin, to be more effective than unfractionated heparin (UFH) in reducing the risk of death and severe cardiac events in patients with rest unstable angina and/or non-ST-segment elevation myocardial infarction (NSTEMI). However, patients with NSTEMI acute coronary syndromes are a heterogeneous group.

METHODS

A meta-analysis using pooled data from ESSENCE and TIMI 11B was performed to examine the efficacy of enoxaparin in different patient subgroups. In addition, a statistical model was developed to test which factors best predicted an enhanced treatment effect.

RESULTS

Enoxaparin was more effective than intravenous dose-adjusted UFH in reducing the incidence of the composite endpoint (including death, myocardial infarction or recurrent angina prompting urgent revascularization) in the majority of subgroups at 43 days after randomization. Univariate analyses revealed that there was a greater benefit with enoxaparin in patients with ST-segment deviation or elevated cardiac enzyme markers on admission, women, nonsmokers and patients with characteristics indicative of higher cardiac risk, including prior percutaneous coronary interventions, being at least 65 years old, prior angina and prior aspirin use. Multivariate statistical modelling of treatment effect revealed that ST-segment depression and electrocardiographic changes were the best predictors of an enhanced treatment effect.

CONCLUSIONS

These data reinforce previous evidence suggesting that enoxaparin administered subcutaneously twice daily may be considered as an alternative to intravenous UFH in the acute treatment of a broad range of patients with unstable coronary artery disease.

Early coronary angiography improves long-term survival in unstable angina

BACKGROUND

The role of early coronary angiography in the evaluation of patients with unstable angina has been controversial. This study was designed to determine the effect of early coronary angiography on long-term survival in patients with unstable angina.

METHODS

We reviewed the Olmsted County Acute Chest Pain Database, a population-based epidemiologic registry that includes all patients residing within Olmsted County who were seen for emergency department evaluation of acute chest pain from 1985 to 1992. Patients with symptoms consistent with myocardial ischemia qualifying as unstable angina were classified as undergoing early (</=7 days of index presentation) angiography or not.

RESULTS

A total of 2264 patients with symptoms consistent with unstable angina were identified with a mean duration of follow-up of 6 years; 892 underwent early angiography. Early angiography patients were younger; less likely to have heart failure; more likely to be male, hypercholesterolemic, and smokers; had prior coronary revascularization; and had a myocardial infarction at the index presentation. After baseline differences were controlled, early angiography was associated with a reduction in all-cause long-term mortality (relative risk 0.63, 95% CI 0.53-0.74). Patients at intermediate or high risk for death or myocardial infarction at presentation were most likely to benefit from early angiography.

CONCLUSION

Early angiography in the evaluation of patients with unstable angina was associated with a reduction in all-cause mortality, particularly in intermediate- and high-risk patients, in this retrospective population-based study.

2000 ACC/AHA guidelines for the management of patients with unstable angina and non-ST-segment elevation myocardial infarction: a practical summary for emergency physicians

There have been numerous significant clinical advances in both the diagnosis and therapy of acute coronary syndrome during the past several years. Even the term "acute coronary syndrome" is a recent creation meant to expand clinical attention in patients with chest pain of coronary origin beyond identification of ST-segment elevation myocardial infarction and prompt initiation of reperfusion therapy and to include the evaluation and management of those patients with unstable angina (UA) or myocardial injury that does not cause ST-segment elevation. Many of these advances have been studied and first implemented outside the emergency department, leading some emergency physicians to be slow to embrace them, and leaving others without a viable practical option to use them outside of the cardiac catheterization laboratory or the coronary care unit. In September 2000, the American College of Cardiology and the American Heart Association issued practice guidelines for the care of patients with UA and non-ST-segment elevation myocardial infarction. The guidelines specifically address the diagnosis and management of UA and non-ST-segment elevation myocardial infarction in the ED, suggesting evidence-based standards for risk stratification, for the use of biologic markers of myocardial damage and other adjunctive diagnostic tests, and for the appropriate use of antiplatelet and antithrombin therapeutic agents. This article provides an overview of the ED-pertinent analyses and recommendations from the 93-page document. A commentary on the implementation of these recommendations in the ED follows in a separate article.

A risk score system for predicting adverse outcomes and magnitude of benefit with glycoprotein IIb/IIIa inhibitor therapy in patients with unstable angina pectoris

Clinical outcomes of patients with unstable angina are variable. We sought to identify predictors of adverse clinical outcomes in patients with unstable angina and to investigate whether these factors would predict the magnitude of benefit achieved with platelet glycoprotein IIb/IIIa inhibition. We analyzed 20 variables in the 1,915 patients enrolled in the Platelet Receptor Inhibition for Ischemic Syndrome Management in Patients Limited by Unstable Signs and Symptoms trial. Five independent predictors were identified: age >65 years, prior coronary artery bypass grafting, antecedent aspirin use, antecedent beta-blocker use, and ST depressions on the presenting electrocardiogram. A risk score system was created using these predictors in which patients were assigned 1 point for the presence of each risk factor. There was a progressive increase in the rate of the composite end point of death, myocardial infarction, or refractory ischemia at 7 days with an increasing number of risk factors. For patients treated with heparin alone, the composite end point event rate was 6.5% in the group with 0 or 1 predictor, 14.6% in the group with 2 predictors, 22.7% in the group with 3 predictors, and 37.1% in the group with 4 or 5 predictors (p <0.00001). When dividing patients into low- (0 or 1 point), medium- (2 or 3 points), and high-risk (4 or 5 points) groups, the addition of tirofiban to heparin therapy was associated with no significant benefit in the low-risk group, a 5.2% absolute reduction in the medium-risk group (p = 0.05), and a 16% absolute reduction in the high-risk group (p = 0.0055). Thus, we have developed a risk score system using 5 variables that can be used to identify patients at high risk for death and cardiac ischemic events and who experience the greatest benefit from the addition of a glycoprotein IIb/IIIa inhibitor to their treatment regimen.

The A-to-Z Trial: Methods and rationale for a single trial investigating combined use of low-molecular-weight heparin with the glycoprotein IIb/IIIa inhibitor tirofiban and defining the efficacy of early aggressive simvastatin therapy

BACKGROUND

The A-to-Z Trial is an ongoing international, multicenter, randomized study designed to investigate 2 issues concerning contemporary care of patients with acute coronary syndromes (ACS). The first issue is whether the use of low-molecular-weight heparin versus unfractionated heparin affects outcomes and safety when used as a therapy adjunctive to baseline treatment with tirofiban and aspirin in patients with non-ST-elevation (nSTE) ACS. The second issue is whether early use of an aggressively dosed statin is superior to a current trial-based "accepted care" regimen of a lower-dose statin started 3 to 6 months after an acute event.

METHODS

The study is conceptually and functionally divided into 2 sequential parts-the "A" Aggrastat and "Z" Zocar phases. The primary A-phase end point is a composite of all-cause mortality, myocardial infarction (MI), and documented refractory ischemia at 7 days. Both nSTE-ACS patients from the A phase and patients with ST-elevation ACS who meet specific risk criteria are eligible to enter the subsequent "Z" (Zocor) chronic phase (Z phase). The primary end point of the Z phase is a composite of cardiovascular death, MI, readmission for ACS, and stroke. The trial will continue until 970 primary events have occurred in the Z-phase population.

CONCLUSION

This trial is evaluating 2 temporally connected sequences of phamacotherapy for ACS. At completion, trial results will provide definitive evidence regarding efficacy and safety of early, intensive statin therapy and better define the role of low-molecular-weight heparin in patients with nSTE ACS.

Risk stratification in non-ST segment elevation acute coronary syndromes with special focus on recent guidelines

Patients with unstable angina or non-ST segment elevation (non-Q-wave) myocardial infarction are a heterogeneous group with respect to their risk of developing clinically significant adverse events such as subsequent myocardial infarction and death. Recent guidelines promote risk stratification of these patients, targeting high-risk patients for maximal antithrombotic and antiischemic therapy and low-risk patients for early discharge. We reviewed current and future modalities for risk stratification of patients and the predictive value of these methods in context with available pharmacologic agents. Unfortunately, most of the data identifying a particular pharmacologic regimen as beneficial in high-risk patients are retrospectively derived from large trials. Until prospective studies that use markers to guide therapy are available, clinicians should be familiar with the use of these risk markers and their application to the role of a given management strategy, including pharmacologic therapy.

Prognostic value of ST segment depression in acute coronary syndromes: insights from PARAGON-A applied to GUSTO-IIb. PARAGON-A and GUSTO IIb Investigators. Platelet IIb/IIIa Antagonism for the Reduction of Acute Global Organization Network

OBJECTIVES

Our objectives were to develop a risk-stratification model addressing the importance of the magnitude and distribution of ST segment depression in predicting long-term outcomes and to validate the model in an analogous patient population.

BACKGROUND

Although patients without ST segment elevation presenting with acute coronary syndromes represent an increasingly frequent population admitted to coronary care units, little attention has been paid to quantifying their ST segment abnormalities.

METHODS

ST segment depression was categorized into three groups: 1) no ST segment depression; 2) 1-mm ST segment depression in two contiguous leads; and 3) ST segment depression > or =2 mm in two contiguous leads. A logistic regression model was developed using Platelet IIb/IIIa Antagonism for the Reduction of Acute coronary syndrome events in a Global Organization Network (PARAGON-A) data to assess the prognostic value of the extent and distribution of ST segment depression in predicting one-year mortality. The model was validated using the non-ST segment elevation population in Global Use of Strategies To Open occluded arteries in acute coronary syndromes (GUSTO-IIb).

RESULTS

ST segment depression was the strongest predictor of one-year mortality, accounting for 35% of the model's predictive power. Patients with ST segment depression > or =2 mm were approximately 6 times (odds ratio [OR] 5.73, 95% confidence interval [CI] 2.8 to 11.6) more likely to die within one year than patients with no ST segment depression. On validation, the model showed good discriminatory power (c-index = 0.75). Patients with ST segment depression > or =2 mm in more than one region were almost 10 times more likely to die within one year than patients with no ST segment depression.

CONCLUSIONS

These data provide new evidence supporting the powerful prognostic value of the baseline electrocardiogram and, in particular, the magnitude and distribution of ST segment depression in predicting unfavorable events.

Is early invasive treatment of unstable coronary artery disease equally effective for both women and men? FRISC II Study Group Investigators

BACKGROUND

The Fragmin and fast Revascularization during InStability in Coronary artery disease (FRISC II) trial compared the effectiveness of an early invasive versus a noninvasive strategy in terms of the incidence of death and myocardial infarction (MI) in patients with unstable coronary artery disease (CAD).

OBJECTIVES

In this subanalysis, we sought to evaluate gender differences in the effect of these different strategies.

METHODS

The patients (749 women and 1,708 men) were randomized to early invasive or noninvasive strategies. Coronary angiography was performed within the first 7 days in 96% and 10% of the invasive and noninvasive groups, respectively, and revascularization was performed within the first 10 days in 71% and 9% of the invasive and noninvasive groups, respectively.

RESULTS

Women presenting with unstable CAD were older, but fewer had previous infarctions, left ventricular dysfunction and elevated troponin T levels. Women had fewer angiographic changes. There was no difference in MI or death at 12 months among women in the invasive and noninvasive groups (12.4% vs. 10.5%, respectively), in contrast to the favorable effect in the invasively treated group of men (9.6% vs. 15.8%, p < 0.001). In an interaction analysis, there was a different effect of the early invasive strategy for the two genders (p = 0.008).

CONCLUSIONS

Women with symptoms and/or signs of unstable CAD are older, but still have less severe CAD and a better prognosis compared with men. In contrast to its beneficial effect in men, an early invasive strategy did not reduce the risk of future events among women. Further research is warranted to identify the most appropriate treatment strategy in women with unstable CAD.

Can myocardial infarction be rapidly identified in emergency department patients who have left bundle-branch block?

STUDY OBJECTIVES

Fibrinolytic therapy is recommended for patients who have chest pain and left bundle-branch block (LBBB). However, the presence of baseline ECG abnormalities makes early accurate identification of acute myocardial infarction (AMI) difficult. The predictive ability of clinical and ECG variables for identifying patients with LBBB and AMI has not been well studied. We sought to determine the prevalence and predictors of myocardial infarction among patients presenting to the emergency department with LBBB on the initial ECG who were evaluated for myocardial infarction.

METHODS

All patients presenting to the ED were prospectively risk stratified on the basis of clinical and historical variables. ECGs from patients with LBBB were compared retrospectively with previously published criteria for identification of AMI. The ability of a new LBBB to predict AMI was also determined.

RESULTS

Twenty-four (13%) of the 182 patients with LBBB had AMI. Clinical and historical variables were similar in patients with and without AMI. A new LBBB had a sensitivity of 42% and a specificity of 65%. The presence of concordant ST-segment elevation or depression had specificities and positive predictive values of 100%; however, sensitivities were only 8% and 17%, respectively. The best diagnostic criterion was the presence of concordant ST-segment elevation or depression on the ECG or an initially elevated creatine kinase MB (sensitivity, 63%; specificity, 99%).

CONCLUSION

ECG criteria for identifying patients with AMI and LBBB identify only a small minority of patients with AMI. Treating all patients with LBBB and chest pain with fibrinolytics would result in treatment of a significant number of patients without AMI.

[Prognostic value of cardiac perfusion scintigraphy associated with the dobutamine test in acute coronary syndromes]

OBJECTIVES

This study aimed to establish the value of myocardial ischemia induced by the dobutamine infusion test associated to 99m technetium isonitrile single photon emission computed tomography in patients with unstable angina or non Q-wave infarction during the first days in the Coronary Care Unit.

METHODS

Fifty three patients with unstable coronary syndromes and common medical treatment were studied with a moderate-dose dobutamine test (5 to 20 microgram/Kg/min) using a 99mTc-MIBI SPECT. The results were correlated with the incidence of recurrent angina, infarction, death or revascularization.

RESULTS

The dobutamine test induced a reversible perfusion defect in 36 patients (68%) and angina in 12 of them (12/36, 33%). However, the patients who had a positive test had a similar incidence of events as those with a negative test (58% vs 59%). Thus, while the sensitivity of the dobutamine test to identify patients at risk was relatively high (68%), its specificity (32%) and its negative predictive value (41%) were low. The patients with dobutamine-induced angina, however, had a higher scintigraphy score (3.0 +/- 1,7 vs 1.6 +/- 1.8, p < 0.02) and a higher incidence of recurrent angina (8/12, 67% vs 13/41, 31%, p < 0.04) than those without, at a comparable double product.

CONCLUSIONS

In conventionally treated patients with unstable coronary syndromes, the specificity of the inducible scintigraphic ischemia with moderate dose of dobutamine performed during the first days is too low to be used as a marker for in-hospital events. However, inducible angina with dobutamine suggests an extensive jeopardized area and/or a particularly reduced ischemic threshold.

An ischemia-guided approach for risk stratification in patients with acute coronary syndromes

The optimal management approach for patients with non-ST-segment elevation acute coronary syndromes continues to be an issue of debate. An ischemia-guided strategy appears to be effective as an alternative to either a very conservative "wait-and-see" approach or a very aggressive routine revascularization approach. The need for another approach is supported by the lack of conclusive evidence-based results favoring an early routine invasive treatment strategy. In the Thrombolysis in Myocardial Infarction (TIMI) IIIB trial, there were no differences in the incidence of death or myocardial infarction (MI) between patients treated with an early invasive approach and those treated with a conservative approach to treatment. Significantly worse outcomes were shown in patients assigned to an early invasive strategy in the Veterans Affairs Non-Q-Wave Infarction Strategies in Hospital (VANQWISH) trial at 1-year follow-up (111 clinical events in the invasive group vs 85 in the conservative group; p = 0.05). Registry information, including that from the Organization to Assess Strategies for Ischemic Syndromes (OASIS), which included approximately 8,000 patients with unstable angina or suspected MI, has even suggested an excess hazard with a routine invasive approach. Patients with non-ST-segment elevation MI observed in the Global Use of Strategies to Open Occluded Coronary Arteries in Acute Coronary Syndromes (GUSTO)-IIB and Platelet IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy (PURSUIT) trials also fared better with an ischemia-guided strategy. Even the recent FRagmin and Fast Revascularization during InStability in Coronary artery disease (FRISC II) trial investigators had to be very selective relative to eliminating high-risk patients in the first week and treating with intense anti-ischemic therapy and 5-7 days of low-molecular-weight heparin therapy to show an advantage for assigned revascularization. A careful clinical evaluation with attention to early risk stratification is essential in the ischemia-guided approach. The Braunwald classification for unstable angina helps identify independent clinical predictors of a poor outcome; high risk is clearly associated with Braunwald class III and type C. Electrocardiographic and biochemical markers for myocardial necrosis (cardiac troponin T or I) are important tools for assessing the presence and degree of ischemia and associated risk for adverse outcome. Noninvasive evaluation of left ventricular ejection fraction is essential for identifying those at high risk due to impaired contractile function. When these conventional markers do not provide conclusive information, noninvasive stress testing is most helpful to further identify those at highest risk for revascularization.

Medical treatment for acute coronary syndromes

The medical treatment of acute coronary syndromes with thrombolytic, antithrombin, and antiplatelet agents is a major area of research and a vast topic for clinical review. This review summarizes important recent findings on the background of existing pathological and clinical knowledge to provide an understanding of the basis of current therapy and the new therapies that are likely to be introduced in the near future. Current controversies regarding the management of these conditions and the choice between medical, interventional, and combined strategies in different situations are also discussed.

Clinical and therapeutic profile of patients presenting with acute coronary syndromes who do not have significant coronary artery disease.The Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy (PURSUIT) Trial Investigators

BACKGROUND

A proportion of patients who present with suspected acute coronary syndrome (ACS) are found to have insignificant coronary artery disease (CAD) during coronary angiography, but these patients have not been well characterized.

METHODS AND RESULTS

Of the 5767 patients with non-ST-segment elevation ACS who were enrolled in the Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin (Eptifibatide) Therapy (PURSUIT) trial and who underwent in-hospital angiography, 88% had significant CAD (any stenosis >50%), 6% had mild CAD (any stenosis >0% to </=50%), and 6% had no CAD (no stenosis identified). The frequency of death or nonfatal myocardial infarction at 30 days was reduced with eptifibatide treatment in patients with significant CAD (18.3% versus 15.6% for placebo, P=0.006) but not in those with mild CAD (6.6% versus 5.4%, P=0.62) and with no CAD (3.0% versus 1. 2%, P=0.28). We identified independent baseline predictors of insignificant CAD (mild or no CAD) and used them to develop a simple predictive nomogram of the probability of insignificant CAD for use at hospital presentation. This nomogram was validated in a separate population of patients with non-ST-segment elevation ACS.

CONCLUSIONS

Patients with suspected ACS found to have insignificant CAD have a low risk of adverse outcomes, do not appear to benefit from treatment with eptifibatide, and can be predicted with a simple nomogram drawn from baseline characteristics. Because patients with significant CAD appear to have an enhanced benefit from eptifibatide treatment, the predictive nomogram developed can be used to determine indications for glycoprotein IIb/IIIa blockade.

Treatment and outcomes of left bundle-branch block patients with myocardial infarction who present without chest pain. National Registry of Myocardial Infarction 2 Investigators

OBJECTIVES

We sought to determine the importance of chest pain on presentation as a predictor of in-hospital treatment and mortality in myocardial infarction (MI) patients with left bundle-branch block (LBBB).

BACKGROUND

Left bundle-branch block patients have a high mortality after MI but are unlikely to receive reperfusion therapy despite evidence from clinical trials demonstrating the efficacy of thrombolytic therapy. Nearly half of MI patients with LBBB present without chest pain.

METHODS

We studied the clinical features, treatment and in-hospital survival of 29,585 patients with LBBB enrolled in the National Registry of MI 2 June 1994 through March 1998). Multivariate logistic regression was used to assess the independent effect of chest pain on reperfusion decisions and in-hospital mortality.

RESULTS

Left bundle-branch block patients with chest pain were greater than five-fold more likely to receive reperfusion therapy (13.6% vs. 2.6%) than LBBB patients without chest pain; they were also more likely to receive aspirin, beta-adrenergic blocking agents, heparin and nitrates (all p < 0.0001). Unadjusted in-hospital mortality was 18% in patients with chest pain and 27% in patients without chest pain. Adjusting for patient characteristics reduced the odds ratio associated with the absence of chest pain from 1.47 (95% confidence interval: 1.41 to 1.54) to 1.21 (95% confidence interval: 1.12 to 1.30). The remainder of the mortality difference was caused by the undertreatment of patients without chest pain, particularly the low utilization of aspirin and beta-blockers.

CONCLUSIONS

Left bundle-branch block patients with MI who present without chest pain are less likely to receive optimal therapy and are at increased risk of death. Prompt recognition and treatment of this high-risk subgroup should improve survival.

Negative T waves shortly after ST-elevation acute myocardial infarction are a powerful marker for improved survival rate

BACKGROUND

Recent studies have reported that negative T waves in the setting of acute coronary events are associated with Thrombolysis In Myocardial Infarction flow grade 3 in the infarct-related artery and with improved parameters of ventricular function rather than with ischemia.

METHODS

Patients enrolled in the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) angiographic substudy (ie, patients with acute infarction randomly assigned to one of 4 thrombolytic regimens who then underwent coronary angiography) were included in this study if they survived at least 24 hours and had no confounding electrocardiographic factors (n = 1505).

RESULTS

More patients had negative T waves develop (NT group, n = 938 [62%]) than not (PT group, n = 567 [38%]). Peak creatine kinase MB, time to thrombolysis, and randomization to accelerated alteplase were no different between the groups. Thirty days after admission, 12 patients in the NT group had died versus 25 patients in the PT group (1.3% vs. 4.4%; P <.001; odds ratio for negative T waves 0.28; 95% confidence interval 0.14-0.56). The difference persisted when only patients who survived at least 3 days were analyzed. After adjusting for relevant covariates (including presence of new Q waves in the follow-up electrocardiogram), negative T waves were an independent predictor for survival (P =. 007; odds ratio for negative T waves 0.38; 95% confidence interval 0. 18-0.78). Patients in the NT group were 35% more likely to have achieved patency of the infarct-related artery, although this difference was not statistically significant.

CONCLUSIONS

Negative T waves shortly after acute myocardial infarction treated with thrombolysis were markers for improved 30-day survival rate. This finding merits prospective testing.

Usefulness of echocardiography in the prognostic evaluation of non-Q-wave myocardial infarction

Patients with non-Q-wave myocardial infarction (MI) are a heterogeneous population with a wide range of coronary disease severity and extent of myocardial necrosis, showing, therefore, different electrocardiographic findings and different outcomes. To evaluate the role of echocardiography in the management of non-Q-wave MI patients, 192 consecutive patients without previous MI were studied (78 with ST segment elevation, 56 with ST depression and 58 without ST modifications). All patients underwent 2-dimensional echocardiography (16-segment model) within 24 hours of admission to the coronary care unit. Wall-motion abnormalities, wall-motion score index, ejection fraction, and end-diastolic and end-systolic volumes were evaluated. In 35 patients, death, reinfarction, recurrent angina, or severe heart failure occurred during the in-hospital phase, whereas the remaining 157 patients had a good outcome. Patients with a poor prognosis were older (68 +/- 6 vs 59 +/- 5 years, p < 0.01), had a worse left-ventricular function (wall-motion score index 1.4 +/- 0.4 vs 1.25 +/- 0.3, p < 0.05; end-systolic volume 54 +/- 25 vs 38 +/- 12 mL/m2, p < 0.01; ejection fraction 50 +/- 10 vs 58 +/- 8%, p < 0.01), and presented more frequently with ST segment depression (49 vs 25%, p < 0.01). The positive and negative predictive values for early clinical events were, respectively: ST segment depression 0.30 and 0.87; wall-motion abnormalities in > 3 segments 0.28 and 0.86; wall-motion score index > 1.33 = 0.28 and 0.87; end-diastolic volume > 46 mL/m2 = 0.49 and 0.91; ST segment depression and wall-motion abnormalities in > 3 segments 0.60 and 0.88. These results underline the usefulness of echocardiography in the early risk stratification of non-Q-wave MI patients, together with electrocardiographic data. Patients with ST segment depression and more extensive wall-motion abnormalities are at higher risk and their management needs a more aggressive approach.

A classification of unstable angina revisited

Unstable angina is a critical phase of coronary heart disease with widely variable symptoms and prognosis. A decade ago, a classification of unstable angina based on clinical symptoms was introduced. This system was then validated by prospective clinical studies to correlate with the prognosis and was linked to angiographic and histological findings. It has been used to categorize patients in many large clinical trials. In recent years, the pathophysiological roles of platelet activation and inflammation in unstable angina have been elucidated. Subsequently, improved markers of myocardial injury, acute-phase proteins, and hemostatic markers that may be associated with clinical outcomes have been identified. Particularly, cardiac-specific troponin T and troponin I have been shown to represent the best predictors of early risk in patients with angina at rest. Accordingly, it is suggested that the original classification be extended by subclassifying one large group of unstable angina patients, ie, those with angina at rest within the past 48 hours (class IIIB), into troponin-positive (T(pos)) and troponin-negative (T(neg)) patients. The 30-days risk for death and myocardial infarction is considered to be up to 20% in class IIIB-T(pos) but <2% in class IIIB-T(neg) patients. Initial results suggest that troponins may function as surrogate markers for thrombus formation and can effectively guide therapy with glycoprotein IIb/IIIa antagonists or low-molecular-weight heparins. These observations provide additional impetus for adding the measurement of these markers to the clinical classification and represent a novel concept of treating these high-risk patients.

Predictors of recurrent ischemic events and death in unstable coronary artery disease after treatment with combination antithrombotic therapy

BACKGROUND

Patients with non-Q-wave acute coronary syndromes (ACS) have substantial rates of recurrent ischemic events, but prognostic studies have been small or preceded the routine use of aggressive combination antithrombotic therapy. We sought to identify predictors of these events after antithrombotic treatment of non-Q-wave ACS.

METHODS

We assessed 30-day rates of a composite triple end point (death, infarction, or refractory angina) and double end point (death or infarction) among 3171 patients with non-ST-segment elevation ACS randomly assigned to enoxaparin or heparin, plus aspirin, for 2 to 8 days. We created multivariable regression models to predict these end points from baseline factors.

RESULTS

Overall, 682 patients (21%) reached the triple end point and 220 (6.8%) reached the double end point. Independent predictors of the triple end point were admission with myocardial necrosis, ST-segment depression, prior angina severity, symptom duration, and allocation to enoxaparin treatment in patients with ST-segment depression (significant interaction). Independent predictors of the double end point were admission with myocardial necrosis, ST-segment depression, enrollment region, age >75 years, prior angina severity, and rales. By deciles, the average predicted risk for the double end point ranged from 2% to 20%: a patient aged <75 years with no risk factors had a 3.5% risk, whereas a patient aged >75 years with 2 additional high-risk features (myonecrosis and ST depression) had a risk of death or reinfarction of 26%.

CONCLUSIONS

Patients with non-ST-segment elevation ACS exhibit a broad range of risk of adverse recurrent ischemic events. The predictive power of the model for the triple end point, using baseline variables, was modest. However, a subgroup at very low risk of the double end point (average 2%) can be identified with baseline variables.

Prognostic significance of ST segment depression in lateral leads I, aVL, V5 and V6 on the admission electrocardiogram in patients with a first acute myocardial infarction without ST segment elevation

OBJECTIVES

We sought to investigate the short-term prognostic value of the admission electrocardiogram (ECG) in patients with a first acute myocardial infarction (MI) without ST segment elevation.

BACKGROUND

ST segment depression on hospital admission predicts a worse outcome in patients with a first acute MI, but the prognostic information provided by the location of ST segment depression remains unclear.

METHODS

In 432 patients with a first acute MI without Q waves or > or = 0.1 mV of ST segment elevation, we evaluated the ability of the initial ECG to predict in-hospital death.

RESULTS

The presence, magnitude and extent of ST segment depression were associated with an increased mortality, but the only electrocardiographic variable that was significant in predicting death after adjusting for baseline predictors was ST segment depression in two or more lateral (I, aVL, V5, or V6) leads (odds ratio 3.5, 95% confidence interval 1.2 to 10.6). Patients with lateral ST segment depression (n = 91, 21%) had higher rates of death (14.3% vs. 2.6%, p < 0.001), severe heart failure (14.3% vs. 4.1%, p < 0.001) and angina with electrocardiographic changes (20.0% vs. 11.6%, p = 0.04) than did the remaining patients, even though they had similar peak creatine kinase, MB fraction levels (129 +/- 96 vs. 122 +/- 92 IU/liter, p = NS). In contrast, ST segment depression not involving the lateral leads did not predict a poor outcome. Among patients who were catheterized, those with lateral ST segment depression had a lower left ventricular ejection fraction (57 +/- 12% vs. 66 +/- 13%, p = 0.001) and more frequent left main coronary artery or three-vessel disease than did the remaining patients (60% vs. 22%, p < 0.001).

CONCLUSIONS

In patients with a first non-ST segment elevation acute MI, ST segment depression in the lateral leads on hospital admission predicts a poor in-hospital outcome.

Unstable Angina

The recent availability of novel antiplatelet and antithrombin agents has revolutionized the therapeutic options for intermediate- and high-risk unstable angina (UA). Current guidelines recommend aspirin, unfractionated heparin (UFH), and antianginal therapy. Low-molecular-weight heparin (LMWH) and direct thrombin inhibitors have significant theoretical advantages and apparent clinical benefits compared with UFH and are good alternatives in selected patients. Glycoprotein (GP) IIb/IIIa receptor inhibition reduces the future risk of myocardial infarction (MI) and may reduce the incidence of death in patients with unstable angina. In particular, these drugs should be considered for use in combination with aspirin and UFH in patients undergoing an "early invasive" approach. Coronary revascularization plays an important role in high-risk patients and in those with refractory angina, but its routine application continues to be controversial. Issues regarding the use of LMWH in combination with GP IIb/IIIa inhibitors and during percutaneous transluminal coronary angioplasty (PTCA) are being addressed in clinical trials. Ideally, the incidence of serious cardiac events in patients with UA will continue to decrease with the ongoing search for potent drug combinations that achieve early control of intracoronary thrombosis.

Newer antithrombotic strategies in the initial management of non-ST-segment elevation acute coronary syndromes

OBJECTIVE

To review the place in therapy of currently available antithrombotic agents in the non-ST-segment elevation acute coronary syndromes, that is, unstable angina and non-Q-wave myocardial infarction (MI). Recommendations are made based on currently available data.

DATA SOURCE

English-language clinical studies, position statements, and review articles pertaining to the management of unstable angina and non-Q-wave MI with currently available products.

STUDY SELECTION

Selection of prospective clinical studies was limited to those focusing on the management of the non-ST-segment elevation acute coronary syndromes, unstable angina, and non-Q-wave MI.

DATA SYNTHESIS

It has yet to be determined which combination of agents (dalteparin, enoxaparin, lepirudin, clopidogrel, ticlopidine, abciximab, eptifibatide, tirofiban) and procedural strategies most significantly reduces mortality and serious events in these patients. The relevant pathophysiology, diagnostic criteria, and risk-stratifying procedures are reviewed in context with information from clinical studies regarding currently available agents for the management of non-ST-segment elevation acute coronary syndromes.

CONCLUSIONS

A large number of new therapeutic classes and agents are available for the treatment of unstable angina and non-Q-wave MI. Although the diagnoses of unstable angina or non-Q-wave MI identify risk, treatment decisions are often based on the presence or absence of ST-segment elevations. Limited prospective evidence delineates the proper utilization of resources to best manage these patients. Efforts should be aimed at identifying particular patients who will best benefit from recently available therapies.