Use of risk stratification to identify patients with unstable angina likeliest to benefit from an invasive versus conservative management strategy

Clinical Outcomes of Comparison Between Type III Coronary Artery Perforation (CAP) and non-CAP Acute Coronary Syndrome Patients During 3-Year Follow-up

Coronary artery perforation (CAP) is a potentially fatal complication of percutaneous coronary intervention (PCI) in acute coronary syndrome (ACS). This study aimed to investigate in-hospital, 1-year, and 3-year clinical outcomes of type III CAP during PCI in patients with ACS. The study retrospectively evaluated 118 patients with CAP and 43,226 case-control patients. Clinical, angiographic, and procedural characteristics, management, and outcomes were analyzed retrospectively at 1-year and 3-year follow-ups. The mean age of the patients was 66.5 ± 11.9 years (61.8% males). There was no significant difference in hospital mortality between the type III CAP and non-CAP groups. The all-cause mortality was 33.3% in the CAP group vs 1.8% in the non-CAP group at 1 year, and 28.3% in CAP group vs 6.9% in non-CAP group at 3 years (p = .001 for both comparisons). The procedural, clinical, and 1 and 3-year outcomes of type III CAP showed a relatively high risk of myocardial infarction, coronary artery bypass graft, cerebrovascular event, stent thrombosis, and major bleeding at the 1 and 3-year follow-ups. In addition, non-CAP ACS patients had better survival (log-rank: p < .001, 34.29 months 95% Confidence Interval [33.58-35.00]) than type III CAP ACS patients (29.53 months 95% Confidence Interval [27.28-31.78]) at the 3-year follow-up visit.

Cardiac intervention rates for older patients with acute myocardial infarction in the United States and Ontario, 2003-2013: a retrospective cohort study

BACKGROUND

Previous work showed lower cardiac intervention rates for patients with acute myocardial infarction (AMI) in Ontario than in the United States. We assessed whether Ontario's efforts to improve access to rapid percutaneous coronary intervention (PCI) for AMI were associated with improved timeliness of care and whether this closed the gap between the 2 jurisdictions.

METHODS

In this retrospective cohort study, we followed adults aged 66-99 years in the US and Ontario for 30 days after admission for incident AMI between 2003 and 2013 using health administrative data from both countries. We calculated the proportion of patients who received cardiac catheterization, PCI and coronary artery bypass grafting on the day of and within 30 days of admission overall and according to AMI type (ST-segment elevation AMI [STEMI] v. non-STEMI) and risk group (low, medium or high predicted risk of 30-d mortality).

RESULTS

We followed 414 216 patients in the US and 112 484 in Ontario. The large disparities in cardiac intervention rates observed in 2003 mostly disappeared over time. By 2013, the proportion of patients who received same-day PCI was only slightly higher in the US than in Ontario (22.3% v. 19.2%), whereas the converse was true for 30-day PCI (44.0% v. 41.3%). In 2013, patients with STEMI in the US and Ontario received PCI at nearly identical rates on the day of admission (66.3% v. 63.8%); however, more patients at high risk with STEMI in the US than in Ontario received PCI, both on the day of admission (55.5% v. 44.7%) and by 30 days (60.5% v. 55.0%).

INTERPRETATION

Despite differences in resources and organization of delivery systems, by 2013, timely receipt of PCI by Ontario patients with AMI lagged only slightly behind that by US patients. A higher supply of PCI centres in the US may have facilitated earlier intervention among patients at high risk with STEMI.

Review: The management of acute myocardial infarction in patients with diabetes mellitus

Diabetic subjects are more likely to experience a myocardial infarction and have worse outcomes compared to non-diabetic subjects. The underlying pathophysiology of the atherosclerotic process is not significantly different in diabetic subjects, but the prothrombotic and procoagulant state with which diabetes is associated is thought to contribute to the higher incidence of and worse prognosis after myocardial infarction. Difficulties of re-establishing vessel patency by thrombolytic or mechanical means contribute to the high morbidity and mortality. The diffuse nature of arterial disease with accompanying metabolic derangement contribute to impaired compensatory mechanisms, increased infarct size and a disproportionately more substantial impairment of left ventricular function. The newer adjuvant antithrombotic and anticoagulant agents have particular roles in management therefore and careful modulation of glucose metabolism in the acute and follow-up phase of an infarct may favourably influence outcome.

TIMI, GRACE and alternative risk scores in Acute Coronary Syndromes: a meta-analysis of 40 derivation studies on 216,552 patients and of 42 validation studies on 31,625 patients

BACKGROUND

Acute coronary syndromes (ACS) represent a difficult challenge for physicians. Risk scores have become the cornerstone in clinical and interventional decision making.

METHODS AND RESULTS

PubMed was systematically searched for ACS risk score studies. They were divided into ACS studies (evaluating Unstable Angina; UA, Non ST Segment Elevation Myocardial Infarction; NSTEMI, and ST Segment Elevation Myocardial Infarction; STEMI), UA/NSTEMI studies or STEMI studies. The c-statistics of validation studies were pooled when appropriate with random-effect methods. 7 derivation studies with 25,525 ACS patients and 15 validation studies including 257,654 people were formally appraised. Pooled analysis of GRACE scores, both at short (0.82; 0.80-0.89 I.C 95%) and long term follow up (0.84; 0.82-0.87; I.C 95%) showed the best performance, with similar results to Simple Risk Index (SRI) derivation cohorts at short term. For NSTEMI/UA, 18 derivation studies with 56,560 patients and 18 validation cohorts with 56,673 patients were included. Pooled analysis of validations studies showed c-statistics of 0.54 (95% CI = 0.52-0.57) and 0.67 (95% CI = 0.62-0.71) for short and long term TIMI validation studies, and 0.83 (95% CI = 0.79-9.87) and 0.80 (95% CI = 0.74-0.89) for short and long term GRACE studies. For STEMI, 15 studies with 134,557 patients with derivation scores, and 17 validation studies with 187,619 patients showed a pooled c-statistic of 0.77 (95% CI = 0.71-0.83) and 0.77 (95% CI = 0.72-0.85) for TIMI at short and long term, and a pooled c-statistic of 0.82 (95% CI = 0.81-0.83) and 0.81 (95% CI = 0.80-0.82) for GRACE at short and long terms respectively.

CONCLUSIONS

TIMI and GRACE are the risk scores that up until now have been most extensively investigated, with GRACE performing better. There are other potentially useful ACS risk scores available however these have not undergone rigorous validation. This study suggests that these other scores may be potentially useful and should be further researched.

Time to coronary angiography in patients with non-ST-segment elevation acute coronary syndrome: how fast should patients go to the catheterization laboratory?

PURPOSE OF REVIEW

This review describes available data on the optimal timing of an early invasive strategy in patients with high-risk non-ST-segment elevation acute coronary syndromes, along with challenges with type of studies. We also discuss the implication of timing in the overall management of the non-ST-segment elevation acute coronary syndrome patients.

RECENT FINDINGS

The issue of timing of the coronary angiography has been addressed mainly with observational analyses. The only, small, randomized clinical trial, the Intracoronary Stenting With Antithrombotic Regimen Cooling-Off, indicated a superiority of an expedited approach compared with a much deferred angiography. A recent observational analysis adopting special statistical methodologies confirmed the finding of the Intracoronary Stenting With Antithrombotic Regimen Cooling-Off trial in patients undergoing an early invasive strategy in the first 48 h of presentation.

SUMMARY

Current evidence is not sufficient to recommend the use of a routine expedite invasive strategy but suggests that it may be a viable approach.

Temporal trends in the use of early cardiac catheterization in patients with non-ST-segment elevation acute coronary syndromes (results from CRUSADE)

We evaluated temporal trends in the use of early (<48 hours) catheterization in patients with non-ST-segment elevation acute coronary syndromes with respect to baseline risk features since publication of the American College of Cardiology/American Heart Association guidelines, which include a class IA recommendation for an early invasive strategy for high-risk patients with non-ST-segment elevation acute coronary syndromes. Overall, we found that early catheterization use increased from 53% to 61% during the 3 years after the guidelines were released, but the increased use of early catheterization was highest (11%) in the group that was at lowest risk of predicted mortality, and it was lowest (6%) in the group at highest risk of predicted mortality who would potentially receive the most benefit from an aggressive treatment approach. In conclusion, despite the overall increase in the use of early catheterization, the gap between the use of an early invasive strategy in the highest and lowest risk patients remains large and tends to increase over time.

Non ST segment elevation acute coronary syndromes: A simplified risk-orientated algorithm

Non-ST segment elevation acute coronary syndromes (NSTE ACS) include a clinical spectrum that ranges from unstable angina to NSTE myocardial infarction. Management goals aim to prevent recurrent ACS and improve long-term outcomes by choosing a treatment strategy according to an estimate of the risk of an adverse outcome. Recent registry data suggest that patients with NSTE ACS frequently do not receive recommended treatment, and that risk stratification is not used to determine either the choice of treatment or the speed of access to coronary angiography. The present article evaluates the evidence for recommended treatment using information from recent trials and guidelines published by the major cardiac organizations in Europe and North America. Using this information, a multidisciplinary group developed a simplified algorithm that uses risk stratification to select an optimal early management strategy. Long-term outcomes are improved by a multi-faceted vascular protection strategy that is initiated at the time of hospitalization for NSTE ACS.

Treatment benefit by perindopril in patients with stable coronary artery disease at different levels of risk

AIMS

Patients with stable coronary artery disease (CAD) are at increased risk. Estimation of individual risk is difficult. We developed a cardiovascular risk model based on the EUROPA study population and investigated whether benefit of long-term administration of the angiotensin-converting enzyme (ACE)-inhibitor perindopril was modified by risk level.

METHODS AND RESULTS

A total of 12 218 patients with stable CAD were treated with 8 mg perindopril or placebo. Baseline patient characteristics were assessed for association with 1091 cardiovascular deaths or non-fatal myocardial infarction (MI). Risk factors were age over 65 years, male gender [hazard ratio (HR) 1.2], previous MI (HR 1.5), previous stroke and/or peripheral vascular disease (HR 1.7), diabetes, smoking, angina (all HR 1.5), and high serum cholesterol and systolic blood pressure. Treatment benefit by perindopril was consistent among high, intermediate, and low risk patients (HRs 0.88, 0.68, and 0.83, respectively). Risk reduction was thus not modified by absolute risk level.

CONCLUSION

Risk factors such as age, male gender, smoking, total cholesterol, and blood pressure continue to play an important role once clinical sequellae of coronary heart disease have developed. Patients at moderate-to-high risk because of uncontrolled risk factors and those with other indications for ACE-inhibitors have the most to gain from ACE-inhibition.

Risk stratification in acute coronary syndromes--does the TIMI risk score work in unselected cases?

BACKGROUND

Management of patients with an acute coronary syndrome (ACS) requires accurate risk stratification to guide appropriate therapy.

AIM

To assess the utility of the TIMI risk score in stratifying patients with possible ACS in routine clinical practice.

DESIGN

Prospective observational study.

METHODS

We recruited 869 consecutive patients with a diagnosis of possible ACS attending the acute medical receiving unit of a district general hospital. The main outcome measures were recurrent myocardial infarction, urgent revascularization, and all-cause mortality. TIMI risk score was calculated for each patient, and each was also assigned a risk group based on electrocardiogram (ECG) changes and troponin levels only. After follow-up, Cox univariate and multivariate regression was used to evaluate the influence of potential risk factors on duration of event-free survival, and likelihood ratio tests to assess the fit of the models.

RESULTS

Increasing TIMI risk score was associated with increased risk of events (p<0.001), as was higher risk group from ECG plus troponin stratification (p<0.001). The likelihood ratio comparison favoured the TIMI risk score (difference 13.910, 5 degrees of freedom, p = 0.016).

DISCUSSION

The TIMI risk score is a valid tool for risk stratification in unselected cases with possible acute coronary syndrome. It is superior to ECG changes and troponin alone, although this simpler method also achieves good risk stratification.

Appropriate invasive and conservative treatment approaches for patients with non-ST-elevation MI

Compelling evidence from randomized clinical trials has established the superiority of an early invasive over a conservative management strategy in patients presenting with non-ST-segment acute coronary syndromes, with a 20% to 40% reduction in recurrent ischemic events in patients undergoing routine early angiography and revascularization when appropriate. Those patients at high risk of death, recurrent myocardial infarction, or ischemia as indicated by elevated concentrations of cardiac troponin, ST-segment deviation, or high clinical risk score derive a greater clinical benefit from early invasive management than patients at lower risk who may be managed effectively with either strategy. Patients who have recurrent ischemia, infarction, hemodynamic instability, or a high-risk stress test should be considered for urgent catheterization regardless of the initial strategy chosen.

Epidemiology of non-ST elevation acute coronary syndromes in the Italian cardiology network: the BLITZ-2 study

AIMS

Acute coronary syndromes without ST-segment elevation (NSTEACS) represent an increasingly frequent cause of hospital admission. The BLITZ-2 study was planned to survey the epidemiology and management strategies of NSTEACS in the Italian cardiological network.

METHODS AND RESULTS

The study included 1888 patients with NSTEACS in 275 hospitals in 3 weeks. At admission, almost 20% of patients showed clinical signs of heart failure, half showed ST-segment depression, and half showed any positive biochemical myocardial necrosis marker. Patients admitted to hospitals without CathLab (n=973) were older (P=0.0005) and with higher Killip class on admission (P<0.0001) when compared with those admitted to hospitals with CathLab (n=915). During index hospitalization, 76% of the patients initially admitted to hospitals with invasive capability underwent coronary angiography and 39% percutaneous coronary intervention when compared with 39 and 17.2% of those admitted to hospitals without CathLab (P<0.001). Overall, 30-day mortality was 2.4% (2.0% in patients with invasive capability vs. 2.9% in hospitals without CathLab, P=0.2). Cardiac ischaemic events at 30 days (recurrent MI, recurrent angina, and re-hospitalization for ACS) were significantly higher in the group of patients admitted to hospitals without CathLab (OR 1.71, 95% CI 1.24-2.35). However, after multivariable adjustment, only advanced age (OR 1.043, 95% CI 1.021-1.065, P<0.0001) and Killip class >1 (OR 1.633, 95% CI 1.020-2.614, P=0.04) resulted in independent predictors of death, in-hospital MI, and re-admission for ACS, whereas the absence of an on-site CathLab did not predict an adverse outcome (OR 1.104, 95% CI 0.734-1.660).

CONCLUSION

According to this, the nationwide registry outcome is only marginally influenced by invasive procedures. Contemporary management of patients with NSTEACS in Italy is primarily driven by resource availability.

FRISC score for selection of patients for an early invasive treatment strategy in unstable coronary artery disease

OBJECTIVE

To develop a scoring system for risk stratification and evaluation of the effect of an early invasive strategy for treatment of unstable coronary artery disease (CAD).

DESIGN

Retrospective analysis of a randomised study (FRISC II; fast revascularisation in instability in coronary disease).

SETTING

58 Scandinavian hospitals.

PATIENTS

2457 patients with unstable CAD from the FRISC II study.

MAIN OUTCOME MEASURES

One year rates of mortality and death/myocardial infarction (MI).

METHODS

Patients were randomly assigned to an early invasive or a non-invasive strategy. From the non-invasive cohort independent variables of death or death/MI were identified.

RESULTS

Seven factors, age > 70 years, male sex, diabetes, previous MI, ST depression, and increased concentrations of troponins and markers of inflammation (interleukin 6 or C reactive protein), were associated with an independent increased risk for death or death/MI. In patients with > or = 5 of these factors the invasive strategy reduced mortality from 15.4% (20 of 130) to 5.2% (7 of 134) (risk ratio (RR) 0.34, 95% confidence interval (CI) 0.15 to 0.78, p = 0.006). Death/MI was also reduced in patients with 3-4 factors from 15.7% (80 of 511) to 10.8% (58 of 538) (RR 0.69, 95% CI 0.50 to 0.94, p = 0.02). Neither death nor death/MI was reduced in patients with 0-2 risk factors.

CONCLUSION

In unstable CAD, this scoring system based on factors independently associated with an adverse outcome can be used shortly after admission to the hospital for risk stratification and for selection of patients to an early invasive treatment strategy.

Relation between baseline risk and treatment decisions in non-ST elevation acute coronary syndromes: an examination of international practice patterns

OBJECTIVES

To examine the interaction between ST segment depression on the baseline ECG and subsequent in-hospital revascularisation on six month mortality among patients with non-ST elevation acute coronary syndromes. To examine whether ST segment depression influenced clinical decision making and whether there was international variation in the use of cardiac procedures across ST segment depression categories.

METHODS

11 453 patients enrolled in GUSTO-IIB (global use of strategies to open occluded coronary arteries), PARAGON (platelet IIb/IIIa antagonism for the reduction of acute coronary syndrome events in a global organisation network) -A, and PARAGON-B were studied. Patients were categorised as having no ST segment depression, 1 mm ST segment depression in two contiguous leads, and ST segment depression > or = 2 mm in two contiguous leads. International practice across four geographic regions was examined: USA, Canada, Europe, and Australia/New Zealand.

RESULTS

Revascularisation appeared to have no impact on survival among patients with no ST segment depression; however, revascularisation was associated with a significant survival benefit among patients with ST segment depression > or = 1 mm. There was an inverse relation between the extent of ST segment depression and the use of angiography as well as angioplasty (p < 0.01). However, patients with ST segment depression > or = 2 mm were more likely to undergo bypass surgery. The only significant trend of increasing use of revascularisation procedures with increasing ST segment depression was observed in the USA.

CONCLUSIONS

International practice patterns in procedure use appear to be insensitive to the extent of ST segment depression. Major opportunities for more efficient delivery of care exist in all regions.

Thrombocytopenia, immunoglobulin treatment, and acute myocardial infarction--a case report

Platelets play a pivotal role in the pathophysiology of the acute coronary syndromes, and platelet inhibition is a cornerstone in the management of these patients. Patients with profound thrombocytopenia who present with an acute coronary syndrome present a difficult challenge. The authors report a patient with immune thrombocytopenic purpura who presented with acute myocardial infarction despite a very low platelet count and who sustained recurrent infarction after receiving immune globulin treatment. The best management of thrombocytopenic patients with acute coronary syndromes is uncertain, but extreme caution is needed before efforts are made to raise the platelet count in order to allow conventional treatment.

Long-term outcomes of regional variations in intensity of invasive vs medical management of Medicare Patients with acute myocardial infarction

CONTEXT

The health and policy implications of the marked regional variations in intensity of invasive compared with medical management of patients with acute myocardial infarction (AMI) are unknown.

OBJECTIVES

To evaluate patient clinical characteristics associated with receiving more intensive treatment; and to assess whether AMI patients residing in regions with more intensive invasive treatment and management strategies have better long-term survival than those residing in regions with more intensive medical management strategies.

DESIGN, SETTING, AND PATIENTS

National cohort study of 158,831 elderly Medicare patients hospitalized with first episode of confirmed AMI in 1994-1995, followed up for 7 years (mean, 3.6 years), according to the intensity of invasive management (performance of cardiac catheterization within 30 days) and medical management (prescription of beta-blockers to appropriate patients at discharge) in their region of residence. Baseline chart reviews were drawn from the Cooperative Cardiovascular Project and linked to Medicare health administrative data.

MAIN OUTCOME MEASURE

Long-term survival over 7 years of follow-up.

RESULTS

Patient baseline AMI severity was similar across regions. In all regions, younger and healthier patients were more likely than older high-risk patients to receive invasive treatment and medical therapy. Regions with more invasive treatment practice styles had more cardiac catheterization laboratory capacity; patients in these regions were more likely to receive interventional treatment, regardless of age, clinical indication, or risk profile. The absolute unadjusted difference in 7-year survival between regions providing the highest rates of both invasive and medical management strategies and those providing the lowest rates of both was 6.2%. For both ST- and non-ST-segment elevation AMI patients, survival improved with regional intensity of both invasive and medical management. In areas with higher rates of medical management, there appeared to be little or no improvement in survival associated with increased invasive treatment.

CONCLUSIONS

In elderly Medicare patients with AMI, more intensive medical treatment provides population survival benefits. However, routine use of more costly and invasive treatment strategies may not be associated with an overall population benefit beyond that seen with excellent medical management. Efforts should focus on directing invasive clinical resources to patients with the greatest expected benefit.

Therapeutic strategies, immediate and mid-term outcomes in non-ST-segment elevation acute coronary syndromes with respect to age: a single-center registry of 488 consecutive patients

BACKGROUND

Elderly patients with non-ST-elevation acute coronary syndromes (NSTE-ACS) may receive benefit from an early invasive strategy. However, aged patients often suffer from comorbidities that may contraindicate an invasive approach and affect prognosis adversely. The impact of comorbidities on an invasive approach to NSTE-ACS in the elderly has not been fully investigated.

HYPOTHESIS

This study sought to examine the outcome of an unselected population of patients with NSTE-ACS stratified according to age and treatment approach.

METHODS

The feasibility and efficacy of an invasive strategy for NSTE-ACS and the 6-month outcome were assessed in 253 unselected consecutive patients > or = 70 years (elderly) and compared with those of 235 unselected consecutive patients < 70 years.

RESULTS

Angiography was not performed in 69 patients (86% > or = 70 years) because of contraindications. In the whole population, the 6-month event rate was significantly higher in elderly compared with younger patients (22 vs. 14%; odds ratio 1.8, 95% confidence interval 1.1-2.9; p < 0.02). This difference was driven by the high event rate observed in the elderly with contraindications to angiography (47 vs. 16% in the elderly treated invasively; p < 0.002). On the other hand, no significant difference was observed in the 6-month event rate between elderly and younger patients undergoing an invasive approach (16 vs. 13%; p = 0.36). Contraindications to angiography-namely, creatinine > or = 1.5 mg/dl and elevated troponin I at admission--were the only independent predictors of 6-month outcome.

CONCLUSIONS

The invasive approach was feasible in 77% of patients > or = 70 years. Those with contraindications to angiography showed a poor mid-term prognosis. The early invasive strategy was associated with more favorable outcomes regardless of age.

Use of the early invasive approach in the management of acute coronary syndromes

Large randomized clinical trials of early invasive versus conservative strategy in patients with non-ST-elevation acute coronary syndromes (NSTE ACS) have been published recently. These studies have clearly shown that intermediate and high-risk patients presenting with NSTE ACS have better outcomes when referred early to cardiac catheterization. Patients who are referred early to cardiac catheterization have a reduction of death, myocardial infarction, and recurrent ischemia, and also have shorter hospital stays. Guidelines recommend referral to cardiac catheterization for intermediate and high-risk NSTE ACS patients within the first 48 hours of presentation. Despite these recommendations, data from a large nationwide registry show that the majority of high-risk patients with NSTE ACS are not being managed with an early invasive strategy.

Myocardial perfusion scintigraphy: the evidence

This review summarises the evidence for the role of myocardial perfusion scintigraphy (MPS) in patients with known or suspected coronary artery disease. It is the product of a consensus conference organised by the British Cardiac Society, the British Nuclear Cardiology Society and the British Nuclear Medicine Society and is endorsed by the Royal College of Physicians of London and the Royal College of Radiologists. It was used to inform the UK National Institute of Clinical Excellence in their appraisal of MPS in patients with chest pain and myocardial infarction. MPS is a well-established, non-invasive imaging technique with a large body of evidence to support its effectiveness in the diagnosis and management of angina and myocardial infarction. It is more accurate than the exercise ECG in detecting myocardial ischaemia and it is the single most powerful technique for predicting future coronary events. The high diagnostic accuracy of MPS allows reliable risk stratification and guides the selection of patients for further interventions, such as revascularisation. This in turn allows more appropriate utilisation of resources, with the potential for both improved clinical outcomes and greater cost-effectiveness. Evidence from modelling and observational studies supports the enhanced cost-effectiveness associated with MPS use. In patients presenting with stable or acute chest pain, strategies of investigation involving MPS are more cost-effective than those not using the technique. MPS also has particular advantages over alternative techniques in the management of a number of patient subgroups, including women, the elderly and those with diabetes, and its use will have a favourable impact on cost-effectiveness in these groups. MPS is already an integral part of many clinical guidelines for the investigation and management of angina and myocardial infarction. However, the technique is underutilised in the UK, as judged by the inappropriately long waiting times and by comparison with the numbers of revascularisations and coronary angiograms performed. Furthermore, MPS activity levels in this country fall far short of those in comparable European countries, with about half as many scans being undertaken per year. Currently, the number of MPS studies performed annually in the UK is 1,200/million population/year. We estimate the real need to be 4,000/million/year. The current average waiting time is 20 weeks and we recommend that clinically appropriate upper limits of waiting time are 6 weeks for routine studies and 1 week for urgent studies.

[Emergency room risk stratification of patients with chest pain without ST segment elevation]

OBJECTIVES

To investigate the prognostic factors in patients who come to the emergency room with chest pain but without ST segment elevation.

PATIENTS AND METHOD

743 consecutive patients were evaluated by recording clinical history, electrocardiogram and troponin I determination, and early (<24 h) exercise testing was done for the low-risk subgroup of patients (n=203). All patients were followed during 3 months for major events (acute myocardial infarction or death).

RESULTS

Major events occurred in 71 patients (9.6%). Multivariate analysis (C statistic=0.79; 95% CI 0.73-0.84; p=0.0001) identified the following predictors: age > or =72 years (OR=1.7; 95% CI, 1.0-2.9; p=0.05), insulin-dependent diabetes mellitus (OR=2.9; 95% CI, 1.5-5.4; p=0.001), previous ischemic heart disease (OR=1.9; 95% CI, 1.1-3.2; p=0.02), ST depression (OR=2.1; 95% CI, 1.2-3.8; p=0.01) and troponin I elevation (OR=2.9; 95% CI, 1.5-5.3; p=0.001). These five predictors were used to construct a risk score based on their odds ratios, which allowed event rate stratification by quartiles of the score: 0-2 points (1.6% events), 3-4 points (8.1% events), 5-7 points (11.9% events) and > or =8 points (26.2% events); p=0.0001. No patient with negative findings in the early exercise testing had major events.

CONCLUSIONS

In patients with chest pain, the combination of clinical, electrocardiographic and biochemical data available on admission to the emergency service allows rapid prognostic stratification. Early exercise testing is advisable for the final stratification of low risk patients.

Risk stratification in patients with unstable angina and non-ST-elevation myocardial infarction

Risk stratification in acute coronary syndromes is important both for prognosis and for treatment. Consistently, using any of a variety of clinical predictors of risk, patients at highest risk for poor outcomes derive the greatest benefit from aggressive therapy with early coronary angiography, glycoprotein IIb/IIIa antagonists, or low molecular weight heparins. By contrast, patients at low risk may be managed conservatively without long-term impact on their risk of death or myocardial infarction. Several clinical and laboratory parameters have been identified as independent, powerful predictors of poor outcome, helping to distinguish high-risk from low-risk patients. Although not a substitute for astute clinical judgment, risk prediction scores may help clinicians to synthesize the relevant clinical data at presentation into an overall assessment of risk, allowing for cost-effective utilization of therapies that add significant expense and morbidity. With the ever-expanding range of pharmacologic and interventional therapies that impact the treatment of patients with unstable angina and non-ST-elevation myocardial infarction (NSTEMI), risk stratification will become increasingly important in targeting therapies to those who are likely to achieve the most benefit. In this review, we first consider the identifiable components of risk in patients presenting with unstable angina or NSTEMI and then evaluate the emerging information regarding differential response to treatment based on the presence of these risk factors.

C reactive protein for risk stratification in acute coronary syndromes? Verdict: unproven

Although C reactive protein is intimately involved with the pathogenic mechanisms that drive acute coronary syndromes, there is no evidence that it is helpful for identifying patient groups who might benefit from particular treatment strategies

Application of current guidelines to the management of unstable angina and non-ST-elevation myocardial infarction

Unstable angina/non-ST-elevation myocardial infarction (UA/NSTEMI) is a common but heterogeneous disorder with patients exhibiting widely varying risks. Early risk stratification is at the center of the management program and can be achieved using clinical criteria and biomarkers, or a combination. In addition to anti-ischemic therapy and aspirin, the thienopyridine clopidogrel is indicated except in patients who are potential candidates for urgent coronary artery bypass grafting (CABG). Platelet glycoprotein (GP) IIb/IIIa antagonists are indicated in high-risk patients likely to undergo percutaneous coronary intervention (PCI) but are not indicated in the management of lower-risk patients who do not undergo PCI. There is a growing body of evidence to support the substitution of the low-molecular-weight heparin (LMWH) enoxaparin for unfractionated heparin (UFH). Three recent trials have demonstrated the benefit of an early invasive strategy with catheterization followed by revascularization in patients at high and intermediate risk. Lower-risk patients should undergo early noninvasive stress testing. An intensive program of secondary prevention is mandatory and should be begun before hospital discharge.

Optimizing glycoprotein IIb/IIIa receptor antagonist use for the non-ST–segment elevation acute coronary syndromes: risk stratification and therapeutic intervention

Despite extensive data supporting their use for non-ST-segment elevation acute coronary syndromes, glycoprotein (GP) IIb/IIIa antagonists are underutilized. This is likely the consequence of confusion as to which patients should receive these agents, as well as to the most appropriate timing and venue for their initiation. We will review the advances in the understanding of GP IIb/IIIa antagonist therapy, emphasizing methods of identifying those most likely to benefit from the use of GP IIb/IIIa receptor blockade. In addition, we will consider appropriate methods/venues for use of GP IIb/IIIa receptor antagonism, including its role in an "early invasive" catheterization strategy.

A new scoring system to stratify risk in unstable angina

BACKGROUND

We performed this study to develop a new scoring system to stratify different levels of risk in patients admitted to hospital with a diagnosis of unstable angina (UA), which is a complex syndrome that encompasses different outcomes. Many prognostic variables have been described but few efforts have been made to group them in order to enhance their individual predictive power.

METHODS

In a first phase, 473 patients were prospectively analyzed to determine which factors were significantly associated with the in-hospital occurrence of refractory ischemia, acute myocardial infarction (AMI) or death. A risk score ranging from 0 to 10 points was developed using a multivariate analysis. In a second phase, such score was validated in a new sample of 242 patients and it was finally applied to the entire population (n = 715).

RESULTS

ST-segment deviation on the electrocardiogram, age > or = 70 years, previous bypass surgery and troponin T > or = 0.1 ng/mL were found as independent prognostic variables. A clear distinction was shown among categories of low, intermediate and high risk, defined according to the risk score. The incidence of the triple end-point was 6 %, 19.2 % and 44.7 % respectively, and the figures for AMI or death were 2 %, 11.4 % and 27.6 % respectively (p < 0.001).

CONCLUSIONS

This new scoring system is simple and easy to achieve. It allows a very good stratification of risk in patients having a clinical diagnosis of UA. They may be divided in three categories, which could be of help in the decision-making process.

Prognostic value of lead aVR in patients with a first non-ST-segment elevation acute myocardial infarction

BACKGROUND

ST-segment elevation in lead aVR has been associated with severe coronary artery lesions in patients with acute coronary syndromes, but the prognostic significance of this finding is unknown.

METHODS AND RESULTS

We analyzed the initial ECG in 775 consecutive patients admitted to our center with a first acute myocardial infarction without ST-segment elevation in leads other than aVR or V1. The rates of in-hospital death in patients without (n=525) and with 0.05 to 0.1 mV (n=116) or > or =0.1 mV (n=134) of ST-segment elevation in lead aVR were 1.3%, 8.6%, and 19.4%, respectively (P<0.001). After adjustment for the baseline clinical predictors and for ST-segment depression on admission, the odds ratios for death in the last 2 groups were, respectively, 4.2 (95% CI, 1.5 to 12.2) and 6.6 (95% CI, 2.5 to 17.6). The rates of recurrent ischemic events and heart failure during hospital stay also increased in a stepwise fashion among the groups, whereas creatine kinase-MB levels were similar. Among the 437 patients that were catheterized within 6 months, the prevalence of left main or 3-vessel coronary artery disease in the 3 groups was 22.0%, 42.6%, and 66.3%, respectively (P<0.001).

CONCLUSIONS

Lead aVR contains important short-term prognostic information in patients with a first non-ST-segment elevation acute myocardial infarction. Because the poorer outcome predicted by ST-segment elevation in lead aVR seems to be related to a more severe coronary artery disease, an early invasive approach might be especially beneficial in patients presenting with this finding.

Economic consequences of routine coronary angiography in low- and intermediate-risk patients with unstable angina pectoris

In low- and intermediate-risk patients with unstable angina pectoris (UAP) and non-ST-elevation acute myocardial infarction (NSTEAMI), routine early invasive management with coronary angiography does not decrease the risk of death or AMI. The economic consequences of this strategy in low- and intermediate-risk patients are unknown. We applied a risk prediction rule to a multihospital practice database and to the population of the Thrombolysis In Myocardial Ischemia trial, phase IIIB (TIMI 3B), which compared early invasive with conservative therapy for UAP and NSTEAMI. We then analyzed the effect of an early invasive strategy with regard to the composite end point of death, AMI, or rehospitalization for ischemia at rest. A logistic regression model was used to compare outcomes in patients with high versus low or intermediate risk scores. The costs and benefits of early invasive management in low- or intermediate-risk patients were assessed. In the practice database, 56% of patients with UAP and NSTEAMI who had low or intermediate risk scores underwent early cardiac catheterization, although early invasive management of these lower risk patients has not been associated with a reduction in the rate of death or MI. In TIMI 3B, when rehospitalization for ischemia at rest was added to the composite end point, invasive management was superior to conservative management at 42 days (p = 0.005) and at 1 year (p = 0.03). If all low- or intermediate-risk patients randomized to conservative therapy in that trial had been treated instead with an early invasive strategy, an estimated 5.4% of rehospitalizations would have been avoided. Within TIMI 3B, such a routine invasive strategy would have resulted in an additional cost of 2,695,700 US dollars with no effect on death or AMI, but it would have led to 34 fewer rehospitalizations. This expenditure of 79,285 US dollars per hospitalization prevented far exceeds the monetary cost of rehospitalization (14,000 US dollars). Although common in clinical practice, routine early invasive management of low- or intermediate-risk patients with UAP generates substantial health-care costs without a mortality benefit or decrease in the risk of AMI. Unless the incremental benefit in quality of life from prevented rehospitalizations for UAP is judged to be worth the large incremental cost (79,285 US dollars per hospitalization prevented), such a strategy is unlikely to be cost effective.

Associations between ST depression, four year mortality, and in-hospital revascularisation in unselected patients with non-ST elevation acute coronary syndromes

OBJECTIVE

To determine the associations between changes on the presenting ECG, in-hospital revascularisation, and four year mortality in patients with non-ST elevation acute coronary syndromes.

DESIGN

Prospective evaluation of all consecutive patients admitted in 1993 to the Green Lane Hospital coronary care unit, Auckland, New Zealand. Late follow up was undertaken at a median of 52 months. The ECGs were analysed after the hospital admission.

SETTING

Tertiary referral centre with direct local coronary care unit admissions.

INTERVENTIONS

Patients underwent physician recommended in-hospital revascularisation or initial conservative management.

RESULTS

The four year survival was 88% in the 115 patients who underwent revascularisation (65 (19%) percutaneous and 53 (16%) surgical revascularisation), compared with 75% in 316 patients managed conservatively (p = 0.024). Four year survival for patients undergoing revascularisation versus initial conservative management with respect to ECG groups was: no ECG changes (n = 101), 97% v 92% (p = 0.35); T wave inversion or 0.5 mm ST depression (n = 108), 89% v 78% (p = 0.18); ST depression > or = 1 mm (n = 122), 80% v 58% (p = 0.014); chi2 = 29, p < 0.001 for the linear trend across the groups. On multivariate analysis, independent predictors of four year mortality were: age (odds ratio (OR) 1.05, 95% confidence interval (CI) 1.01 to 1.08; p = 0.0046); ECG group (OR 1.88, 95% CI 1.21 to 2.95; p = 0.043); radiological pulmonary oedema (OR 2.81, 95% CI 1.18 to 7.05; p = 0.025); and revascularisation (OR 0.43, 95% CI 0.20 to 0.90; p = 0.023).

CONCLUSIONS

Among unselected patients with non-ST elevation acute coronary syndromes, in-hospital revascularisation is associated with decreased mortality at up to four years after admission. This association appears greater in patients with ST depression of > or = 1 mm on the presenting ECG.

"Routine invasive" versus "selective invasive" approaches to non-ST-segment elevation acute coronary syndromes management in the post-stent/platelet inhibition era

Is a "routine invasive" or "selective invasive" strategy the best approach for patients with non-ST-segment elevation acute coronary syndrome (ACS)? A "selective invasive" strategy incorporates ischemia-guided use of aggressive medical therapy followed by angiography and revascularization for angina or stress-induced myocardial ischemia. The "routine invasive" strategy (cardiac catheterization followed by percutaneous coronary intervention within 24 to 48 h of symptom-onset) is frequently employed, but no randomized, controlled trials have demonstrated improved clinical outcomes. Recently, the second Fragmin and fast Revascularization during InStability in Coronary artery disease (FRISC-II) and the Treat angina with Aggrastat and determine Cost of Therapy with an Invasive or Conservative Strategy-Thrombolysis in Myocardial Infarction (TACTICS TIMI-18) trials found significant reductions in death, recurrent myocardial infarction, or hospitalization for biomarker-positive ACS. Also, the third Randomized Intervention Trial of unstable Angina (RITA-3) recently reported a halving of refractory angina and reduction in the use of antianginal medication with early intervention. Early trials failed to demonstrate the superiority of the "routine invasive" approach, presumably because of fewer revascularizations, unavailability of stents, and more recent use of glycoprotein IIb/IIIa inhibitors and low-molecular-weight heparins. The FRISC-II, TACTICS TIMI-18, and RITA-3 studies indicate that higher-risk patients benefit from early revascularization, but that aggressive antiplatelet, antithrombin, and anti-ischemic therapy are also important. While all three trials support an "early invasive" approach in intermediate- and high-risk patients, other trials support a more "conservative" approach in those without electrocardiographic changes or enzyme elevations. Optimal management should incorporate both strategies.

Small molecule glycoprotein IIb/IIIa receptor inhibitors as upstream therapy in acute coronary syndromes: insights from the TACTICS TIMI-18 trial

Glycoprotein (GP) IIb/IIIa inhibitors are beneficial in unstable angina/non-ST-segment elevation myocardial infarction (UA/NSTEMI). In large trials, the GP IIb/IIIa inhibitors tirofiban and eptifibatide were each found to reduce the risk of death or myocardial infarction (MI) in these patients at 30 days. These agents appear to be of greatest benefit in patients with a positive troponin at baseline, diabetes or ST-segment depression, recurrent angina, prior aspirin use, or a Thrombolysis In Myocardial Infarction (TIMI) risk score > or = 4. The Treat angina with Aggrastat and determine Cost of Therapy with an Invasive or Conservative Strategy (TACTICS) TIMI-18 trial was designed to compare the benefits of an early invasive versus a conservative strategy in high-risk UA/NSTEMI patients treated with GP IIb/IIIa inhibition. Patients were treated with tirofiban (for 48 h) plus aspirin and heparin and randomized to either invasive therapy (coronary angiography and revascularization when feasible) or conservative treatment (angiography only for patients with recurrent ischemia at rest or a positive stress test). A significant reduction in death or MI was demonstrated at 30 days (p = 0.02) and at 6 months (p = 0.0498). Death, MI, or rehospitalization for an acute coronary syndrome was also reduced with the invasive therapy at six months (p = 0.025). These results provide evidence to physicians that early GP IIb/IIIa inhibition in combination with a prompt invasive approach should be used more widely in UA/NSTEMI patients, particularly those at high risk.

Critical review of unstable angina and non-ST elevation myocardial infarction

Within the coronary vasculature the progression of a stable atherosclerotic plaque into a vulnerable and ultimately unstable lesion leads to a cascade of events culminating in the clinical presentation of unstable angina or acute myocardial infarction. In recent years studies have provided new insights in to the pathology and natural history, stimulating advances in diagnosis, treatment, and management. The review discusses the progress made including the role of inflammation, cardiac biomarkers, antiplatelet therapy, and percutaneous intervention. Current issues of debate and future directions are also addressed.

Usefulness of the TIMI risk score in predicting both short- and long-term outcomes in the Veterans Affairs Non-Q-Wave Myocardial Infarction Strategies In-Hospital (VANQWISH) Trial

We sought to test the validity and clinical utility of the Thrombolysis In Myocardial Infarction (TIMI) risk score for patients who have non-Q-wave myocardial infarction. A post hoc analysis of the Veterans Affairs Non-Q-Wave Infarction Strategies In-Hospital (VANQWISH) Trial was performed, wherein patients were assigned a TIMI risk score from which both 30-day and 12-month outcomes (death, nonfatal myocardial infarction, or urgent revascularization) were assessed. At 30 days, the TIMI risk score showed a close match between observed and predicted probabilities of events after adjustment for overall event rates. The event rate at 30 days was 6% for a score of 0 to 2, 10% for a score of 3, 13% for a score of 4, and 14% for a score of 5 to 7 (p = 0.003 and c statistic 0.59). Discriminative ability of the score was greater in the conservative group at 30 days (p = 0.0004, c statistic 0.67). The score remained modestly predictive of events at 1 year (c statistic 0.60). Conservative strategy patients had better 30-day outcomes than the invasive strategy patients if their score was 0 to 2 (odds ratio 0.24, 95% confidence interval 0.08 to 0.76). No significant difference in outcomes between strategies was detected for a score > or =3. The TIMI risk score provides moderate incremental prognostic information in high-risk patients, during both short- and long-term follow-up.

The role of pharmacotherapy and catheter-based intervention in the management of patients with non-ST-segment elevation acute coronary syndromes

The American College of Cardiology/American Heart Association Task Force on Practice Guidelines has published recommendations regarding diagnosis and treatment of patients with non-ST-segment elevation (NSTE) acute coronary syndromes (ACS). The acute ischemia pathway presented in these guidelines encompasses both an early invasive strategy and an early conservative strategy. The recognition of the role of platelet biology in ACS led to the development of glycoprotein (GP) IIb/IIIa receptor antagonists for the management of patients with NSTE ACS. Based on studies of risk stratification models for NSTE ACS, as well as a better understanding of the underlying biology of serum markers of myocardial necrosis, refinements have been made in identifying which patients benefit most from intravenous platelet receptor antagonism and the use of early invasive strategies. The available data suggest that for the NSTE ACS patient with intermediate- to high-risk features, the early initiation of intravenous platelet receptor antagonism with a small molecule GP IIb/IIIa receptor blocker, followed by timely cardiac catheterization with attempts at revascularization is the superior management strategy. In the majority of cases where such patients present to a facility without cardiac catheterization capability, stabilization with antiplatelet, antithrombotic, and anti-ischemic therapies should be undertaken prior to timely tertiary percutaneous coronary intervention referral.

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 Myocardial Ischemia Reduction with Acute Cholesterol Lowering trial: MIRACuLous or not, it's time to change current practice

The Myocardial Ischemia Reduction with Aggressive Cholesterol Lowering (MIRACL) study was the first trial to assess whether statins might be of clinical benefit in those with recently unstable coronary disease. MIRACL found that high-dose atorvastatin was safe and reduced the incidence of the composite endpoint, death, non-fatal myocardial infarction, resuscitated sudden cardiac death or emergent rehospitalization for recurrent ischemia at 16 weeks when compared with placebo. Despite a number of important study limitations, MIRACL's findings and the prior observation that inpatient initiation of lipid-lowering therapy is associated with higher rates of subsequent utilization, suggest that it is prudent to begin statin therapy when patients present with an acute coronary syndrome.