Noninvasive, medical management for non-ST-elevation acute coronary syndromes

Despite emphasis on the use of invasive management strategies for patients with non-ST-elevation acute coronary syndromes (NSTE ACS) in recent practice guidelines, 27% to 56% of NSTE ACS patients do not undergo diagnostic angiography, and a further 45% to 78% do not undergo revascularization procedures during the initial hospitalization. These medically managed patients (also termed noninvasive management) have a greater frequency of medical comorbidities and high-risk clinical characteristics and are less likely to receive guideline-recommended medications, compared with patients who undergo revascularization procedures. The rates of short and long-term adverse outcomes are also substantially higher in medically managed NSTE ACS patients, but more widespread implementation of contemporary medical therapies in this population is limited by exclusion of medically managed patients from many randomized clinical trials.     

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.     

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 antiischemic therapies should be undertaken prior to timely tertiary percutaneous coronary intervention referral.     

Peripheral arterial disease, acute coronary syndromes, and early invasive management: the TACTICS TIMI 18 trial

BACKGROUND: Patients with peripheral arterial disease (PAD) represent a high-risk patient subset in the setting of non-ST-segment elevation acute coronary syndromes (NSTE ACS). The efficacy and safety of early invasive management for such patients remains unclear. Hypothesis: Early invasive management would be well tolerated and effective among patients with NSTE ACS and PAD. METHODS: Patients from the Treat angina with Aggrastat and determine Cost of Therapy with an Invasive or Conservative Strategy-Thrombolysis In Myocardial Infarction (TACTICS-TIMI) 18 trial were stratified by the presence or absence of PAD and assessed with respect to baseline clinical factors. The outcomes of patients with PAD and NSTE ACS were examined with respect to treatment assignment to either early invasive therapy or conservative treatment of NSTE ACS. Finally, the bleeding and stroke rates of patients with PAD managed invasively were compared with patients with PAD managed conservatively. RESULTS: Of 2219 patients with NSTE ACS overall, 166 (7.5%) had concomitant PAD. Compared with those patients without PAD, those with PAD were older (75 vs. 62 years, p < 0.001) and were more likely to have high-risk clinical features, including prior histories of bypass surgery (39 vs. 20%, p < 0.001) or diabetes mellitus (38 vs. 27%, p = 0.002), and more ST-segment depression on their 12-lead electrocardiogram (43 vs. 29%, p < 0.001). Among such patients, early invasive management was associated with significant reductions in the risk of myocardial infarction (MI) at 30 days (11.4 vs. 2.3%, p = 0.03). At 180 days, compared with early conservative management, early invasive treatment for patients with PAD and NSTE ACS was associated with similar reductions in MI (12.7 vs. 3.5%, p = 0.04), and was also accompanied by significant reductions in risk of death (10.1 vs. 2.3%, p = 0.05). No excess in bleeding or stroke rates was noted among patients with PAD managed invasively. CONCLUSIONS: Among patients with NSTE ACS and a history of PAD, early invasive management is well tolerated and accompanied by significant reductions in morbidity and mortality when compared with a more conservative, ischemia-driven approach.     

Interpretation of new treatment guidelines for non-ST-segment elevation acute coronary syndromes: "ischemia-guided" versus "early invasive" strategies

The American College of Cardiology/American Heart Association Task Force on Practice Guidelines has recently published recommendations regarding the diagnosis and management of patients with non-ST-segment elevation (NSTE) acute coronary syndromes (ACS). Conventional therapy for non-ST-segment elevation acute coronary syndrome (NSTE ACS) has traditionally employed an "ischemia-guided" approach in which diagnostic cardiac catheterization and revascularization are only used in patients with objective-evidence of residual myocardial ischemia as identified by recurrent symptoms or provocative stress testing. More recent studies, however, have demonstrated improved clinical outcomes with the use of an "early invasive" approach, employing routine coronary angiography early in the patient's hospital course, followed by percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) surgery where appropriate. Improved clinical outcomes associated with an "early invasive" strategy may have evolved as a consequence of recent advances in both adjunctive pharmacotherapy and revascularization technique. For example, use of GP IIb/IIIa inhibitors and/or low-molecular-weight heparin prior to catheterization have been shown to reduce clinical events in NSTE ACS patients, and may reduce the risk of an invasive approach by plaque passivation prior to interventional therapy. Perhaps more importantly, the combined use of GP IIb/IIIa inhibitors and intracoronary stenting may reduce the potential early hazard of an invasive approach by specifically decreasing the incidence of death and non-fatal myocardial infarction associated with percutaneous intervention. In spite of the benefits of this synergistic combination of pharmacology and mechanical revascularization, risk stratification remains important in identifying high-risk individuals most likely to benefit from an "early invasive" approach.     

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.     

Preventing thrombosis: update of first-line therapy in the management of non-ST segment elevation acute coronary syndromes

Non-ST segment elevation acute coronary syndrome (NSTE ACS) has a high rate of recurrence. Both antithrombotic and antiplatelet agents in association with coronary revascularization play an important role in the prevention of an adverse outcome. Acetylsalicylic acid, heparin and low molecular weight heparin (especially enoxaparin), and the intravenous small-molecule glycoprotein IIb/IIIa inhibitors, are of proven value. Recently, clopidogrel has been shown to reduce recurrent ischemic events, both early and during the first year after the index ACS. Furthermore, two recent trials have shown that an early invasive strategy is preferable to a conservative approach in the higher risk patient. As yet, no study has shown either the efficacy or the safety of combining all these treatment modalities in the management of the NSTE ACS patient. The initial choice of antithrombotic and antiplatelet agents and a strategy for early revascularization is made after considering the risk of recurrent acute ischemic events. For patients destined to have an early invasive strategy, it is desirable to choose an anti-thrombotic/antiplatelet combination that will reduce events before revascularization, enhance the revascularization procedure and not be associated with excessive bleeding. A risk-determined algorithm is presented, which applies observations made at the time of presentation to decide the optimal management for the individual patient.     

Contemporary approach to the diagnosis and management of non-ST-segment elevation acute coronary syndromes

The management of patients with acute coronary syndromes (ACS) has evolved dramatically over the past decade and, in many respects, represents a rapidly moving target for the cardiologist and internist who seek to integrate these recent advances into contemporary clinical practice. Unstable angina and non-ST-segment elevation myocardial infarction (MI) comprise a growing percentage of patients with ACS and is emerging as a major public health problem worldwide, especially in Western countries, despite significant improvements and refinements in management over the past 20 years. Against this backdrop of a multitude of randomized, controlled clinical trials that have established the scientific foundation upon which evidence-based treatment strategies have emerged and become increasingly refined, the clinician is frequently confronted with panoply of choices that can create uncertainty or confusion regarding "optimal management". While the debate about the ideal approach to the management of non-ST-segment elevation (NSTE) ACS (i.e., routine "early invasive strategy" versus an "ischemia-guided", or "conservative", strategy) has been ongoing for over a decade, clinical trials results provide compelling evidence that intermediate- and high-risk ACS patients derived significant reductions in both morbidity and mortality with mechanical or surgical intervention, especially when revascularization is coupled with aggressive, multifaceted (anti-platelet, antithrombin, anti-ischemic and anti-atherogenic) medical therapy along with risk factor modification. For these reasons, it seems especially timely and appropriate to present a state-of-the-art paper that reviews the latest advances in the management of NSTE ACS, mindful of the fact that even this noble effort to synthesize and integrate a prodigious amount of scientific information and cardiovascular therapeutics is destined to evolve still further as our full-scale assault on optimizing clinical outcomes by harmonizing the advances in mechanical and pharmacologic interventions continues unabated.     

Comparison of results of percutaneous coronary intervention for non-ST-elevation acute myocardial infarction or unstable angina pectoris in men versus women

Previous randomized trials have addressed the impact of gender on outcomes, showing worse results in women assigned to invasive strategies compared with men with non-ST-elevation (NSTE) acute coronary syndrome (ACS). However, there is still a significant amount of controversy on strategies of treatment on the basis of gender. This study evaluated the impact of gender on treatment strategies and outcomes in patients with NSTE ACS in a high-volume, single-site tertiary center. We identified 1,197 consecutive patients with NSTE ACS (381 women, 816 men) who underwent percutaneous coronary intervention during their index hospitalizations. Patients were stratified by gender and baseline clinical and angiographic characteristics, and in-hospital and 9-month clinical outcomes were compared between the 2 groups. There were clear differences in baseline characteristics between men and women with ACS at presentation. Women were, on average, slightly older than men, with more hypertension and morbid obesity, but there were no differences in racial backgrounds or the prevalence of diabetes or dyslipidemia, nor were there treatment disparities in pharmacologic interventions. Women and men with ACS had similar rates of percutaneous coronary intervention on index admission. Women had a greater incidence of bleeding complications requiring blood transfusions. Overall, in-hospital and 9-month event-free survival were equivalent for the 2 genders. In conclusion, in this single-site observational study, patients with NSTE ACS who underwent angiography followed by percutaneous coronary intervention demonstrated no significant gender differences in treatment or in-hospital or 9-month event-free survival. From these results, interventional strategies should not be based on gender.     

Evolution in cardiovascular care for elderly patients with non-ST-segment elevation acute coronary syndromes: results from the CRUSADE National Quality Improvement Initiative.

OBJECTIVES: This study evaluated the impact of age on care and outcomes for non-ST-segment elevation acute coronary syndromes (NSTE ACS). BACKGROUND: Recent clinical trials have expanded treatment options for NSTE ACS, now reflected in guidelines. Elderly patients are at highest risk, yet have previously been shown to receive less care than younger patients. METHODS: In 56,963 patients with NSTE ACS at 443 U.S. hospitals participating in the Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes With Early Implementation of the American College of Cardiology/American Heart Association Guidelines (CRUSADE) National Quality Improvement Initiative from January 2001 to June 2003, we compared use of guidelines-recommended care across four age groups: <65, 65 to 74, 75 to 84, and > or =85 years. A multivariate model tested for age-related differences in treatments and outcomes after adjusting for patient, provider, and hospital factors. RESULTS: Of the study population, 35% were > or =75 years old, and 11% were > or =85 years old. Use of acute anti-platelet and anti-thrombin therapy within the first 24 h decreased with age. Elderly patients were also less likely to undergo early catheterization or revascularization. Whereas use of many discharge medications was similar in young and old patients, clopidogrel and lipid-lowering therapy remained less commonly prescribed in elderly patients. In-hospital mortality and complication rates increased with advancing age, but those receiving more recommended therapies had lower mortality even after adjustment than those who did not. CONCLUSIONS: Age impacts use of guidelines-recommended care for newer agents and early in-hospital care. Further improvements in outcomes for elderly patients by optimizing the safe and early use of therapies are likely.     

Recent trends in the care of patients with non-ST-segment elevation acute coronary syndromes: insights from the CRUSADE initiative

BACKGROUND: The extent to which national health quality improvement initiatives have altered reported treatment gaps among patients with non-ST-segment elevation acute coronary syndromes (NSTE ACS) is unknown. We sought to determine recent trends in adherence to guideline-based therapies for NSTE ACS. METHODS: We evaluated the treatment of patients with high-risk (positive cardiac markers and/or ischemic ST-segment changes) NSTE ACS enrolled in the Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes With Early Implementation of the ACC/AHA (American College of Cardiology/American Heart Association) Guidelines (CRUSADE) Quality Improvement Initiative from 2002 through 2004 (a total of 113 595 patients over 11 calendar quarters). We analyzed adherence to guideline-recommended therapies, including medications used in the acute care period (<24 hours after presentation), invasive procedures, in-hospital outcomes, and discharge therapies and interventions. RESULTS: The use of each class I guideline recommendation, as well as overall adherence to the guidelines, improved significantly (P<.001) during the study period. In the acute care setting, the use of antiplatelet agents increased by 5% and beta-blockers by 12%; at hospital discharge, the use of antiplatelet agents increased by 3% and beta-blockers by 8%. Heparin use in the acute care period increased by 6%, largely owing to a 9% increase in the use of low-molecular-weight heparin. Use of glycoprotein IIb/IIIa inhibitors in the acute care period also increased by more than 13%. At discharge, clopidogrel use increased by 22%, lipid-lowering agents by 11%, and angiotensin-converting enzyme inhibitors by 5%. While adherence improved, many patients still failed to receive 100% indicated treatments at the end of the study period. CONCLUSIONS: During the 4 years since the initial release of the ACC/AHA guidelines for NSTE ACS, adherence to class I recommendations has significantly improved among hospitals participating in CRUSADE. Still, further improvements are needed for optimal implementation of the these guidelines.     

Primary PCI for ST-segment elevation myocardial infarction in a patient treated with subcutaneous enoxaparin utilizing point-of-care Enox test

The superiority of enoxaparin compared with unfractionated heparin in the medical management of patients with non-ST elevation acute coronary syndromes (NSTE ACS) has been demonstrated in clinical trials. Further, enoxaparin has been shown to be safe and effective during PCI, including in combination with glycoprotein IIb/IIIa inhibitors. Whether enoxaparin is superior to unfractionated heparin in patients with NSTE ACS under-going early invasive strategy is currently being tested in a large clinical trial. Data on the use of enoxaparin in patients undergoing primary angioplasty for ST-segment elevation myocardial infarction are limited. Unlike patients who present to the catheterization laboratory after several doses of enoxaparin where in a steady state anticoagulation might have been achieved, patients who present early after administration of a single dose of subcutaneous enoxaparin may not have an adequate level of anticoagulation for PCI. The ability to monitor activity of enoxaparin in such patients using a point-of-care test might be useful. This report describes a patient with ST-segment elevation myocardial infarction who presented for primary angioplasty 75 minutes after administration of subcutaneous enoxaparin. The Rapidpoint Enox test measured 135 seconds and the patient's corresponding serum anti-Xa level was 0.12 IU/mL indicating a suboptimal level of anticoagulation for PCI. Procedural success was attained using additional 0.3-mg/kg intravenous enoxaparin.     

Renal insufficiency increases mortality in acute coronary syndromes regardless of TIMI risk score

BACKGROUND: Non ST-segment elevation acute coronary syndromes (NSTE ACS) are the most frequent cause of admission to intensive care units. Early risk assessment and implementation of optimal treatment are of special importance in these patients. Previous studies have demonstrated that renal insufficiency is an independent risk factor in patients with cardiovascular disease. AIM: To assess the effects of renal function on the course of treatment and prognosis in patients with NSTE ACS admitted to hospitals without on-site invasive facilities but with a possibility of immediate transfer to a reference centre with a catheterisation laboratory. METHODS: Twenty-nine community hospitals without on-site invasive facilities participated in the Krakow Registry of Acute Coronary Syndromes - a prospective, multicentre, web-based, observational registry. Renal insufficiency (RI) was defined as creatinine clearance (CrCl) <60 ml/min. RESULTS: NSTE ACS was diagnosed in 1396 patients. Renal insufficiency was diagnosed in 34% of all patients. Only 17% of them had been diagnosed with RI prior to admission. Transfer for invasive treatment was undertaken in 10% of RI patients as compared to 16% of patients with CrCl >60 ml/min (NS). In-hospital mortality among patients remaining on conservative treatment in community hospitals was significantly higher among RI patients (4.0 vs. 0.6%; p <0.001). Thienopyridines were less frequently used in RI patients (46 vs. 54%; p <0.05). In-hospital mortality among RI patients remaining in community hospitals and treated conservatively was higher than among non-RI patients in each TIMI risk score group: 7.3 vs. 2.4% (p <0.05) in the high risk group, 4.1 vs. 1.4% (NS) in the moderate and 3.6 vs. 0% (p <0.001) in the low risk group. Multivariate logistic regression analysis identified reduced creatinine clearance and a history of heart failure as independent factors influencing mortality. CONCLUSIONS: Renal insufficiency was present in one-third of NSTE ACS patients. Patients with renal insufficiency had worse clinical risk profile and received less aggressive treatment. Patients with NSTE ACS and renal insufficiency treated conservatively had higher in-hospital mortality. Renal insufficiency modifies mortality irrespective of the TIMI risk score. Creatinine clearance should be considered in modification of the TIMI risk score scale.     

Impact of home warfarin use on treatment patterns and bleeding complications for patients with non-ST-segment elevation acute coronary syndromes: observations from the CRUSADE quality improvement initiative.

AIMS: To examine treatment patterns and outcomes of patients with non-ST-segment elevation acute coronary syndrome (NSTE ACS) receiving long-term warfarin anticoagulation. METHODS AND RESULTS: We examined acute medication and invasive cardiac procedure use and in-hospital outcomes among 101,078 patients with NSTE ACS included in the CRUSADE registry. On admission, 7201 patients (7%) were on home warfarin therapy. Compared with non-anticoagulated patients, these patients were older and had more comorbidities, but were less likely to receive acute antiplatelet and antithrombin medications. Patients on warfarin were also less likely to undergo coronary angiography (adjusted OR 0.77, 95% CI 0.70-0.86) and percutaneous coronary intervention (adjusted OR 0.80, 95% CI 0.75-0.86), and had longer waiting times for these procedures when performed. Although patients on warfarin had higher rates of death and major bleeding compared with non-anticoagulated patients, these differences were no longer significant after multivariable adjustment [ORs 0.90 (95% CI 0.80-1.02) and 1.02 (95% CI 0.93-1.11)]. Among patients on warfarin, however, early use of antiplatelet medications was associated with increased transfusion risk. CONCLUSION: Despite higher-risk characteristics, warfarin-anticoagulated patients are often more conservatively managed, as early use of antithrombotic therapies may be associated with increased bleeding. Further investigation is needed to determine the optimal choice of therapies for this population.     

非ST段抬高急性冠状动脉综合征诊疗策略新进展

随着对非ST段抬高急性冠状动脉综合征病理生理机制理解的不断深入,使其治疗方式不断得到提高,临床预后不断得到改善。低分子肝素、血小板膜糖蛋白Ⅱb/Ⅲa受体拮抗剂及早期再血管化治疗对高危的患者均显示出强大的临床益处,而氯吡格雷的益处似乎覆盖了所有的低、中、高危患者,直接凝血酶抑制剂的作用值得进一步探讨。危险分层策略是作出治疗决定的基础,为新治疗的选择提供了依据。     

Heart failure with preserved left ventricular systolic function among patients with non-ST-segment elevation acute coronary syndromes

Previous studies of non-ST-segment elevation acute coronary syndromes (NSTE ACSs) complicated by heart failure (HF) have focused primarily on patients with left ventricular systolic dysfunction defined by an ejection fraction (EF) <40%. Little is known about HF with preserved systolic function (EF > or =40%) in the NSTE ACS population. We identified high-risk patients with NSTE ACS (ischemic electrocardiographic changes and/or positive cardiac markers) from the CRUSADE quality improvement initiative who had an EF recorded and who had information on HF status. Management and outcomes were analyzed and compared based on the presence or absence of HF and whether left ventricular EF was > or =40%. Of 94,558 patients with NSTE ACS, 21,561 (22.8%) presented with signs of HF, and most had HF with preserved systolic function (n = 11,860, 55%). Mortality rates were 10.7% for HF/systolic dysfunction, 5.8% for HF/preserved systolic function, 5.7% for no HF/systolic dysfunction, and 1.5% for no HF/preserved systolic function. Use of guideline-recommended medical therapies and interventions was frequently significantly lower in those with HF regardless of EF compared with those without HF, except for use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. In conclusion, NSTE ACS complicated by HF with preserved systolic function is common and associated with a 2.3-fold higher mortality compared with NSTE ACS without HF or systolic dysfunction. Guideline-recommended therapies and interventions are under-utilized in patients with NSTE ACS and HF, with and without preserved systolic function, compared with those without HF.     

Early versus delayed invasive strategy for intermediate‐ and high‐risk acute coronary syndromes managed without P2Y12 receptor inhibitor pretreatment: Design and rationale of the EARLY randomized trial

According to recent literature, pretreatment with a P2Y₁₂ ADP receptor antagonist before coronary angiography appears no longer suitable in non–ST‐segment elevation acute coronary syndrome (NSTE‐ACS) due to an unfavorable risk–benefit ratio. Optimal delay of the invasive strategy in this specific context is unknown. We hypothesize that without P2Y₁₂ ADP receptor antagonist pretreatment, a very early invasive strategy may be beneficial. The EARLY trial (Early or Delayed Revascularization for Intermediate‐ and High‐Risk Non–ST‐Segment Elevation Acute Coronary Syndromes?) is a prospective, multicenter, randomized, controlled, open‐label, 2‐parallel‐group study that plans to enroll 740 patients. Patients are eligible if the diagnosis of intermediate‐ or high‐risk NSTE‐ACS is made and an invasive strategy intended. Patients are randomized in a 1:1 ratio. In the control group, a delayed strategy is adopted, with the coronary angiography taking place between 12 and 72 hours after randomization. In the experimental group, a very early invasive strategy is performed within 2 hours. A loading dose of a P2Y₁₂ ADP receptor antagonist is given at the time of intervention in both groups. Recruitment began in September 2016 (n = 558 patients as of October 2017). The primary endpoint is the composite of cardiovascular death and recurrent ischemic events at 1 month. The EARLY trial aims to demonstrate the superiority of a very early invasive strategy compared with a delayed strategy in intermediate‐ and high‐risk NSTE‐ACS patients managed without P2Y₁₂ ADP receptor antagonist pretreatment.     

Small peptide GP IIb/IIIa receptor inhibitors as upstream therapy in non-ST-segment elevation acute coronary syndromes: results of the PURSUIT, PRISM, PRISM-PLUS, TACTICS, and PARAGON trials.

The primary pathophysiologic mechanism underlying all non-ST-segment elevation acute coronary syndromes (NSTE ACS) is the formation of platelet-rich coronary thrombi in response to spontaneous or intervention-induced endothelial damage with exposure of subendothelial substrates. Antagonists of the glycoprotein (GP) IIb/IIIa receptor ameliorate this process by blocking the final common pathway for platelet aggregation. Based upon collective data in over 24,000 patients, clinical trials have demonstrated that treatment of NSTE ACS patients with GP IIb/IIIa agents results in an approximate 12% relative risk reduction in the incidence of death or myocardial infarction at 30 days. The magnitude of this clinical benefit is increased in patients who are troponin-positive and who are referred for early percutaneous intervention. Potential benefits of GP IIb/IIIa inhibitor use must be weighed against an increased risk of bleeding. Ongoing controversies exist concerning the relative efficacy of different GP IIb/IIIa antagonists, the accurate use of platelet function tests to define safe and efficacious drug dosing, the adjunctive use of additional anti-thrombotic agents, and the optimal timing of upstream therapy before diagnostic cardiac catheterization and revascularization.     

Use of cardiac catheterization for non-ST-segment elevation acute coronary syndromes according to initial risk: reasons why physicians choose not to refer their patients

BACKGROUND: Despite the recommendation for an early invasive strategy in the treatment of patients who present with non-ST-segment elevation (NSTE) acute coronary syndromes (ACS), referral for cardiac catheterization is suboptimal; the reasons why some patients are not referred remain unclear. METHODS: Patients were recruited into the prospective, observational Canadian ACS Registry II between October 1, 2002, and December 31, 2003; 2136 patients with NSTE ACS identified through the registry were divided into tertiles according to the Thrombolysis in Myocardial Infarction risk score and the rates of catheterization compared. In addition, the most responsible physicians were asked to indicate the main reason they did not refer their patients for catheterization. RESULTS: The rate of referral for catheterization was 64.7%. Patients who underwent catheterization had lower in-hospital (0.8% vs 3.7%; P < .001) and 1-year mortality rates (4.0% vs 10.9%; P < .001) compared with those who did not. Higher-risk patients were referred at a similar rate as low-risk patients (62.5% vs 66.9%; P = .25). Among the reasons provided by the most responsible physician as to why patients were not referred for catheterization, 68.4% of patients were thought to be "not at high enough risk"; however, 59.1% of these patients were found to be at intermediate to high risk according to their baseline Thrombolysis in Myocardial Infarction risk score. CONCLUSIONS: Cardiac catheterization is not used optimally in patients who present with NSTE ACS. Despite better in-hospital and 1-year outcomes in those patients who are referred for catheterization, many higher-risk patients are not being referred because of the perception that they are not at high enough risk. A significant opportunity remains to improve on accurate risk stratification and adherence to an early invasive strategy for higher-risk patients.     

老年人急性冠脉综合征介入治疗研究进展

老年人非ST段抬高急性冠脉综合征和ST段抬高性心肌梗死的共同问题包括症状不典型、合并危险因素多、临床证据不充分。老年人非ST段抬高急性冠脉综合征早期给予经皮冠状动脉介入治疗减少死亡或心肌梗死绝对和相对危险度,长期随访显示其改善生存和症状的优越性。老年人ST段抬高性心肌梗死介入治疗主要获益来自减少再次心肌梗死和重复血运重建;再灌注及时性和可行性是挽救濒危心肌和改善临床预后的重要因素;选择经皮冠状动脉介入治疗或溶栓取决于患者是否存在心源性休克、时间延搁、合并病等因素,多数情况下倾向选择经皮冠状动脉介入治疗。年龄是老年人急性冠脉综合征介入治疗临床疗效的重要影响因素。