Assessment of non-ST-segment elevation acute coronary syndromes with cardiac magnetic resonance imaging

OBJECTIVES: The goal of this study was to determine: 1) if the presence of significant coronary stenosis in patients presenting with non-ST-segment elevation acute coronary syndromes (NSTE-ACS) can be predicted by cardiac magnetic resonance (CMR) imaging; and 2) if the analysis of several CMR methods improves its diagnostic yield compared with analysis of individual methods. BACKGROUND: With modern acquisition techniques, several CMR methods for the assessment of coronary artery disease (CAD) can be combined in a single noninvasive scanning session. Such a multicomponent CMR examination has not previously been applied to a large patient population, in particular those with a high prevalence of CAD in an acute situation. METHODS: Sixty-eight patients presenting with NSTE-ACS underwent CMR imaging of myocardial function, perfusion (rest and adenosine-stress), viability (by late contrast enhancement), and coronary artery anatomy. Visual analysis of CMR was carried out. First, all CMR data were reviewed in combination ("comprehensive analysis"). In further separate analyses, each CMR method was analyzed individually. The ability of CMR to detect coronary stenosis >/=70% on X-ray angiography was determined. RESULTS: Comprehensive CMR analysis yielded a sensitivity of 96% and a specificity of 83% to predict the presence of significant coronary stenosis and was more accurate than analysis of any individual CMR method; CMR was significantly more sensitive and accurate than the Thrombolysis In Myocardial Infarction risk score (p < 0.001). CONCLUSIONS: Cardiac magnetic resonance imaging accurately predicts the presence of significant CAD in patients with NSTE-ACS. In this study, a comprehensive analysis of several CMR methods improved the accuracy of the test.     

介入治疗非ST段抬高的急性冠状动脉综合征

目的　观察介入治疗非ST段抬高的急性冠状动脉综合征 (acutecoronarysyndromes ,ACS)的安全性及临床效果。方法　 16 5例ACS患者 ,接受急诊介入治疗的 89例 ,经内科治疗病情改善后再介入治疗的 76例。所有“罪犯”病变均予治疗 ,其中 4 1例患者同时接受了“罪犯”与非“罪犯”病变血管的治疗。介入方法有经皮冠状动脉腔内成形术 (PTCA) +支架、直接植入支架及切割球囊扩张。结果　 16 5处“罪犯”病变PTCA后植入支架 134枚 ,直接植入支架 4 8枚。术后残余狭窄均 <10 % ;前向血流达TIMI 3级 ;136例患者心绞痛消失 ,11例有不典型胸痛 ,2 4h后消失 ;术前仅有胸闷症状的 18例患者 ,术后 15例消失 ,3例减轻 ;无术中死亡及急诊冠状动脉旁路移植术 (CABG)病例。随访 139例患者 2～ 18个月 ,2 0例再发心绞痛 ,有 14例冠状动脉造影提示再狭窄 ,其中 11例再次行PTCA ,1例PTCA +支架 ,2例接受外科CABG ;无急性心肌梗死、猝死及心功能恶化发生。结论　在条件具备的介入中心 ,由经验丰富和技术娴熟的介入治疗医生施行或在其指导下 ,对非ST段抬高的ACS患者进行介入治疗是积极有效的治疗措施 ,近、远期临床效果较满意 ,手术成功率及安全性较高     

Extent of ST-segment depression and cardiac events in non-ST-segment elevation acute coronary syndromes.

AIMS: We sought to determine whether the extent of myocardial ischaemia on the admission electrocardiogram (ECG) has independent predictive value for short-term risk stratification of patients with non-ST-segment elevation acute coronary syndromes (NSTE ACS). Although the presence of ischaemic ECG changes on admission has been shown to predict outcome, the relationship between the extent of ECG changes and the risk of cardiac events is still ill defined. METHODS AND RESULTS: We analysed the admission ECGs of 5192 ACS patients enrolled in the GUSTO-IIb trial, without an ECG indication for thrombolysis. ECG tracings showing one or more of the following were eligible: ST-segment depression >0.5 mm, T-wave inversion >1 mm, and ST-segment elevation >0.5 mm but <1 mm. ECG variables associated with unfavourable 30 day outcomes in a univariable analysis were further assessed in a multivariable logistic regression model including independent clinical predictors. In the multivariable clinical, enzymatic, and ECG model, the sum of ST-segment depression (in millimetres) in all leads was a powerful independent predictor of 30 day death (P<0.0001), with a continuous increase in risk with the extent of ST-segment depression. The sum of ST-segment depression (P<0.0001) and the presence of minimal inferior ST-segment elevation (P<0.0001) or anterior ST-segment elevation (P=0.0182) were also independent predictors of the composite of death and myocardial infarction or reinfarction. The extent of ST-segment depression showed a highly significant correlation with the prevalence of three-vessel (P<0.0001) or left main coronary disease (P<0.0001), and also with the peak levels of creatine kinase (P<0.0001) during the index episode of ACS. CONCLUSION: In patients with NSTE ACS, the sum of ST-segment depression in all ECG leads is a powerful predictor of all-cause mortality at 30 days, independent of clinical variables and correlates with the extent and severity of coronary artery disease. The presence of even minimal (<1 mm) ST-segment elevation in anterior or inferior leads is independently associated with adverse outcomes.     

Chronic kidney disease in patients with non-ST-segment elevation acute coronary syndromes

Purpose

Chronic kidney disease has been linked to high mortality rates in patients with ST-segment elevation myocardial infarction but has not been well described for patients with non-ST-segment elevation acute coronary syndromes. We examined the treatment and outcomes of patients with both non-ST-segment elevation acute coronary syndromes and moderate to severe chronic kidney disease.

Subjects and Methods

We evaluated 45 343 patients with non-ST-segment elevation acute coronary syndromes enrolled in the CRUSADE Quality Improvement Initiative and compared treatments and outcomes in patients with and without moderate to severe chronic kidney disease.

Results

Patients presenting with moderate to severe chronic kidney disease (n = 6560) were older, more often diabetic, and more likely to present with signs of congestive heart failure. Adherence to Class IA/IB guidelines recommendations was lower in patients with moderate to severe chronic kidney disease, who were significantly less likely to be treated with medications, undergo invasive cardiac procedures, and be given discharge counseling. Moderate to severe chronic kidney disease was associated with a 50% increased risk of mortality and a 70% increased likelihood of transfusion. Despite having a higher risk of adverse outcomes, patients with moderate to severe chronic kidney disease were treated less aggressively than patients with normal renal function.

Conclusions

These findings suggest that, in patients with moderate to severe chronic kidney disease, safety concerns about adverse outcomes and the absence of trial data for this population may limit the use of guidelines-recommended therapies and interventions for non-ST-segment elevation acute coronary syndromes. The decreased use of discharge counseling in patients with moderate to severe chronic kidney disease and non-ST-segment elevation acute coronary syndromes may represent therapeutic nihilism.     

Percutaneous coronary intervention in diabetic patients with non-ST-segment elevation acute coronary syndromes.

Key pathophysiologic mechanisms of diabetes-related coronary disease include inflammation and a prothrombotic state. In the setting of non-ST-segment elevation acute coronary syndromes diabetic patients are at high risk for subsequent cardiovascular events. At the same time, they derive greater benefit than non-diabetic counterparts from aggressive antithrombotic therapy, early coronary angiography, and stent-based percutaneous coronary intervention. The mainstays of antithrombotic therapy for diabetic patients undergoing percutaneous revascularization include aspirin, clopidogrel, platelet glycoprotein IIb/IIIa receptor antagonists, and heparin or low-molecular-weight heparin. Despite dramatic reduction in restenosis conferred by drug-eluting stents, diabetic patients remain at increased risk for repeat revascularization. More efforts are needed both in terms of local drug elution as well as systemic pharmacologic therapies to further contain the excessive neointimal proliferation that characterizes the diabetic response to vascular injury.     

Pathogenesis and early management of non-ST-segment elevation acute coronary syndromes

NSTE ACS is a clinically significant problem. Endothelial dysfunction triggered by traditional cardiovascular risk factors (and perhaps by other as yet unidentified risks) in the susceptible host leads to the formation and development of atherosclerotic plaque. Inflammatory mediators and mechanical stresses contribute to plaque rupture by disrupting the protective fibrous cap. In about 25% of patients who have ACS, typically those who are younger, female, or smokers, plaque erosion seems to be the main underlying pathologic mechanism. Endothelial alteration, inflammation,or exposure of the lipid core results in the release of TF, vWF, and PAF. The release of these factors leads to platelet activation and aggregation as well as to the formation of a fibrin clot, resulting in arterial thrombosis that occludes the vessel. A variety of factors, including circulating catecholamines, LDL levels, blood glucose levels, and systemic thrombogenic factors, can affect the extent and stability of the thrombus, thereby determining whether the occlusion is complete and fixed, labile and nonocclusive (NSTE ACS),or clinically silent resulting in a mural thrombus and plaque growth. The acute treatment of NSTEACS is directed at interrupting the prothrombotic environment surrounding the ruptured plaque; thus, antiplatelet agents such as aspirin, clopidogrel, and glycoprotein IIb/IIla receptor antagonists,as well as anticoagulants such as heparin, are the mainstays of early therapy.     

曲美他嗪治疗非ST抬高急性冠脉综合征的临床观察

目的：观察曲美他嗪与常规药物相结合治疗非ST段抬高的急性冠脉综合征（NSTEACS）的疗效。方法：60例NSTEACS被随机分为治疗组及对照组各30例,对照组常规给予硝酸酯类、抗血小板药物、β受体阻滞剂、低分子肝素;治疗组在常规治疗的基础上加用曲美嗪20mg,3次/d,连续观察4周,观察胸痛消失率、动态心电图的变化（ST-T改变及恶性心律失常发生率）及心率,血压的变化。结果：治疗组胸痛消失率、ST-T改善更为明显,恶性心律失常发生率明显减少（P〈0.05）,曲美他嗪对心率、血压无影响（P〉0.05）。结论：在常规治疗NSTEACS基础上联合应用曲美他嗪可以改善心肌缺血,减少胸痛的发作次数及恶性心律失常发生率,对血液动力学无影响,是安全、有效的治疗方法。     

Revised guidelines for the management of non-ST-segment elevation acute coronary syndromes

Unstable angina (UA) and non-ST-segment elevation myocardial infarction (NSTEMI) refer to a spectrum of acute severe cardiac disorders characterized by myocardial oxygen demand and supply mismatch, caused by atherosclerotic coronary artery disease. Patients presenting with acute coronary syndromes represent a major medical problem, accounting for 2.5 million hospitalizations and 500,000 deaths annually in the United States alone. Of these, 1.5 million have a final diagnosis of UA, and myocardial infarction (ST-segment and non-ST-segment elevation) accounts for the remaining 1 million. The management of UA/NSTEMI presents a challenge to the cardiologist because treatment strategies continue to evolve. A number of trials have now assessed the safety and efficacy of early revascularization strategies in the treatment of patients with UA/NSTEMI, whereas others have focused on pharmacologic adjunctive therapy. An optimal single strategy encompassing most patients’ needs is not clear. This review focuses on the revised American College of Cardiology/ American Heart Association guidelines for the management of patients presenting with UA/NSTEMI.     

Impact of congestive heart failure in patients with non-ST-segment elevation acute coronary syndromes

The presence of congestive heart failure (CHF) has been associated with treatment disparities and worse outcomes in patients with ST-segment elevation myocardial infarction, but the incidence and effect of CHF in patients with non-ST-segment elevation acute coronary syndromes (NSTE ACSs) has not been well characterized. We evaluated 45,744 patients with NSTE ACS (positive cardiac markers and/or ischemic ST-segment changes) who were treated at 424 hospitals in the CRUSADE Quality Improvement Initiative between March 2000 and March 2003. Treatment patterns and in-hospital outcomes in patients with signs of CHF on presentation and those who developed in-hospital CHF were compared with those in patients without CHF. In total, 10,398 patients (22.7%) had signs of CHF on presentation, and 1,664 patients (3.6%) later developed in-hospital CHF. Compared with patients without CHF, early (<24 hours from presentation) medications and invasive cardiac procedures were used less often in patients with signs of CHF on presentation. Likewise, patients with in-hospital CHF were less likely than those without CHF to receive acute antiplatelet agents and undergo cardiac catheterization but more likely to receive acute beta blockers, angiotensin-converting enzyme inhibitors, and heparin and to undergo coronary artery bypass grafting. Adjusted mortality was higher in patients with signs of CHF on presentation (odds ratio 2.64, 95% confidence interval 2.31 to 3.01) and those with in-hospital CHF (odds ratio 4.93, 95% confidence interval 4.05 to 5.99) than in patients without CHF. In conclusion, CHF occurs frequently in patients with NSTE ACS but is associated with less aggressive treatment and a higher risk of mortality. Further study is needed to determine the causes of these treatment differences and the optimal therapeutic approach for patients with NSTE ACS and concomitant CHF.     

Initial experience with a magnetic navigation system for invasive treatment in patients with non-ST-segment elevation acute coronary syndromes

Background: Magnetic navigation system (MNS) assisted percutaneous coronary intervention (MPCI) has been demonstrated an advantage over conventional PCI (CPCI) in complex lesions and tortuous vessels. However, the benefits of MNS in clinical unstable and vulnerable lesions were little studied. The aim of this study is to evaluate the feasibility and benefits of MPCI versus CPCI in patients with non‐ST‐segment elevation acute coronary syndromes (NSTE‐ACS). Methods: Thirty‐seven consecutive patients with NSTE‐ACS undergoing MPCI were compared with 37 matched CPCI patients selected from the same concurrent database. Time to cross lesion, fluoroscopy time, and contrast usage to cross lesion were used as primary end‐points. Results: Of the 37 culprit lesions in MPCI, 36 were crossed successfully giving a success rate of 97.3%. The procedure and the fluoroscopy time to cross the lesion were similar between the magnetic and conventional PCI groups (82.0 ± 67.9 seconds vs. 85.8 ± 59.2 seconds, P = 0.692, and 62.6 ± 57.6 seconds vs. 65.4 ± 49.5 seconds, P = 0.738, respectively). In Type A/B1 lesions, there seemed no difference in contrast use (2.7 ± 0.7 mL vs. 3.3 ± 0.9 mL, P = 0.284). But as lesion complexity increased from type B2 to C, significantly less contrast was needed in type B2 (5.1 ± 2.6 mL vs. 7.9 ± 4.0 mL, P = 0.019) and type C (9.8 ± 5.7 mL vs. 14.7 ± 7.4 mL, P = 0.030). No major adverse cardiac events were observed in either the MPCI or CPCI group. Conclusions: MNS assisted technique appears to be feasible and effective in NSTE‐ACS patients with more complex lesions; however, it probably offers little benefit in simple lesions like ACC/AHA type A/B1. (J Interven Cardiol 2011;24:549–554)     

Regional outcomes after admission for high-risk non-ST-segment elevation acute coronary syndromes

Purpose

An analysis of reginal variation across the United States in the treatment and outcomes of patients with non-ST-segment elevation acute coronary syndromes (NSTE ACS) has not been previously performed.

Subjects and Methods

We assessed contemporary practice and outcomes in 56,466 high-risk patients with NSTE ACS (positive cardiac markers and/or ischemic ST-segment changes) admitted to 310 hospitals across four defined regions in the United States from January 1, 2001, to September 30, 2003. Patient clinical characteristics, acute (<24 hours) and discharge medications, in-hospital procedures, and in-hospital case-fatality rates were evaluated.

Results

Statistically significant but clinically small differences in baseline characteristics including age, gender, rates of diabetes, hypertension, and smoking, as well as medical treatment, including a greater than 5% variation in acute use of beta-blockers, clopidogrel, and statins use, were noted across regions. Adjusted rates of revascularization were similar across regions. Overall in-hospital case-fatality rate was 4.1%, with the highest rates in the Midwest (4.6%) and the lowest in the Northeast (3.5%). Adjusted odds ratios (OR) (95% confidence interval [CI] for death were significantly higher in the Midwest (OR 1.42, CI 1.19-1.70), West (OR 1.40 CI 1.05-1.87), and South (OR 1.33, CI 1.08-1.62), compared with the Northeast.

Conclusions

Management of high-risk patients with NSTE ACS is relatively uniform across the United States. However, in-hospital case-fatality rates vary significantly by region, and the differences are not explained by adjustment for standard clinical variables.