Management of cardiogenic shock complicating myocardial infarction

Up to 10% of acute coronary syndromes are complicated by cardiogenic shock (CS) with contemporary mortality rates of 40–50%. The extent of ischemic myocardium has a profound impact on the initial, in-hospital, and post-discharge management and prognosis in this patient population. Individualized patient risk assessment plays an important role in determining appropriate revascularization, drug treatment with inotropes and vasopressors, mechanical circulatory support, intensive care support of other organ systems, hospital level of care triage, and allocation of clinical resources. This review will outline the underlying causes and diagnostic criteria, pathophysiology, and treatment of CS complicating acute coronary syndromes with a focus on (a) potential therapeutic issues from the perspective an interventional cardiologist, an emergency physician, and an intensive care physician, (b) the type of revascularization, and (c) new therapeutic advancements in pharmacologic and mechanical percutaneous circulatory support.     

Optimal course of treatment in acute cardiogenic shock complicating myocardial infarction

Introduction: About 5% of patients with myocardial infarction suffer from cardiogenic shock as a complication, with a mortality of ≥30%. Primary percutaneous coronary intervention as soon as possible is the most successful therapeutic approach. Prognosis depends not only on the extent of infarction, but also – and even more – on organ hypoperfusion with consequent development of multiple organ dysfunction syndrome.

Areas covered: This review covers diagnostic, monitoring and treatment concepts relevant for caring patients with cardiogenic shock complicating myocardial infarction. All major clinical trials have been selected for review of the recent data.

Expert commentary: For optimal care, not only primary percutaneous intervention of the occluded coronary artery is necessary, but also best intensive care medicine avoiding the development of multiple organ dysfunction syndrome and finally death. On contrary, intra-aortic balloon pump – though used for decades – is unable to reduce mortality of patients with cardiogenic shock complicating myocardial infarction.     

IABP在急性心肌梗死并心源性休克救治中应用现状

急性心肌梗死作为临床上常见的疾病,起病急,易引起并发症,其中,心源性休克死亡率较高。临床上常规应用补液、扩血管、升压及溶栓、血管重建等。近年来,IABP被广泛应用于临床,它作为一种辅助装置可以增加血液灌流,降低心脏后负荷,降低心脏做功,从而快速改善循环灌注不足状态。本综述研究IABP作为血流动力辅助装置,应用于急性心肌梗死并发心源性休克患者的临床现状。     

Oxidative stress and antioxidants in patients with cardiogenic shock complicating acute myocardial infarction

BACKGROUND: Lipid peroxidation and derived oxidized products are being intensively investigated because of their potential to cause injury and because of their pathogenic role in several diseases. The view that an excess of lipid peroxidation products is present and is relevant in the pathogenesis of cardiogenic shock-induced damage has still not received definitive support. METHODS: To evaluate the extent of lipid peroxidation, the status of enzymatic and nonenzymatic antioxidants in patients with cardiogenic shock that complicate acute myocardial infarction (AMI) and to compare with normal subjects. RESULTS: Compared with normal subjects, cardiogenic shock patients had higher malondialdehyde, conjugated dienes and reduced activities of erythrocyte antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and lower concentrations of reduced glutathione (GSH) in erythrocyte and in plasma GSH, vitamin C, vitamin E and in beta-carotene. CONCLUSIONS: Cardiogenic shock is associated with greater than normal lipid peroxidation and with an imbalance in antioxidants' status. These results indicate that low activities of SOD, CAT, GPx and low concentrations of GSH, vitamin C, vitamin E and beta-carotene in the circulation of patients with cardiogenic shock complicating AMI may be due to increased utilization to scavenge lipid peroxides. Decrease in plasma concentrations of GSH, vitamin E and beta-carotene seems to be responsible for the elevation of lipid peroxidation in cardiogenic shock complicating AMI compared with MI.     

Clinical review: mechanical circulatory support for cardiogenic shock complicating acute myocardial infarction

Acute myocardial infarction is one of the 10 leading reasons for admission to adult critical care units. In-hospital mortality for this condition has remained static in recent years, and this is related primarily to the development of cardiogenic shock. Recent advances in reperfusion therapies have had little impact on the mortality of cardiogenic shock. This may be attributable to the underutilization of life support technology that may assist or completely supplant the patient's own cardiac output until adequate myocardial recovery is established or long-term therapy can be initiated. Clinicians working in the intensive care environment are increasingly likely to be exposed to these technologies. The purpose of this review is to outline the various techniques of mechanical circulatory support and discuss the latest evidence for their use in cardiogenic shock complicating acute myocardial infarction.     

急性心肌梗死合并心源性休克的血运重建策略

尽管早期血运重建的广泛开展,急性心肌梗死合并心源性休克仍是治疗的重点和难点。另外,急性心肌梗死伴心源性休克患者往往合并多支血管病变,其最佳血运重建策略尚无定论。本文就心源性休克定义及病因,急性心肌梗死合并心源性休克早期血运重建的重要性及血运重建策略选择方面做一综述。     

Aortic counterpulsation in cardiogenic shock during acute myocardial infarction

Intra-aortic balloon counterpulsation is the most widely used form of mechanical hemodynamic support in the setting of cardiogenic shock due to ST-segment elevation myocardial infarction (STEMI). Intra-aortic balloon pump (IABP) is also strongly recommended (class 1b) in the current European guidelines for treatment of STEMI. The evidence of a possible benefit of IABP in this setting is based mainly on registry data and a few randomized trials. Cardiogenic shock and subsequent death due to STEMI result from three factors: hemodynamic deterioration, occurrence of multiorgan dysfunction and systemic inflammatory response. IABP does not cause an immediate improvement in blood pressure, but the recent SHOCK II trial shows positive effects on multiorgan dysfunction. Some experimental and clinical studies have indicated that IABP results in hemodynamic benefits as a result of afterload reduction and diastolic augmentation with improvement of coronary perfusion. However, the effect on cardiac output is modest and may not be sufficient to reduce mortality. Furthermore we can say that the use of IABP before coronary revascularization in the setting of STEMI complicated with cardiogenic shock may make the interventional procedure safer by improving left ventricular unloading. The purpose of the present review is to clarify the state of the art on this topic.     

Cardiogenic shock complicating myocardial infarction

Cardiogenic shock is the primary cause of death among patients hospitalized with acute myocardial infarction. It is defined as tissue hypoperfusion resulting from ventricular pump failure in the presence of adequate intravascular volume. These patients need rapid assessment and appropriate institution of supportive therapies including vasopressor and inotropic agents, ventilatory support, and intra-aortic balloon pump counterpulsation. Emergency coronary artery revascularization is the only therapy that reduces mortality, and this should be provided early to patients to achieve maximal benefit, unless further care is deemed futile. Whereas newer support devices can provide better hemodynamic augmentation, their impact on mortality is limited. Novel therapies are needed to further decrease mortality rates, which remain high despite reperfusion therapy.     

主动脉球囊反搏在急性心肌梗死合并心源性休克病人中的应用效果分析

在急性心肌梗死(acute myocardial infarction, AMI)的病程发展过程中,心源性休克是严重的合并症之一.因心肌坏死、收缩能力降低使心泵血功能严重障碍,导致病人病死率极高,达80%～100%[1],严重威胁病人的生命,并给家庭及社会造成不同程度的疾病负担.     

Current clinical management of acute myocardial infarction complicated by cardiogenic shock

ABSTRACT

Introduction

Cardiogenic shock (CS) remains the leading cause of death among patients admitted with acute myocardial infarction (AMI). Early restoration of blood flow of the infarct-related artery is of paramount importance, either with percutaneous coronary intervention (PCI) or with coronary artery bypass grafting (CABG). In addition, early risk stratification is a critical task and required to guide complex decisions on management and therapy of CS after AMI. The use of short-term mechanical circulatory support (MCS) is increasing, although evidence for their effectiveness is limited.     

Proinflammatory cytokines in acute myocardial infarction with and without cardiogenic shock

BACKGROUND: Inflammatory response is an important feature of acute coronary syndromes and myocardial infarction (MI). The prognostic value of proinflammatory cytokines in patients with acute MI complicated by cardiogenic shock is unknown. METHODS AND RESULTS: In 41 patients admitted with acute MI (age 60 +/- 11 years, six females, 19 Killip class IV) serial plasma concentration of tumor necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6) and interleukin 1 receptor antagonist (IL-1Ra) were measured. Seven patients with cardiogenic shock (CS) developed a systemic inflammatory response syndrome (SIRS). Patients with CS-particularly those who developed SIRS-showed significantly higher cytokine levels than patients with uncomplicated MI. In patients with CS and SIRS peak levels of IL-1Ra were 223,973 pg/ml, IL-6 252.8 pg/ml and TNF-alpha 7.0 pg/ml. In CS without SIRS IL-1Ra levels were 19,988 pg/ml, IL-6 109.3 pg/ml and TNF-alpha 3.8 pg/ml. In uncomplicated MI peak IL-1Ra levels were 1,088 pg/ml, IL-6 34.1 pg/ml and TNF-alpha 2.6 pg/ml. CONCLUSIONS: The inflammation-associated cytokines TNF-alpha, IL-6 and IL-1Ra are significantly elevated in patients with MI complicated by CS when compared to patients with uncomplicated MI. Among shock-patients IL-1Ra levels are promising diagnostic markers for early identification of patients developing SIRS, heralding a poor outcome.     

Pathophysiology of acute myocardial infarction

More than 80% of acute myocardial infarcts are the result of coronary atherosclerosis with superimposed luminal thrombus. Uncommon causes of myocardial infarction include coronary spasm, coronary embolism, and thrombosis in nonatherosclerotic normal vessels. Additionally, concentric subendocardial necrosis may result from global ischemia and reperfusion in cases of prolonged cardiac arrest with resuscitation. Myocardial ischemia shares features with other types of myocyte necrosis, such as that caused by inflammation, but specific changes result from myocyte hypoxia that vary based on length of occlusion of the vessel, duration between occlusion and reperfusion, and presence of collateral circulation.     

急性心肌梗死并发心源性休克的危险因素分析

目的 从合并症中筛选急性心肌梗死(AMI)并发心源性休克(CS)的危险因素,为临床早期识别高危患者提供依据.方法 对解放军总医院1993年1月至2009年12月17年中收治的5523例AMI患者资料进行回顾性分析,根据患者是否发生CS分为两组,应用多因素logistic回归模型筛选AMI患者并发CS的危险因素.结果 5523例AMI患者中有197例发生了CS,发生率为3.57％;CS组30 d住院病死率明显高于非CS组[55.33％(109/197)比7.49％(399/5326),P＜0.001].Logistic回归分析显示,年龄[优势比(OR)=1.03,95％可信区间(95％CI)为1.02 ～ 1.05,P＜0.001]、陈旧性心肌梗死(OR=1.57,95％CI为1.13～2.19,P=0.007)、陈旧性脑梗死(OR=1.98,95％CI为1.20～ 3.27,P=0.008)、慢性肾功能不全(OR=1.76,95％ CI为1.23～2.51,P=0.002)、肺部感染(OR=1.72,95％CI为1.17～2.52,P=0.006)是AMI并发CS的独立危险因素.受试者工作特征曲线(ROC曲线)分析显示该模型有较高的判别CS患者的能力,ROC曲线下面积(AUC)为0.81(95％CI为0.75～0.85,P＜0.001).结论 高龄、合并陈旧性心肌梗死、陈旧性脑梗死、慢性肾功能不全、肺部感染多种疾病是AMI并发CS的危险因素.     

急性心肌梗死并发心源性休克的临床特征与救治

目的　评价急性心肌梗死 (AMI)并心源性休克的临床特征 ,总结救治经验。方法　 10 8例 AMI患者 ,分为休克组 (11例 )与非休克组 (97例 ) ,对比分析两组患者的临床特征、处理与近期预后的异同。结果　两组患者年龄、性别、糖尿病、冠心病、高脂血症、陈旧性心肌梗死病史及梗死部位无显著性差异 (P均 >0 .0 5 )。与非休克组比较 ,休克组肌酸磷酸激酶和心肌肌钙蛋白 I升高〔(31979.7± 2 2 2 71.1) nm ol· s- 1· L- 1比 (17795 .2± 14 979.7) nmol· s- 1· L- 1和 (90 .7± 6 1.1) μg/ L 比 (39.9± 5 2 .1) μg/ L,P均 <0 .0 5〕,左室射血分数降低 (0 .4 6± 0 .12比 0 .5 5± 0 .12 ,P<0 .0 5 ) ,急性肺水肿、心律失常和肺炎合并症增多 (6 4 %比 14 % ,P<0 .0 0 1;5 5 %比 2 1% ,P<0 .0 5 ;4 6 %比 12 % ,P<0 .0 1) ,采用溶栓治疗、冠状动脉造影、主动脉内气囊反搏者多 (46 %比 18% ,73%比 2 6 %和 36 %比 4 % ,P均 <0 .0 5 )。两组住院期病死率无显著性差异 (0比 4 % ,P>0 .0 5 )。结论　 AMI并休克者心肌梗死面积大 ,急性肺水肿、心律失常和肺炎合并症多 ,需主动脉内气囊反搏者多。正确判断、严密监测、及时有效处理 ,可明显改善患者的早期预后。     

主动脉内球囊反搏支持下急性心肌梗死的急诊介入治疗

目的探讨主动脉内球囊反搏支持下的急性心肌梗死合并心源性休克患者行急诊介入治疗的可行性、安全性及疗效。方法回顾性分析浙江大学医学院附属第2医院2005年9月至2007年2月确诊急性心肌梗死合并心源性休克,在主动脉内球囊反搏支持下行急诊介入治疗的患者27例,观察血流动力学改变、急诊介入治疗特点、住院期间及术后1个月的病死率、主要心脏不良事件、心功能恢复状况。结果应用主动脉内球囊反搏30min后血流动力学即开始改善,2～6h达血流动力学稳定。27例患者在主动脉内球囊反搏支持下均成功完成急诊介入治疗,无术中死亡,住院期间死亡2例,随访1个月死亡1例。术后1个月的左室射血分数和室壁运动评分均较术后第1天显著改善。结论主动脉内球囊反搏支持下的急诊介入治疗能显著提高急性心肌梗死合并心源性休克患者的生存率,显著改善心肌梗死后的心功能状态。     

Management of cardiogenic shock attributable to acute myocardial infarction in the reperfusion era

Cardiogenic shock is the leading cause of death among patients hospitalized with acute myocardial infarction. It is defined as tissue hypoperfusion resulting from ventricular pump failure in the presence of adequate intravascular volume. Rapid assessment and triage of patients presenting in cardiogenic shock followed by appropriate institution of supportive therapies including vasopressor and inotropic agents, mechanical ventilatory support, and intra-aortic balloon pump counterpulsation are critical for effective management of these patients. However, emergency percutaneous coronary intervention or coronary artery bypass graft surgery is required to decrease mortality rates. Novel approaches, including inhibition of nitric oxide synthase and new mechanical support devices, may further decrease mortality rates, which remain high despite reperfusion therapy.     

Efficacy of veno-arterial extracorporeal membrane oxygenation in acute myocardial infarction with cardiogenic shock

AimWe analyzed the results of acute myocardial infarction (AMI) complicated by cardiogenic shock (CS) necessitating extracorporeal membrane oxygenation (ECMO), and investigated for the associated risk factors for poor clinical outcomes.MethodsWe retrospectively reviewed the medical records of 27 patients who required ECMO for AMI associated with CS between April 2006 and July 2010. Mean age was 63.7 ± 11.0 (range: 45–81) years, and there were 16 males (59.3%).ResultsThe mean duration of ECMO support was 30.2 ± 30.1 (range: 1–141) h. Cardiopulmonary resuscitations (CPR) were performed in 21 patients (77.8%) before ECMO initiation. Twenty-two patients (81.5%) were successfully weaned off ECMO, and 16 patients (59.3%) survived to discharge. The 30-day mortality was 37.0% (10/27 patients). Complications developed in 17 patients (63.0%: pneumonia in 10 patients, acute renal failure in 10 patients, massive bleeding in 4 patients, and thromboembolic event in 1 patient). The period between CPR initiation and ECMO commencement was a significant risk factor for ECMO weaning failure. High pre-ECMO serum lactate level was identified as a significant risk factor for poor survival on univariated and multivariated analysis.ConclusionECMO support could improve survival in patients who suffer AMI associated with CS, and early ECMO initiation yields better outcomes (successful ECMO weaning).