A Case of Spontaneous Coronary Artery Dissection: It is Not Always Plaque Rupture

Background

Spontaneous coronary artery dissection (SCAD) is an extremely rare cause of acute coronary syndrome (ACS). Patients may present with a broad spectrum of clinical scenarios, ranging from angina pectoris to myocardial infarction, cardiogenic shock, and sudden death. Standard therapy has not been established; current treatments range from conservative management to percutaneous revascularization or coronary artery bypass surgery.

Objective

SCAD greatly mimics ACS, and this diagnosis should be considered when evaluating young patients who present with ACS with or without classical risk factors for coronary artery disease.

Case Report

We report a case of a 45-year old man who presented with chest pain typical of ACS. He had no risk factors except for a smoking history of 2.5 pack-years. Once the clinical findings suggested acute inferolateral myocardial infarction, the patient underwent emergent cardiac catheterization, which revealed left anterior descending coronary artery dissection. This in itself is not a common cause of inferolateral ST elevation changes on electrocardiogram.

Conclusion

This case highlights the fact that although SCAD is a rare entity, it is increasingly being recognized as a significant cause of ACS. Urgent angiography should be considered if SCAD is suspected, because early diagnosis and appropriate management significantly improve the outcome in these patients.     

Historical perspective and contemporary management of acute coronary syndromes: from MONA to THROMBINS2

Acute coronary syndrome (ACS) remains a major burden on morbidity and mortality in the United States. Medical professionals and students often use the mnemonic ‘MONA’ (morphine, oxygen, nitroglycerin and aspirin) to recall treatments for ACS; however, this list of therapies is outdated. We provide a historical perspective on ‘MONA,’ attempt to uncover its origin in the medical literature, and demonstrate the myriad changes that have occurred over the last 50 years of ACS management. We have developed a novel mnemonic, ‘THROMBINS₂’ (thienopyridines, heparin/enoxaparin, renin–angiotensin system blockers, oxygen, morphine, beta blocker, intervention, nitroglycerin, statin/salicylate) to help bedside clinicians recall all the elements of contemporary ACS management. We demonstrate the mortality benefit for each component of contemporary ACS management, correlating the continued improvement with historical data on mortality after myocardial infarction. We encourage providers to utilize this mnemonic to explore options and guide treatments in ACS patients.     

Usefulness of synthesized 18-lead electrocardiography in the diagnosis of ST-elevation myocardial infarction: A pilot study

Objective

This was a pilot retrospective case-series study performed to investigate whether synthesized 18-lead electrocardiogram (ECG) could improve the accuracy of infarction site diagnosis in patients presenting with ST-elevation myocardial infarction (STEMI).

The utility of the standard 12-lead electrocardiogram in the prediction of proximal right coronary artery occlusion in acute inferior myocardial infarction

Prior studies have proposed several electrocardiogram criteria for identifying patients with acute inferior ST-segment elevation myocardial infarction (iSTEMI) caused by obstruction of the proximal part of the right coronary artery (RCA). We applied 11 of these criteria and three new ones to the admission electrocardiograms of 80 patients admitted with an acute iSTEMI in order to evaluate their utility. All patients received thrombolytic treatment and underwent coronary angiography during the hospitalization. Four previously described criteria (ST-segment depression in lead V1, ST-segment depression in leads V1-V3, maximum ST-segment depression in the precordial leads, and ST-segment depression in lead V3 of 1) were useful in identifying patients with obstruction of the proximal part of the RCA. Among the six criteria, ST depression in V1-V3 had the highest specificity (77.2%) and positive predictive value (56.5%), and a new criterion-the arithmetic sum of the ST-elevation in V3/ST-elevation in III < 0.5--had the highest sensitivity (80.9%) and negative predictive value (86.7%). Six criteria were helpful in identifying patients with acute iSTEMI caused by obstruction of the proximal part of the RCA. One of these has not been previously reported and has the higher specificity and negative predictive value.     

aVR导联ST段偏移性急性下壁心肌梗死的犯罪血管判断及预后分析

目的研究aVR导联ST段偏移对急性下壁心肌梗死（IAMI）犯罪血管的判断及预后分析。方法收集2000～2008年IAMI（包括同时伴右心室梗死）76例,按入院时aVR导联ST段有否偏移分为aVR导联ST段偏移组37例,无ST段偏移组39例,全部患者行冠状动脉造影术（发病后8小时内）,根据冠状动脉造影及临床资料,分析患者冠状动脉病变部位及临床预后。结果①ST段偏移组37例患者中,aVR导联ST段抬高26例,其中右冠状动脉（RCA）闭塞24例,左回旋支（LCX）闭塞2例;aVR导联ST段下移11例,其中RCA闭塞1例,LCX闭塞10例。②无ST段偏移组39例患者中,RCA闭塞37例,LCX闭塞2例。③ST段偏移组合并有糖尿病、并发症、心肌梗死后心绞痛的发生率及住院病死率均明显高于无ST段偏移组;ST段偏移组PCI后心肌缺血再灌注损伤的发生率明显高于无ST段偏移组。结论aVR导联ST段偏移情况对预测IAMI的犯罪血管、判断病情预后有较好的参考价值,是梗死相关动脉成功再通后心肌缺血再灌注损伤的强力预测因素。     

不同血栓抽吸方法治疗ST段抬高心肌梗死的效果比较

目的 采用不同血栓抽吸方法治疗急性ST段抬高心肌梗死,了解疗效的差异.方法 急性ST段抬高心肌梗死患者,行经皮冠状动脉介入治疗(percutaneous coronary intervention,PCI)术;冠状动脉造影示靶血管可见血栓负荷;术中采用抽吸导管抽吸血栓.排除血流动力学不稳定;支架内血栓形成;冠状动脉旁路移植术(coronary artery bypass grafting,CABG)术后;年龄＞75岁;既往脑卒中病史; PCI失败或抽吸导管无法通过病变的患者.所有入选患者根据术中应用手动抽吸导管的情况分为3组:只单独Diver抽吸导管抽吸患者304例,只单独Export抽吸导管抽吸患者452例,以及此两种抽吸导管组合抽吸患者203例.记录3组患者基线资料,比较3组间血流分级(TIMI),住院期间及出院后6个月内主要心血管不良事件.结果 抽吸导管组合抽吸组患者的年龄更大(56.3±14.5)岁 vs (55.7±12.0)岁 vs (58.4±17.3)岁(P＜0.01),合并高血压的比例更高(61.3% vs 62.1% vs 65.0%,P＜0.01),缺血时间相对较长(4.9±5.3) h vs (4.3±8.7) h vs (5.8±7.2) h(P＜0.01).PCI术中3组术前的TIMI0级的患者以两种抽吸导管组合抽吸组居多(51.0% vs 54.8% vs 55.9%,P＜0.05),其余各组在术前和术后的TIMI差异均无统计学意义.结论血栓抽吸导管组合抽吸未能进一步降低无复流的发生率.     

两种负荷心电图试验对冠心病的诊断价值研究

目的 评价运动心电图试验(EET)、双嘧达莫心电图负荷试验(DPET)及联合应用(联合试验AD对冠心病的诊断价值。方法 选择183例冠状动脉造影(CAG)检查的患者，并在同期内(间隔小于1周)接受。EET、DPET检查。将CAG结果分别与EET、DPET和AT结果进行对比分析。结果 这两种无伤检查和联合检查诊断冠心病的敏感性分别为67．2％、60．3％和55．2％，特异性分别为：70．4％、74．4％和92．8％，准确性分别为：69．4％、69．9％和85．3％。结论 EET和DPET联合应用对冠心病的诊断具有较高的特异性和准确性，且费用低、无创伤，适宜基层医院推广。     

体表心电图对急性下壁心肌梗死患者梗死相关动脉及闭塞部位的预测价值

目的：探讨体表心电图(ECG)对 ST 段抬高性急性下壁心肌梗死(IAMI)患者梗死相关动脉及闭塞部位的预测价值。方法选择 ST 段抬高性 IAMI 患者95例,记录入院时18导联 ECG,并行急诊经皮冠状动脉介入治疗,按照冠状动脉造影(CAG)结果进行分析。结果 ST Ⅲ抬高>STⅡ预测右冠状动脉(RCA)闭塞的敏感度和特异度分别为93.4%、73.7%;ST V3/Ⅲ≤1.2、ST aVL 下移>STⅠ预测 RCA 闭塞的敏感度分别为88.2%和92.1%;而 ST V3R-V5R 抬高判断 RCA 闭塞的特异度为100%;ST V3/Ⅲ<0.5预测 RCA 近段闭塞的敏感度为86.7%;ST V4R 抬高判断 RCA 近段闭塞的特异度为93.5%,ST Ⅲ抬高≤ STⅡ判断左回旋支(LCX)闭塞的敏感度和特异度分别为73.7%和93.4%,ST V2压低>0.15 mV 预测 LCX 近段闭塞的敏感度为87.5%。结论体表心电图Ⅲ、V3、V4R、aVL 导联 ST 段改变对预测 RCA 闭塞有价值,而 ST V2压低有助于预测 LCX 闭塞。     

Dual Antiplatelet Therapy for Long-term Secondary Prevention of Atherosclerotic Cardiovascular Events

PurposeDual antiplatelet therapy (DAPT) with aspirin and a P2Y₁₂ inhibitor is currently recommended to prevent further ischemic events after percutaneous coronary intervention and acute coronary syndrome (ACS). Guidelines currently recommend a minimum of 6 months after elective drug-eluting stent placement and at least 12 months of DAPT after ACS; however, the benefits of prolonged treatment are unclear. The purpose of this review was to conduct a detailed examination of the data refuting or supporting the use of DAPT beyond 1 year in patients with ACS and in patients receiving percutaneous coronary intervention with stenting.MethodsA search of PubMed was performed to identify articles published in the last 20 years that addressed the role of DAPT beyond 12 months’ duration.FindingsA number of studies have shown ischemic benefits associated with prolonging DAPT beyond 12 months, but this finding is dependent on the patient population studied and the quality of the study design. Many studies also show that longer duration therapy has been associated with increased bleeding risk. In patients with previous myocardial infarction completing at least 1 year of DAPT, continuing DAPT with a reduced dose of ticagrelor 60 mg BID is a regimen to be considered for these patients; in general ACS patients, a reduced dose of 60 mg BID of ticagrelor after the first year of DAPT should be considered; and in the post–percutaneous coronary intervention patients, DAPT beyond 1 year should be considered after careful evaluation of the patient's thrombotic and bleeding risks.ImplicationsThe duration of DAPT, and the choice of P2Y₁₂ inhibitor, should be tailored to the individual patient. To optimize patient outcomes, the benefits and risks associated with prolonging DAPT need to be evaluated, considering comorbidities and the presence of bleeding and ischemic risk factors. Despite some limitations, risk scores, such as the DAPT score, are available to help guide decisions for the best approach for each patient.     

急性下壁心肌梗死心电图的改变与相关冠脉病变的关系

[目的]探讨急性下壁心肌梗死时心电图ST段改变对判断心肌梗死相关冠状动脉病变的关系.[方法]对50例急性下壁心肌梗死ST段改变与冠状动脉造影结果对比分析.[结果]①血管闭塞发生在右冠状动脉占70.0%,回旋支占30.0% ②ST段抬高Ⅲ/Ⅱ〉1,提示右冠状动脉阻塞的敏感性91.4%,特异性86.7% Ⅲ/Ⅱ≤1提示回旋支闭塞的敏感性86.7%,特异性91.4% ③Ⅰ、aVL导联ST段压低预测右冠脉阻塞敏感性71.4%,特异性80.0%,Ⅰ、aVL导联ST段抬高预测回旋支阻塞敏感性80.0%,特异性71.4%.[结论]下壁心肌梗死时心电图对梗死相关动脉有重要的预测价值.     

急诊经皮冠状动脉介入治疗术前心电图参数对术后心肌再灌注水平的预测价值

目的探讨急性ST段抬高型心肌梗死（STEMI）患者经皮冠状动脉介入治疗（PCI）术前心电图参数预测急诊PCI术后的心肌再灌注水平的价值,寻找能够尽早提示急诊PCI术后疗效的检测手段。方法回顾性分析65例行急诊PCI术的急性STEMI患者发病时心电图的各项参数与术后心肌梗死溶栓治疗（TIMI）分级的相关程度,筛选无复流现象的独立危险因素。结果65例急诊PCI患者中,无复流患者17例,发生率为26．2％。比较无复流组与正常血流组患者的术前心电图参数,ST段抬高类型差异有统计学意义（P〈0．05）,以ST段呈C型抬高者无复流发生率最高（34．8％,16／46）;而QRS记分、ST段抬高导联数目、ST段抬高总和差异无统计学意义。多因素logistic回归分析表明：C型ST段抬高是无复流现象发生的独立危险因素（OR=8．956,95％CI=1．189,67．456,P=0．033）。结论作为一项简明的心电图参数,C型ST段抬高可以预测急诊PCI术后冠状动脉无复流现象,有利于术前、术中预见性地采取防治该现象的措施。     

Synthetic Cannabinoid Abuse Resulting in ST-Segment Elevation Myocardial Infarction Requiring Percutaneous Coronary Intervention

Background

Synthetic cannabinoids (SC) are recreational designer drugs intended to mimic delta-9-tetrahydrocannabinol while surreptitiously circumventing classification by the Drug Enforcement Administration.

ST Segment Elevation Differs Depending on the Method of Measurement

Objectives: The literature seldom specifies the location or method of measurement of ST segment elevation (STE) for determining eligibility in reperfusion trials. The objective of this study was to assess if different methods of measurement of STE in precordial leads of patients with anterior acute myocardial infarction due to left anterior descending occlusion result in significantly different scores.
Methods: This was a retrospective review of diagnostic electrocardiograms (ECGs) of consecutive patients presenting to our emergency department with acute myocardial infarction who had emergent primary percutaneous coronary intervention, left anterior descending occlusion, and no bundle branch block. STE was measured at the J point and at 60 milliseconds after the J point, relative to the PR segment, in leads V1–V6. STE by the two methods was compared for each lead, as were ST scores (sum of STE in leads V1–V6) and the sum of the STE in V2–V4. Eligibility for reperfusion therapy using 1-mm and 2-mm STE criteria in two consecutive anterior leads, as well as ST scores and the sum of the STE in V2–V4, were evaluated.
Results: Thirty-seven ECGs were analyzed. Mean ST measurements in every lead were significantly lower when measured at the J point versus 60 milliseconds after the J point, as were ST scores (9.7 ± 2.14 mm vs. 14.9 ± 2.69 mm; p < 0.00001). Fewer ECGs met enrollment criteria when based on STE at the J point versus at 60 milliseconds after the J point. Fewer ECGs met an ST score of 6 mm when measured at the J point (70% vs. 88%).
Conclusions: In anterior STE myocardial infarction, STE measurements produce different results depending on the method of measurement. Future clinical trials should specify the method of measurement.     

Current controversies in the use of aspirin and ticagrelor for the treatment of thrombotic events

Introduction: A P2Y₁₂ inhibitor plus aspirin is the most widely used antiplatelet strategy to prevent adverse outcomes in the setting of atherothrombotic vascular disease.

Areas covered: A paucity of robust evidence for an optimal dose, gastrointestinal toxicity, ineffectiveness in high-risk patients and interactions with other antiplatelet agents, are major controversies associated with aspirin therapy. Ticagrelor is a reversibly binding oral P2Y₁₂ receptor blocker that mediates potent inhibition of adenosine diphosphate-induced platelet function. It is more effective than clopidogrel in preventing thrombotic events in acute coronary syndrome patients. The absence of a beneficial effect for ticagrelor versus clopidogrel in ACS observed in the North American subgroup of the PLATelet inhibition and patient Outcomes (PLATO) trial has been attributed to a higher concomitant aspirin dose.

Expert commentary: Ongoing studies are now investigating the plausibility of removing aspirin therapy in the setting of potent P2Y₁₂ receptor blockade via ticagrelor monotherapy or replacing aspirin with an oral anticoagulant.     

冠状动脉造影正常的急性心肌梗死的临床特点和预后

【目的】探讨冠状动脉造影正常的急性心肌梗死(AMI)患者的临床特点及相关病因和预后。【方法】对432例临床诊断为AMI患者进行冠状动脉造影,冠状动脉造影正常的AMI为观察组,冠状动脉造影异常者为对照组。观察冠状动脉造影正常的AMI患者的易患因素、临床特点及预后。【结果】432例AMI患者中,22例冠状动脉造影显示正常(占5.09%),观察组年龄明显低于对照组(P<0.05),呼吸道感染、吸烟、过度悲伤、高脂饮食、过敏和免疫系统疾病较对照组明显增多(P<0.01),而高血压、高血脂及糖尿病较对照组明显降低(P<0.01),同时观察组左室功能较好,梗死后心绞痛发生率低(P<0.05)。【结论】AMI患者中约有5.09%的患者冠状动脉造影正常。此类患者既往多无高血压、糖尿病及高血脂病史,以年龄轻、呼吸道感染、吸烟、高脂饮食和过度悲伤、患有过敏和免疫系统疾病、心功能预后较好为其临床特点。     

急性ST段抬高型心肌梗死行急诊冠状动脉介入术患者家属真实体验的质性研究

目的探讨急性ST段抬高型心肌梗死(ST-segment elevation myocardial infarction,STEMI)行急诊冠状动脉介入术(percutaneous coronary intervention,PCI)治疗患者家属在早期就诊、PCI术前后、入住冠心病重症监护室(cardiac care unit,CCU)和普通病房等不同阶段的体验及需求。方法采用半结构式和Colaizzi现象学研究法多次访谈患者家属,并分析资料。结果 18名家属体验及需求归纳为:(1)急诊室阶段,惊恐与无助,震惊与自责,焦虑与担忧;(2)CCU阶段,担心照顾不周以及患者病情加重,渴望守护;(3)普通病房阶段,缺乏照护经验,告知病情态度不一,担忧未来,期待医护人员支持。结论家属在患者就医不同阶段的体验及需求不同,应根据不同阶段的需求提供有针对性的护理措施。     

急性下壁心肌梗死累及右心室或侧后壁时对心电图胸前导联ST段影响的研究

目的 :探讨急性下壁心肌梗死累及右心室或侧后壁时 ,对心电图胸前导联 ST段改变的影响及其临床意义。方法 :对 1 1 8例首次急性下壁心肌梗死患者的心电图进行比较分析。结果 :急性下壁心肌梗死时心电图下壁导联 ST段抬高幅度与胸前导联 ST段改变均呈负相关 (P均 <0 .0 1 )。在 1 6例同时合并右室梗死的患者中 ,胸前导联 ST段改变幅度〔V2 导联为 (0 .6 3± 1 .82 ) mm〕及与下壁导联 ST段抬高的比值 (V2 / a VF为0 .84± 1 .6 1 )均高于单纯下壁梗死组〔V2 导联为 (0 .35± 1 .6 5 ) m m,V2 / a VF为 0 .2 9± 1 .2 8〕;而 38例同时合并侧后壁梗死的患者胸前导联 ST段压低的幅度〔V2 导联为 (- 1 .2 0± 1 .5 2 ) mm〕及与下壁导联 ST段抬高的比值 (V2 / a VF为 - 0 .33± 1 .1 5 )均低于单纯下壁梗死组 ,且差异具有显著性意义 (P<0 .0 1或 P<0 .0 5 )。如去掉累及右室梗死和侧后壁梗死的病例 ,可使急性下壁心肌梗死心电图下壁导联与胸前导联 ST段的相关性显著提高 (r=- 0 .797,P<0 .0 1 )。结论 :急性下壁心肌梗死患者同时合并右室梗死可使心电图胸前导联 ST段趋于抬高 ;而合并侧后壁梗死则使胸前导联 ST段进一步降低 ,二者呈相反关系。     

Single Coronary Artery Presenting with Cardiogenic Shock due to Acute Myocardial Infarction

Percutaneous coronary revascularization plays an important role in the management of acute coronary syndrome. Unpredictable angiographic findings of anomalous coronary arteries may, however, compromise the otherwise high and predictable success rates of this intervention. We report a case of failed coronary angioplasty of the left anterior descending artery through an anomalous left main coronary artery originating from the right coronary sinus in a 33-year-old man with acute myocardial infarction complicated by cardiogenic shock. Subsequently the patient performed successful emergency coronary artery bypass graft.     

Comparison of some criteria for diagnosing a myocardial infarction after aorto-coronary bypass grafting (CABG)

Summary. The incidence of myocardial infarction during a 1-year follow-up period after coronary bypass surgery (CABG), i.e. a recent myocardial infarction (RMI), was studied in 86 patients. Different criteria for the diagnosis of a RMI were compared. Clinical observation, including ECG and serum enzyme analysis, diagnosed RMI in 8% of patients. Specific ECG changes indicating RMI (ECGsp) occurred in 12% of cases, and if less specific ECG changes were also taken into account (ECGsp+nonsp) RMI was found in 30% of cases. Asynergy, detected by two-plane ventriculography, indicated RMI in 24% of the patients, and was probably the most valid of the criteria examined. The differences in diagnostic accuracy of the various criteria highlight the importance of defining diagnostic criteria.