AGATI, Luciano

AUTORE, Camillo

LINO S

MUSARO S.

PICCININNO M

English

Archivio della ricerca- Università di Roma La Sapienza

Role of Echocardiography in Acute ChestPain SyndromeCamillo Autore, MD, Luciano Agati, MD, Marco Piccininno, MD, Stefano Lino, MD, andSalvatore Musarò, MDFewer than one third of patients presenting to the emer-gency department with complaints of chest pain have anacute coronary syndrome. The electrocardiogram pro-vides a specific diagnosis only in 40% of patients withacute myocardial infarction. The presence of regionalwall-motion abnormalities at echocardiography in pa-tients without known coronary artery disease is a mod-erate indicator of an increased likelihood of acute myo-cardial ischemia or myocardial infarction with a positivepredictive accuracy of about 50%. More important, theabsence of regional wall-motion abnormalities identifiesa subset of patients unlikely to have a myocardial in-farction with a negative predictive accuracy of about95%. Echocardiography can provide incremental prog-nostic information to identify patients at risk of early orlate cardiac events, even after consideration of clinical,historical, and electrocardiographic variables. The ap-plication of new contrast agents to echocardiographywill probably allow an early and more accurate evalu-ation of patients with chest pain of uncertainsignificance. Q2000 by Excerpta Medica, Inc.Am J Cardiol 2000;86(suppl):41G–42GThe evaluation of patients presenting to the emer-gency department with chest pain is challengingfor the clinician. Little objective evidence is availableto differentiate patients with coronary artery diseasefrom those who have other causes of chest pain. It isestimated that 5 million patients present annually tothe emergency department with chest pain and thatonly a small fraction ultimately will be diagnosed ashaving an acute coronary syndrome (ACS). Data com-ing from a recent multicenter study have shown thatabout one third of patients presenting with chest painwere diagnosed as having an ACS, 10% with acutemyocardial infarction (MI) and 20% with unstableangina.1 Because of the limitation of historical, phys-ical, and electrocardiographic data, many of thesepatients are admitted to the hospital, with elevatedestimated costs for unnecessary admission. Despitethis low threshold for admission, up to 8% of patientswith acute MI are erroneously sent home.2 A greatproportion of these patients, about 75%, had less typ-ical symptoms and were less likely to have electro-cardiographic evidence of ischemia. Death or poten-tially lethal complications occurred in about 25% ofmissed patients with acute MI. The electrocardiogramprovides a specific diagnosis in about 40% of MIpatients and a specific diagnosis in only 5% of thewhole population. Thus, the diagnostic dilemma existsfor those patients with typical or atypical chest painand nondiagnostic electrocardiogram. This subset ofpatients accounts for 20–45% of patients presentingto the emergency department with chest pain; a sig-nificant proportion of these patients subsequently willshow signs of myocardial injury. Serial troponin ormyocardial creatine kinase isozyme (CK-MB) deter-mination and serial electrocardiographic recordingsrepresent the classical diagnostic tools of the emer-gency department clinician. Chest pain emergencyunits have been created to facilitate urgent therapy forpatients with a serious cardiovascular event and totriage lower-risk patients to less intensive, more cost-effective inpatient care or discharge home.ECHOCARDIOGRAPHYIn patients with chest pain and uncertain diagnosis,the echocardiographic demonstration of new wall-mo-tion abnormalities classifies them as having an ACS:The patient must be admitted to the hospital. What isthe diagnostic accuracy of echocardiography? Fewstudies have systematically examined the efficacy ofechocardiography in emergency department patientswith chest pain. Most studies performed with echo-cardiography in emergency department patients withpossible ischemia have attempted to identify onlythose with MI. However, the early identification ofpatients with unstable angina is also important; thenumber of patients admitted with unstable angina hasincreased. Published data on this issue are reported inTable I.3–6 Although these studies were performedwith different protocols on the selection of patientsand the timing of echocardiographic examination, dif-ferent sample populations, and different end pointsfrom which to consider the accuracy of echocardiog-raphy, they reported similar results with a very highnegative predictive value of 94–98% and a low pos-itive predictive value of 31–50%. The sensitivity wasvery low in the study of Gibler et al.5 However, thisstudy included a patient population at lower risk, with,5% having either MI or unstable angina; moreover,the lower sensitivity may also have resulted fromperforming echocardiography at the end of a 9-hourrule-out protocol, by which time wall-motion abnor-malities may have resolved. In the study of Kontos etal,6 excluding patients with historical or electrocardio-graphic evidence of previous MI significantly im-From the Department of Cardiovascular and Respiratory Sciences, “LaSapienza” University of Rome, Rome, Italy.Address for reprints: Camillo Autore, MD, Department of Cardio-vascular and Respiratory Sciences, University “La Sapienza” of Rome,Policlinico Umberto I, Viale del Policlinico 155, 00161 Rome Italy.41G©2000 by Excerpta Medica, Inc. 0002-9149/00/$ – see front matterAll rights reserved. PII S0002-9149(00)00991-7proved both sensitivity and specificity of echocardi-ography.Echocardiography may also diagnose other non-ischemic causes of chest pain whose identificationoffers the opportunity to initiate the appropriate man-agement: pulmonary embolism, hypertrophic cardio-myopathy, pericarditis, and aortic dissection.Echocardiography can provide incrementalprog-nostic information to identify patients at risk of earlyor late cardiac events, even after consideration ofclinical, historical, and electrocardiographic variables.The event rates within 48 hours of emergency depart-ment admission are different for patients with andwithout left-ventricular systolic dysfunction and forthose with different degrees of left-ventricular systolicdysfunction. A significantly greater event rate existsfor patients with left-ventricular systolic dysfunctionas a group and for those with even mild-to-moderatewall-motion abnormalities, compared with patientswithout left-ventricular dysfunction.4 In patients ad-mitted with chest pain, left-ventricular wall-motionindex was associated with an odds ratio of 2.2 forcomplications (recurrent myocardial ischemia, heartfailure, or arrhythmia),7 and in a multivariate modelthe results did not change appreciably after adjustingfor age, history of infarction, and the presence of anabnormal electrocardiogram. Moreover, in patientswho completed at least 4 hours of observation with anegative repeat electrocardiogram and cardiac serumenzymes, a negative stress echocardiogram was pre-dictive of an excellent prognosis.8ECHOCARDIOGRAPHY IN THEEMERGENCY DEPARTMENTEchocardiography must be performed by a trainedoperator and interpreted by a physician experienced inwall-motion analysis. Although images may be poorin some cases, adequate images are obtainable inabout 90% of cases. Wall motion may be normal inpatients with small infarctions; however, these pa-tients have a low risk of complications. Previous MIcan make it difficult to identify new wall-motion ab-normalities. The severity of ischemia, its duration, andthe extent of the ischemic zone may affect the persis-tence of wall-motion abnormalities in patients withunstable angina. Imaging performed after symptomresolution may be associated with reduced sensitivity,whereas performing echocardiography during thesymptomatic episode or within 1 hour will make thefindings more reliable. In the presence of new wall-motion abnormalities, we cannot rely on the underly-i g pathophysiologic substrate (ischemia, stunning,hibernation, or necrosis), although preservation ofnormal wall thickness and normal reflectivity suggestan acute event. Serial enzyme assays or electrocardi-ography will clarify whether an MI is the cause ofwall-motion abnormalities. Thus, the echocardio-graphic examination, although useful in patients withhigh suspicion of MI and nondiagnostic electrocardio-gram, cannot guide the physician to initiate reperfu-sion therapy.CONCLUSIONIn the emergency department, an early, bedside,echocardiographic examination is a safe and cost-effective technique to further evaluate patients withchest pain and elusive clinical findings and nondiag-nostic electrocardiograms; it may identify very low-risk patients who can be safely discharged or enter ashort rule-out protocol. In the near future, contrastechocardiography, combining a simultaneous visual-ization of left-ventricular wall motion and perfusion(by using a microvascular tracer), should improve thediagnostic accuracy of echocardiographic examinationin the emergency department.1. Roberts R, Fromm RE. Management of acute coronary syndromes based onrisk stratification by biochemical markers.Circulation 1998;98:1831–1833.2. Lee TH, Rouan GW, Weisberg MC, Brand DA, Acampora D, Stasiulewicz C,Walshon J, Terranova G, Gottlieb L, Goldstein-Wayne B, et al. Clinical charac-teristics and natural history of patients with acute myocardial infarction senthome from the emergency room.Am J Cardiol1987;60:219–224.3. Peels CH, Visser CA, Kupper AJ, Visser FC, Roos JP. Usefulness of two-dimensional echocardiography for immediate detection of myocardial ischemia inthe emergency room.Am J Cardiol1990;65:687–691.4. Sabia P, Afrookteh A, Touchstone DA, Keller MW, Esquivel L, Kaul S. Valueof regional wall motion abnormality in the emergency room diagnosis of acutemyocardial infarction: a prospective study using two-dimensional echocardiog-raphy.Circulation 1991;84(suppl I):85–92.5. Gibler WB, Runyon JP, Levy RC, Sayre MR, Kacich R, Hattemer CR,Hamilton C, Gerlach JW, Walsh RA. A rapid diagnostic and treatment center forpatients with chest pain in the Emergency Department.A n Emerg Med1995;25:1–8.6. Kontos MC, Arrowood JA, Paulsen WH, Nixon JV. Early echocardiographycan predict cardiac events in emergency department patients with chest pain.AnnEmerg Med1998;31:550–557.7. Fleischmann KE, Lee TH, Come PC, Goldman L, Cook FE, Caguoia E,Johnson PA, Albano MP, Lee RT. Echocardiographic prediction of complicationsin patients with chest pain.Am J Cardiol1997;79:292–298.8. Colon PJ III, Guarisco JS, Murgo J, Cheirif J. Utility of stress echocardiog-raphy in the triage of patients with atypical chest pain from the emergencydepartment.Am J Cardiol1998;82:1282–1284.TABLE I Echocardiographic Diagnosis of Acute Myocardial Infarction in Patients withChest PainYear Patients Sensitivity Specificity PPV NPVPeels et al3 1990 43 92 53 46 94Sabia et al4 1991 180 93 60 31 98Gibler et al5 1995 901 47 99 50 99Kontos et al6 1998 260 91 (97)* 75 (84)* 44 98*Excluding patients with historical or electrocardiographic evidence of previous myocardial infarction.NPV 5 negative predictive value; PPV 5 positive predictive value.42G THE AMERICAN JOURNAL OF CARDIOLOGYT VOL. 86 (4A) AUGUST 17, 2000

Role of echocardiography in acute chest pain syndrome

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Role of echocardiography in acute chest pain syndrome

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