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A Fatal Standard of Care for Heart Attack Victims?

By Gene Moen

Published in Trial News, the monthly newspaperof the Washington State Trial Lawyers’Association in January 1998

Medical negligence wrongfuldeath cases involving a delayin diagnosis and treatmentof cardiovascular disease often presenta common fact pattern. Autopsiesreveal atherosclerotic narrowing ofcoronary arteries with the left anteriordescending artery the most commonsite of disease. In the weeks and sometimesmonths prior to their deaths,patients report chest pain radiating totheir shoulders and arms or a tightnessin their chests that was aggravated byexercise. Physicians ruled out cardiacproblems based on exercise testing andelectrocardiograms (EKG), and treatedfor a variety of ailments includingulcers, gallstones, and panic disorder.The opportunity was thus lost for adiagnosis of ischemic heart diseaseand use of life-saving procedures suchas angioplasty or bypass surgery.

In retrospect these erroneousdiagnoses are disturbing. However,the medical literature is far from clearin establishing a standard of care forthe patient with ongoing chest pain.For years, physicians have relied onexercise stress testing (treadmill test),but this reliance is misplaced and maybe fatal. Recent publications haveconcluded that “false negative” resultsfrom an exercise test are common, andthat under certain circumstances thetest may not be useful in identifyingsomeone with coronary artery diseaseand a risk of sudden death from cardiacarrest. Annals of Emergency Medicine19:1-170 (1997) and Am Heart J.123:1312-1323 (1992).

Recent reports advocate placinggreater importance on a quantitativeanalysis of risk factors and symptoms.A study by the National Institutes ofHealth identified the acute cardiacischemia (ACI) predictive instrument,which is a computer program thatyields a single number percent risk ofACI based on risk factors, symptoms,and EKG profiles. The results may beprinted at the top of an EKG monitorstrip. In one recent report, the ACIpredictive instrument was rated as veryaccurate with a large clinical impactbased on high quality clinical studies.Annals of Emergency Medicine 29:38-43 (1997).

Another study places greatimportance on analysis of three basicpieces of data: age, sex, and symptomcharacterization (typical, atypical,nonanginal). For example, the probabilityis 92% that a man, aged 50-59, andpresenting with typical angina, hascoronary artery disease. Chest pain ischaracterized as typical angina if it issubsternal, precipitated by exertion, andis relieved within 10 minutes by rest ornitroglycerin. Atypical angina is discomfortthat has the same qualities as typicalangina but is not reproducibly broughton with exertion or reproduciblyrelieved with rest and/or nitroglycerin.Nonanginal pains are those not fallingin the previous two categories. Forindividuals reporting symptoms of angina,an analysis of typical risk factors suchas smoking, diabetes, hypertension,or cholesterol is not as useful as it isin patients who are asymptomatic. AmHeart J. 123:1312-23 (1992).

When a patient reports to thehospital with chest pain, the “level” ofthe pain is not important:

An important corollary to the modernclassification of angina pectorisis the following: Mild angina (does notequal) Mild disease. This importantcorollary serves to emphasize thefact that even mild discomfort can beassociated with very severe degrees ofobstructive coronary artery disease.Therefore it is not correct to treatpatients with mild angina pectoris oneway and patients with more severeforms of angina pectoris another way.

Am Heart J. 123: 1317 (1992).

The presence of typical anginapectoris should trigger a full investigationinto its cause, with coronary arterydisease at the top of the differentialdiagnosis list.

Based on these analytical tools,many patients who are sent home froman emergency room, or referred forgastrointestinal workup after a normalexercise stress test, should receive furtherevaluation for coronary artery disease.

What should be done in furtherevaluation is not so well established.The literature abounds with studiesof diagnoses in the emergency roomor of assessment after a myocardialinfarction, but it is deficient in studies ofdiagnostic tools to use for the individualexperiencing chest pain with no priorhistory of heart disease. The diagnosticsteps available for physicians evaluatingchronic chest pain can be brokendown as follows. The early tests are: (1)Symptoms, risk factors, history; (2)Nitroglycerin leading to diagnostic painrelief and vasodilation; (3) Heart MuscleEnzymes such as creatine kinase-MB; and (4) EKG. The intermediatetests are: (5) Exercise Stress Test; (6)Thallium - Exercise Stress Test; (7)Echocardi-ography with or withoutExercise Test; and (8) Holter monitor.Advanced tests: angiography orcoronary arteriography.

These tests are listed approximatelyin the order of their preference; however,some physicians choose thalliumexercise stress test, echocardiography,and Holter monitoring without preferenceto order. Angiography is moreinvasive and expensive than the othertesting procedures, but it is also the“gold standard” for diagnosis of coronaryartery disease. One report suggeststhat a patient of either sex sufferingfrom typical angina should be analyzedby coronary arteriography directly,without any of the intermediate tests.It is suggested that men over 40 andwomen over 50 with symptoms ofatypical angina should also receivecoronary arteriography directly. Theintermediate tests are appropriate onlyin lower risk individuals such as menunder 40 years old or women under50, or those patients suffering fromnon-anginal discomfort. Am Heart J.123:1312-23 (1992).

Symptoms and History

The first step in evaluating chest painis analysis of the readily available patientdata including age, sex and symptomcharacterization. The physician shoulddetermine whether the patient hastypical angina pectoris by examiningwhether the pain is sensitive to exertionand nitroglycerin therapy. The moststriking statistic is that typical anginapectoris is diagnostic of coronary arterydisease with very high probability. Inthe age range of 40 to 69 the probabilityof coronary artery disease in personswith typical angina ranges from 55% to94%. Am. Heart J. 123:1317.

Nitroglycerin

Nitroglycerin is useful as a painkiller, as a vasodilator, and as a diagnostictool. Sublingual nitroglycerin is criticalto characterizing anginal pain astypical or atypical. Nitroglycerin relaxessmooth muscle causing bloodvessels to dilate. The effect is to reduceboth preload and afterload (or backpressure)on the heart and reduce theamount of work the heart must do. Theprimary action of nitrates is on venoustone where dilation reduces the returnof blood to the heart. The reducedvolume of blood decreases ventriculardimensions, lowers tension on theheart muscle and reduces oxygendemand.

Vasodilation also can appreciablywiden the opening of a coronary arterynarrowed by plaque formation. Becausethe victim of angina is at the thresholdof myocardial infarction, even a smallincrease in the opening of a narrowedartery can be important and may belife-saving. It can provide the additionaltime to allow further diagnostic ortreatment steps to be taken.An emergencyroom physician who fails to usenitroglycerin as a diagnostic tool forpatients older than 40 years with chestpain is potentially liable for substandardcare if the patient subsequently succumbsto coronary artery disease.

EKG

The next two steps often taken inthe emergency room are an EKG andenzyme tests. The EKG is a sensitive indicatorof ischemia when recordings aretaken at the time of an ischemic event.The National Institutes of Health identifyEKGs as the “standard of care” inemergency rooms: “[S]ensitivity for the[EKG]…is 61%…and specificity equals95%. Positive predictive value for AMI[acute myocardial infarction] is 73%…,and negative predictive value is 92%…” Although EKGs are the standard ofcare they “should not be relied on tomake the diagnosis but should ratherbe included with history and physicalexamination characteristics to identifypatients who appear to be at high riskfor ACI [acute cardiac ischemia].”“Accuracy in diagnosis is not perfectbut is very high for AMI and is lowerfor unstable angina.” Ann. EmergencyMed. 29:19 (1997). The NIH studyalso notes that the accuracy of an EKGis dependent on the experience of theoperator. Negligent reading of abnormalEKGs is a common source of malpracticeclaims.

While positive results from an EKGare very important, a normal EKG doesnot rule out ischemia resulting fromcoronary artery disease. Even patientswith severe heart disease may at discretetimes show normal EKG tracings,especially when the EKG is donewhile the patient is not experiencingchest pain.

Myocardial Enzymes

Enzymes that are normally acomponent of heart muscles arereleased into the blood when heartmuscle cells die during a myocardialinfarction. These enzymes are indicativeof a myocardial infarction, but notischemia alone. For example, a patientsuffering chest pain from ischemicevents caused by a narrowed coronaryartery may have undetectable levelsof cardiac enzymes in her/his blooddespite the seriousness of the arterydisease. For this reason, enzymeanalysis has little value in characterizingischemic events during unstableangina pectoris.

Enzymes may be detected during afairly narrow window of time followinga myocardial infarction, and shouldbe measured serially over a period of12 to 24 hours and not on a one-shotbasis. The first signs of enzymes in theblood appear 6 to 10 hours followinga myocardial infarction with the peakof enzyme concentration in the bloodoccurring 17 to 24 hours postinfarction. Serum levels of enzymesreturn to normal in 36 to 72 hours.Interestingly, the NIH study foundthere were no controlled clinical studiesthat showed that enzyme tests wereeffective for deciding what care isrequired for a patient reporting withchest pain. The study suggested thatfuture research into other heart muscleproteins might increase the sensitivityof the tests or broaden the window ofsensitivity; however, at the times manypatients are treated for chest pains,enzyme tests are of little value.

Exercise Stress Testing

Exercise stress testing is the intermediatelevel diagnostic tool of choicefor most physicians. Many cardiologynegligence cases involve patients whohad a negative exercise stress testwhich, when coupled with negativeenzyme analysis, led physicians toconclude that a patient’s chest painwas noncardiac, despite all the hallmarksymptoms of cardiac ischemia.Several recent studies are highly criticalof exercise stress tests because once apatient has presented with symptomsthat characterize angina, the exercisestress test adds little to the diagnosis. TheNIH study notes that known unstableangina with recent chest pain is acontraindication to exercise stresstesting. Ann. Emergency Med. 29:34(1997).

The diagnostic value of exercisestress testing is greatly enhanced by theaddition of imaging of the blood flowover the surface of the heart withradioactive tracers such as radioactivethallium - 201 injected intravenously.The NIH study suggested that the use ofthallium in the emergency room shouldbe restricted to specialized and limitedsituations in which the clinical triad ofhistory, ECG changes, and enzymatic/laboratory measurements is not available.However, for non-ER evaluations theuse of a thalium stress test is likely tobe more predictive than a “plain” testin diagnosing cardiovascular disease.

Echocardiography

Echocardiography creates imagesfrom reflected sound waves and revealsthe motion of surfaces of the heartwalls, the valves, blood flow, and thecardiac chambers. The transducer maybe placed on the chest wall or insertedinto the esophagus in a procedurecalled transesophageal echocardiography(TEE). Cardiac ischemia causes themotion of the myocardium to changealmost immediately to either smalleramplitude motions (hypokinetic) or touncoordinated motions (dyskinetic).These changes in motion as well ascardiac wall thickenings and dissectedarteries may be detected by theechocardiographer.

The difficulty with echocardiographyis that patients suffering fromchronic chest pain may not be ischemicwhen they report to the hospital, andmay not show the characteristic changesin the motion of the myocardium. Ann.Emergency Med. 29:73. An additionalcomplicating factor is that the accuracyof echocardiography is highly dependenton the skill and experience of theoperator. In short, echocardiographyis a highly specialized method withlimited practical application which, ifavailable, may provide useful resultsduring episodes of chest pain. The NIHstudy concludes that echocardiography“still has a false-negative rate that precludesdischarging all patients withnegative echocardiography findings.”

Holter Monitor

The Holter monitor is an electrocardiogramproduced while the patientwears the monitor continuously whilegoing about his/her activities. The advantageof Holter monitoring is thatit can pick up EKG changes during anepisode of ischemia when those changesare most dramatic. “In patients withunstable angina, predischarge Holtermonitoring may be helpful in detectingcontinuing ischemia and stratifyingpatients into groups who can continueon a conservative medical therapyregimen.” Eugene Braunwald: HeartDisease: A textbook of cardiovascularmedicine. W.B. Saunders Co. (1992).

A 1993 study concluded thatHolter monitoring identified a group ofpatients with increased risk of adversecardiac events where exercise stresstesting was nondiagnostic. Holtermonitoring identified those patientsunlikely to have a serious cardiac eventwith a predictive value of 99%. “Noexercise variable considered was apredictor of adverse events, and anegative Holter monitor, even whencoronary artery disease had beendocumented, reliably predicted a verylow cardiac risk.” Am J Cardiology72:892 (1993).

A recent trend in remote monitoringof cardiac function is telephonic “eventmonitors.” These devices send electrocardiographicinformation over telephonelines to the hospital and aretriggered by the patient in responseto pain episodes. Event monitoringis preferred over Holter monitoringin recent studies comparing the two.Ann Internal Med. 124:16 (1996);Arch Intern Med 157:537 (1997).Event monitoring may become thefuture standard of care for the diagnosisof cardiac disease, but it has not yetachieved that status.

Arteriography or Angiography

Angiography or arteriography arethe “gold standards” for diagnosis ofcoronary artery disease. Most of theother methods described above havebeen characterized by comparison toangiography. Physicians are slow to usethese methods because they are expensive,invasive, and require a catheterizationlaboratory. This reluctance toutilize the more expensive diagnostictests is reinforced by the dictates ofmanaged care cost standards and theuse of primary care physicians as “gatekeepers”who must justify referrals formore expensive procedures.Considering the accuracy andsensitivity of angiography, its underusemay be false economy in casesof patients reporting symptoms ofangina. Coronary arteriography hasbeen identified in some reports as thelogical second step for anyone withtypical angina and for men over 40 andwomen over 50 reporting with atypicalangina.

The American College ofCardiology/American Heart Assoc.Task Force issued guidelines forcoronary angiography. Their list of“conditions for which there is generalagreement that coronary angiographyis justified in patients with knownor suspected coronary heart diseaseincludes symptomatic patients withangina pectoris that is unresponsiveto medical treatment, unstable anginapectoris, variant angina pectoris,angina pectoris with other listed riskfactors, and atypical chest pain of uncertainorigin that EKGs or thalliumstress tests indicate high probabilityof coronary artery disease.” J. Am CollCardiol 10:935-950 (1987).

CONCLUSION

The current standard for treatmentof patients with chest pain is anEKG, nitroglycerin, and enzyme testsfollowed by an exercise stress test.Based on this protocol patients havebeen told that their chest pain wasnot cardiac, but caused by emotionalstress, gastrointestinal problems, orgallbladder disorders. These diagnosesare often tragically wrong and basedon a misplaced faith in the value of anEKG or a negative exercise stress test. Ifstress testing is to be used, it should besupplemented with thallium imagingof the blood flow supplying the heart.Such imaging increases the dollarcosts of an exercise stress test aboutthree fold; however, the human costsof the present standard of care areunacceptable.

An attorney faced with a potentialmedical negligence claim involvinga heart attack after complaints ofchest pain, must evaluate the medicalrecords to determine if the physiciannegligently relied on tests which haveproven to be inadequate for diagnosingischemic heart disease. Regardlessof current or common practice, thestandard for medical negligence is thatof a “reasonably prudent” physician.Recent studies and reports haveestablished that prudence calls formore than simply following outdatedstandards. There is ample medicalliterature that provides the attorneywith a basis for challenging long-heldstandards and mandating considerationof further diagnostic testing for chestpain that may lead to myocardialinfarction and death.

ACRONYMS

ECG = EKG = electrocardiogram.This analysis of the electrical eventsoccurring during a heart beat was developedin Holland which explains thewide usage of K instead of C in theacronym.

ETT is an exercise treadmill test.An treadmill is used to raise the rateat which the heart beats and increasethe heart’s demand for blood flow. Thepatient is monitored by electrocardiography

(ECG). The typical test lastsabout 10 minutes and involves increasesin the speed of walking and the incline.These graded changes in the test most often follow an agenda called the“Bruce Protocol.”

ACI is acute cardiac ischemia.Ischemia is the starvation of musclecells for oxygen brought on by a reductionof blood flow.

MI is a myocardial infarction. Aninfarction is muscle cell death causedby an extended starvation of musclecells for oxygen. The area of the heartthat has died will not recover well andif the infarction is extensive, a transplantmay be the only treatment.

Eugene M. Moen is a partner in theSeattle firm of Chemnick, Moen &Greenstreet, where his practice emphasizesmedical negligence and other complexlitigation. Roger J. Leslie has a Ph.D. Inmolecular biology and received his J.D. In1997 from Seattle University Law School.He is presently an associate with the lawfirm of Lembhard G. Howell.

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