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A clinically relevant classification of chest discomfort
574
J AM COLL CARDIOL 1983;I(2):574-5
LETTERS TO THE EDITOR
Tetralogy Versus Tetrad and a Wish for the New Journal In wishing your new Journal God speed, I would encourage you to continue to educate and guide us journalistically; at the same time, do please resist your inclination to tidy up the language. I noticed with dismay your sanction of the unhappy neologism "Tetrad" on page 1279 of the June 1981 issue of your earlier brainchild and until recently our official journal, The American Journal of Cardiology. I had hoped this was a one-time editorial aberration because the previous volume (46) had shown all five Fallot articles properly titled as "Tetralogy." But no! Volume 48 carried two Tetrads and Tetralogy was not even indexed-rejected after 93 years of distinguished usage . . . ! You were not, of course, introducing a new word. Tetrad made a brief, self-conscious appearance in the surgical literature a few decades previously but was soon dropped by all including its inventors. As an admirer of your journalistic leadership, I would be slow to regard you as historically insensitive. However. I may have no option if you have been talked into believing that Fallot in his use of Tetralogy has been etymologically wrong all the time. This must be the most fragile of arguments. Respect for the proper usage of the language is a birthright of the new journal; you will preserve this by consigning Tetrad into the outer darkness with Dysrhythmia and other horrible neologisms.
physical activity. Thus, discomfort which is clearly, but only sometimes, related to exertion is considered to be "cxertional." Is there prompt relief by rest or nitroglycerin? The word "prompt" is considered to imply a time span ranging from approximately 30 seconds to 10 minutes. The word "relief" is intended again to imply a general causal relation either to cessation of physical activity or to administration of sublingual nitrates. When all three questions are judged by the physician to have been answered in the affirmative, the discomfort is interpreted as "typical angina." When only two of the three answers are affirmative, the discomfort is interpreted as "atypical angina." When fewer than two answers are affirmative, the discomfort is interpreted as "rionanginal." This classification, although highly subjective, has several strengths. First, it is practical-being easily learned, remembered and applied. Second, it is relevant. Thus, by analysis
3 ,..------=::-
- - --
-
-
-,
Non Anginal
Discomfort
2
0
WALTER SOMERVILLE, MD, FACC 149. Harley Street London WIN IHG England
-
3
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z
lJ.J ::J
2
0
lJ.J Cl: u,
A Clinically Relevant Classification of Chest Discomfort A successful diagnosis of coronary artery disease begins with the patient history, and therefore with an effective and relevant classification of chest pain. It was recently pointed out, however, that previously published formats are insufficiently explicit to allow reproducible clinical application (I). In 1980, we (2) reported our initial experience with a classification similar to that employed in the Coronary Artery Surgery Study, which appears well suited to routine clinical use. This classification is based on three readily determined historical characteristics which are generally accepted as being "typical" of ischemic cardiac discomfort: Is the discomfort substernal? The word "substernal" is intended to be anatomically precise. It therefore excludes the epigastrium, the parasternal area or a transthoracic distribution unless a substernal component is also present. Is it precipitated by exertion? The word "precipitated" is intended to imply a general-but not exclusive-causal relation to
0 12
9 6
3 0
0 .2
0.4 0.6 0 ·8 PROBABILITY
Figure 1. Beta frequency distributions of probability for angiographic coronary artery disease according to symptom classificanon. The x axis is the probability of disease and the Y axis ISthe frequency of that probability, expressed in terms of the number of patients withm each symptom group. For each symptom classification, two distribution curves are Illustrated The curve labeled H represents the distribution of probability calculated from the mean and standard deviation (6) for each patient from a computer program that employs pooled estimates from published data of angiographic prevalence accordmg to age, sex and symptom class (5). The curve labeled A IS the distribution of the observed angiographic prevalence, normalized to the "effective" sample size represented by the mean probability: N = pq/SD 2 , where p is mean probability, q = 1 - P and SD is the standard deviation of p. For each symptom class, the dtstributions of probabihty and angiographic prevalence are similar 0735-1097/831020574-2$03 00
J AM COLL CARDIOL 1983.1(2) 574-5
LEITERS
575
Table 1. Probability Versus Prevalence of Coronary Artery Disease (CAD) Patients Symptom Class
(0+)
(0-)
CAO Probability (mean ± I SO)
CAO Prevalence (mean ± I SO)
Nonanginal discomfort Atypical angina Typical angina
18 33 46
20 II 4
0.245 ± 0.150 0.673 ± 0.159 0.938 ± 0.050
0.474 ± 0.174 0.750 ± 0.147 0.920 ± 0.056
0+ = number of patients With 2:50% diameter narrowing of at least one major coronary artery; 0 coronary arteries, SO = standard deviation
of the patient's age, sex and symptoms, we (3,4) recently reported an excellent linear correlation (r = 0.96; probability [p] <0.001) between the probability of disease and its empiric angiographic prevalence in 8,192 patients. Table I summarizes our personal experience with this symptom classification in 132 consecutive symptomatic patients who were catheterized for the purpose of diagnosing coronary artery disease. The probability of disease was calculated for each patient by analysis of age, sex and symptom class as a continuous function derived from previously published data (5,6) on more than 15,000 symptomatic patients undergoing angiography. Both probability and prevalence increased in parallel as the symptom class' 'worsened." Within each symptom class, there was no significant difference between the prevalence predicted by probability analysis and that observed at angiography. Analysis of the probability density functions for these data (6) supports the conclusion that this chest pain classification accurately defines patient subsets with clinically important differences in angiographic disease prevalence (Fig. I). As a basis for reference, then, Table 2 summarizes the probability for coronary artery disease according to age, sex and symptom classification as predicted from our current computerized data base (5). We believe, therefore, that explicit characterization of the pres-
=
number of patienls With <50% diameter narrowing in all major
ence and quality of chest discomfort as described herein satisfies the physician's requirement of a clinically relevant, effective means for estimating each patient's risk for coronary artery disease. GEORGE A. DIAMOND, MD Cardiac Stress Laboratory Cedars-Sinai Medical Center 8700 Beverly Boulevard Los Angeles. California 90048
References Sanunga JT Iriabihty of a chest pain history quesnonnaire to predict coronary disease in the exercise laboratory (letter). Am J Cardiol 1982;50:1084-5 2 Diamond GA. Forrester JS, Hirsch M, et al. Application of conditional probabihty analysis to the clinical diagnosis of coronary artery disease. J Chn Invest 1980;65.1210-1 3. Chairman BR, Bourassa MG, DaVIS K, et al. Angiograpluc prevalence of high nsk coronary artery disease in patient subsets (CASS). Circulation 1981,64.360 4. Diamond GA, Forrester JS Probabihty of CAD (letter) CIrculation 1982;65:641 5 Diamond GA CADENZA: Computer-assisted diagnosis and evaluation of coronary artery disease. 1979: Seattle, Cardiokinencs, (software and documentation magnetic tape). 6 Diamond GA, Forrester JS. Improved mterpretanon of a continuous variable m diagnostic testing: probabilisnc analysis of scintigraphic rest and exercise left ventricular ejection fractions for coronary disease detection Am Heart J 1981;102:189-95.
Table 2. Probability of Angiographic Coronary Artery Disease Age (yr)
AS
NA
TA
AA
Women
35-45 45-55 55-65 65-75
0.007 0.021 0.054 0.115
± ± ± ±
0.006 0.018 0.042 0.078
0.027 0.069 0.127 0.171
± 0.024 ± 0.051
± 0.080 ± 0.097
0.155 0317 0.465 0.541
0037 0.077 0.111 0.113
± ± ± ±
0.024 0.040 0.049 0.050
0.105 0.206 0.282 0.282
± 0.063 ± 0.090 ± 0.100 ± 0.100
0428 0.601 0.690 0.700
± 0.174 ± 0.169
0.454 0.677 0.839 0.947
± ± ± ±
± ± ± ±
0.809 0.907 0.939 0.943
± 0.104 ± 0.049 ± 0.029 ± 0.026
± 0.111 ± 0.160
0.186 0167 0.108 0.055
Men
35-45 45-55 55-65 65-75
0.144 0.129 0.106 0.103
Each estrmate IS the average disease probability (± 1 standard deviauon) over the mdicated age range assuming average levels for the conventional Framingham risk factors AA = atypical angina. AS = asymptomatic. NA = nonangmal discomlort. TA = typical angina
J AM COLL CARDIOL 1983;I(2):574-5
LETTERS TO THE EDITOR
Tetralogy Versus Tetrad and a Wish for the New Journal In wishing your new Journal God speed, I would encourage you to continue to educate and guide us journalistically; at the same time, do please resist your inclination to tidy up the language. I noticed with dismay your sanction of the unhappy neologism "Tetrad" on page 1279 of the June 1981 issue of your earlier brainchild and until recently our official journal, The American Journal of Cardiology. I had hoped this was a one-time editorial aberration because the previous volume (46) had shown all five Fallot articles properly titled as "Tetralogy." But no! Volume 48 carried two Tetrads and Tetralogy was not even indexed-rejected after 93 years of distinguished usage . . . ! You were not, of course, introducing a new word. Tetrad made a brief, self-conscious appearance in the surgical literature a few decades previously but was soon dropped by all including its inventors. As an admirer of your journalistic leadership, I would be slow to regard you as historically insensitive. However. I may have no option if you have been talked into believing that Fallot in his use of Tetralogy has been etymologically wrong all the time. This must be the most fragile of arguments. Respect for the proper usage of the language is a birthright of the new journal; you will preserve this by consigning Tetrad into the outer darkness with Dysrhythmia and other horrible neologisms.
physical activity. Thus, discomfort which is clearly, but only sometimes, related to exertion is considered to be "cxertional." Is there prompt relief by rest or nitroglycerin? The word "prompt" is considered to imply a time span ranging from approximately 30 seconds to 10 minutes. The word "relief" is intended again to imply a general causal relation either to cessation of physical activity or to administration of sublingual nitrates. When all three questions are judged by the physician to have been answered in the affirmative, the discomfort is interpreted as "typical angina." When only two of the three answers are affirmative, the discomfort is interpreted as "atypical angina." When fewer than two answers are affirmative, the discomfort is interpreted as "rionanginal." This classification, although highly subjective, has several strengths. First, it is practical-being easily learned, remembered and applied. Second, it is relevant. Thus, by analysis
3 ,..------=::-
- - --
-
-
-,
Non Anginal
Discomfort
2
0
WALTER SOMERVILLE, MD, FACC 149. Harley Street London WIN IHG England
-
3
o>-
z
lJ.J ::J
2
0
lJ.J Cl: u,
A Clinically Relevant Classification of Chest Discomfort A successful diagnosis of coronary artery disease begins with the patient history, and therefore with an effective and relevant classification of chest pain. It was recently pointed out, however, that previously published formats are insufficiently explicit to allow reproducible clinical application (I). In 1980, we (2) reported our initial experience with a classification similar to that employed in the Coronary Artery Surgery Study, which appears well suited to routine clinical use. This classification is based on three readily determined historical characteristics which are generally accepted as being "typical" of ischemic cardiac discomfort: Is the discomfort substernal? The word "substernal" is intended to be anatomically precise. It therefore excludes the epigastrium, the parasternal area or a transthoracic distribution unless a substernal component is also present. Is it precipitated by exertion? The word "precipitated" is intended to imply a general-but not exclusive-causal relation to
0 12
9 6
3 0
0 .2
0.4 0.6 0 ·8 PROBABILITY
Figure 1. Beta frequency distributions of probability for angiographic coronary artery disease according to symptom classificanon. The x axis is the probability of disease and the Y axis ISthe frequency of that probability, expressed in terms of the number of patients withm each symptom group. For each symptom classification, two distribution curves are Illustrated The curve labeled H represents the distribution of probability calculated from the mean and standard deviation (6) for each patient from a computer program that employs pooled estimates from published data of angiographic prevalence accordmg to age, sex and symptom class (5). The curve labeled A IS the distribution of the observed angiographic prevalence, normalized to the "effective" sample size represented by the mean probability: N = pq/SD 2 , where p is mean probability, q = 1 - P and SD is the standard deviation of p. For each symptom class, the dtstributions of probabihty and angiographic prevalence are similar 0735-1097/831020574-2$03 00
J AM COLL CARDIOL 1983.1(2) 574-5
LEITERS
575
Table 1. Probability Versus Prevalence of Coronary Artery Disease (CAD) Patients Symptom Class
(0+)
(0-)
CAO Probability (mean ± I SO)
CAO Prevalence (mean ± I SO)
Nonanginal discomfort Atypical angina Typical angina
18 33 46
20 II 4
0.245 ± 0.150 0.673 ± 0.159 0.938 ± 0.050
0.474 ± 0.174 0.750 ± 0.147 0.920 ± 0.056
0+ = number of patients With 2:50% diameter narrowing of at least one major coronary artery; 0 coronary arteries, SO = standard deviation
of the patient's age, sex and symptoms, we (3,4) recently reported an excellent linear correlation (r = 0.96; probability [p] <0.001) between the probability of disease and its empiric angiographic prevalence in 8,192 patients. Table I summarizes our personal experience with this symptom classification in 132 consecutive symptomatic patients who were catheterized for the purpose of diagnosing coronary artery disease. The probability of disease was calculated for each patient by analysis of age, sex and symptom class as a continuous function derived from previously published data (5,6) on more than 15,000 symptomatic patients undergoing angiography. Both probability and prevalence increased in parallel as the symptom class' 'worsened." Within each symptom class, there was no significant difference between the prevalence predicted by probability analysis and that observed at angiography. Analysis of the probability density functions for these data (6) supports the conclusion that this chest pain classification accurately defines patient subsets with clinically important differences in angiographic disease prevalence (Fig. I). As a basis for reference, then, Table 2 summarizes the probability for coronary artery disease according to age, sex and symptom classification as predicted from our current computerized data base (5). We believe, therefore, that explicit characterization of the pres-
=
number of patienls With <50% diameter narrowing in all major
ence and quality of chest discomfort as described herein satisfies the physician's requirement of a clinically relevant, effective means for estimating each patient's risk for coronary artery disease. GEORGE A. DIAMOND, MD Cardiac Stress Laboratory Cedars-Sinai Medical Center 8700 Beverly Boulevard Los Angeles. California 90048
References Sanunga JT Iriabihty of a chest pain history quesnonnaire to predict coronary disease in the exercise laboratory (letter). Am J Cardiol 1982;50:1084-5 2 Diamond GA. Forrester JS, Hirsch M, et al. Application of conditional probabihty analysis to the clinical diagnosis of coronary artery disease. J Chn Invest 1980;65.1210-1 3. Chairman BR, Bourassa MG, DaVIS K, et al. Angiograpluc prevalence of high nsk coronary artery disease in patient subsets (CASS). Circulation 1981,64.360 4. Diamond GA, Forrester JS Probabihty of CAD (letter) CIrculation 1982;65:641 5 Diamond GA CADENZA: Computer-assisted diagnosis and evaluation of coronary artery disease. 1979: Seattle, Cardiokinencs, (software and documentation magnetic tape). 6 Diamond GA, Forrester JS. Improved mterpretanon of a continuous variable m diagnostic testing: probabilisnc analysis of scintigraphic rest and exercise left ventricular ejection fractions for coronary disease detection Am Heart J 1981;102:189-95.
Table 2. Probability of Angiographic Coronary Artery Disease Age (yr)
AS
NA
TA
AA
Women
35-45 45-55 55-65 65-75
0.007 0.021 0.054 0.115
± ± ± ±
0.006 0.018 0.042 0.078
0.027 0.069 0.127 0.171
± 0.024 ± 0.051
± 0.080 ± 0.097
0.155 0317 0.465 0.541
0037 0.077 0.111 0.113
± ± ± ±
0.024 0.040 0.049 0.050
0.105 0.206 0.282 0.282
± 0.063 ± 0.090 ± 0.100 ± 0.100
0428 0.601 0.690 0.700
± 0.174 ± 0.169
0.454 0.677 0.839 0.947
± ± ± ±
± ± ± ±
0.809 0.907 0.939 0.943
± 0.104 ± 0.049 ± 0.029 ± 0.026
± 0.111 ± 0.160
0.186 0167 0.108 0.055
Men
35-45 45-55 55-65 65-75
0.144 0.129 0.106 0.103
Each estrmate IS the average disease probability (± 1 standard deviauon) over the mdicated age range assuming average levels for the conventional Framingham risk factors AA = atypical angina. AS = asymptomatic. NA = nonangmal discomlort. TA = typical angina