|Year : 2021 | Volume
| Issue : 3 | Page : 179-181
Cleansing the augean stables - Time to reclassify coronary artery disease
Department of Cardiology, Saraf Hospital, Kochi, Kerala, India
|Date of Submission||26-Sep-2021|
|Date of Decision||19-Oct-2021|
|Date of Acceptance||11-Nov-2021|
|Date of Web Publication||14-Dec-2021|
Department of Cardiology, Saraf Hospital, Kochi, Kerala
Source of Support: None, Conflict of Interest: None
Although there have been spectacular developments in the diagnosis and treatment of coronary artery disease (CAD), the diagnostic terminology has not evolved accordingly. The present diagnostic terms are symptom, complication, and electrocardiogram based instead of the causative pathology. In the present era of excellent therapies, angina and infarction need not occur. When our efforts are directed at preventing these ill effects of CAD, the present diagnostic terms seem anachronistic. This article presents a simple, logical, and practical approach to CAD terminology.
Keywords: Classification, coronary artery disease, obstructions, terminology
|How to cite this article:|
Thomas G. Cleansing the augean stables - Time to reclassify coronary artery disease. J Pract Cardiovasc Sci 2021;7:179-81
That is why it was called Babel —because there the Lord confused the language of the whole world. Genesis 11:9 NIV
The ICD-10-CM Official Guidelines for Coding and Reporting FY 2022 (effective from October 1, 2021) have been released. This document uses the terms such as angina pectoris, acute myocardial infarction (MI), ST elevation MI (STEMI), non-ST elevation MI (NSTEMI), transmural MI, nontransmural MI, or subendocardial MI for the classification of coronary artery disease (CAD). The vague term acute coronary syndrome and the terms Q and non-Q MI are passé. As such, the present diagnostic terminology for CAD presents a confusing situation like the biblical Babel.
Although there have been spectacular developments in the diagnosis and treatment of CAD, the diagnostic terminology has not evolved accordingly. The present diagnostic terms are symptom, complication, and electrocardiogram (ECG) based instead of the causative pathology. For example, a certain disease would be diagnosed as “death” in pre-historic times, “devil” in the era of witchcraft, and “ague” during the medieval periods. We now know that it is falciparum malaria caused by plasmodia, and by eliminating the plasmodia, we can abort the fever and death. In the case of CAD, we are stuck in the medieval period with diagnostic terms such as angina and infarction representing the complications of coronary obstructions. We have to get out of this rut. It is time to clean the Augean Stables of CAD terminology.
The babel of terms such as STEMI and NSTEMI does not reflect the present-day realities. A case of AMI successfully reperfused is no longer an “infarction.” There is a need to describe cases of “aborted” and “threatened” infarctions. ECG-based terms are grossly inadequate. “STEMI” can occur with other ECG patterns like new-onset left bundle-branch block fulfilling the Sgarbossa criteria, hyperacute T waves, the de Winter and Wellens patterns, and precordial ST depressions of a true posterior wall infarction. Will such conditions be NSTEMI? Such oddities are possible with the current terms. Similarly, with sensitive enzyme markers, ischemia, injury, and infarction form a disease continuum. The current terms based on effects were coined when proper investigations and treatments were not available. MI meant dead tissue and angina meant serious lifestyle limitations. In the present era of excellent therapies, angina and infarction need not occur. When our efforts are directed at preventing these ill effects of CAD, the present diagnostic terms seem anachronistic. A better diagnostic terminology has been proposed earlier.
Basically, CAD is due to “obstructions” in the coronary arteries. Hence, the basic term to be used is coronary obstructive syndrome (COS). This can be of three types: total COS (TCOS), partial COS (PCOS), and mixed COS (MCOS). Further, each of these can be subclassified into acute or chronic, depending on the clinical presentation. Thus, there are six terms acute TCOS, chronic TCOS, acute PCOS, chronic PCOS, acute MCOS, and chronic MCOS which should be used as the primary working diagnoses. Any clinical situation in CAD can fit into one of these subsets of COS.
Their usage has been described earlier [Figure 1]. In brief, the primary term to be used is COS. As usual, the clinical presentation with or without electrocardiographic evidence is the basis for the primary working diagnosis. To have a complete diagnosis, the primary diagnosis is to be qualified by the symptom functional class, investigation results, complications, associated conditions, and treatment given as and when required. The new terms are based on the assumed operating pathology rather than its effects. Thus, acute STEMI or equivalent, which qualifies for urgent thrombolytic or revascularization therapy, comes under the category of acute TCOS. If treated properly, there should be no infarction. This term indicates salvageable myocardium. Cases in which the disease process could not be arrested and progressed to infarction can be classified as per the Fourth Universal Definition of MI. A clinical situation would be like this: acute TCOS (primary diagnosis), ST elevation in V1-V4 (investigation), successful reperfusion with primary angioplasty (treatment). On the rounds, we may say “Mr A has acute total with ECG changes in V1-V4.” Note: in conventional terms, this is a case of acute anteroseptal infarction. Since the patient had no wall motion abnormalities, we may have prevented an infarction and it would be unfair to label this patient as “MI.” The concept of acute TCOS will legitimize the use of thrombolytic/intervention therapy at the earliest stage, even before ECG changes occur and thus prevent infarctions.
|Figure 1: Diagnostic flowchart. The primary term to be used is coronary obstructive syndrome. Different etiologies can be specified in parentheses such as chronic partial coronary obstructive syndrome (graft) for graft obstructions, chronic partial coronary obstructive syndrome (bridge) for myocardial bridge, or acute partial coronary obstructive syndrome (spasm) for coronary artery spasm.|
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A few pertinent points need to be emphasized. Newer terms such as occlusion MI and STEMI equivalent have been described All such situations can be brought under the ambit of this classification. The term mixed COS is a unique category. As there are three major coronary arteries, different active pathologies can coexist in different territories. At present, this important subset has not been recognized. Now, the ICD-10-CM has alluded to such situations stating, “Subsequent STEMI and NSTEMI MI, is to be used when a patient who has suffered a type 1 or unspecified AMI has a new AMI within the 4-week time frame of the initial AMI.”
It is important to note that despite the similarities, these terms are not angiographic findings. They describe clinical situations and convey an abstract clinicopathologic concept. Note the word “obstruction” is used in the initial diagnosis instead of “occlusion.” Obstruction connotes an abstract concept like “obstruction of justice.” An angiogram could reveal an occlusion. The recent additions to the CAD lexicon like occlusion MI and MI with nonobstructive coronary arteries (MINOCA) would be acute TCOS and acute PCOS, respectively. Although there may be no anatomical occlusion, “obstruction” to flow due to demand-supply mismatch and dynamic mechanisms like coronary spasm is in operation in MINOCA. Once the basic system is understood, the clinician can use his ingenuity and describe any clinical situation aptly. By using this schema, the clinician will think in terms of the actual pathology and provide a clear picture of the disease at a particular time. It will help in planning proper treatment strategies and encourage better communication by avoiding ambiguous terms and confusing definitions.
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Conflicts of interest
There are no conflicts of interest.
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