Modern era of cardiology aims to treat ACS as and when it develops .That is , as soon as the vulnerable plaque ruptures or a thrombus blocks the victim’s coronary artery.
But this can be achieved only if the patient reacts to this event.We know 20% of ACS can be totally silent. Some produce very vague symptoms especially in elderly and diabetics. ECG and enzyme changes may help us in patients who do not have clear symptoms.There are variety of markers available for STEMI & UNSTEMI.(CPK-MB, Troponin T , myoglobin etc) Now we are working at finding a marker for ischemia without necrosis. Ischemia modified albumin is one such molecule that is showing promise.
The ER department world over have vigorous screening protocols to diagnose ACS for the patients with chest pain. There are thousands of triaging protocol in the emergency management of chest pain.In spite of the highest awareness and availability of scientific expertise , knowledge base the error rate of diagnosing ACS stands at an astonishing 58%. This may seem odd , but this is what this land mark article in NEJM tell us (Data from Boston , Milwaukee etc).
Out of 10500 patients with suspected ACS. Only 17 % had real ACS. 55% were admitted initially as ACS later turned out to be non cardiac .This may seem acceptable for many even if it is an act of unnecessary admission and investigation. It gives us , a sense of satisfaction for not missing a diagnosis of ACS. But it has it’s own risk of complication arising out of unnecessary investigations.It is a chain reaction of suspicion that may end up in a coronary angiogram in many ! .It is also a well recognised fact these patients spend atleast an average of 2 days to get rid of the ACS tag over their necks .
Experience has taught us simple presence of a human being as a patient within an ICU ( however short the stay may be ) can be a health hazard and risk . This 55 % error , which does exactly this to our patients with chest pain who reach the ER never bothers us This is because we feel credited both academically as well as financially .
In the same study 2.3 % (About 25 patients) with true ACS were sent home after a missed diagnosis . Paradoxically this 2.3% has worried the medical professionals too much . . . This happens , even as we do not have proper data on how many of them had a real adverse event after a missed ACS.
So the message here is even in best centres both missed and wrong diagnosis are rampant. while wrong diagnosis (25 fold more here ) is easily accepted by the medical community .We can justify this as a screening camp for ACS , akin to arresting a group of suspected criminals in a preventive raid , later releasing for want of evidence.
In the morals of criminal judiciary , it is often said one can afford to lose a real offender from the clutches of law , but a innocent should never be punished in any circumstance .
In medical parlance this goes something like this . . . Thousand patients shall die because of his or her illness but not even a single healthy person should die due to unnecessary treatment.
The above thoughts were in response to the excellent original article on missed diagnosis of ACS from NEJM. http://content.nejm.org/cgi/content/full/342/16/1163?ijkey=652d8337709a8bf84c813f4c9d685863ee053162
Final message : (Sorry for the lengthy message !)
Can we afford to miss an ACS in emergency room ?
“Definitely not” . . .but do we succeed in that ? The answer is same “definitely not “
When we are able to accept with pride every time we make a wrong diagnosis of ACS in perfectly normal people , It may to provocative to say we can also afford to do the same when we occasionally miss a diagnosis of ACS as well . Law of statistics dictates for every correct diagnosis made there is many fold number of wrong or missed diagnosis takes place. May be , reducing that is the only aim of medicine.
We need to realise with even with a 55% of false positive initial diagnosis 2% real ACS escape net !The only fool proof method for not missing , even a single case of ACS is to label every patient with chest pain as ACS .
In this vexing issue , we should realise , in field of medical decision making , errors due to acts of commission ( Making an inappropriate drug/procedure /surgery is easily accepted by medical professionals as well as the court of law !) . But acts of omission , like missing a diagnosis or failure to prescribe a drug or perform a procedure is rarely accepted and is considered a great negligence and bring intense guilty feeling among the physicians .
This perception is definitely not warranted in this greatest profession of glorious uncertainties ! Both acts of commission and omission cause significant damage to patients . In this modern era , we have clear statistics that reveal , acts of commission leads far ahead over it’ s counterpart in injuring our people .
Hippocrates got it right over 2000 years ago . First let us do no harm . . .
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The problem with general public is , they never understand this basic fact – medical science is nothing but a , on going research on human body .If only we understand this we can accept the millions of medical mistakes* that occur every day in the global medical profession . The major aim of modern medical science is to reduce that .
Dr.S.Venkatesan MD 