Very often in clinical practice cardiologists are asked to R/O significant coronary artery disease in asymptomatic persons .This population includes people with multiple risk factors like diabetes, HT dyslipidemia and non specific ST/T changes in ECG.
Many of us have lost the confidence of ruling out CAD in these population without looking at their coronary angiogram.
Is it a right way of practicing cardiology ?
What we need to realise is, we are asked to rule out any critical lesions that are going to make a impact on these other wise comfortable patients. Nothing wrong if you miss a 30% lesion in PDA or OMs or diagonals !
Can we do this without doing coronary angiogram ?
Yes , we can .
Step by step Ask these questions
- Ask the patient , if he /she can climb three flight of stairs without any difficulty or
- Walk briskly for 20 minutes (5km/hr)
If yes , give a certificate that he has no critical left main or proximal LAD disease.
If you do not believe in his words , put him on a tread mill , if he crosses stage 3 Bruce in TMT ( 9 mts)
give the above certificate “with a frame” now .
For still suspicious physicians , We have one more investigation called echocardiography !
Echo : The forgotten tool for screening left main lesion.
Modern day echo machines have a 3mm resolution power (Many have 2mm ) .While , we are expected to look for 3mm vegetation to R/O Infective endocarditis , rarely is a cardiologist , tuned to look for the left main ostium in routine echocardiography which averages 4-5mm is size. (Left main by echo link to another article)
In short axis view just tilt at the level of pulmonary valves (Atrio- pulmonary sulcus) one can visualise the left main ostium and the proximal left main emerging from the 4 o clock position. If you are lucky you can see the entire left main.
If nothing satisfies the physician (Or the patient) ,Refer him for sliced CT scan , catheter coronary angiogram , or a nuclear Imaging .Be ready for the attendant anxiety, interpretation errors, corporate pressures , urge to balloon , kick backs etc etc
By the way , how can one be happy by ruling out only left main disease ? Is it not other lesions possible ?
Experience (Not science) has taught us no critical coronary obstruction is possible , if a patient walks for 9 minutes in treadmill (10METS).
Even if it is there (A remote chance) there is little documented benefit of any revascularisation procedure.
Counter point ?
Is it not a “crazy idea“ to rely on patients history in ruling out CAD in these era , where angiograms relayed live into cardiologists ipad ?
Science has no value if it is not applied for the patients welfare. Meticulous clinical examination (And application of mind) is the foundation stone on which any medical investigation and therapy should be based upon. Most of the inappropriate coronary revascularisation are due to neglect of this vital component of clinical examination.
(I wonder , is it really possible these ” acts of omission” be deliberate some times ! )
Final message
Clinical interrogation may miss an insignificant CAD , but it can never miss a critical CAD* .
Do not do coronary angiogram routinely to R/O CAD.
It is not the way cardiology is to be practiced !
If only we apply those simple, time tested concepts in every day practice we not only save millions of Rupees , but also thousands of futile diagnostic tests and associated untoward effects can be avoided.
* Senstivity of ruling out any CAD is about 70% , but it’s capcity to R/O critical CAD approaches 100%.
Reference:
Please refer your own Brain.
Dr.S.Venkatesan MD 