In this mean world ,most truths exist without evidence . . . and often falsehoods masquerade as truths with overwhelming evidence !
Human biology has always been a mystery and can express in dramatic ways . While , many disorders combine to play havoc on the body , few tend to protect each other. HT and DM can join a deadly coalition to attack the heart .Smoking causes extensive peripheral vascular disease , still thrombo angitis of coronary arteries ( due to smoking ) is virtually unknown. Tuberculosis does not have the courage to attack the heart valves , while it can inflict serious injuries all over the body . Similarly , systemic hypertension and Rheumatic heart disease does not combine well . So , it can be assumed some unique and hidden protective factors are at play among different pathological entities and their target organs.
A brief account of how COPD could be related to CAD ! (* Mostly Imaginary !)
We know , COPD , stresses the right ventricle by pressure overload and in extreme situation affects the LV function because of hypoxia. It rarely impacts the coronary artery disease . This has been our consistent observation. While COPD patients often land up with LV dysfunction , investigations reveal they are more of a dilated cardiomyopathy and their coronary arteries are entirely normal. Diffuse atherosclerotic CAD is a rarity in patients with history of bronchial asthma. Coronary micro circulation is also observed to be largely intact in most people with COPD .
We haven’t got a call from our pulmonology wards in many decades , for a true emergency coronary consult . Mind you ours is a 200 year old Institution , with 3000 beds , largest east of Suez canal !
It’ s very rare for bronchial asthma patients to die of a cardiac event. Thousands of elderly patients throng our ER with acute severe asthma every winter , still extremely rare to precipitate an acute coronary event !
We are yet to see critical triple vessel disease in a patients with documented bronchial asthma and COPD . Even non-critical CAD is far less frequent in COPD vis a vis general population . It is indeed a strange observation , considering both entities are rampant in the community .
What could be mechanism for the perceived disconnect between COPD and CAD ?
Is it a myth ? Does it happen in all geographical zones ? If hypoxia is the sine qua non of COPD , one would rather expect a close association with CAD , isn’t ?
One suggestion that keeps erupting from my cortex . It is the wide swinging intra thoracic pressures in COPD or asthmatic individuals . . . somehow responsible . These wide swings of pressure are transmitted to aortic root . They transform into good coronary perfusion pressure , keep the vessels clean by pressure vacuuming effect .
We have asked our epidemiological unit to analyse the 25 year data from our coronary care unit to decode the mystery .
Meanwhile, a diagonally opposite question was asked in UK and found a partial proof as well . Our experience do not agree with this study conclusions .
What is your take on the issue ?
How can a opinion (rather an Imaginary essay !) based on personal observation projected as a scientific fact ? We need to observe , analyse and publish the data . This is what the scientific world expects us to do . Unfortunately , the journey form observation into publication has been kept purposefully difficult . In my opinion bulk of the international peer reviewed medical journals with high impact factor can convert any junk data into a scientifically palatable recipe !