Drugs are poisons , whenever it is administered without valid purpose. it can enter human body in many ways (Oral, intravenous, percutaneous etc ) And now we have another route namely intracoronary !
In quest for prevention of restenosis, many of the anti cancer drugs are now delivered directly inside the coronary arteries .These drugs are secreted like a sustained release tablet from the drug coated stents.These drugs are expected to prevent restenosis within the stented segment.But, after years of intense debate and research , we realised that , drugs eluted from the stent could damage the distal coronary vascular bed and coronary microcirculation.( And thus came the epidemic of acute stent thrombosis ! )
The tender and sensitive coronary microvasculature is constantly exposed to these powerful anticancer and immmunosuppresive drugs .It is a great surprise , no body thought of this dangerous drug -coronary artery interaction ! It required the genius of Renu virmani and others to point out this.
But still , the cardiology community by and large , fails to consider this an important issue.This is proven by the fact, usage of DES is still increasing and used mainly as an off label indication.
Read this land mark article from circulation
Questions that need to be answered
- What is the long term effects of drugging a coronary artery ?
- Is no reflow or slow flow more common after DES , because of the adverse drug reaction in the distal vascular bed ?
- If a patient with DES undergoes a CABG later what would be the impact of the drug on the graft ? Will the functional vasodilatation affected ?
Final message
A drug , to get a legal clearance it has to undergo hundreds of rigorous tests . Finally it is cleared for that specific indication for which it is tested .Just because a drug is cleared for one purpose ( Paclitaxel for malignancy ) it does not mean it is safe to use for any other purpose for which it is deemed to be useful . Exactly the opposite is happening in the the field of interventional cardiology . No body wondered to think what would be the effect of these drugs on the normal coronary endothelial cells and vasculature.Is it not a crime , without analysing this particular issue , dozens of drug eluting stents have been released in the market . And now, sounds of crying foul is heard world wide !
Let us thank , the so called negative forces in cardiology for making this an issue . In science , the watch dogs should bark at times of danger not wag the tail !
A normally functioning circulatory system is vital for our survival . We have about 6000 ml of blood, circulating all over the body in an approximate time of 15-20 seconds.The pressure at which this blood moves across the body is called the blood pressure . Hypertension or simply , high blood pressure is an undesirable hemodynamic disturbance in human circulatory system.Systemic hypertension is the most common type of hypertension. The blood pressure is primarily dependent on the status of the blood vessel(vascular resistance) and cardiac contractility. This regulation is under many neural and hormonal factors.Further the blood pressure varies depending upon the blood vessel calibre, and the local milieu.There is a progressive drop in blood pressure from major arteries to the small arteries .The pressure drop is maximum across the arterioles to reach the venules .The venous circulation has the lowest pressure, it ends up at right atrium with a mean pressure of 0- 5mmhg.
Dr.S.Venkatesan MD 
