We know Nitroglycerine(NTG) as a most powerful epicardial coronary dilator . We use it for instant relief during episodes of coronary arterial spasm in cath lab.
What will happen if we administer NTG over a stented segment ?
Does it dilate it with same vigor ? What will be the consequence ?
A perfect setting for stent migration isn’t ?
Let us bust the myth around NTG . NTG rarely show visible coronary dilating effect except in the setting of coronary spasm .
Does a LAD with 3 mm diameter become 3.1 or 3.2 and so on with NTG ?
No .It won’t .It is my belief. It is well known , NTG’s action varies significantly in normal and diseased endothelium . Again , there is an irony .It seems , it can act only in normal endothelium , but we need require it’s therapeutic action only in pathological segments.Further any stented segment would contain clusters of both normal and abnormal endothelium .
One more inference is that, stented segment exerts constant pressure on intima making any pharmacological vasodilatation irrelevant .
Importance of radial strength of a stent
This issue of vaso-dilator induced stent migration may not arise in self expanding wall stent with high radial force.But we do not know how long these metals will carry this metallic property .Balloon delivered stents ( currently used 99% of times ) do not have permanent radial strength .
Final message
I am yet to comprehend what nitrates are expected to do (and what it really does ?) in a patient post PCI ? (By the way . . . why we need to prescribe Nitrates it in the first place ? but In real world most continue to take this for many reasons .)
We need to analyse the micro-vasomotion at the stent -coronary intimal interface.The dynamism in this narrow space can be critical , and may make the difference between life and death !
After thought .
In the hind sight, this post appears quixotic for myself . But some one , some where , may generate a great idea out of it , that will help our patients.
Dr.S.Venkatesan MD 