For medical science to defy logic , is a not a great new discovery . “Diabetes is a major risk factor for heart disease but controlling diabetes may not remove this risk factor” Similarly severe mulitvessel CAD occurs without any symptoms and compromise on LV function . It is a natural human instinct to open of any thing that is obstructing on their path . The same logic applies in physicians when we encounter blocks in the vascular highways .
For a moment compare it with an express way .
We realise many roads have a reserve capacity . Even if the road is half blocked , traffic congestion rarely happens as the original road’s width is sufficiently large for the projected traffic . Some other roads have emergency service lanes (Collaterals) that can take care the flow of traffic.
Another question to ask is , Where does the road lead to ? and why we are traveling ?
If it leads to a “dead sea” or a “bottom less cliff’ there is no purpose to travel further . Similarly , when you find a destructed kidney with little nephron mass( or dead myocardium ) there is absolutely no purpose in opening the block . (Some may believe the act of opening block , by itself is a success / sorry- story !)
This is what happened in the lase decade . Interventional radiologists , vascularologists , cardiologists started opening renal artery obstructions , at their whims and fancies, in many elderly and middle-aged population .To their surprise (This surprise is due to ignorance ) they found no worthwhile benefit either in the BP reduction or worsening renal function .
Now comes the evidence in 2009 as ASTRAL trial from UK . ( As usual the evidence came late after , few lakhs of kidneys been injured !*
* Renal interventions are notorious for many complications , which is often not reported . Read this article to know it better.
http://www.nejm.org/doi/pdf/10.1056/NEJMoa0905368
Final message
Common sense can work great wonders than the much hyped RCTs . (Except ASTRAL of course !) In this era of scarcity of such sense we can expect another study soon , to nullify ASTRAL and give us further license to pursuit the good old human instinct ! Already silent noises are made in interventional corridors questioning the outcome of ASTRAL.
Dr.S.Venkatesan MD 