Interventional Cardiologist’s favourite play time is to get rid of of obstructions across any blood vessel , valve or a conduit . This has been well practiced for over 2 decades in both coronary and valvular obstruction.Now they wanted more and have since started implanting valves percutaneously. (Aortic valve -TAVR in particular )
Why do balloons work in Mitral stenosis but not in Aortic stenosis ?
It remains a mystery at-least to me ,how PTMC (Percutaneous mitral commissurotomy ) became a default strategy for relieving mitral valve stenosis, while BAV (Balloon Aortic valvotomy) was never considered good enough for opening Aortic stenosis.
The reason is, mitral stenosis(Rheumatic) primarily involve the commissures, while degenerative aortic stenosis involve leaflets more and calcification is much extensive and hence balloons are less effective .Since the initial reports of BAV had more complication like stroke , AR, the interest has waned (except in children with BCAV ).
The arrival of TAVR in big way has made things difficult for BAV to prove its real worth and at best it was considered a bridge therapy.Curiously , BAV is often used as an integral part of TAVR as pre-dilatation with various wires across the valve.Hence , every procedure of TAVR,whether you like it or not carries the huge risk of BAV (please note,these are the same risk which made it unpopular earlier !)
Now , with accumulating data(Funny we got trained in BAV during TAVR we have double confirmed BAV is not that risky after all, even in calcific aortic valve. We also learnt BAV does open up the valve significantly (exact gain contributed by BAV during the TAVR is not quantified as yet).Hence many believe BAV is grossly underutilized modality .
Final message (As usual , without evidence )
BAV, considered just a bridge therapy to TAVR/SVR , (mind you,it may not be flimsy bridge , but a near permanent steel bridge that can outsmart the much hyped TAVR!) Let us recall again the mitral valve logic where you just require dilatation for stenosis .Some degree of AR during BAV is acceptable as do we accept MR in PTMC.As I said earlier the perceived complications of BAV has rapidly declined. For those who are interested in health economics , a single patient’s cost of TAVR can be shared and could confer a fresh bout of life to 20 patients with severe aortic stenosis who can be tackled well with BAV.
I agree , BAV can not reach the glory of PTMC, but definitely its going to come back and expected to give a tough fight to TAVR in atleast high risk patients.BAV has a potential to become a therapy of choice in patients with critical aortic stenosis with severe LV dysfunction as even a small gain in orifice with a balloon can provide a big booster effect on LV function.
A thought and a counter
BAV is retro technique with low efficiency and with high complication rate .
However, isn’t ironical , complications with TAVR ,which includes 25 % of permanent pacemaker assistance is accepted .(with a pride ?) while that of BAV is magnified and made to look unacceptable.Of course , many have mastered BAV and complications has come down recently .I have heard few anecdotal examples where TAVR was abandonded for some reason after pre-dilating the aortic valve and patient doing fine with BAV in the long term.Its being predicted BAV is going to reemerge (already is !) as a useful strategy in critical calcific Aortic stenosis
The emprical utterrings in this discussion are dangerous and unethical and not evidence based !
It would appear “not doing” a large randomised trial comparing one to one (BAV vs TAVR) in a real “high risk” setting of AS amounts to ” unethical” act as complication with BAV has grossly reduced in recent times ! Its our duty to provide best or near best to our patients.Let us ensure reasonable inferiority/Non inferiority is accepted that can prevail over a perceived superior modality , if it comes at low cost !
Further reading
1.
Dr.S.Venkatesan MD 