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Archive for the ‘TAVR /TAVI’ Category

Interventional cardiologists generally do not believe (rather relish) in simple balloon dilatations to remove any vascular blocks. It is a mundane job for their talent-rich hands. After conquering the coronaries, we made exclusive valvular stents. No surprise, TAVR has taken over the aortic interventions with all its glamour and vigor, though it is definitely not an ideal choice in all.

SCAI, the prestigious journal in Interventional cardiology has a recent article , that has a not-so pleasant message for TAVR lovers.

Very soon, BAV could pose a direct challenge to cardiologists’ heart throb TAVI. Though, it suggests BAV as an adjunct or bridge , there is every reason to belive the bridge can outlive the lives of many co-morbid subsets in TAVR eligible cohorts. (ACC 2014 guidelines already has a grossly under-rated 2B/ Evidence C Indication for BAV)

It seems reasonable to believe BAV, with considerable improvement in hardware, technology, and expertise can be an alternative to TAVR in high-risk aortic stenosis in a substantial number of patients.

It is also worth pondering over a less discussed aspect of BAV. The apparent high adverse events with BAV in calcific AS reported in the past-PARTNER days are now proven to be either exaggerated, outdated, or outright false. (For the evidence seekers, there was never a control BAV arm in none of those big studies on TAVR. It was purely a Surgery vs TAVR study. (A flaw in the aim of the study?) They may call it unethical to have a BAV limb, my understanding is, the absence of which is more unethical, as we claim superiority of TAVR without a less invasive option of BAV as control )

The fact of the matter is, in many centers, the risk of sudden death or acute aortic regurgitation is either comparable to or acceptable when compared to transcatheter aortic valve replacement (TAVR). It is worth emphasizing that BAV can be performed regardless of the load and location of calcium, while TAVR requires minimum elastic calcific load assistance to hold the valve in place. Further, BAV-related issues can now be effectively managed with efficient hemodynamic management.

Final message

If not scientiifally discriminated*, new age BAV can upgrade itself from the “self imposed contraindication” to, a sustainable alternative to TAVR ,atleast in selected sub-group of patients with isolated AS. This reality sould be perceived not only in the cost perspective, but also in the overall superiority in avoiding all those menacing complications with TAVR.

Postamble

*Very difficult task for the humble balloon to prevail over glamarous TAVR. Still,there is some hope(.We can get it from the emerging DEB story, where balloons are able to get rid of stents from the coronaries).

Reference

This is an interesting and important paper in the BAV vs TAVR debate. The funny thing is, even after reading it twice, I am unable to clarify which procedure this paper really favors!

1.Alkhouli M, Zack CJ, Sarraf M, Bashir R, Nishimura RA, Eleid MF, Nkomo VT, Sandhu GS, Gulati R, Greason KL, Holmes DR, Rihal CS. Morbidity and Mortality Associated With Balloon Aortic Valvuloplasty: A National Perspective. Circ Cardiovasc Interv. 2017 May;10(5):e004481. doi: 10.1161/CIRCINTERVENTIONS.116.004481. PMID: 28495894.

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TAVR is the new state of the art Aortic valve replacement procedure done by cardiologists .Nearly 200 thousand implants have been done , and it is
backed up by major trials TAVI TAVR valve dislodgement embolism partent a b What keeps the Aortic prosthesis in situ in the aortic root/Annulus  ?

The valve is not actively fixed but passively positioned in aortic root by either self expanding or balloon expanded valve  system .It retains the position by two different forces acting on the valve in two difffernt directions , but work coherently to keep the valve static .The radial force of the hardware is centrifugal and the elastic force exerted by annulus is centripetal .It may appear mysterious how these oppose each other in a balanced way and arrest the valve in the desired site. Fortunately, there is little  supero- inferior force operating and hence the chances of dislodgement is low .It should also be mentioned we are not yet clear about the best site for TAVR. Annular , supra annular ,or is it at lower virtual annulus , all has some advantages and disadvantages.

Is progressive aortic annular dilatation possible in these degenerative aortic valve ?
Aortic stenosis is chronic degenerative disease. Generally we expect the annulus is narrow and fixed. However for some reason if the aortic annulus loses it constricting force or the root dilates or fresh calcium deposits, there is definite risk  (Not theoretical :See Reference ) of valve destabilisation  , dislodgement and embolisation . *It is vital to understand the para-valvular leak could be a  remote precursor of such potential dislodgement as it represents  micro gaps  in the prosthetic / tissue interface.

How many such  embolisation of valves  are reported following TAVR ?

While the incidence of para valvular leak is common ,(up to 20%) fortunately valve embolisation is reported between .3 to 7.5% (Ref 2). Stastically , subclinical   destabilisation, malpostion  and dislodgement should be more common. The timing of displacement is not clearly reported in literature .It can occur  at any time between few hours after implantation to a much delayed (months after ) complication .

Final message

TAVR is a major break through in Interventional cardiology .It gives us hope for possible TAMR (mitral) and other valve repair modalities .Though dislodgement of prosthesis appear a rare event it is tempting  to ask ,  whether we should work towards a actively fixing valve in aortic root ? That remains a open question !

Reference

1. A survivor of late prosthesis migration and rotation following percutaneous transcatheter aortic valve implantation. Pang PY, Chiam PT, Chua YL, et alEur J Cardiothorac Surg 2012;41:1195-6.

2.Thirty-day results of the SAPIEN aortic Bioprosthesis European Outcome (SOURCE) Registry: A European registry of transcatheter aortic valve implantation using the Edwards SAPIEN valve.Thomas M, Schymik G, Walther T, et al. Circulation 2010;122:62-9.

3.Migration of the transcatheter valve into the left ventricle Christopher Cao , Su C. Ang , Michael P. Vallely Mart Annals of Cardiothoracic Surgery Vol 1, No 2 (July 2012 4.Delayed Transcatheter Heart Valve Migration and Failure Vuyisile T. Nkomo, Rakesh M. Suri, ,J Am Coll Cardiol Img. 2014;7(9):960-962.

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