Will Transcatheter Implants Send Coronaries to Stent Jail?

In my last post, I argued that 40% of patients over age 70 presenting for AVR surgery  with a stenotic aortic valve will Stent Jailhave a bicuspid shaped valve and therefore will not be eligible for a transcatheter device.  What about the 60% that have a tricuspid valve?  Are all of these candidates for a transcatheter procedure?  I don’t think so.  As it turns out,  “significant coronary artery disease” is another major contraindication/exclusion in the PARTNERS Trial and is also contraindicated in the European Guidelines.

How significant is concomitant coronary artery disease and why would it be contraindicated?

Again, based on research done by Dr. William Roberts, a cardiac pathologist who has studied aortic valves for over 40 years, over 65% of stenotic tricuspid patients also present with CAD so severe that at least one bypass graft was necessary at the time of valve surgery.  I have again taken the liberty to graph the data Dr. Roberts presented  in table format only.

Robert's CAD Data

This data is significant because the PARTNER Trial specifically excludes patients with CAD.  Here is the specific exclusion statement:

7. Untreated clinically significant coronary artery disease requiring revascularization.

And if a coronary stent procedure is done beforehand to alleviate a coronary obstruction, the patient is excluded from a transcatheter procedure for 6 months, effectively eliminating transcatheter as an option for most of these patients.  Here is the exclusion statement in the PARTNER Trial.

4. Any therapeutic invasive cardiac procedure performed within 30 days of the index procedure, (or 6 months if the procedure was a drug eluting coronary stent implantation)

Why are CAD patients being excluded?  Below are a few pictures that might explain the reason.  Careful examination of angiograms post implant of both a balllon expandable and a self expanding transcatheter valve show the distinct possibility of the implant obstructing the coronary ostia, not from blood flow, but from subsequent guide catheter insertion.   The last photo clearly shows an ostium with an obstructed entrance.  By implanting a transcatheter valve, the patient’s coronaries may become predictably inaccessible in the future.  I assume most cardiologists would agree this is a good reason to exclude transcatheter procedures in patients presenting with CAD.  By providing an immediate less invasive procedure, a future less invasive procedure may be forfeited.

Guide Cath obstrut BalloonGraphic Source, Anatomy of the Aortic Valve Complex and Its Implications

Guide Cath obstrut SelfGraphic Source, Anatomy of the Aortic Valve Complex and Its Implications

Ventor Position

In summary – if only 60% of patients over age 70 present with a stenotic tricuspid valve and 65% of these have severe CAD, that leaves only 21% of all stenotic AVR patients over age 70 eleigible for a transcatheter procedure (did I do the math right?).

My point – Transcatheter procedures will not dominate the market due to fundamental clinical restraints.  AVBG, which is agnostic to valve shape or concomitant coronary artery disease, is a logical less invasive choice for many patients.

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