March 2009 Archives:

March 24 » Is The Scaffolding Coming Down?

March 11 » Broadcasting Live Cases

March 10» Bent Out of SHAPE

March 24, 2009 -- 1:55pm EDT

Is The Scaffolding Coming Down?
Today's good news about Abbott's bioabsorbable stent brings the following analogy to mind.

Scaffolding on Building

A stent is often described as a "scaffold" inside the artery. Indeed, in the era of POBA (Plain Ol' Balloon Angioplasty) elastic recoil of the arterial plaque could reblock the freshly-opened artery, or the ragged interior surface left after the balloon fractured the plaque would lead to increased rates of restenosis.

So angioplasty pioneers developed the stent, a scaffold to hold the artery open. Recoil virtually disappeared. Abrupt closure, which led to emergency CABG 3-5% of the time, was reduced by a factor of 20. And while stents reduced restenosis, these devices produced their own unique brand of complications.

Scaffolding in Artery

Unlike their construction counterpart, scaffolding inside the artery cannot be removed when the job is finished. Metal stents are permanent. They (hopefully) get covered over by endothelial cells and are incorporated into the lining of the artery, but cell growth can occur inside the stent, reblocking the blood flow (in-stent restenosis) or in the case of drug-eluting stents, the endothelial healing can be delayed, causing platelets to aggregate around the bare metal structure, causing a blood clot and possible heart attack (late stent thrombosis).

These complications are small in number (very small in the case of late stent thrombosis) but they complicate what should be a simple task. Fix the arterial wall until it heals and then "Take Down The Scaffolding!"

There's also the issue of the "straight-jacket", as Dr. Charles Simonton of Abbott calls it. A metal stent must, by its presence, restrict the normal natural flexibility of the coronary artery (which is beating and moving all the time). Certainly the newer stents with thinner struts are better, but patients with 7, 8 or more stents can get into the realm of what's called a "full-metal jacket". And too much metal can compromise future therapy as well -- bypass surgery, for example.

Enter (or exit!) the bioabsorbable stent. As recent results have shown, the stent, having done its job, disappears after two years. Normal motion is restored to the artery which, in many ways, acts like it did before the stent was placed, except that the blockage is gone.

These are, of course, hopes. The early trial was only 30 patients. Abbott announced a second phase today which will bring the total to 110. All agree that larger trials with more patients and more complex anatomy must be done. All also agree that this technology, if it proves as safe and effective as the small trial, could revolutionize the treatment of coronary artery disease yet again.

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March 11, 2009 -- 7:30pm EDT

Broadcasting Live Cases
Last Friday, my short video, recalling the origins of the "Live Demonstration Course" in interventional cardiology, was shown during the final day of CRT 2009, an interventional meeting chaired by Dr. Ron Waksman of the Washington Hospital Center.

The venue was the "FDA Workshop: Should Live Cases be Broadcast to Meetings? Regulation in Education and Training."

Recently U.S. Representative Henry Waxman and Senator Charles Grassley have been concerned about the ethical implications of broadcasting live cases involving angioplasty, stents, and related devices. So, as a pioneer in the development of this educational format, I felt obliged to offer the historical context. In fact, coronary angioplasty would not exist if it were not for the live demonstration course.

The early live cases we did in the eighties focused a great deal on the patient -- Dr.'s Gruentzig, Dick Myler, etc., would have active live conversations with the patient -- the audience got to know them a bit and the human side of the patient and physician experience was transmitted, along with the medical techniques. This real-time, holistic look into the cath lab was a key educational component of these courses. And, everyone on the team and in the audience felt invested in each patient's best outcomes.

Those of us who participated in creating those courses had no question
that a live case broadcast was an advantage for the patient who chose to be included, not a negative. And, we saw how viewers' participation in the entire unfolding case, and observing the decision-points, was a powerful physician training tool.

While demonstration case broadcast has radically changed, it's worth looking at the effect this approach had on the profession, and identifying what factors, perhaps even guidelines, need to be present to determine its continuing potential to be an effective and ethical educational tool moving forward.

My video (supported by a grant from Abbott Vascular) is currently viewable at CRTonline's version of YouTube, called CardioTube.

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March 10, 2009 -- 6:15pm EDT

Bent Out of SHAPE
Today the Texas House of Representatives has been holding a public hearing on bill HB 1290, sponsored by Rep. Rene Oliveira, which mandates that any health insurance plan that covers medical screening must also cover Coronary Artery Calcium (CAC) screening, a test which currently is NOT covered by Medicare or by most insurance. This would be a major step forward for this imaging technology.

Two years ago, the Houston-based Society for Heart Attack Prevention and Eradication (SHAPE) group issued a set of guidelines for early detection of heart disease. As reported on Angioplasty.Org, the SHAPE recommendations generated quite a bit of controversy at the time, with passionate advocacy of the test on the part of the SHAPE authors, and comments from others in the cardiology community, such as Dr. Philip Greenland of Northwestern, who called the report "an apparent effort to subvert the long-standing evidence-based guidelines approaches" of the major heart societies, such as the ACC and AHA. A Texas bill, virtually the same as the current one, was voted down in committee.

Which is why, to everyone's surprise, Dr. Morteza Naghavi, founder of SHAPE and Chairman of the SHAPE Task Force, stated in a Friday press release that, "We are also pleased to know that the American Heart Association has elected to support the bill as well."

Well, not exactly.

As Larry Husten, former editor of theheart.org, reported last night in his blog CardioBrief, the AHA has denied any endorsement. He writes that the AHA spokesperson said:

I contacted Dr. Naghavi of SHAPE. He told me that he'd been informed of the AHA endorsement during a conference call last Thursday by Michael Gray of Rep. Olivera’s staff. Reportedly Joel Romo of the AHA had conveyed news of the AHA's support to Mr. Gray and was "upbeat about it."

This afternoon the SHAPE Society sent me the following statement:

Obviously, there's just a bit of politics going on here, most of it outside the House of Representatives. What's interesting is that among the many distinguished members of the SHAPE Task Force are Dr. Pamela Douglas, a past-president of the American College of Cardiology and Dr. Valentin Fuster, a past-president of the American Heart Association.

Angioplasty.Org will be posting an in-depth report on the SHAPE recommendations and their implications in today's healthcare environment. Stay tuned.

Late Update: SHAPE has revised its press release and removed the reference to the AHA endorsement, but you can still read the cached version here.

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