Technology May 'Reinvent' Subintimal Recanalization

BY TIMOTHY F. KIRN

LAS VEGAS -- With the introduction of new endovascular technology, subintimal recanalization of chronic total occlusions of peripheral arteries has come of age, said speakers at a meeting on peripheral intervascular interventions sponsored by Medical Media Communications.

"Subintimal recanalization is not the only way to treat chronic occluded vessels, but it is one of the tools that is useful and certainly everyone should be comfortable with the concept and have some experience with it," said Dr. Mark W. Burket, the director of vascular medicine at the Medical University of Ohio at Toledo.

The major advantage of subintimal recanalization, in which the catheter glide wire is passed into the vessel wall to bypass the occlusion rather than punching directly through it, is that a dissection of the subintimal space is more likely to produce a smooth lumen than is a dissection directly through plaque, Dr. Burket said.

Therefore the procedure can reduce the need for stents and reduce the likelihood of restenosis.

The first case of subintimal recanalization was done in 1987, accidentally, and the patient did well for 9 years, he noted.

Reported success rates in various patient series are 80%, with 60%-75% still doing well at 1 year.

In cases of heavily calcified occlusions, it may not be possible to pass through a lesion anyway, he added. And for softer occlusions, recanalization is probably cheaper than either using a laser or an atherectomy device. The problem with the technique has been getting the glide wire back into the true lumen once the occlusion has been passed.

New devices, however, are solving that problem, Dr. Burket said. These devices--the CrossPoint TransAccess and the Outback Re-Entry catheters, for example--have needles or special bent tips for re-entering the lumen.

Endovascular treatment of total occlusions in almost any location remains feasible, provided the occlusion is not too long, according to Dr. Mark C. Bates, in his related presentation.

At his institution, an endovascular approach is the standard of care for total occlusions of the subclavian arteries, provided the occlusion does not include the internal mammary or vertebral arteries, said Dr. Bates, who practices in Charleston, W.Va.

Dr. Bates said they also do smaller, hypoplastic aorta occlusions, iliac occlusions, and superficial femoral artery occlusions, though this location may be the possible exception to the feasibility of the endovascular approach because occlusions in the superficial femoral artery tend to be long.

"In my opinion, all chronic occlusions can be treated, particularly with the new ways of making sure you get back into the true lumen," he said.

The new devices can even be used to punch through the arterial wall into the extravascular space or the adjacent venous system to create a bypass of the occlusion using stents, said James Joye, D.O., who practices in Mountain View, Calif., in another related presentation.

Dr. Joye described treating 14 patients with total occlusions of the distal superficial femoral artery in this manner. With follow-up of up to 3 years, one patient thrombosed after the procedure, and received a successful bypass, and two patients have reoccluded. Overall, the primary patency rate is 77%, the assisted patency rate is 85%, and the secondary patency rate is 92%.

"I am not suggesting that you run out and do this," Dr. Joye said. "I'm just saying this is an early look at a potential option."

When asked to comment upon this article, Dr. Ronald Fairman, chief of the division of vascular surgery, Hospital of the University of Pennsylvania, Philadelphia, stated: "I do feel it is important to remind physicians that subintimal angioplasty is an excellent first consideration when approaching total occlusions.

"In my own institution and division, there has been a recent willingness to jump to laser-assisted angioplasty and/or atherectomy, before attempting a subintimal approach.

"We now have a larger tool-box including longer balloons, nitinol stents, as well as smaller wire platforms to enhance our ability to offer endovascular options for total occlusions. One should also consider the cost of disposables, which can ramp up quickly during an endovascular procedure, as well as the potential for reinterventions with a particular approach," Dr. Fairman concluded.