A Medical Device Daily

Treating long segments of a blocked artery with subintimal angioplasty, followed by stenting, as needed, is highly successful in restoring blood flow non-surgically and preventing amputation, according to a study presented yesterday at the 30th Annual Scientific Meeting of the Society of Interventional Radiology (SIR; Fairfax, Virginia) ongoing in New Orleans.

As opposed to traditional angioplasty, which works by directly expanding the space in the narrowed lumen, subintimal angioplasty is performed in the artery wall to create a new non-diseased channel underneath the diseased lumen area.

The study examined treating long segments of small vessels in the legs and feet (the superficial femoral arteries and tibial arteries) in patients with chronic critical limb ischemia. These patients had restricted blood flow to their feet from peripheral arterial disease (PAD), and most were not candidates for arterial bypass surgery, the treatment frequently offered to patients with chronic critical limb ischemia and facing amputation of the foot and leg.

PAD – the result of fatty plaque buildup in the arteries – can lead to decreased blood flow to the legs, in turn leading to significant pain when walking and, worse, eventually gangrene and amputation. Patients in the study already had tissue loss or rest pain (pain even when not walking) from the lack of blood.

Lead study author David Spinosa, MD, an interventional radiologist at Fairfax Radiology (Fairfax, Virginia), said the study shows that "we can treat very severe [PAD] in the smallest vessels, even those with long lesions, with subintimal angioplasty and stenting, potentially saving these patients from amputation."

He called the finding significant "because patients with severe critical limb ischemia typically have poor wound healing and increased risk of infection following bypass surgery in the leg. Subintimal angioplasty can offer a less-invasive treatment in both patients who are candidates for bypass surgery and in those who may not be."

Using guided imaging, the interventional radiologist threads a catheter through the femoral artery in the groin, to the blocked artery in the legs. He then passes through the layers in the blocked artery wall and then back into the lumen (the interior channel) of the artery. He then inflates a balloon to open a channel in the wall of the vessel where it is narrowed, using a stent when necessary.

The longer the length of the segment clogged with plaque, the more difficult it is to treat and to keep open.

The study involved 79 patients with chronic critical limb ischemia: 77% had tissue loss and 23% had rest pain alone. The patients were divided into two groups, both of which had the superficial femoral artery/popliteal segments treated: group one, made up of patients having lesions less than 200 mm long, received subintimal angioplasty with stenting; group two had lesions longer than 200 mm. All received subintimal angioplasty and stenting, to determine if routine stenting was beneficial.

Re-establishing straight line blood flow to the foot was accomplished in 100% of the patients. The six-month limb salvage rates in group one were 86%, and 90% for group two. Stenting the longer segments over 200 mm did not appear to improve limb salvage compared to stenting as needed after subintimal angioplasty.

Spinosa said it is important "that we can offer potentially successful treatment for these long lesions in patients who typically have few options other than amputation."

In another study presented at the SIR conference:

A new non-surgical treatment for prostate cancer – termed a "male lumpectomy" – was shown to be an effective treatment while also preserving urinary and sexual function in a majority of men.

The procedure uses focal cryoablation to target only the tumor itself, thus sparing healthy tissue in and around the prostate gland, compared to the traditional approach which involves destroying or removing all of the tumor. Sexual dysfunction (in 75% of cases) and urinary incontinence (10%) are common complications of surgery. And about 50% of patients treated by brachytherapy experience impotence in the long term.

Up to 35% of prostate tumors are solitary and unilateral and do not spread quickly. Thus, many can be treated with a local treatment less likely to cause side effects.

In this ongoing study, 60 patients were treated with focal cryoablation. Preliminary results for the 42 men who have completed between one-year and eight years follow-up showed 40 (95%) had stable prostate-specific antigen tests, indicating no evidence of cancer. High rates of potency also were maintained.

Of the 32 patients who were potent prior to the procedure, 25 (78%) remained potent, compared to 20%-40% potency rates in patients treated with unilateral nerve-sparing radical prostatectomy and 50% long-term potency rates for radiation therapy, including brachytherapy. No patient reported incontinence.

"Treating only the tumor instead of the whole prostate gland is a major and profound departure from the current thinking about prostate cancer," said study author Gary Onik, MD, an interventional radiologist at Florida Hospital/Celebration Health (Celebration, Florida), who pioneered prostate cancer cryoablation in the early 1990s. Onik refers to focal cryoablation treatment for prostate cancer as "male lumpectomy," reflecting the origins of the approach in the breast-sparing surgery that has replaced radical mastectomy as the preferred treatment.

In a cryoablation procedure, the interventional radiologist inserts a probe through the skin, using imaging to guide the needle to the location of the tumor. The probe then circulates extremely cold gas to freeze and destroy the tumor. The procedure, which is carried out under general anesthesia, is routinely done on an outpatient basis and patients return to normal activities within one to two weeks, depending on the extent of treatment needed.

"Focal cryoablation changes the whole picture in terms of complications, and the cancer control is as good as for any other treatment. Focal cryoablation appears to preserve urinary and sexual function superior to any other treatment yet available," Onik said.

Cryoablation has been used for many years by surgeons in the operating room for a variety of tumors, but in the last few years, the probes have become small enough, and are now insulated, so that they can be used by interventional radiologists through a small nick in the skin.