Despite surgical options and a wide array of perctunaeous approaches which include angioplasty, laser ablation and stent placement; the treatment of infrainguinal occlusive disease continues to be a challenging problem. The reasons include altered hemodynamics relative to coronary circulation, more diffuse pattern of disease, physiologic stress forces unique to areas of motion like the adductor region and points of repetitive flexion like the common femoral and popliteal vessels.
Although short term results are excellent for accessible lesions. Restenosis at the site of intervention continues to the achilles heal of infrainguinal percutaneous revascularization relative to bypass. Theoretical causations of restenosis include barotrauma associated with a reactive intimal hyperplasia with bare angioplasty as well as nitinol stent placement.
Various studies report patencies approaching 50-60% at 24 months for nitinol stent treatment of focal SFA disease configurations.
In May 2003, the FDA cleared the SilverHawk Plaque Excision System (FoxHollow Technologies, Redwood City, CA) for the treatment of peripheral arteries. The system is composed of a low-profile monorail catheter and palm-sized drive unit witha single on/off swithch to control plaque excision. Upon activation, a minute carbide cutting blade located on the catheter tip rotates at 8,000 RPM. The operator places the catheter tip just proximal to the target lesion, activates blade rotation, and adnvances the cutter through the length of the lesion. With each pass, thin shavings of plaque are exercised and packed into the distal end of the nosecone to maximize the plaque collection capacity. The device can then be removed, the nose cone emptied of plaque, and reinserted to treat additional lesions.
The Silverhawk plaque Excision System achieves plaque apposition without the use of a balloon which theoretically may reduce the potential for barotrauma and dissection associated mid and long-term restenosis. The Cathter design facilitates plaque excision from vessels over a wide range of diameters (2-7mm) and particularly from the infrageniculate vessels which are resistant to stent placement and angioplasty.
The Following is from a presentation by Dr Venkatesh Ramaiah, a vascular surgeon at the Arizona Heart Hospital, reported one-year data from the multi-centre TALON registry. According to the 2000 Transatlantic Inter-Society Consensus study (TASC), angioplasty and stenting have a one year patency rate of 61-67%. In peer-reviewed, published literature, surgical bypass results at one year have demonstrated patency rates of 77-81%.
Ramaiah stated that of the 87 patients followed for one year after treatment with SilverHawk, nearly 30% of the procedures were for the most severe form of peripheral arterial disease. In addition, 36% of the patients had multiple blockages treated during a single procedure. The average lesion length treated was 7.5cm in arteries above the knee. Despite the long length of the blockages treated and the high percentage of multiple blockages treated, the average procedure time for plaque excision was 31 minutes. Before plaque excision, the arteries treated, on average, were 85.6% blocked with plaque. Treatment with SilverHawk reduced the blockage by over 85% to a residual 10.5%.
Follow-up data is available for 317 lesions that have reached the six month time point. Revascularisation occurred in 35 of the 317 lesions for an overall target lesion revascularisation rate of 11.0%. The target lesion revascularisation rate in patients with a single lesion treated was 4.6% (3/65). Of the 85 chronic total occlusions lesions with follow-up data that have reached the six month time point, the target lesion revascularisation rate was 8.2% (7/85).
Although this is dated literature, it is representative of the early quoted results to support use of the Silverhawk Atherectomy Device. Anectdotal reports from my colleagues generally is of the "I get mixed results" and "it's a niche product". 1. Why has there not been a prospective randomized trial comparing SilverHawk to other modalities?
kindly give me the details about the access and the sizes of giudewires/ sheath etc over which this device will be used.
Dr.C.Anand, DNB resident, Vascular Surgery, Army Hospital, New Delhi
Posted by: Dr.C.Anand | November 08, 2011 at 04:24 AM