Peripheral Artery Disease and Intermittent Claudication

Description

Alternative Names

Surgery

In severe cases, procedures to open obstructed blood vessels using angioplasty or with the use of grafts that bypass the obstructed blood vessels are effective. Some evidence suggests that surgical procedures are advantageous in patients with obstruction above the knee and that more conservative measures might be just as effective for obstructions below the knee.

Surgical Bypass

Surgical bypass has, until recently, been the gold standard for extensive PAD. It involves using a graft that acts as a new blood vessel that allows the blood to flow around the obstructed artery. The new graft may be a natural vein taken from a different location in the leg or it may be made from a synthetic material. In one study, the natural vein remained open after four years in nearly half of the patients, while the synthetic vein (made from polytetrafluoroethylene [PTFE]) had closed in all but 12% of patients.

Artificial veins tend to pose a much a higher risk for blood clots and the consequences of re-obstruction are must more severe than when the natural vein recloses. To keep the artificial vein open certain oral anti-clotting agents, such as aspirin or warfarin, may be used. (Such agents are not effective at all with the natural vein.)

Percutaneous Transluminal Angioplasty

Percutaneous transluminal angioplasty (PTA) is an approach that has several variations. The object of the procedure is to open the obstructed blood vessels that are causing intermittent claudication. Angioplasty is being increasingly used, especially in patients who have other medical conditions. Some experts believe that it is not only much less expensive, but it is also more effective than surgical bypass.

The procedure requires only a local anesthetic and patients can return to normal activity in 24 to 48 hours. Complication rates are low. The effects are not permanent, but it the procedure can be repeated without any greater risk than with the original one.

Procedures. The standard procedure is balloon angioplasty. A thin tube is inserted through an artery in the groin and passed through the blocked artery. A wire is threaded through the tube. A deflated balloon is passed over the wire to the obstruction. There, it is inflated and opens the artery.

Because of the risk for reclosure from blood clots after the operation, various other procedures are used or are being investigated.

• More recent techniques employ a stent, an expandable metal mesh tube that is implanted during angioplasty at the site of the blockage. A new type of self-expanding stent called the SMART stent system was approved in late 2003. The SMART stent is used specifically for the treatment of PAD caused by a blockage in the iliac artery, which runs through the pelvic area.
• Another approach uses radioactive implants (brachytherapy) in combination with PTA, which help prevent the arteries from closing after angioplasty. In a major 2002 analysis, this approach produced greater benefits compared to PTA alone, at least in the short term.
• Lasers are also being investigated that uses light pulses to remove cholesterol plaque and blood clots from the blood vessels. A 2004 report suggested that laser therapy may be particularly useful in patients with PAD who are not good candidates for bypass surgery.
• A new type of angioplasty treatment called PolarCath opens blocked arteries by cooling and dilating them with a nitrous oxide-filled balloon. A 2004 study showed that this procedure, also called cryoplasty therapy, has a 9-month failure rate of less than 20%, which is significantly lower the 40%-50% failure rate reported after angioplasty or stenting procedures.

Preventing Blood Clots and Reclosure of the Artery. Anticoagulants, such as aspirin, warfarin, or heparin, may used to prevent blood clots occurring during surgery. All of these agents increase the risk for bleeding.

Alteplase (Activase), also called t-PA, and reteplase (Retavase) are thrombolytic agents (commonly known as a "clot-busters"). These agents break up existing clots. They may be used either before, during, or after angioplasty if a blood clot is present.

Reclosure of the blood vessels from blood clotting, even long after surgery, is an important complication and is still a risk even with stenting and brachytherapy. Repeat surgery may be needed.

Other Complications. An English study reported major complications following surgery in 2.4% of cases. They included pneumonia, stroke, kidney failure and heart attack. Emergency follow-up surgery for bleeding or sudden blockage from a blood clot was required in 2.3% of cases.

Intermittent Pneumatic Compression

Intermittent pneumatic compression (e.g., Arterial Flow, VenaFlow) is a mechanical technique normally used to treat leg ulcers or swelling from fluid build-up. The device involves enclosing the lower leg in an inflatable fabric appliance, such as a cuff-like legging or boot. A pump is used to inflate the appliance, which then exerts pressure on the limb. Typically, a controlling unit applies different frequencies and pressures. Some devices, for instance, apply pressure in a wave-like motion that simulates the natural increase in blood flow during walking. A 2002 analysis of 26 studies suggested that this treatment may be beneficial for PAD patients who cannot undergo invasive surgeries. It may even prove to be a viable alternative to medical treatments in some cases.