A Refresher on the Percutaneous Treatment of Lower Extremity PAD
- Volume 18 - Issue 12 - December 2010
- Posted on: 12/30/10
- 0 Comments
- 7443 reads
Key words: peripheral arterial disease, atherosclerosis, atherectomy, claudication, kissing technique, dissection, debulking, recanalization, subintimal, restenosis
Atherosclerosis is a systemic disease affecting all major vascular beds. In the cerebrovascular system, atherosclerosis can result in stroke; in the coronary system, it can result in myocardial infarction, and in the peripheral arteries, atherosclerosis can result in claudication or acute limb ischemia.
Peripheral arterial disease (PAD) affects 12-20% of Americans age 65 and older with only 50% of that age group being symptomatic.1 Approximately 12 million people in the U.S. alone have PAD.2 Risk factors for atherosclerosis, and therefore, for PAD, include active smoking, dyslipidemia, diabetis mellitus, and hypertension. Risk is higher in patients with diabetes mellitus. It is estimated there is a 3-fold greater risk for PAD in those with diabetes also over the age of 50.2 The International Diabetes Federation estimates that somewhere in the world, a leg is lost to diabetes every 30 seconds.3 Each year there are 150,000 lower-extremity amputations, with a $270-million price tag.4
PAD greatly impacts quality of life, making walking difficult or worse, and increasing the risk of heart attack, stroke, leg amputation, and even death. PAD, symptomatic or asymptomatic, is a powerful independent predictor of coronary artery disease (CAD) and cerebrovascular disease (CVD) (Table 1).5 In the Coronary Artery Surgery Study (CASS) Registry, for patients with known CAD, the presence of PAD increased cardiovascular mortality by 25% during a 10-year follow up.6 Recognizing the symptoms and early diagnosis of PAD, therefore, is very important. In a 2001 study, only 49% of those receiving amputations had any diagnostic vascular evaluation prior to amputation.7
PAD treatment options include medical therapy, endovascular therapy, and surgery. Medical therapy includes risk factor modification, exercise, and drug therapy.
Endovascular therapy includes peripheral transluminal angioplasty, stenting, atherectomy, and thrombolytic therapy. Surgical options consist of bypass grafts, endarterectomy, and amputation.
Over the past decade, percutaneous revascularization therapies for the treatment of patients with PAD have evolved tremendously, and a great number of patients can now be offered treatment options that are less invasive than traditional surgical options. In this article, we will discuss the percutaneous treatment of PAD.
Percutaneous treatment of lower extremity obstruction can be divided into three anatomic zones:8
Common iliac arteries (bilateral)
External iliac arteries (bilateral)
Common femoral arteries
Superficial femoral arteries
Anterior tibial artery
Posterior tibial artery
Inflow Tract Area Interventions
Atherosclerosis affecting iliac or aortoiliac vessels manifest as hip or leg claudication. Atherosclerosis in these vessels can also result in erectile dysfunction. In 1999, the Trans-Atlantic Intersociety Consensus (TASC) group developed treatment guidelines based on lesion location and characteristics (Figure 1).9 The recommendations were for treating TASC-type A to B lesions with an endovascular approach and type C to D lesions surgically. However, with the rapid evolution of endovascular techniques, type C and D lesions can now be treated percutaneously, with long-term patency rates comparable to surgery, and without the associated morbidity and mortality.10
Iliac arteries have a higher rate of dissection and elastic recoil. Therefore, primary stenting is the preferred strategy in iliac artery disease, although some operators are still using provisional stenting.11 A meta-analysis of 14 studies performed since 1990 involving either percutaneous transluminal angioplasty (PTA) or stenting reveals higher procedural success with stenting (39% lower risk of long-term failure with stenting).12
Iliac arteries can be stented with balloon-expandable or self-expandable stents, with 80% primary patency at 1 year with self-expandable stents.13 Balloon-expandable stents have an 87% primary patency at 1 year14 and have great radial force, allowing for increased placement precision in ostial lesions. Self-expanding stents have no risk of external compression or deformation. They are flexible and can be delivered from the contra lateral approach, allowing normal vessel tapering.
If atherosclerosis of the common iliac arteries also involves the terminal aorta, then balloon-expandable or self-expandable stents can be used with either the “hugging” or “kissing” technique. The hugging technique should be used if atherosclerosis is affecting the terminal aorta and ostia of common iliac arteries to minimize the risk of aortic dissection. The hugging technique uses two self-expandable stents, deployed simultaneously from the terminal aorta into each common iliac artery.
The kissing stenting technique (Figure 2) is used if atherosclerosis mainly affects ostia of both common iliac arteries and minimally affects the terminal aorta. It offers excellent procedural outcome (100%) and patency (92%).15