Treating critical limb ischemia in peripheral arterial disease (PAD) patients with below-the-knee angioplasty is thwarted by restenosis, the need for repeat treatments and the continued progression of atherosclerotic disease, leading to tissue death and amputation. However, interventional radiologists have found that drug-eluting stents (DES) lessen the rate of repeat procedures to open these small arteries, according to results presented at the Society of Interventional Radiology (SIR) annual meeting in San Diego this week.
"This is encouraging news for PAD patients with critical limb ischemia. The smaller blood vessels below the knee are more difficult to treat due to their size (3 mm) and are more prone to reclog than larger vessels. The use of DES in the tiny infrapopliteal arteries of the leg may significantly impact their care," said Dimitris Karnabatidis, MD, assistant professor of interventional radiology at Patras University Hospital in Rion, Greece. "DES have emerged as a potential solution to the limitations of endovascular treatment of PAD patients with critical limb ischemia," he added.
The researchers from a single center studied 103 patients in a double-arm prospective registry who had critical limb ischemia and who underwent infrapopliteal revascularization with angioplasty and placement of either a DES (with sirolimus) or a bare-metal stent (BMS). The patients had regular follow-ups up to three years, and researchers studied how they did by stent type. In the first group, 75.6 percent of diabetics were treated with BMS, and in the second group, 87.1 percent of diabetics were treated with DES.
At three years, those patients with DES had "significantly higher patency;" reduced restenosis of the vessels; and consequently less clinical recurrence requiring repeat angioplasty, according to Karnabatidis.
"In the DES group, an estimated 60 percent of the treated arteries remained open at three years. This is significantly longer than the BMS group, where the arteries remained open only approximately 10 percent at three years," Karnabatidis said. "This corresponds to a more than 5 times increased risk of vessel reclogging when BMS were used," he added.
"Because of the reduced vessel restenosis, repeat angioplasties were necessary in only 15 percent of the patients in the drug-eluting stent group versus almost 35 percent in the BMS group up to three years-this being the equivalent to an almost 2.5-fold risk of repeat procedures in the case of bare metal stents," Karnabatidis noted. "These statistical results are based on three-year adjusted survival analysis after application of a Cox model for multivariable analysis."
If a person has critical limb ischemia, it means he or she is at great risk for tissue death due to lack of blood flow, which carries oxygen and nutrients to the cells. The researchers said that severely restricted blood flow results in severe pain in the feet or toes, even while resting, and sores and wounds that will not heal. Tissue death and amputation are imminent at this advanced stage of PAD, which is caused by atherosclerosis, the hardening and narrowing of the arteries over time due to the buildup of fatty deposits called plaque.
"Multicenter randomized trials are necessary to support these promising results and build on the level of clinical evidence supporting the integral value of infrapopliteal drug-eluting stents in critical limb ischemia treatment," he added. In the United States, DES are FDA-approved for the coronary arteries, but not for infrapopliteal arteries. In Europe, DES have CE Mark approval for below-the-knee use.