A New Stent to Prevent Lower Limb Amputations?
When arteries below the knee become so narrowed by atherosclerosis that bumps and scrapes on the feet and ankles fail to heal and leg pain is relentless, the risk of amputation soars.
But physicians have few evidence-based and durable options for treating patients in this situation when peripheral artery disease has advanced to a diagnosis of chronic limb-threatening ischemia (CLTI) in the lower leg.
A clinical trial led by Columbia interventional cardiologist Sahil A. Parikh, MD, shows that a new type of bioresorbable scaffold can restore flow through the artery better than the current standard of care.
“As a physician who treats these patients and who has lost family members to this disease, I am hopeful that this device—which has not yet been approved by the FDA—will allow us to save more limbs and lives of our future patients,” says Parikh, who is associate professor of medicine at Columbia University Vagelos College of Physicians and Surgeons and director of endovascular services at Columbia University Irving Medical Center.
What is CLTI
Chronic limb-threatening ischemia is the most severe stage of peripheral artery disease when pain is present at rest and the limb shows signs of gangrene or an ulcer.
Medical treatment can frequently help with prevention of peripheral artery disease, but once CLTI develops, up to 40% of patients will require amputation within six months. Between 1 million to 3 million Americans have CLTI and the incidence is growing with the increasing diabetes epidemic.
Below the knee obstructions are tricky
While there are several options for treating obstructions in arteries above the knee, arteries below the knee are notoriously hostile to treatment. Previous trials have failed to show an advantage for stents, which also restrict the use of future surgical treatments.
The current standard of care is balloon angioplasty, which some studies show is better than bypass surgery for treating CLTI in the lower leg, but the opened artery will usually become clogged again.
The new trial was undertaken to investigate the potential benefit of a drug-eluting resorbable stent (Esprit BTK from Abbott, which releases a drug to prevent further clogging) to improve clinical outcomes over the standard of care for patients with below-the-knee CLTI who needed treatment.
Study results and next steps
Among patients in the trial who received the stent, only 26% experienced a re-narrowing of the artery, a second procedure to clear the artery, and/or amputation in the year following the procedure compared to 56% of the 88 patients who received the standard of care.
In addition to outperforming the standard of care in the trial, the resorbable stent was also as safe as the balloon procedure during the first year after the procedure.
Although the number of amputations prevented in the first year was essentially the same among both groups of patients, the percentage of stent patients who did not experience reclogging of the artery was substantially higher (76% vs 50%) compared to the balloon patients.
“We will continue to follow the patients out to five years,” Parikh says. "We expect that both groups of patients will have relief of symptoms and excellent wound healing, which has so far been shown to be similar in both groups. However, we expect that if the scaffolds stay open and the blood flow is preserved, these patients will be less likely to develop new wounds or painful symptoms and have superior quality of life.
“Additional analyses are ongoing to better understand how the patients will do over time and improve our understanding of the disease, which will hopefully lead to better care for all patients with peripheral artery disease and CLTI.”