Vascular surgeons find ways to treat previously untreatable problems

March 02, 2022
 a series of three images of an artery with blocked blood flow before, during and after intervention
This series of images shows, from left, a deep artery of the thigh that has a calcification blockage, a closeup of the inflated Shockwave balloon and the artery after blood flow was restored. Images provided

If blood vessels are like highways, then buildups of calcium, known as calcifications, are like boulders, blocking the road and inhibiting traffic – blood – from getting where it needs to go. That’s a problem when blood flow to an outlying area, like the legs and feet, becomes so sparse that the limb could die. It’s also a problem when surgeons need to use those highways to deliver repair materials to fix aneurysms and dissections.

Now, vascular surgeons at MUSC Health are seeing such good outcomes when using a relatively new device for dealing with calcifications in the lower half of the body that they have started exploring additional uses for it. They’ve even initiated a trial for an especially hard-to-treat patient population.

“I think the biggest thing is that there are patients that we’re able to treat now who historically had no good options. And I think this is a game-changer for a subset of patients who are really, really hard to treat, with the amount of calcium that they have,” said Mathew Wooster, M.D.

“I think the biggest thing is that there are patients that we’re able to treat now who historically had no good options. And I think this is a game-changer for a subset of patients who are really, really hard to treat, with the amount of calcium that they have."

Dr. Mathew Wooster

MUSC Health was an early adopter of the Shockwave device a few years ago, Wooster said. A doctor threads the device through blood vessels until it arrives at a blockage, then uses sonic pressure waves to break up the calcium.

Elizabeth Genovese, M.D., compared the effect to smashing a bag of ice. Instead of a single fused block of ice, the bag contains lots of smaller ice cubes after smashing. The smaller pieces are more easily moved aside. Within a blood vessel, breaking up the calcification clears the way for surgeons to maneuver. Simply using a balloon angioplasty – a balloon that the doctor inflates inside the vessel – to push against the calcification and make space for a stent or blood flow can instead result in dissection, or injury to the inner wall of the blood vessel, Genovese said.

“These blockages – they’re as hard as your teeth. That's the degree of calcification that’s in there,” she said.

Using the Shockwave device to break up the calcification means fewer dissections, she said.

Elizabeth Genovese, MD 
Dr. Elizabeth Genovese

“When I reduce the rate of dissection, I actually don't need to use as many stents. And then if I use it in conjunction with a stent, it really helps the stent take its full circular confirmation,” she said.

In other words, the stent can more fully open into its proper tube shape instead of being pinched and distorted into whatever shape the calcifications will allow for.

Lithotripsy, or the use of sound waves, has been used for years to break up kidney stones so they can pass in the urine. Whereas the goal of breaking up the kidney stones is to get them out of the body, doctors don’t try to remove the broken up calcium – it's too dangerous, Genovese said. Breaking the calcifications instead gives doctors the space they need to treat a problem.

That’s helped patients like William Gallimore and Annemarie Schiefer, both of whom had problems with their legs.

Gallimore was transferred to MUSC Health with a wound that wouldn’t heal.

“That was the best thing that ever happened, was Dr. Genovese, because other doctors have tried to do what Dr. Genovese did and they couldn't make progress,” said Gallimore’s wife, Mary Gallimore. “I praise God for Dr. Genovese.”

“I treat a lot of patients with critical limb ischemia,” Genovese explained. “Those are patients who have such poor blood flow to their legs and their feet that they are at risk of losing their legs. They will present either with constant pain in their feet because the flow is so bad, or they'll present with a non-healing wound.

“In both of those situations, people have about a 20% to 25% risk of losing their legs within the first year of that diagnosis,” she continued. “So the goal is to salvage their legs by improving the blood flow to either heal a wound or to get them out of rest pain, which is the term we use when their feet hurt because they're aching from lack of blood flow.”

Mathew Wooster, MD 
Dr. Mathew Wooster 

Calcium builds up partly due to age, but it’s also associated with smoking, diabetes, high blood pressure and chronic kidney disease – factors that are especially prevalent in the Southeast, Genovese said.

Both Gallimore and Schiefer had trouble walking because they were in so much pain. The pain was terrible, Schiefer said – so much so that walking to the mailbox was arduous. Even a shopping trip in downtown Summerville, where they live, was too painful, said her husband, Peter. Now, she said, after Wooster performed the procedure, it’s like she has new legs.

“Since the surgery, it’s like night and day,” her husband agreed.

Seeing the success in patients like Schiefer, Wooster has been working with interventional cardiologists on a clinical trial to use the Shockwave device to make space for the delivery of valve replacements and stent grafts.

Usually, transcatheter aortic valve replacement (TAVR), which replaces the aortic heart valve, and endovascular aneurysm repair (EVAR) and fenestrated EVAR (FEVAR), which place stent grafts in the abdominal aorta, are performed in a minimally invasive manner whenever possible. Wooster said the team performs about 400 TAVRs and 200 to 300 EVARs/FEVARs each year.

“The before and after images are actually pretty astounding.”

Dr. Elizabeth Genovese

Calcification, though, can block the artery so much that the doctors are unable to thread the repair devices through.

“Of those patients, there's about 20% to 30% of them where the devices we’re trying to put in are bigger than the artery that they have,” Wooster said. “And so historically, what that would mean is either they're not a candidate for that treatment or we use an alternative access. We can go through their arm, or we can go through the carotid artery, but those are all associated with much higher complication rates than being able to go through the femoral artery.”

Instead, in the trial, he is using the Shockwave device to clear the iliac artery, in the lower abdomen, as an alternative pathway. Since September, he’s used this approach on about 20 patients.

For the trial, he first attempts to insert the repair device without treating the artery with Shockwave. “If the device is able to go in, and we don't have to treat them, we’re putting them in a separate registry,” he said. “The purpose of that registry is to help us better predict who actually will need treatment and who does not.”

Wooster said he anticipates having a total of 300 patients, with 100 of those treated using Shockwave.

Genovese said that looking at the blood flow that is achieved after using Shockwave is remarkable.

“The before and after images are actually pretty astounding.”

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