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May 22, 2006

Laser Ablation — Treating Venous Malformations With Less Pain, Fewer Side Effects
By Dan Harvey
Radiology Today
Vol. 9 No. 10 P. 12

Large venous malformations are one of the more unsettling physical disorders for both patients and the physicians who treat them. The condition is present at birth and its often severe symptoms manifest in young children. Painful and unsightly, large venous malformations can create significant deformity and cause profound emotional turmoil.

Beyond the appearance issues, these malformations can be life-threatening, as they can lead to thrombi and pulmonary emboli, making effective treatment crucial.

Existing effective treatments, particularly sclerotherapy, can be prolonged and painful, which can he hard for a child to tolerate. However, interventional radiologists are successfully employing nonsurgical laser technology, which is already approved for treatment of varicose veins, to provide a safer and less painful alternative—not only for children but for all patients afflicted with large venous malformations.

The efficacy of the new technique—which involves endovascular laser ablation—was demonstrated in a study conducted by researchers at Children’s Hospital Boston, who reported their findings at the Society of Interventional Radiology’s (SIR) 31st Annual Scientific Meeting held in Toronto in April. The research showed that endovascular laser ablation of abnormal veins, a technique involving a laser fiber within a catheter, effectively relieves symptoms, circumvents complications associated with existing therapies, and provides faster recovery.

Enlarged Veins
Venous malformations are spongelike lesions consisting of abnormal veins. The abnormality results from a deficiency of smooth muscle cells in vein walls. This deficiency inhibits the veins from contracting, which subsequently causes them to enlarge. The enlargement leads to tissue swelling and pain, similar to the swelling and throbbing associated with an injury to an extremity.

Many venous malformations are hard to diagnose, as they can be quite small and asymptomatic or located deep within the body, where they can escape detection. Larger venous malformations, on the other hand, are highly visible. When they occur in limbs, they are extremely painful and can cause nerve damage or potentially lethal pulmonary emboli.

Treatment options include elastic compression stockings, aspirin, surgical removal of the veins, or sclerotherapy. Sclerotherapy is a widely used and effective procedure involving the direct injection of a solution, called a sclerosant, into abnormal veins. The solution irritates the walls of the abnormal veins, causing the vessels to shrink.

However, sclerotherapy has notable disadvantages. Patients need three to six procedures to completely resolve the condition. As the procedure can be painful, serial treatment can be especially problematic for children. Recovery is often prolonged and uncomfortable, especially when venous malformations affect extremities. Also, when used to treat large venous malformations, the procedure requires large amounts of sclerosant, which can lead to toxicity complications.

Ablative Option
Endovascular laser technology provides a less painful alternative with fewer side effects. Endovascular laser ablation is a nonsurgical treatment with no serious reported side effects and can be better tolerated by children.

Patricia E. Burrows, MD, one of the physicians involved in the Children’s Hospital Boston study, became interested in the procedure because she often treats children and young adults with vascular malformations. In particular, she treats patients with large venous malformations, including children with Klippel-Trenaunay-Weber syndrome, which is characterized by port-wine stains, varicose veins, and bony and soft-tissue hypertrophy involving an extremity. “Those with the syndrome have very large veins running up the side of the leg,” says Burrows, who is now at St. Luke’s-Roosevelt Hospital in New York City. “Those veins often cause significant symptoms including pain and, as the children get older, thrombi and pulmonary emboli.”

While in Boston, she developed a treatment that involved embolizing veins with a MicroCaster. “I’d do an extensive venogram to make sure the veins were deep,” she relates. “With the abnormal veins, I’d identify location of connections within the deep vein system and close off the connections with coils. Then I’d sclerose the entire venous network, either with alcohol or sodium tetradecyl.”

That technique, she indicates, is effective but a bit risky, as it requires a significant amount of sclerosant, which can cause significant swelling and pain. Some patients needed weeks or months to recover. In addition, there’s a risk of damaging the deep veins and causing a pulmonary embolism. “We did everything we could to minimize that risk and didn’t have any serious complications,” she reports.

Then, an even better alternative presented itself. Burrows heard about the endovenous laser technique that was approved for treatment of varicose veins, and she got the idea of adapting the technology to large venous malformations. She started using it one year ago, she reports. The results have been gratifying.

Nonsurgical Procedure
Burrows believes the endovascular laser ablation represents a major advance in the treatment of large venous malformations. Essentially, the procedure involves the application of laser energy that heats an abnormal vein from the inside, sealing it. During treatment, an interventional radiologist uses a diode laser fiber positioned inside an angiocatheter to close the veins.

When Burrows employs the procedure, she often uses general anesthesia because many of her patients are children. When treating young adults, she uses local anesthesia. Following anesthetization and preparation, she inserts the angiocatheter at an anatomical point that provides a connection with the deep venous system. “Usually, it’s a vein near the big toe,” says Burrows, adding that she sometimes uses ultrasound guidance to place the needle directly into the deep vein.

She then studies the deep venous system with venograms to make sure the system is continuous. “That’s very important because, with this condition, there are often gaps or obstructions in the deep system,” she points out.

During the procedure, Burrows keeps the cannula attached to the catheter connected to a pressurized perfusion of heparinized saline. That way, she can actively flush the deep veins while ablating the superficial veins to help minimize any trauma from the ablation.

Once all that is done, Burrows studies the superficial, anomalous veins with venograms to identify the large channel, and she performs catheterization with the endovenous laser sheath. “I then take it up to the upper extent of the vein, where it connects with the deep system using fluoroscopy,” she says. As the veins are often very tortuous, fluoroscopic guidance is necessary to pass the guide wire all the way to the top.

Once at the top, she’ll sometimes use a coil to close the upper connection, which is often the largest one. “Next, I put the laser fiber into the catheter and apply the tumescent anesthesia all around the big vein,” she continues. “I then apply the laser energy as I pass the catheter down to the insertion point.”

Often, there is more than one affected vein channel, so she repeats the process as many times as necessary. Also, Burrows sometimes finds the channels are so tortuous that she needs to catheterize them in segments. “So, I may end up doing five or six passes of the laser fiber,” she says.

After that, if the vein is still patent, she’ll still inject some sclerosant—usually sodium tetradecyl foam. “I’ve found that some of the large channels don’t close with the laser alone,” she says. “It’s very effective, and it allows you to use much less of the foam. So, there’s less toxicity, and patients don’t have much pain and swelling after the procedure. Patients can recover faster and return to their normal activities.”

At that point, Burrows may still sclerose some adjacent branches to treat the whole network in continuity. Finally, she applies an ACE wrap for compression. Afterward, she’ll do another study of the deep veins to make sure there are no problems.

In addition to pain reduction, the procedure has the aesthetic benefit of reducing the “bluish” skin color caused by the malformation.

Other Considerations
Though it’s effective, the procedure does have a disadvantage: Burrows reports that the laser procedure can take twice as long as sclerotherapy. Therefore, she feels that if a physician only needs to treat a small lesion, or if a lesion is easily treatable with sclerotherapy alone, then it’s probably not worth the extra time to perform an ablation.

As such, Burrows feels the best candidates for the new technique are patients with large lesions that otherwise would require the serial treatment of sclerotherapy. The laser procedure allows her to treat more of the malformation in one sitting because she doesn’t have to use as much sclerosant.

As far as patient reaction, Burrows says that those who have already undergone sclerotherapy concur that this treatment is easier to recover from and far less painful. “They experience some pain with the laser procedure, but it’s quite tolerable, they tell me,” she says. “Some of our older patients are able to get up and walk after the procedure, and they’re able to put on their elastic stocking and go back to work.”

She adds that some patients who underwent more extensive procedures still required a week of recovery, but that still represents a reduction from sclerotherapy.

The Study
For their study conducted at Children’s Hospital Boston and presented at April’s Society of Interventional Radiology meeting, Burrows and colleagues (including Jacques C. Tham, MD; Ahmad Alomari, MD; and Brian D. Davison, MD) wanted to demonstrate the efficacy of endovascular laser ablation in treating low-flow vascular malformations.

In the study, which was conducted over an 11-month period beginning in January 2005, 28 patients with symptomatic large vascular malformations were treated with 38 endovascular laser ablations. Thirty-seven of the ablations were followed with adjunctive sclerotherapy. Vascular malformations were located on patients’ face and tongue (six), neck (two), chest wall (one), upper extremity (two), and lower extremity (17).

All the laser ablations were technically successful. Symptoms were reduced or eliminated in 96% of patients. Twenty-three patients reported no pain or a decrease in pain following the laser ablation. Moreover, there were no major complications. One patient experienced slightly increased pain one month after the procedure, but this was resolved with repeat treatment. Four patients experienced postprocedure numbness or paresthesias, while three developed blisters or mild cutaneous bleeding.

The researchers concluded that endovascular laser ablation with adjunctive sclerotherapy is a safe and effective technique in the treatment of low-flow vascular malformations. Additionally, the new laser technique is less painful for the patient than existing therapies.

Looking Ahead
One thing researchers didn’t do in the study was look at every single vein treated in follow-up to see how many of veins were completely ablated, says Burrows. “We did as many as we could and found that in about 50% of cases, the veins were not completely ablated with one procedure, even though the patients were improved,” she says. “So, we’re now working on trying to determine the best energy setting for the most complete ablation.”

Burrows reports that endovascular laser technology attracted a lot of interest following the presentation. She now expects that physicians treating venous malformation will try and obtain the technology. “Many physicians who work in children’s hospitals don’t have access to the equipment, but they’re in the process of trying to get it,” she says. “I’m sure that physicians working with adult patients will start using it soon as well.”

— Dan Harvey is a freelance writer based in Wilmington, Del., and a frequent contributor to Radiology Today.

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