A Medical Device Daily

Research presented Friday at the Society of Interventional Radiology’s (SIR; Fairfax, Virginia) 32nd annual scientific meeting that began Thursday and continues through tomorrow in Seattle, shows that cryoablation — a non-surgical image-guided treatment of kidney tumors — is as effective as laparoscopic technique in viable candidates.

The trial shows that percutaneous cryoablation results in a slightly lower recurrence rate of the tumor, a shorter hospital stay, no major complications, and a 59.5% lower hospital cost than the laparoscopic treatment. During cryoablation, argon gas enters the tip of the probe and extracts heat from the surrounding cells, resulting in an “ice ball” that freezes and kills the tumor.

The non-surgical treatment spares most of the healthy kidney tissue and can be repeated as often as needed, according to SIR. The treatment had no major complications as opposed to the surgical group, with complications in 6% of that arm.

The radiologist uses imaging to pinpoint the tumor and then inserts the cryoprobe through the skin. The procedure can be performed under general anesthesia, but is often possible with only local anesthesia and conscious sedation.

By using imaging the radiologist can avoid going through any adjacent structures or harming healthy tissue. If necessary, adjacent structures can be displaced prior to the ablation to minimize collateral damage. Laparoscopy, on the other hand, requires general anesthesia, as well as multiple abdominal incisions to allow access for the surgical instruments. It is also associated with a longer recovery time, SIR said.

“This early-stage research indicates that percutaneous cryoablation in the appropriate patient population can effectively kill tumors, while also offering patients a shorter hospital stay, a faster recovery, and an excellent safety profile, all at a lower cost than laparoscopy,” said study author J. Louis Hinshaw, MD, of the University of Wisconsin (Madison). “Unfortunately, not all patients are viable candidates for percutaneous ablation, and we work closely with our urology colleagues to ensure that each patient receives the most appropriate treatment.”

The FDA has approved both radiofrequency ablation and cryoablation for use in soft tissue tumors, of which renal cell carcinoma is one.

According to two studies presented at the meeting, a non-surgical treatment using stent-grafts to repair an injured or diseased thoracic aorta offers patients less risk of paraplegia as well as lower morbidity and mortality rates when compared to surgery.

During surgical repair, the patient is at increased risk of paraplegia because the thoracic aorta is clamped, cutting off blood to the spinal column. The interventional radiology treatment does not interrupt the blood supply because the endograft is advanced inside the artery, using imaging to guide it from the femoral artery in the groin to the precise location in the aorta where it is deployed to create a new wall in the aorta from the inside.

The study, out of London, involved 190 patients in a database from 1997 to 2006. All patients had diseased aortas in the thoracic area, such as degenerative aneurysm, dissections, ulcer, and other pathology.

In the second study, based at a trauma center in Canada and involving 104 patients, all the patients were healthy, but had suffered a life-threatening injury to the thoracic portion of the aorta. In the surgical trauma group, adverse events were not due to underlying disease, and could be more clearly attributed to the procedure. In both institutions, the data strongly suggests that the interventional treatment was not only an important option to consider, but should be the treatment of choice, according to SIR.

The incidence of death and permanent paralysis in the London group, which only included the interventional treatment, was 1.6%. In the trauma study, which also included a comparison to surgery, there was a 7.4% incidence of pneumonia and no incidences of death or paralysis in the interventional patients. In the surgery group, there was an 11% incidence of death, a 15.6% incidence of paralysis, and a 37.5% incidence of pneumonia.

Another study presented Friday demonstrates that a new technique “safely and effectively” removes blood clots in the body faster, reducing patient risk for pulmonary embolism (PE) and disability.

The interventional radiology treatment was also shown to have a positive impact on patients’ quality of life, relieving symptoms such as pain and swelling, as well as greatly improving their ability to be active.

The “rapid lysis” technique combines a clot-dissolving drug with a clot removal device, thus improving the breaking up and dissolving of the clot, which is then vacuumed out of the vein and into the catheter, non-surgically clearing away the deep vein thrombosis (DVT). Blood flow is restored throughout the leg, resolving symptoms.

Patients in the study had extensive, large-volume DVT that commonly ran the length of the leg from the ankle to the pelvis, and often into the vena cava. Although the body may eventually dissolve clots, in the time needed to do so, permanent damage to the vein may occur, causing permanent disability and pain. In addition, previous studies have shown that clots in the larger veins will rarely clear on their own.

“The new combination technique offers a significant advancement in the treatment of DVT, often allowing the interventional radiologists to break up the clot in one treatment. It has worked on even the largest, most difficult clots and could become the new standard technique, potentially changing the way all DVT patients are treated,” says Mark Garcia, MD, interventional radiologist at Christiana Care Health System (Wilmington, Delaware).

This treatment worked on the largest, most difficult clots, allowing resolution of DVT quickly and safely while restoring blood flow in the vein, according to SIR.

The treatment can reduce the length of a hospital stay and reduce costs. The current standard catheter-directed thrombolysis treatment uses a clot- dissolving drug only and, although highly effective, can take two to four days to work. This increases the patients’ risk of bleeding as well as increasing their stay in the ICU.

Although the catheter-directed thrombolysis technique has been available for about a decade, many DVT patients don’t receive it, according to SIR. Instead, many patients are treated with blood thinners alone, which can help prevent a life threatening PE, but does not help dissolve the clot.