A Medical Device Daily

With the AngioJet Rheolytic Thrombectomy System from Possis Medical (Minneapolis), an interventional radiologist can use imaging to guide a catheter and the device into a vein and advance it to a blood clot.

A study on the system was released earlier this week at the annual meeting the Society of Interventional Radiology (Fairfax, Virginia) in Seattle.

The device sprays a diluted clot-dissolving drug into the clot, helping to break it up and deliver the drug to a larger surface area throughout for faster, more efficient removal.

A powerful saline jet within the device creates a vacuum that draws the clot into the catheter, thus removing it from the body as the catheter is withdrawn. The interventional radiologist pulls back the device in a spiral motion which allows for greater removal of clot.

In the study, 102 patients (62% male, 38% female), mean age 47, were treated for 118 cases of large volume DVT, with 51% having complete clot removal as well as restoration of blood flow. Thirty-one percent had a substantial amount (59%) of the clot removed with blood flow restored; 11% had partial and 4% had minimal clot removal; 43% were completed at the initial setting and did not need further infusion of medicine to dissolve clot.

Follow-up ultrasound exams at six months showed 78% veins to be open with no DVT and 83% open at 12 months with no DVT. The quality of life survey, up to one year, showed that since treatment, 68% had no pain, 67% percent had no more swelling and 78% no longer had heat or burning discomfort.

In another report:

An outpatient, non-surgical treatment for a benign bone tumor called osteoid osteoma both destroys the tumor and eliminates debilitating pain, research presented last Friday shows. In 91% of those treated in the study, the treatment ended patients’ pain immediately, with no post-procedure complications.

This non-surgical technique — radiofrequency ablation (RFA) — heats and destroys the nerve endings in the tumor that were causing pain. It also preserves the patient’s healthy bone, prevents major surgery and eliminates the need for lengthy rehabilitation and recovery.

The interventional radiologist can visualize the tumor with computed tomography and insert the needle into the correct area while monitoring the heat, thereby ensuring that the entire tumor is destroyed and will not grow back.

“Our research showed the interventional treatment’s success rate is as good as surgery’s, but without the risk. Plus, almost all of our patients walked out of the hospital within hours of the procedure pain-free,” said interventional radiologist Eran Hayeems, MD, of the University Health Network and Mount Sinai Hospital (Toronto).

The treatment is available throughout the U.S., is FDA-approved, and is covered by most insurance providers.

Often, lesions are deep inside the bone and not readily visible on the surface to a surgeon. Therefore surgeons must remove a wider area around the tumor, and still may not succeed in getting the entire tumor. For example, if a typical lesion is under 1 cm a surgeon may need to remove up to 5 cm of surrounding bone. That can sometimes result in bone grafting in order to prevent future bone fractures. The surgery can also require up to six months of rehabilitation.

In RFA, heat is delivered directly into the tumor via a probe that is inserted through the skin using CT, MR and/or ultrasound imaging for guidance. From the tip of the needle, radiofrequency energy is transmitted into the targeted tissue where it produces heat and kills the tumor. RFA is a nonsurgical, localized treatment that spares healthy tissue without any systemic side effects. RFA can be performed without affecting the patient’s overall health and most people can resume their usual activities in a few days.

Osteoid osteomas are relatively rare benign bone tumors that affect mainly young people (teens to 20’s) who are otherwise healthy. The study involved 26 patients, 19 male and seven female, with a mean age of 29. Twenty-three of the patients had lower extremity or pelvic lesions, and three had upper extremity or scapular lesions. The procedure was technically successful in 100% of the cases with no peri- or post-procedural complications. In ninety-one percent of the patients treated there was resolution of pain. Four patients were lost to follow-up.

• SIR researchers during the meeting urged more comprehensive imaging for patients presenting to hospitals with stroke symptoms.

MRI and echocardiography to image the heart greatly enhances the detection of the cause and selection of the best treatment of cardioembolic strokes, the “meanest” type of stroke.

A cardioembolic stroke occurs when a thrombus dislodges from the heart, travels through the cardiovascular system and lodges in the brain, first cutting off the blood supply and then often causing a hemorrhagic bleed — a double whammy of both types of stroke, ischemic first and then hemorrhagic.

The study found that MRI detected nearly twice as many sources of stroke in the heart than echocardiogram alone. It also showed the ability of MRI to reveal more heart disease conditions that contribute to clot formation in the first place. Echocardiography, however, was strong in the detection of heart valve lesions. Combined, these imaging systems can more clearly identify underlying causes of future stroke, helping doctors decide the best initial therapy and the best treatment to prevent secondary stroke.