Device Trials and News

From Staff Reports

Electrical stimulation compared to intermittent pneumatic compression of the foot is a phase I study that is testing the equivalence of the two techniques in stimulating blood flow out of the leg as a potential means of preventing blood clot formation in the leg veins. This randomized, single-blind, active-controlled study involves treating one lower extremity and using the other as a control. Either mild electrical stimulation of the plantar muscles of the foot or intermittent pneumatic compression will be applied at one session, with the opposite treatment applied on the same foot at least 48 hours later. The primary outcome will be Doppler venous blood flow velocity changes measured over 4 hours. The single-center study is being sponsored by the State University of New York at Buffalo, and plans to enroll 40 healthy patients (20 obese, 20 normal weight). According to the sponsor, a plantar foot stimulation device could be battery operated and inserted into a sock, for the patient to wear while immobile, standing, or walking with assistance. The study got underway in June 2005.

Accuracy of ThromboView in the detection of deep vein thrombosis (DVT) is a phase II study that is testing the use of a 99mTc-labelled humanized monoclonal antibody specific for D-dimer fragments of cross-linked fibrin that are found in acute DVT as a visualizing technique using nuclear medicine imaging. This diagnostic, nonrandomized study involves intravenous injection of [99mTc] ThromboView into patients with suspected initial or recurrent DVT in whom DVT has been confirmed or excluded by standard contrast venography. The primary outcomes will be estimates of the sensitivity of the antibody in patients with confirmed DVT, and estimates of specificity in patients with excluded DVT. The multicenter study, sponsored by Agen Biomedical, has plans to enroll 180 patients, and began in March 2005.

Prevention of stroke in asymptomatic patients (ACT I) is a phase III study that is testing the equivalence in patient outcomes of carotid artery stenting compared with carotid endarterectomy. This randomized, open-label study is comparing the Xact Rapid Exchange Carotid Stent System (in conjunction with the EmboShield Cerebral Protection System) with surgery for the prevention of strokes in patients with extracranial carotid stenotic disease but no clinical symptoms. The primary outcomes are the occurrence of major adverse events 30 days following the procedure and the occurrence of ipsilateral strokes at 31-365 days post procedure. The multicenter study, sponsored by Abbot Vascular Devices, plans to enroll 1,540 patients and began in April 2005.

Multidetector spiral computed tomography alone and in combination with lower limb compression ultrasonography for the detection of pulmonary embolism is a study that is testing the noninferiority of the diagnostic use of helical computed tomography (hCT) in terms of safety and effectiveness, compared with the standard approach using hCT plus ultrasonography. Both methods include the use of clinical probability and the D-dimer test. This randomized, double-blind study involves outpatients admitted to the emergency department for suspected pulmonary embolism. The primary outcome will be the number of thromboembolic events in the 3-month follow-up period for each group. The secondary outcome will be direct costs incurred in each study arm. The single-center study has an expected enrollment of 1,500 patients; it began in January 2005.

The General and Plastic Surgery Devices panel of the Food and Drug Administration voted in August to give Class II device status to five previously unclassified products, meaning that they would require 510(k) premarket notification. These new Class II "devices" are: medical maggots, medicinal leeches, surgical bone wax, tissue expanders, and drug-laced wound dressings. These products had been left out of consideration as devices in the amendments made to the Food, Drug, and Cosmetic Act in 1976. Although each type of product had previously received 510(k) clearance as "unclassified" devices, this new move brings these devices into harmony with the FDA's new goals for special controls for manufacturers to maintain safety and efficacy. In 2004, Ronald Sherman, M.D., gained the first 510(k) clearance for medical maggots for debriding nonhealing, necrotic skin and soft tissue wounds, but the panel believed that additional concerns regarding the "environmental risk" that these products posed in the hospital needed to be addressed. Medicinal leeches--used to prevent clotting as an adjunct to graft healing--were suggested for "medium priority" special control guidance, in part because of their potential as an after-use biohazard due to their blood-absorbing nature.