PATRIOT Evaluates FlowCardia's Crosser to Mediate CTO Recanalization

October 22, 2009—James D. Joye, DO, presented findings from the PATRIOT (Peripheral Approach to Recanalization in Occluded Totals) trial in the late-breaking trials session at the Vascular Interventional Advances meeting in Las Vegas, Nevada. PATRIOT is the pivotal study of the Crosser catheter (FlowCardia, Inc., Sunnyvale, CA) to mediate chronic total occlusion (CTO) recanalization. The primary efficacy endpoint is advancement of the Crosser catheter into or through total occlusions and achievement of distal vessel position with any conventional guidewire. The primary safety endpoint is freedom from perforation.

The Crosser system is composed of two features: the Generator and the Crosser catheter. The Generator converts AC power into high-frequency current and piezoelectric crystals within the transducer convert high-frequency current into vibrational energy. The Crosser catheter is a nitinol core wire that transmits mechanical vibration to the metal tip of the catheter at 20,000 cycles per second with a 20-micron amplitude.

According to Dr. Joye, the PATRIOT study's inclusion criteria were infrainguinal occlusion less than 30 cm in length and more than 30 days old, with reference vessel diameters of 2 mm or greater. Patients had either a previous attempt at a standard wire passage through the occlusion (n=13) or an attempt with a guidewire concurrent with the use of the Crosser (n=72).

The study included 85 patients with a mean age of 72 years, of which 52 (61%) were males and 33 (39%) were females. Other patient characteristics included coronary artery disease (66%), diabetes (49%), chronic renal insufficiency (14%), hypertension (87%), hyperlipidemia (81%), and history of smoking (54%). Symptoms of patients in the study included claudication (98%), edema (34%), rest pain (59%), necrosis (15%), and ulcers (25%). Rutherford Class for patients in the study were: Category 1 (1.2%), Category 2 (7.1%), Category 3 (42.4%), Category 4 (30.6%), Category 5 (16.5%), and Category 6 (2.4%).

Dr. Joye detailed the occlusion characteristics as follows: CTO locations were in the common femoral (2.4%), superficial femoral (61.2%), popliteal (20%), tibial (10.6%), tibioperoneal trunk (3.5%), and peroneal (2.4%) arteries. The mean occlusion length was 117.5 mm and the mean reference diameter was 4.5 mm. The mean age of occlusions was 16 months. Calcification was severe in 54.8% of patients, moderate in 20.2% of patients, and mild-to-none in 25% of patients.

The average total procedural time was 102 minutes with an average total fluoroscopy time was 36 minutes. Dr. Joye noted that the procedural time was relative short indicating that "use of the device made crossing the occlusions quite facile." Procedures were followed by an average length of hospital stay of 1.6 days. The average amount of contrast agent used was 242 cc.

Results from the PATRIOT study's primary efficacy endpoints demonstrated that 84% of the guidewire-resistant CTOs were successfully recanalized with the Crosser catheter. Of the primary safety endpoint, there were no clinical perforations related to Crosser. Other endpoints were freedom from limb loss, clinical perforation, and repeat revascularization through 30 days in 80 of 85 patients (94.1%).

Dr. Joye summarized that the Crosser catheter safely traversed 84% of guidewire resistant CTOs without any clinical perforations. There was an 81% efficacy in lesions ≥ 15 cm. The average lesion length was 12 cm, and average activation time was 126 seconds. Therefore, the Crosser catheter proved to be a safe and valuable tool for crossing CTOs in the lower extremities, concluded Dr. Joye.