PO-02-058 USING A NOVEL IN VITRO HUMAN BLOOD LOOP MODEL TO EXPLAIN SCAR TISSUE FORMATION A PHYSICIAN MAY ENCOUNTER IN EXTRACTING CORONARY SINUS LEADS

The Medtronic Attain Stability Model 4798 (ASQ) coronary sinus (CS) lead was designed with an active fixation helix for precise placement and extractability. We sought to understand extractability of ASQ as compared a 1. favorable such Performa 4598, 2. the Star Fix® in which considerable fibrotic tissue growth involves expanded lobes, making extraction process very challenging. Typically, animal models are used growth, however, studies limited value. In this study, we novel vitro human blood loop model evaluate flow profiles coagulation response has shown be surrogate scar formation. This allows improved control accelerated test conditions comparison models. To assess thrombus formation early indicator long-term development three CS leads impact vein design. donor were placed inside closed system representing average diameter. Loops primed freshly drawn heparinized blood, donated via IRB approved program. Heparin concentration chosen from prior titration prevent clotting alone. Experiments run five hours at 37°C under continuous comparable known rates. Change rate over time measured. Post exposure, subjected histological evaluation. On histologic evaluation (n=6) showed mean coverage 70.8±28% minimal 3±1.5% on 3±1.7% (n=3) (p < 0.05) (Image 1). At constant pump speed, 95th percentile drop 165mL/min implants only 13mL/min 9mL/min Performa. demonstrates how design can subsequent vascular is contrast, lobes disruption consistent clinical findings significant that result challenging procedure.