NUMERICAL MODELING OF VASCULAR STRESSES DURING LEAD EXTRACTION: SUBCLAVIAN VS. FEMORAL

摘要

Transvenous lead extraction is a critical and growing technique used to treat patients with chronically implanted pacemakers and defibrillators. This procedure is commonly executed via the subclavian vein or the femoral vein. Some physicians' experiences indicate that the femoral approach results in fewer vascular tears. This study is aimed to present a physics-based comparative assessment of intravenous mechanical stresses for chronic lead management between the two approaches. Finite Element (FE) modeling is employed to quantify the vascular stress distributions. A full 3-D model including veins, heart, fibrotic scar regions and the lead was created to simulate the different lead extraction methods. Results: (1) highest stresses are generally in the vicinity of SVC lead attachments: (2) femoral approach results in a -uniform distribution of stress over the scar while the subclavian approach leads to patches of concentrated high stress; (3) 2-3 times higher maximum vascular stress during subclavian; (4) insignificant maximum stress at the apex for both; (5) inverse variation of stress levels with: (ⅰ) branch-to-scar distance for S C method; and (ⅱ)vein wall thickness in both methods. (6) lower stress levels for scars with longer attachment lengths. The importance and effectiveness of mechanical stress analysis in risk analysis for chronic lead management is illustrated. Overall, the localized intravascular wall stress is meaningfullv higher for subclavian vs. femoral extraction with same SVC shear force. This may help explain the higher rate of SVC tears when extracting from the left subclavian approach. The individual anatomy (e.g. vascular angles) is a key factor in the resulting stress and this understanding may be critical when choosing an extraction approach and future lead design.