Numerical study of the influence of anastomotic configuration on hemodynamics in miller cuff models.

Abstract

Enhanced hemodynamics via geometric alteration is believed to play a role in the favorable redistribution of intimal hyperplasia (IH) in infragenicular supplementary vein cuffs. We aimed to elucidate the consequence of altering geometric configuration in anastomotic hemodynamics in cuff models. A well-validated numerical scheme was used to simulate pulsatile flows in three cuffed anastomotic models with length-to-height ratio (LHR) of 1.4, 2.2 and 3.2, and a St. Mary's boot with LHR of 2.2 at a mean flow rate of 130 mL/min. Characteristic flow patterns and wall shear stress (WSS) distributions were compared. A cohesive vortex is only present in the cuff of LHR = 1.4 and in the boot. The vortex in the cuffs becomes increasingly disorganized with increasing cuff LHR. The area of flow separation at the graft toe, prominent in the cuff of LHR = 3.2, is significantly reduced in the cuff of LHR = 1.4 and eliminated in the boot. All cuffs are characterized by flow separation, flow reversal and a sharp drop in WSS immediately distal to the cuff toe, phenomena not observed in the boot. The cuff configuration, specifically the LHR, is critical in controlling local hemodynamics. A large LHR could lead to reduced cuff performance. The study suggests the benefits of geometric optimization for reconstruction of cuffed anatomoses.