The clinical histories of the Medtronic Parallel (MP) and St. Jude Medical (SJM) Standard valves suggest pivot geometry influences the thrombogenic characteristics of bileaflet prostheses. This work studied the effects of various pivot geometries on markers of platelet damage in a controlled, in vitro apparatus. The Medtronic Parallel valve, two St. Jude Medical valves, and two demonstration prostheses were used to study the effects of bileaflet pivot design, gap width, and size on platelet secretion and anionic phospholipid expression during leakage flow. A centrifugal pump was used to drive blood through a circuit containing a bileaflet prosthesis. Samples were taken at set time intervals after the start of the pump. These samples were analyzed by cell counting, flow cytometry, and enzyme-linked immunosorbant assay. No significant differences were observed in platelet secretion or anionic phospholipid expression between experiments with the SJM 27 Standard regular leaker, the SJM 20 regular leaker, and the MP 27 valves. Significant differences in platelet secretion and anionic phospholipid expression were observed between a SJM 27 Standard regular leaker and a SJM 27 high leaker valve. These studies suggest that leakage gap width within bileaflet valve pivots has a significant effect on platelet damage initiated by leakage flow.

As a primarily prophylactic operation, the efficacy of carotid endarterectomy (CEA) depends on attaining a complication rate as low as possible. Complications can be classified by time period (periprocedural and late) or type (local and systemic). The authors' purpose is to describe the incidence of complications associated with CEA, identify causative factors, and suggest steps that can be taken to minimize their occurrence.

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