Thrombus formation and blood contacting surface in pneumatic diaphragm blood pump

For investigating the thrombus formation in a pneumatic diaphragm blood pump and the critical factors responsible for thrombus formation on smooth polyurethane blood contacting surfaces, four in vivo implanted blood pumps (implanted for 6 to 25 days) and four unused pumps were studied by scanning electron microscopy (SEM). The results demonstrate that one of the important reasons for thrombus formation in blood pumps is the morphology of the surface inside the blood chamber. Some surface defects were observed on the blood contacting surface. The defects could have been caused by material properties, the fabrication process, or excessive bending stress. The diaphragm and housing junction (DHJ) is a critical area where the thrombus formation of ten occurs. Marked reduction in thrombus formation for an improved pump is attributed to material pretreatment, stringent quality control, and reasonable redesign of the DHJ structure