Protocol and Initial Surface Analysis of Explanted Blood Sacs for the Penn State Pediatric Ventricular Assist Device

Open Access
Author:
Ceneviva, Nicholas E
Area of Honors:
Bioengineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Keefe B Manning, Thesis Supervisor
  • Keefe B Manning, Honors Advisor
  • William Joseph Weiss, Faculty Reader
Keywords:
  • ventricular assist device
  • pediatric
  • cardiovascular device
  • thrombosis
  • VAD
  • PVAD
  • optical profilometry
Abstract:
Approximately 2,000 children between the age of 5 and 16 are on the heart transplant list as a result of cardiovascular disease. Only a small portion of these children actually receive a transplant. As a result, there is a need for a pediatric left ventricular assist device (PVAD) as an alternative treatment. Penn State has designed their own PVAD; however, like all ventricular assist devices, thrombus formation is a major concern that may lead to device failure or life-threatening events in the patient. One explanation for the thrombus formation is that it occurs in areas of low shear rate, but the blood contact surface of the polymer sac also plays a role in thrombus formation. The surface of explanted PVAD blood sacs from animal trials carried out at the Penn State Hershey Medical Center is to be analyzed to determine if surface topography plays a role in thrombus formation. To do this, a protocol is developed that allows for the analysis of the same sac sample using multiple microscopy techniques. The samples are first analyzed using confocal microscopy to determine if platelets and/or fibrin, components of thrombi, are present. Then using environmental scanning electron microscopy, the surface of the sample is analyzed. Finally, after degradation of any biological deposits, optical profilometry is used to obtain quantitative data on the surface roughness. In future studies, this protocol will result in surface data than can be correlated with flow data to further understand the cause of the thrombus formation. The correlation can lead to better designed devices and blood sacs that are less likely to induce thrombosis.