Quantitative Haemodynamic Evaluation of Aortic Cannulas

Abstract:
We have designed a new type of aortic cannula for extracorporeal circulation which we hypothesize has superior haemodynamic characteristics compared with existing types. The aim of the study was to perform a quantitative evaluation of the haemodynamic performance of commercially available aortic cannulas against our new design. Six existing cannulas and two self-designed, modified DLP cannulas were investigated. Pressure drop, peak velocity and wall thickness were obtained from in vitro experiments. Pressure drop and turbulent stresses were obtained by in vivo experiments. At 5 L/min the pressure drops of the new design were 18-25 mmHg in vitro and 20 mmHg in vivo compared with 25-92 mmHg in vitro and 28-90 mmHg in vivo for the six commercially available cannulas. Turbulent stresses of the new design varied between 25 and 50 N/m² in vivo compared with 125-500 N/m². Both in vivo and in vitro results showed a clear haemodynamic superiority of the new cannula-tip design compared with all existing types.