Femoral arteries energy dissipation and filtering function remain unchanged after cryopreservation procedure

The aim was to evaluate our cryopreservation method effects on the mechanical properties and filtering function of human superficial femoral arteries (SFA). SFA segments from 10 multiorgan donors were divided into two groups: fresh, tested 24-48 h after harvesting, and cryopreserved/defrosted, tested after 1 month of cryopreservation. The cooling process was carried out in three steps: 2 degrees C/min until -40 degrees C; 5 degrees C/min until -90 degrees C and finally a rapid cooling by transferring the bag to vapour phase of liquid nitrogen (-142 degrees C). Thawing was made in two steps, a slow warming time by exposing the bag to 20 degrees C during 20 min, followed by a rapid warming by immersion in a 40 degrees C warm bath until defrost. In a circulation mock, arterial pressure [Pressure signal (P)] and diameter [Diameter (D)] were registered at similar stretch-frequency, P and flow levels. A compliance transfer function (D/P) was used for the on-line assessment of the arterial wall elastic (E), viscous (eta), and inertial (M) properties. To evaluate the arterial wall filter function, the arterial wall D/P frequency response was characterized, the cut-off frequency (fc) was quantified, and the viscous energy dissipation (Weta) was calculated. After cryopreservation, there were not significant changes in E, eta, M, Weta, and fc.