Effects of Cryopreservation on the Viscoelastic Properties of Human Arteries

Abstract

The purpose of this study was to use our newly developed mock circulation loop to determine the effects of cryopreservation on the common carotid artery (CCA) and the superficial femoral artery (SFA). Fourteen healthy arteries (7 CCA and 7 SFA) harvested from multiple organ donors between the ages of 18 and 35 years were tested before and after cryopreservation at -140 degrees C using dimethyl sulfoxide and the vapor phase of liquid nitrogen. Mean storage time was 4.2 months. The mock pulse rate was 60 beats/min and the following four systolic/diastolic pressures settings were used: 50/110, 80/140, 110/170, and 140/200 mm Hg. Simultaneous measurements of intra-arterial pressure and external arterial diameter were made using an intra-arterial pressure sensor and external piezoelectric sensors. Measured data were used to calculate pulsatility, volumetric compliance, stiffness, midwall radial arterial stress, Young's modulus, and the incremental modulus. After SFA cryopreservation, no significant changes were observed. Conversely, CCA cryopreservation led to a significant decrease in compliance and pulsatility and a significant increase in stiffness. Young's modulus, the incremental modulus, and midwall radial arterial stress did not change significantly. A clearcut decrease in hysteresis was observed after cryopreservation in the CCA. No evidence of structural changes was detected on light and scanning electron microscopy. Baseline findings in this study were consistent with classification of the CCA as an elastic artery and the SFA as a muscular artery. Cryopreservation had no effect on the viscoelastic properties of muscular arteries (SFA). Cryopreservation affected only values related to the cylindrical shape of the elastic arteries (CCA). It had no effect on values related to wall structure.