Impact of freezing/thawing procedures on the post-thaw viability of cryopreserved human saphenous vein conduits.
BACKGROUND
Cryopreserved human blood vessels are important tools in reconstructive surgery. However, patency of frozen/thawed conduits depends largely on the freezing/thawing procedures employed.


METHODS
Changes in tone were recorded on rings from human saphenous vein (SV) and used to quantify the degree of cryoinjury after different periods of exposure at room temperature to the cryomedium (Krebs-Henseleit solution containing 1.8M dimethyl sulfoxide and 0.1M sucrose) and after different cooling speeds and thawing rates following storage at -196 degrees C.


RESULTS
Without freezing, exposure of SV to the cryomedium for up to 240 min did not modify contractile responses to noradrenaline (NA). Pre-freezing exposure to the cryomedium for 10-120 min attenuated significantly post-thaw maximal contractile responses to NA, endothelin-1 (ET-1) and potassium chloride (KCl) by 30-44%. Exposure for 240 min attenuated post-thaw contractile responses to all tested agents markedly by 62-67%. Optimal post-thaw contractile activity was obtained with SV frozen at about -1.2 degrees C/min and thawed slowly at about 15 degrees C/min. In these SV maximal contractile responses to NA, ET-1 and KCl amounted to 66%, 70% and 60% of that produced by unfrozen controls. Following cryostorage of veins for up to 10 years the responsiveness of vascular smooth muscle to NA was well maintained.


CONCLUSIONS
Cryopreservation allows long-term banking of viable human SV with only minor loss in contractility.
Müller-Schweinitzer
Else
E
Division of Cardiothoracic Surgery, University Hospital, CH-4031 Basel, Switzerland. dremueller36@bluewin.ch
Striffeler
Heinz
H
Grussenmeyer
Thomas
T
Reineke
David C
DC
Glusa
Erika
E
Grapow
Martin T R
MT
D000368:Aged; D000369:Aged, 80 and over; D015925:Cryopreservation / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D005615:Freezing; D006801:Humans; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D012501:Saphenous Vein / Q000502:physiology; D013997:Time Factors
D011189:Potassium Chloride; D009638:Norepinephrine