Preservation of canine segmental pancreatic autografts: Cold storage versus pulsatile machine perfusion

Abstract

The reliability of cold storage and pulsatile machine perfusion for preservation of open-duct segmental pancreatic grafts for 24, 48, and 72 hours was determined in a canine autograft model. The tail (left limb) of the pancreas on a pedicle of splenic artery and vein was transplanted to the pelvis with vascular anastomoses to the iliac vessels and the remainder of the pancreas was excised. Twenty nonpreserved grafts functioned immediately (the recipients became normoglycemic, plasma glucose < 150 mg/dl), 16 long term (80%). Collins solution (CS, osmolality 300 mosm/kg) and a silica gel filtered plasma solution (SGF-I, osmolality 430 mosm/kg) were compared for cold storage at 4°C. The long-term functional survival rate for grafts stored for 24 hours in SGF-I was 9 12 (75%) and in CS was 8 12 (67%). When graft preservation time was extended to 48 hours, 9 12 (75%) stored in SGF-I and 4 10 (40%) in CS functioned long term. The preservation failure rates were 0% in grafts stored in SGF for up to 48 hours, but were 20% and 50% for grafts stored in CS for 24 and 48 hours. Storage at 72 hours was not satisfactory; even when SGF-I was used, the preservation failure rate was 57%. SGF was also used as the perfusate for pancreas preservation on the Mox-100 machine at a pressure of 30 mm Hg (achieved by leaving the port opposite the connected pancreas open). Lower pressures gave insufficient perfusion and higher pressures led to severe edema of grafts. Mean (±S.E.) flow (ml/min) through the grafts were 4.5 ± 0.3 initially, 6.5 ± 0.7 at 24 hours and 6.3 ± 0.9 at 48 hours. With SGF-I only 6 12 (50%) of grafts perfused for 24 hours and only 1 8 (12%) for 48 hours functioned long term. With a modified perfusate (SGF-II, osmolality 470–500 mosm/kg) the results were slightly improved; 7 12 (58%) grafts perfused for 24 hours and 5 10 (50%) for 48 hours functioned long term. The mean (±S.E.) flow rate (ml/min) was 5.0 ± 0.6 in grafts that functioned long term and was 8.3 ± 1.0 in those that failed due to preservation complications. Mean (±S.E.) peak serum amylase levels (I.U./L.) were similar in recipients of fresh grafts (3953 ± 365) and those stored hypothermically in SGF (4226 ± 327), but were significantly lower in recipients of machine perfused grafts (2988 ± 228). Although the percentage of successful transplants varied according to the preservation techniques, the mean (±S.E.) IVGTT K-values in recipients with functioning grafts were similar between the groups (−1.44 ± .19 to −1.82 ± .17%). The pure pancreas preservation failure rates with machine perfusion were between 30% and 40% at 24 to 48 hours, compared to 0% in those simply stored in cold SGF for 24 to 48 hours. We conclude that pancreas preservation by cold storage in high osmolar silica gel filtered plasma is more reliable than pulsatile machine perfusion and provides sufficient time to complete the logistical maneuvers necessary for clinical pancreas transplantation from cadaver donors.