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Biologic fate of cryopreserved human saphenous allografts: case report and hypothesis
W W Hoover1, T F Kresowik, R T Cook
1Department of Pathology, University of Iowa Hospitals and Clinics, Iowa City.
Insights
Cryopreserved venous allografts used in femoroperoneal bypasses may show histologic changes due to vessel wall anoxia. These changes, including karyorrhexis and neutrophilic infiltrate, appear similar in human and experimental settings, suggesting non-immunologic mechanisms.
Area of Science:
- Vascular Surgery
- Histopathology
- Immunology
Background:
- Critical limb ischemia necessitates vascular reconstruction, often employing allografts.
- Cryopreserved saphenous vein allografts are utilized for femoroperoneal bypass procedures.
- Understanding graft histology is crucial for assessing patency and long-term outcomes.
Observation:
- A patient undergoing femoroperoneal bypass with a cryopreserved saphenous allograft for critical limb ischemia experienced a fatal myocardial infarction 48 hours post-operatively.
- Histological examination of the explanted allograft revealed karyorrhexis and focal neutrophilic infiltration in the media.
- A layer of fibrin was present on the intimal surface, with nonspecific luminal deposition of immunoglobulins and fibrinogen observed via immunoperoxidase studies.
Findings:
- The histological findings in the cryopreserved venous allograft included cellular degeneration (karyorrhexis) and acute inflammation (neutrophilic infiltrate).
- Immunoperoxidase staining demonstrated non-specific deposition of immune reactants, suggesting potential damage rather than specific immune rejection.
- Histologic changes observed in this human allograft were consistent with those seen in experimental cryopreserved venous allografts.
Implications:
- The observed histological changes in cryopreserved venous allografts may primarily result from anoxia of the vessel wall during preservation.
- These findings suggest that non-immunologic factors, such as ischemic injury, play a significant role in early allograft pathology.
- Further research into preservation techniques that mitigate anoxic injury is warranted to improve outcomes of vascular allografts.
Abstract:
A femoroperoneal bypass using a cryopreserved human saphenous allograft was performed on a patient who presented with critical ischemia of the left lower extremity. The patient died of myocardial infarction 48 hours later and the graft was examined histologically. There was karryorhexis and focal neutrophilic infiltrate in the media underlying a layer of fibrin on the intimal surface. Immunoperoxidase studies showed nonspecific luminal deposition of immunoglobulins and fibrinogen. The histologic changes that occur in cryopreserved venous allografts are similar in experimental and human material and may be the result of anoxia of the vessel wall rather than immunologic mechanisms.