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Replacement of the Abdominal Aorta with an Aortic Homograft in a Patient with an Aortic Dissection
Replacement of the Abdominal Aorta with an Aortic Homograft in a Patient with an Aortic Dissection John B. Steinberg, MD. Samuel A. Nickell, MD. M. Alex Jacocks. MD. Paul Stelzer. MD*. Oklahoma City, Oklahoma. and N e w York. N e w York
The use of aortic and femoral homografts in early vascular surgery has been abandoned for the more successful and abundant synthetic substitutes. With the recent introduction of Cryopreservation, homograft use has again met with improved success. A 40-year-old man who had a DeBakey Type I aortic dissection initially underwent replacement of the aortic root with a pulmonary homograft. Subsequently, in the presence of an intraabdominal infectious process, progressive mesenteric and lower limb ischemia was treated by replacing the abdominal aorta with an aortic homograft. Thirty-six months postoperative the patient has a functioning gastrointestinal tract and no vascular insufficiency of the lower extremities and no evidence of degeneration of the homograft. Further laboratory studies should be undertaken using the newer and improved cyropreserved homograft in the presence of, or potential for, an intraabdominal infectious process. (Ann Vasc Surg 1991 ;5:538-541). KEY WORDS: ischemia.
Abdominal aorta; homograft; cryopreservation; aortic dissection;
Based on the early laboratory and clinical work of G r o s s and associates [I], the aortic homograft was used as the vascular graft in the first aortic resection for occlusive disease by Oudot [2] and in the first resection of an abdominal aortic aneurysm by DuBost [3]. Due to the lack of availability, a high incidence of complications, and degenerative changes, surgeons abandoned the homograft for the more successful and abundant synthetic substitutes. Recently, newer and improved methods of preparing homografts
From homa homa Lenox
the Department of Surgery, University of OklaHealth Sciences Center, Oklahoma City, Oklaand the Department of Cardiothoracic Surgery, Hill Hospital*, New York, New York.
Presented at the 42nd Annual Meeting of the Southwestern Surgical Congress, LaQuinta, California, April 2225, 1990. Reprint requests: M. Alex Jacocks, MD, Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73190.
using cryopreservation have resulted in better graft survival. Homografts preserved as such have been used with great success in cardiac surgery at our institution [4]. We expanded this experience to include reconstruction of the distal abdominal aorta of a patient with intraabdominal sepsis.
CASE REPORT While refereeing a soccer game on June 4, 1988, a previously healthy, very active 40-year-old man suffered sudden chest, lower back, and leg pain with associated hemodynamic collapse and paraplegia. The patient was transferred to a local hospital by ambulance where an anteroposterior chest film revealed a non-widened mediastinum and a decreased left and absent right femoral pulse. A right groin exploration with Fogarty thrombectomy failed to restore inflow. An exploratory laparotomy was then performed, and an aortic dissection involving the entire abdominal aorta was observed. The intima distal to the re-entry site in the right iliac artery was
538
VOLUME 5
N o 6 - 1991
R E P L A C E M E N T OF A B D O M I N A L AORTA WITH AORTIC H O M O G R A F T
tacked down, restoring flow to the right leg. Due to persistent hypotension, there was concern for the proximal aorta. The anesthetized patient was then transferred to our institution by helicopter and taken directly to the operating room. A median sternotomy was performed, revealing a DeBakey Type I aortic dissection. Using left femoral arteryright atrial cardiopulmonary bypass, a valved pulmonary homograft was used to repair the aortic root. Six days later the patient developed signs and symptoms of mesenteric and right leg ischemia. At exploratory laparotomy, a gangrenous cecum and peritoneal fluid containing Gram negative rods were encountered. No flow was detected by Doppler ultrasound in the superior mesenteric artery (SMA), the inferior mesenteric artery, or the right common iliac artery. The abdominal aortic bifurcation was reconstructed with a non-valved aortic homograft. The proximal anastomosis was performed end-to-end between the infrarenal aorta and the proximal end of the aortic homograft. Anastomoses were performed between the left common itiac and a buttonhole in the homograft, between the right common iliac and the homograft innominate artery, and between the right external iliac and the homograft left subclavian artery (Fig. 1, a-c). Flow was restored to the SMA through a saphenous vein graft from the homograft. A right hemicolectomy with primary anastomosis was performed. At the conclusion of this procedure, flow was demonstrated by intraoperative Doppler ultrasound in the SMA and arteries of both lower extremities. Wood's lamp evaluation of the bowel with fluorescein dye revealed viable bowel. Cultures of the peritoneal fluid were positive for Enterococcus and Serratia and a course of vancomycin and gentamicin was administered. At a second look laparotomy 24 hours later, viable bowel and flow in all grafts were again confirmed. The patient had a stormy postoperative course requiring two subsequent laparotomies for intraabdominal sepsis, including resection of necrotic distal ileum, a pericardial window for an infected pericardial effusion, and a bout of candida sepsis. He was discharged home after 90 days in the hospital. A malabsorption syndrome slowly improved over the subsequent year. A magnetic resonance image (MRI) scan done 34 months postoperatively revealed normal contour of the intraabdominal graft with no aneurysms or excessive calcification. The patient has now been followed 36 months from the original operation. He has a functioning gastrointestinal tract, is gaining weight, has an intact peripheral circulation without symptoms of arterial occlusive disease, and has returned to his profession as a nurse anesthetist.
DISCUSSION Following the pioneering work of Gross [1] and the success of Oudot [2] and DuBost [3], homografts b e c a m e the conduits of choice in vascular surgery with gratifying results. D u B o s t ' s patient survived for eight years before succumbing to a myocardial infarction [5]. Smullens [6] also reported p a t e n c y of an abdominal aortic homograft
539
after eight years, and Brock [7] reported p a t e n c y after 19, 21, and 22 years in three patients. H o w ever, these and other surgeons [8] found that homografts were becoming more difficult to obtain as the demand for them increased. Besides being scarce, homografts were also difficult to sterilize and preserve, and they developed structural changes [9, 10] that often resulted in w e a k e n e d walls and aneurysmal dilatation. Consequently, they began using the newer, more abundant, easier to obtain, synthetic vascular substitutes [11]. Long-term success has been achieved with the synthetic grafts. Infection, however, continues to be a serious complication. Though the incidence of a bacterial graft infection is low (0.9-2.6%) in elective aortic reconstruction, a v e r y significant mortality ( 1 7 4 3 % ) and amputation rate (17-31%) results when the problem occurs [12-14]. Though much less c o m m o n , fungal graft infections are also encountered [15]. T r e a t m e n t of the infected graft usually includes excision of the vascular prosthesis and placement of an extraanatomic bypass to avoid distal ischemia [14]. A second operation m a y then be required to reconstruct an anatomical b y p a s s when the infectious process has been eradicated. If immediate anatomical replacement of the infected prosthesis could be obtained with a conduit that is resistant to bacterial colonization, the morbidity and mortality from multiple operative procedures and failures of extraanatomic b y p a s s grafts would be decreased or avoided. This same logic could be applied to the individual with an existing intraabdominal infection that requires a first-time aortic or arterial reconstruction. Endothelial cell seeding of a polytetrafluoroethylene (PTFE) vascular graft improves resistance to bacterial infections [16]. Others support the use of autogenous vascular conduits in contaminated and infected fields [17-19]. Consequently, one might assume that the biologic homograft would also be met with success in such cases. This is supported by the successful use of c r y o p r e s e r v e d homografts in active endocarditis where excellent functional results and a decreased incidence of reinfection have been achieved [20-22]. Our patient had a D e B a k e y T y p e I aortic dissection that required replacement of the aortic root. We used a c r y o p r e s e r v e d pulmonic homograft (an adequate-size aortic homograft was not available at the time). Subsequently, in the presence of Gramnegative peritonitis secondary to mesenteric ischemia, he required reconstruction of the abdominal aorta because the dissection c o m p r o m i s e d his right iliac system and superior mesenteric artery. The distal aorta was replaced using a nonvalved aortic homograft. H e subsequently has done very well and has no infectious or occlusive complications 36 months, postoperatively. Interestingly, the patient had no history of hypertension, no evidence of
540
R E P L A C E M E N T OF A B D O M I N A L AORTA WITH AORTIC H O M O G R A F T
ANNALS OF
VASCULARSURGERY
II
a b c Fig. 1. Magnetic resonance images six months after aortoiliac reconstruction with nonvalved aortic homograft. (a) Homograft sewn upside down in abdomen with left common iliac sewn into a buttonhole on its proximal portion. (b) Right common iliac is anastomosed to homograft innominate artery and right external iliac to homograft left subclavian artery, (c) Schematic demonstrating the anastomotic sites. (Used with permission from Stelzer P, and Elkins RC. Homograft valves and conduits: application in cardiac surgery. Curr Prob Surg 1989;26:383-452. Mosby Year Book, Inc.)
Marfan's syndrome, no aortic stenosis, and no coarctation of the aorta or bicuspid aortic valve. Pathology revealed cystic medial necrosis of the aortic wall. There is a report of a fatal aortic dissection in a scuba diver, suggesting that decompression bubbles may form in the aortic wall causing areas of cystic medial necrosis and perhaps precipitate dissection [23]. Our patient was an avid scuba diver. Homografts were originally preserved at 4~ in an isotonic solution or serum containing antibiotics ("fresh" homografts) [2,24,25], freeze-dried [26i27], or by quick-freezing and sterilization by irradiation [28]. These grafts had high failure rates related to degeneration, infection, or calcification. Consequently, their use was abandoned [9,29], and prosthetic grafts and porcine valves were used. With the advent of cryopreservation, homografts are once again being used more frequently for cardiac procedures [4]. Grafts are initially sterilized and intubated in an antibiotic solution and nutrient medium. They are then cryopreserved in the vapor phase of liquid nitrogen until ready for use. This results in a viable graft [30]. Cryopreserved homograft valves used in the aortic position have been reported to have 100% freedom from reoperation
for degenerative changes 10 years after operation as compared to 89% for those preserved as "fresh" homografts [30]. In addition to improved preservation techniques, vascular surgical techniques have improved since the original use of the homograft conduit in the abdomen. The use of silk sutures in the original reports [2,3,6] has been abandoned for monofilament synthetic sutures with a lower incidence of inflammatory reaction, fraying, and pseudoaneurysm formation. The use of present-day antibiotics has also improved the outcome in vascular surgery. Another problem facing the surgeon during the early era of vascular surgery was the availability of homografts. A unique and successful procurement program has been developed at the University of Oklahoma [31], which includes educating both the lay and medical public of organ and tissue transplantation. This, along with the development of central banks for processing and preserving homografts, has resulted in a constant supply of aortic and pulmonic homografts. As the homograft supply increases, surgical techniques improve and cryopreservation techniques become more refined. Homograft use in anatomical positions other than the heart should be considered.
VOLUME 5 No 6 - 1991
REPLACEMENT OF ABDOMINAL AOR]A WITH AORTIC HOMOGRAFT
An especially interesting application would be the use of homografts for replacement of infected grafts. Since they are nonsynthetic, they could possibly be used in infected fields successfully.
CONCLUSION This case shows that the use of a homograft
conduit for vascular reconstruction in an infected field can be done successfully. Caution must be used when interpreting this case report, since the use of homografts in the early fifties was abandoned after these grafts were noted to be structurally inferior. The newer methods of cryopreservation, however, have improved the structural integrity of such grafts.
ACKNOWLEDGMENTS The authors wish to thank Judy Wheeler for preparation of the manuscript, Linda O'Rourke for the literature preparation, and M. LaWaun Hance for the illustration.
REFERENCES 1. GROSS RE, HURWITT ES, BILL AH, et al. Preliminary observations on the use of human arterial grafts in the treatment of certain cardiovascular defects. N Engl J Med 1948;239:578-579. 2. OUDOT J, BEACONSFIELD P. Thrombosis of the aortic bifurcation treated by resection and homograft replacement. Arch Surg 1953;66:365-374. 3. DUBOST C, ALLARY M, OECONOMOS N. Resection of an aneurysm of the abdominal aorta. Reestablishment of the continuity by a preserved human arterial graft, with result after five months. Arch Surg 1952;64:405-408. 4. STELZER P, ELKINS RE. Homograft valves and conduits: applications in cardiac surgery. Curr Prob Surg 1989;26:383452. 5. DUBOST C. The first successful resection of an aneurysm of the abdominal aorta followed by re-establishment of continuity using a preserved human arterial graft. Ann Vasc Surg 1986;1:147-149. 6. SMULLENS SN, TEMPLETON JY. Eight year patency of abdominal aortic homograft. Am J Surg 1970;120:116-118. 7. BROCK L. Long term success with homograft reconstruction of the aorta for the cure of aneurysm. Guy's Hosp Reports 1973 ;122:12%134. 8. DE BAKEY ME, CRAWFORD ES, COOLEY DA, et al. Surgical considerations of occlusive disease of the abdominal aorta and iliac and femoral arteries: analysis of 803 cases. Ann Surg 1958;148:306-324. 9. SZILAGYI DE, MCDONALD RT, SMITH RF, et al. Biologic fate of human arterial homografts. Arch Surg 1957; 75:506-529. 10. SZILAGYI DE, RODRIQUEZ FJ, SMITH RF, et al. Late fate of arterial allografts: observations 6 to 15 years after implantation. Arch Surg t970;101:721-733.
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11. DEBAKEY ME, COOLEY DA, CRAWFORD ES, et al. Clinical application of a new flexible knitted dacron arterial substitute. Am Surg 1958;24:862-869. 12. EDWARDS WH, MARTIN RS, JENKINS JM, et al. Primary graft infections. J Vasc Surg 1987;6:235-239. 13. LORENTZEN JE, NIELSEN OM, ARENDRUP H, et al. Vascular graft infection: an analysis of sixty-two graft infections in 2411 consecutively implanted synthetic vascular grafts. Surge~' 1985;98:81-86. 14. YEAGER RA, MC CONNELL DB, SASAKI TM, et al. Aortic and peripheral prosthetic graft infection: differential management and causes of mortality. Am J Surg 1985;150: 36M3. 15. DOSCHER W, KRISHNASASTRY KV, DECKOFF SL. Fungal graft infections: case report and review of the literature. J Vasc Surg 1987;6:398-402. 16. BIRINYI LK, DOUVILLE EC, LEWIS SA, et al. Increased resistance to bacteremic graft infection after endothelial cell seeding. J Vasc Surg 1987;5:193-197. 17. RICH NM, HUGHES CW. The fate of prosthetic material used to repair vascular injuries in contaminated wounds. J Trauma 1972;12:459-467. 18. EHRENFELD WK, WILBUR BG, OLCOTT CN, el al. Autogenous tissue reconstruction in the management of infected prosthetic grafts. Surgery 1979;85:82-92. 19. SEEGER JM, WHEELER JR, GREGORY RT, et al. Autogenous graft replacement of infected prosthetic grafts in the femoral position. Surgel7 1983;93:39-45. 20. ZWISCHENBERGER JB, SHALABY TZ, CONTI VR. Viable cryopreserved aortic homograft for aortic valve endocarditis and annular abscesses. Ann Thorac Surg 1989;48: 365-370. 21. TUNA IL, ORSZULAK TA, SCHAFF HV, et al. Results of bomograft aortic valve replacement for active endocarditis. Ann Thorac Surg 1990;49:619-624 . . . . . 22. MATSUKI O, ROBLES A, GIBBS S, et al. Long-term performance of 555 aortic homografts in the aortic position. Ann Thorac Surg 1988;46:187-191. 23. JAMES R, HAYMAN JA. Fatal dissecting aneurysm of the aorta in a diver. Pathology 1986;18:345-347. 24. GROSS RE, BILL AH, PIERCE EC. Methods for preservation and transportation of arterial grafts: observations on arterial grafts in dogs. Report of transplantation of preserved arterial grafts in nine human cases. Surg Gynecol & Obstet 1949;88:689-701. 25. YACOUB M, KITTLE CF. Sterilization of valve homografts by antibiotic solutions. Circulation 1970;41 (Suppl 11):2%32. 26. ROSS DN. Homograft replacement of the aortic valve. J Cardiovasc Surg 1965;Suppl:89-94. 27. BARRATT-BOYES GB. A method for preparing and inserting a homograft aortic valve. Br J Surg 1965;52:847-856. 28. MALM JR, BOWMAN FO, HARRIS PD, et al. An evaluation of aortic valve homograft sterilized by electron beam energy. J Thorac Cardiovasc Surg 1967;54:471-477, 486490. 29. BEACH PM, BOWMAN FO, KAISER GA, et al. Aortic valve replacement with frozen irradiated homografts: long term evaluation, Circulation 1972;45 (Suppl 1):29-35. 30. O'BRIEN MF, STAFFORD EG, GARDNER MAH, et al. A comparison of aortic valve replacement with viable cryopreserved and fresh allograft valves, with a note on chromosomal studies. J Thorac Cardiovasc Surg 1987;94:812-823. 31. JONES D J, HANCE ML, STELZER P, et al. Procurement of hearts for valve homografts: one year's experience. J Okla State Med Assoc 1988;81:510-512.
The use of aortic and femoral homografts in early vascular surgery has been abandoned for the more successful and abundant synthetic substitutes. With the recent introduction of Cryopreservation, homograft use has again met with improved success. A 40-year-old man who had a DeBakey Type I aortic dissection initially underwent replacement of the aortic root with a pulmonary homograft. Subsequently, in the presence of an intraabdominal infectious process, progressive mesenteric and lower limb ischemia was treated by replacing the abdominal aorta with an aortic homograft. Thirty-six months postoperative the patient has a functioning gastrointestinal tract and no vascular insufficiency of the lower extremities and no evidence of degeneration of the homograft. Further laboratory studies should be undertaken using the newer and improved cyropreserved homograft in the presence of, or potential for, an intraabdominal infectious process. (Ann Vasc Surg 1991 ;5:538-541). KEY WORDS: ischemia.
Abdominal aorta; homograft; cryopreservation; aortic dissection;
Based on the early laboratory and clinical work of G r o s s and associates [I], the aortic homograft was used as the vascular graft in the first aortic resection for occlusive disease by Oudot [2] and in the first resection of an abdominal aortic aneurysm by DuBost [3]. Due to the lack of availability, a high incidence of complications, and degenerative changes, surgeons abandoned the homograft for the more successful and abundant synthetic substitutes. Recently, newer and improved methods of preparing homografts
From homa homa Lenox
the Department of Surgery, University of OklaHealth Sciences Center, Oklahoma City, Oklaand the Department of Cardiothoracic Surgery, Hill Hospital*, New York, New York.
Presented at the 42nd Annual Meeting of the Southwestern Surgical Congress, LaQuinta, California, April 2225, 1990. Reprint requests: M. Alex Jacocks, MD, Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73190.
using cryopreservation have resulted in better graft survival. Homografts preserved as such have been used with great success in cardiac surgery at our institution [4]. We expanded this experience to include reconstruction of the distal abdominal aorta of a patient with intraabdominal sepsis.
CASE REPORT While refereeing a soccer game on June 4, 1988, a previously healthy, very active 40-year-old man suffered sudden chest, lower back, and leg pain with associated hemodynamic collapse and paraplegia. The patient was transferred to a local hospital by ambulance where an anteroposterior chest film revealed a non-widened mediastinum and a decreased left and absent right femoral pulse. A right groin exploration with Fogarty thrombectomy failed to restore inflow. An exploratory laparotomy was then performed, and an aortic dissection involving the entire abdominal aorta was observed. The intima distal to the re-entry site in the right iliac artery was
538
VOLUME 5
N o 6 - 1991
R E P L A C E M E N T OF A B D O M I N A L AORTA WITH AORTIC H O M O G R A F T
tacked down, restoring flow to the right leg. Due to persistent hypotension, there was concern for the proximal aorta. The anesthetized patient was then transferred to our institution by helicopter and taken directly to the operating room. A median sternotomy was performed, revealing a DeBakey Type I aortic dissection. Using left femoral arteryright atrial cardiopulmonary bypass, a valved pulmonary homograft was used to repair the aortic root. Six days later the patient developed signs and symptoms of mesenteric and right leg ischemia. At exploratory laparotomy, a gangrenous cecum and peritoneal fluid containing Gram negative rods were encountered. No flow was detected by Doppler ultrasound in the superior mesenteric artery (SMA), the inferior mesenteric artery, or the right common iliac artery. The abdominal aortic bifurcation was reconstructed with a non-valved aortic homograft. The proximal anastomosis was performed end-to-end between the infrarenal aorta and the proximal end of the aortic homograft. Anastomoses were performed between the left common itiac and a buttonhole in the homograft, between the right common iliac and the homograft innominate artery, and between the right external iliac and the homograft left subclavian artery (Fig. 1, a-c). Flow was restored to the SMA through a saphenous vein graft from the homograft. A right hemicolectomy with primary anastomosis was performed. At the conclusion of this procedure, flow was demonstrated by intraoperative Doppler ultrasound in the SMA and arteries of both lower extremities. Wood's lamp evaluation of the bowel with fluorescein dye revealed viable bowel. Cultures of the peritoneal fluid were positive for Enterococcus and Serratia and a course of vancomycin and gentamicin was administered. At a second look laparotomy 24 hours later, viable bowel and flow in all grafts were again confirmed. The patient had a stormy postoperative course requiring two subsequent laparotomies for intraabdominal sepsis, including resection of necrotic distal ileum, a pericardial window for an infected pericardial effusion, and a bout of candida sepsis. He was discharged home after 90 days in the hospital. A malabsorption syndrome slowly improved over the subsequent year. A magnetic resonance image (MRI) scan done 34 months postoperatively revealed normal contour of the intraabdominal graft with no aneurysms or excessive calcification. The patient has now been followed 36 months from the original operation. He has a functioning gastrointestinal tract, is gaining weight, has an intact peripheral circulation without symptoms of arterial occlusive disease, and has returned to his profession as a nurse anesthetist.
DISCUSSION Following the pioneering work of Gross [1] and the success of Oudot [2] and DuBost [3], homografts b e c a m e the conduits of choice in vascular surgery with gratifying results. D u B o s t ' s patient survived for eight years before succumbing to a myocardial infarction [5]. Smullens [6] also reported p a t e n c y of an abdominal aortic homograft
539
after eight years, and Brock [7] reported p a t e n c y after 19, 21, and 22 years in three patients. H o w ever, these and other surgeons [8] found that homografts were becoming more difficult to obtain as the demand for them increased. Besides being scarce, homografts were also difficult to sterilize and preserve, and they developed structural changes [9, 10] that often resulted in w e a k e n e d walls and aneurysmal dilatation. Consequently, they began using the newer, more abundant, easier to obtain, synthetic vascular substitutes [11]. Long-term success has been achieved with the synthetic grafts. Infection, however, continues to be a serious complication. Though the incidence of a bacterial graft infection is low (0.9-2.6%) in elective aortic reconstruction, a v e r y significant mortality ( 1 7 4 3 % ) and amputation rate (17-31%) results when the problem occurs [12-14]. Though much less c o m m o n , fungal graft infections are also encountered [15]. T r e a t m e n t of the infected graft usually includes excision of the vascular prosthesis and placement of an extraanatomic bypass to avoid distal ischemia [14]. A second operation m a y then be required to reconstruct an anatomical b y p a s s when the infectious process has been eradicated. If immediate anatomical replacement of the infected prosthesis could be obtained with a conduit that is resistant to bacterial colonization, the morbidity and mortality from multiple operative procedures and failures of extraanatomic b y p a s s grafts would be decreased or avoided. This same logic could be applied to the individual with an existing intraabdominal infection that requires a first-time aortic or arterial reconstruction. Endothelial cell seeding of a polytetrafluoroethylene (PTFE) vascular graft improves resistance to bacterial infections [16]. Others support the use of autogenous vascular conduits in contaminated and infected fields [17-19]. Consequently, one might assume that the biologic homograft would also be met with success in such cases. This is supported by the successful use of c r y o p r e s e r v e d homografts in active endocarditis where excellent functional results and a decreased incidence of reinfection have been achieved [20-22]. Our patient had a D e B a k e y T y p e I aortic dissection that required replacement of the aortic root. We used a c r y o p r e s e r v e d pulmonic homograft (an adequate-size aortic homograft was not available at the time). Subsequently, in the presence of Gramnegative peritonitis secondary to mesenteric ischemia, he required reconstruction of the abdominal aorta because the dissection c o m p r o m i s e d his right iliac system and superior mesenteric artery. The distal aorta was replaced using a nonvalved aortic homograft. H e subsequently has done very well and has no infectious or occlusive complications 36 months, postoperatively. Interestingly, the patient had no history of hypertension, no evidence of
540
R E P L A C E M E N T OF A B D O M I N A L AORTA WITH AORTIC H O M O G R A F T
ANNALS OF
VASCULARSURGERY
II
a b c Fig. 1. Magnetic resonance images six months after aortoiliac reconstruction with nonvalved aortic homograft. (a) Homograft sewn upside down in abdomen with left common iliac sewn into a buttonhole on its proximal portion. (b) Right common iliac is anastomosed to homograft innominate artery and right external iliac to homograft left subclavian artery, (c) Schematic demonstrating the anastomotic sites. (Used with permission from Stelzer P, and Elkins RC. Homograft valves and conduits: application in cardiac surgery. Curr Prob Surg 1989;26:383-452. Mosby Year Book, Inc.)
Marfan's syndrome, no aortic stenosis, and no coarctation of the aorta or bicuspid aortic valve. Pathology revealed cystic medial necrosis of the aortic wall. There is a report of a fatal aortic dissection in a scuba diver, suggesting that decompression bubbles may form in the aortic wall causing areas of cystic medial necrosis and perhaps precipitate dissection [23]. Our patient was an avid scuba diver. Homografts were originally preserved at 4~ in an isotonic solution or serum containing antibiotics ("fresh" homografts) [2,24,25], freeze-dried [26i27], or by quick-freezing and sterilization by irradiation [28]. These grafts had high failure rates related to degeneration, infection, or calcification. Consequently, their use was abandoned [9,29], and prosthetic grafts and porcine valves were used. With the advent of cryopreservation, homografts are once again being used more frequently for cardiac procedures [4]. Grafts are initially sterilized and intubated in an antibiotic solution and nutrient medium. They are then cryopreserved in the vapor phase of liquid nitrogen until ready for use. This results in a viable graft [30]. Cryopreserved homograft valves used in the aortic position have been reported to have 100% freedom from reoperation
for degenerative changes 10 years after operation as compared to 89% for those preserved as "fresh" homografts [30]. In addition to improved preservation techniques, vascular surgical techniques have improved since the original use of the homograft conduit in the abdomen. The use of silk sutures in the original reports [2,3,6] has been abandoned for monofilament synthetic sutures with a lower incidence of inflammatory reaction, fraying, and pseudoaneurysm formation. The use of present-day antibiotics has also improved the outcome in vascular surgery. Another problem facing the surgeon during the early era of vascular surgery was the availability of homografts. A unique and successful procurement program has been developed at the University of Oklahoma [31], which includes educating both the lay and medical public of organ and tissue transplantation. This, along with the development of central banks for processing and preserving homografts, has resulted in a constant supply of aortic and pulmonic homografts. As the homograft supply increases, surgical techniques improve and cryopreservation techniques become more refined. Homograft use in anatomical positions other than the heart should be considered.
VOLUME 5 No 6 - 1991
REPLACEMENT OF ABDOMINAL AOR]A WITH AORTIC HOMOGRAFT
An especially interesting application would be the use of homografts for replacement of infected grafts. Since they are nonsynthetic, they could possibly be used in infected fields successfully.
CONCLUSION This case shows that the use of a homograft
conduit for vascular reconstruction in an infected field can be done successfully. Caution must be used when interpreting this case report, since the use of homografts in the early fifties was abandoned after these grafts were noted to be structurally inferior. The newer methods of cryopreservation, however, have improved the structural integrity of such grafts.
ACKNOWLEDGMENTS The authors wish to thank Judy Wheeler for preparation of the manuscript, Linda O'Rourke for the literature preparation, and M. LaWaun Hance for the illustration.
REFERENCES 1. GROSS RE, HURWITT ES, BILL AH, et al. Preliminary observations on the use of human arterial grafts in the treatment of certain cardiovascular defects. N Engl J Med 1948;239:578-579. 2. OUDOT J, BEACONSFIELD P. Thrombosis of the aortic bifurcation treated by resection and homograft replacement. Arch Surg 1953;66:365-374. 3. DUBOST C, ALLARY M, OECONOMOS N. Resection of an aneurysm of the abdominal aorta. Reestablishment of the continuity by a preserved human arterial graft, with result after five months. Arch Surg 1952;64:405-408. 4. STELZER P, ELKINS RE. Homograft valves and conduits: applications in cardiac surgery. Curr Prob Surg 1989;26:383452. 5. DUBOST C. The first successful resection of an aneurysm of the abdominal aorta followed by re-establishment of continuity using a preserved human arterial graft. Ann Vasc Surg 1986;1:147-149. 6. SMULLENS SN, TEMPLETON JY. Eight year patency of abdominal aortic homograft. Am J Surg 1970;120:116-118. 7. BROCK L. Long term success with homograft reconstruction of the aorta for the cure of aneurysm. Guy's Hosp Reports 1973 ;122:12%134. 8. DE BAKEY ME, CRAWFORD ES, COOLEY DA, et al. Surgical considerations of occlusive disease of the abdominal aorta and iliac and femoral arteries: analysis of 803 cases. Ann Surg 1958;148:306-324. 9. SZILAGYI DE, MCDONALD RT, SMITH RF, et al. Biologic fate of human arterial homografts. Arch Surg 1957; 75:506-529. 10. SZILAGYI DE, RODRIQUEZ FJ, SMITH RF, et al. Late fate of arterial allografts: observations 6 to 15 years after implantation. Arch Surg t970;101:721-733.
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