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Transfemoral placement of intraluminal polyurethane prosthesis for abdominal aortic aneurysm
JOURNALOF SURGICALRESEARCH40, 305-309 (1986)
Transfemoral Placement of lntraluminal Polyurethane Prosthesis for Abdominal Aortic Aneurysm ALEXANDER
BALKO, M.D.,’ GEORGE J. PIASECKI, M.S., DHIRAJ M. SHAH, M.D.,* WILFRED I. CARNEY, M.D., ROBERT W. HOPKINS, M.D., AND BENJAMIN T. JACKSON, M.D.
Departments of Surgery? Providence VA Medical Center, Rhode Island Hospital and Miriam Hospital, Brown University Program in Medicine, Providence, Rhode Island 02908, and *Albany Medical College, Albany, New York 12208 Presented at the Annual Meeting of the Association for Academic Surgery, Cincinnati, Ohio, November IO- 13, 1985 Because of the significant mortality associated with the conventional surgical approach to abdominal aortic aneurysms (AAA) in the high risk patients and in those with ruptured aneurysms, we have developed a new approach to this problem, intraluminal aneurysm exclusion. This was achieved by an intraluminal prosthesis which approximated the diameter of the aorta above and below the aneurysm and is inserted through the femoral artery. The prothesis consisted of biomedical grade elastomeric polyurethane with a NITINOL and/or stainless steel frame and was designed in such a configuration that it could be compressed inside a 15 F catheter and then regain its original shape after being discharged inside the aorta. The polyurethane prosthesis tolerated static pressures in excess of 300 Torr. Aneurysmal aortas were created in three adult sheep using large knitted Dacron patches (6 X 9 cm) sewn onto a longitudinal aortotomy. After 4-6 weeks, an intraluminal prosthesis was passed transfemorally to the location of the aortic aneurysm. Following satisfactory placement and expansion of the prosthesis, a laceration was produced in the aneurysmal wall. No bleeding developed, which confirmed the integrity of the prosthesis in excluding the aneurysm from the aorta proper. Pulsation in the iliac arteries indicated the presence of aortic blood flow through the prosthesis. Autopsy examination demonstrated directly that the prosthesis was open and that its two ends were fixed in the aorta above and below the aneurysm. The study has demonstrated that intraluminal AAA exclusion could be achieved with an intraluminal polyurethane prosthesis inserted through the femoral artery. 0 1986 Academic R-ES, IIIC.
over this treatment remains, mainly due to reports of early and late aneurysmal ruptures [2, 7, 10, 121. Because of these problems, we developed a new approach to dealing with the high risk aneurysm. Instead of graft replacement or thrombosis of the aneurysm, we propose intraluminal aneurysm exclusion, using a newly developed polyurethane prosthesis which can be introduced transfemorally. This report describes our aneurysmal model and initial experience with this new technique.
INTRODUCTION
The standard treatment for abdominal aortic aneurysm is endoaneurysmorrhaphy with graft replacement. This method is associated with a mortality rate of less than 5% [ 131. However, patients with severe risk factors have an operative mortality reported to be between 20 and 66% [6]. Risks identified by Leather et al. include severe cardiac, renal, and pulmonary disorders, as well as morbid obesity [ 111. Advocates of the nonresective treatment of aneurysms in this high risk group have published series with acceptable morbidity and mortality rates [ 1, 8, 9, 111, but controversy ’ To whom reprint requests should be addressed: Surgical Service (112), Providence VA Medical Center, Davis Park, Providence, R.I. 02908.
MATERIALS
AND METHODS
Polyurethane prostheses were constructed from biomedical grade elastomeric polyurethane and stainless-steel and/or NITINOL wire frames (Fig. 1). NITINOL is an alloy consisting of nickel and titanium, with shape-
305
0022-4804186 $1 SO Copyright 0 I986 by Academic FESS, Inc. All rigbu of reproduction in any form resewed.
306
JOURNAL OF SURGICAL RESEARCH: VOL. 40, NO. 4, APRIL 1986
FIG. 1. I&alumina1 polyurethane prosthesis in fully expanded form (dimensions: length-8 cm; diameter10 mm).
memory properties. The design of the wire frame allowed the prosthesis to be compressed into a 15 F catheter, and when released from the catheter, the prosthesis expanded back to its original shape. Adult sheep, weighing 50-60 kg, were anesthetized with Surital 750 mg iv, and general endotracheal anesthesia with halothane and O2 was utilized during the operation. Sheep were placed on the operating table with their right side down. A long left-sided paraspinal incision provided a retroperitoneal approach to the abdominal aorta. Following heparinization and aortic clamping, a long aortotomy was made, starting from 1 cm below the level of the renal arteries and ending 1 cm above the aortic bifurcation. All bleeding lumbar arteries were ligated. A 6 X 9 cm knitted Dacron patch was then sewn onto the aortotomy (Fig. 2). Four to six weeks of healing time was allowed prior to transfemoral placement of the intraluminal prosthesis. For placement of the prosthesis, each animal was anesthetized, and the aortic aneurysm was exposed. A femoral cutdown was performed and the prosthesis was introduced
FIG. 2. Abdominal aortic aneurysm model with knitted Dacron patch sewn onto the aorta.
BALK0
ET AL.: INTRALUMINAL
307
PROSTHESIS
through a 15 F catheter to the level of the in excluding the aneurysm from the aorta aneurysm. Proper placement of the prosthesis proper. Postmortem examination demon-
was monitored by palpating the catheter tip at the neck of the aneurysm since fluoroscopy
strated directly that the prosthesis was open and that its two ends were fixed in the aorta
was not available. The catheter was slowly withdrawn, and the prosthesis was ejected so as to extend from just above the aneurysm to the aortic bifur-
above and below the aneurysm (Fig. 3). The polyurethane prosthesis was tested for bursting strength and tolerated static pressures in excess of 300 Torr.
cation. In this short term model the aneurysma1 wall was opened shortly after graft insertion, and the prosthesis and its placement were carefully evaluated. The care and use of animal subjects followed guidelines as established by AAALAC. RESULTS
Three adult sheep had satisfactory placement of the intraluminal prosthesis under direct control. Once the prosthesis expanded within the aneurysm, pulsation of the aneurysm immediately ceased in each case. Pulsation in the iliac arteries indicated the presence of aortic flow through the expanded prosthesis. A laceration was produced in the aneurysmal wall, and no bleeding developed which confirmed the integrity of the prosthesis
DISCUSSION
Our concept of intraluminal aneurysm exclusion seems the least invasive method of treating aneurysms, which makes its application for the high risk patient appealing. Angiographic visualization of the aneurysm would be a requirement both prior to and during insertion of the intraluminal prosthesis. Once dimensions of the aneurysm and suitability of this technique are determined, a properly sized prosthesis would be inserted by the angiographer working together with the vascular surgeon. Besides the high risk group, one could also consider patients who present with a ruptured aneurysm. After initial clamping is achieved, the prosthesis could be inserted in order to avoid further blood loss
FIG. 3. Excised aortic aneurysm which is excluded by the intraluminal
prosthesis.
308
JOURNAL OF SURGICAL RESEARCH: VOL. 40, NO. 4, APRIL 1986
and in order to decrease operating time in the moribund patient. Another indication for this approach could be a situation where an aneurysm was found to be inflammatory at the time of laparotomy, and further dissection deemed imprudent due to the densely adherent small bowel. Indeed, if our approach were to prove feasible in the high risk patients and shown to have a lower morbidity and mortality rate than present techniques, one could extend its use to more routine aneurysms. Abdominal aortic aneurysms smaller than 5 cm could be considered, since they tend to be more localized to the aorta, without iliac involvement, and further growth and rupture of the aneurysm would hopefully be arrested. An autopsy study of unoperated abdominal aortic aneurysms by Darling showed that aneurysms measuring between 4.1 and 5.0 cm had a similar rate of rupture when compared to those measuring between 5.1 and 7.0 cm. In addition, the vast majority of aortic ruptures occurred retroperitoneally, along the dilated portion of the lateral wall; rarely near the neck of the aneurysm or near the bifurcation [4]. A properly positioned intraluminal prosthesis could eliminate the pressure on the aneurysmal lateral walls and prevent subsequent rupture. Although our results demonstrated that insertion of an intraluminal polyurethane prosthesis transfemorally is feasible, there remain many questions and long term considerations. Short and long term biologic interactions between prosthesis and aortic wall need further investigation. Potential adversities include embolization of the gelatinous debris lining the aneurysm during insertion of the prosthesis, migration of the prosthesis, and erosion through the aortic wall. Polyurethane deterioration and calcification have to be studied. One significant disadvantage of using NITINOL is its potential premature expansion inside the catheter, and therefore constant cold saline irrigation is required during insertion. Aortic aneurysms not suitable for this technique would include the following characteristics: (a) renal artery involvement or neck just distal to the renals, (b) patent inferior mes-
enteric artery, (c) presence of iliac aneurysmal disease, and (d) iliac occlusive disease or tortuosity precluding insertion of the catheter. In order to determine whether our technique could be applied to a specific AAA, angiography would be a requirement, with particular attention to the previously mentioned factors. The nonresective management of abdominal aortic aneurysms involves thrombosis of the aneurysm and axillo-bifemoral bypass. Its advantages over the standard treatment in high risk patients include the avoidance of a major laparotomy, general anesthesia, large fluid shifts, and blood loss. Despite several favorable series [ 1, 8, 9, 1 I], others have reported aneurysmal ruptures [2, 7, 10, 121, specifically at the aneurysmal neck. This led Kwaan to adopt the total aneurysm exclusion technique [9]. However, laparotomy is required and partially defeats the original intent of this approach. Several groups have reported the placement of NITINOL coils inside the dog aorta and iliac arteries [3, 51; however, in the process of transforming its shape from a straight wire to a coil, considerable whipping motion occurs and results in endothelial damage with a highly thrombogenic surface. This wire movement would lead to significant embolization, since the human aneurysm is lined with gelatinous debris. On the other hand, the intraluminal prosthesis expands with the NITINOL or stainless steel to a predetermined diameter and would tend to displace the aneurysmal lining laterally, rather than mobilizing it. In summary, our results demonstrate that insertion of an intraluminal polyurethane prosthesis transfemorally is feasible, and that intraluminal aneurysm exclusion can be achieved acutely. Studies are in progress in order to determine the long term effectiveness. This technique may become applicable for treating abdominal aortic aneurysms, especially in high risk patients, since this approach is less invasive than current methods. ACKNOWLEDGMENT The authors thank George T. Donnelly for his expert technical assistance throughout the study.
BALK0
ET AL.: INTRALUMINAL
REFERENCES 1. Berguer, P., Scheider, J., and Wilner, H. I. Induced thrombosis of inoperable abdominal aortic aneurysm. Surgery 84: 425, 1978. 2. Cho, S. I., Johnson, W. C., Bush, M. L., Jr., Widrich, W. C., Muse, J. B., and Nabseth, D. C. Lethal complications associated with nonresective treatment of abdominal aortic aneurysm. Arch. Surg. 117: 1214, 1982. 3. Cragg, A. H., Lund, G., Rysavy, J., Salomonowitz, R., Castaneda-Zuniga, W., and Amplatz, K. Percutaneous arterial grafting. Radiology 150: 45, 1984. 4. Darling, R. C., Messina, C. R., Brewster, D. C., and Ottinger, L. W. Autopsy study of unoperated abdominal aortic aneurysms. Curdiovas. Surg. 56(3): 161, 1977. 5. Dotter, C. T., Buschmann, R. W., McKinney, M. K., and Rosch, J. Transluminal expandable NITINOL coil stent grafting: Preliminary report. Radiology 147: 259, 1983. 6. Gardner, R. J., Gardner, N. L., Tamay, T. J., Warden, H. E., James, E. D., and Watne, A. L. The surgical experience and a one to sixteen year follow-up of 277 abdominal aortic aneurysms. Amer. J. Surg. 135: 226, 1978. 7. Inahara, T., Geary, G. L., Mukhejee, D., and Egan,
8.
9.
10.
11.
12.
13.
PROSTHESIS
309
J. M. The contrary position to the nonresective treatment for abdominal aortic aneurysm. J. Vas. Surg. 2: 42, 1985. Kannody, A. M., Leather, R. P., Goldman, M., Corson, J. D., and Shah, D. M. The current position of nonresective treatment for abdominal aortic aneurysm. Surgery 94: 591, 1983. Kwaan, J. H., Khan, R. J., and Connolly, J. E. Total exclusion technigue for the management of abdominal aortic aneurysm. Amer. J. Surg. 146: 93, 1983. Kwaan, J. H. M., and Dahl, R. K. Fatal rupture after successfulsurgical thrombosis of an abdominal aortic aneurysm. Surgery 95: 235, 1984. Leather, R. P., Shah, D. M., Goldman, M., Rosenberg, M., and Karmody, A. M. Nonresective treatment of abdominal aortic aneurysm. Arch. Surg. 144: 1402, 1979. Schanzer, H., Papa, M. C., and Miller, C. M. Rupture of surgically thrombosed abdominal aortic aneurysm. J. Vas. Surg. 2: 278, 1985. Thompson, J. E., Garrett, W. V., Patman, R. D., Talkington, C. M., and Williams, S. J., III. Elective surgery for abdominal aortic aneurysms. In J. J. Bergan, and Yao, J. S. T. Eds. Aneurysms: Diagnosis and Treatment. New York: Grune & Stratton, 1982. Pp. 287-301.
Transfemoral Placement of lntraluminal Polyurethane Prosthesis for Abdominal Aortic Aneurysm ALEXANDER
BALKO, M.D.,’ GEORGE J. PIASECKI, M.S., DHIRAJ M. SHAH, M.D.,* WILFRED I. CARNEY, M.D., ROBERT W. HOPKINS, M.D., AND BENJAMIN T. JACKSON, M.D.
Departments of Surgery? Providence VA Medical Center, Rhode Island Hospital and Miriam Hospital, Brown University Program in Medicine, Providence, Rhode Island 02908, and *Albany Medical College, Albany, New York 12208 Presented at the Annual Meeting of the Association for Academic Surgery, Cincinnati, Ohio, November IO- 13, 1985 Because of the significant mortality associated with the conventional surgical approach to abdominal aortic aneurysms (AAA) in the high risk patients and in those with ruptured aneurysms, we have developed a new approach to this problem, intraluminal aneurysm exclusion. This was achieved by an intraluminal prosthesis which approximated the diameter of the aorta above and below the aneurysm and is inserted through the femoral artery. The prothesis consisted of biomedical grade elastomeric polyurethane with a NITINOL and/or stainless steel frame and was designed in such a configuration that it could be compressed inside a 15 F catheter and then regain its original shape after being discharged inside the aorta. The polyurethane prosthesis tolerated static pressures in excess of 300 Torr. Aneurysmal aortas were created in three adult sheep using large knitted Dacron patches (6 X 9 cm) sewn onto a longitudinal aortotomy. After 4-6 weeks, an intraluminal prosthesis was passed transfemorally to the location of the aortic aneurysm. Following satisfactory placement and expansion of the prosthesis, a laceration was produced in the aneurysmal wall. No bleeding developed, which confirmed the integrity of the prosthesis in excluding the aneurysm from the aorta proper. Pulsation in the iliac arteries indicated the presence of aortic blood flow through the prosthesis. Autopsy examination demonstrated directly that the prosthesis was open and that its two ends were fixed in the aorta above and below the aneurysm. The study has demonstrated that intraluminal AAA exclusion could be achieved with an intraluminal polyurethane prosthesis inserted through the femoral artery. 0 1986 Academic R-ES, IIIC.
over this treatment remains, mainly due to reports of early and late aneurysmal ruptures [2, 7, 10, 121. Because of these problems, we developed a new approach to dealing with the high risk aneurysm. Instead of graft replacement or thrombosis of the aneurysm, we propose intraluminal aneurysm exclusion, using a newly developed polyurethane prosthesis which can be introduced transfemorally. This report describes our aneurysmal model and initial experience with this new technique.
INTRODUCTION
The standard treatment for abdominal aortic aneurysm is endoaneurysmorrhaphy with graft replacement. This method is associated with a mortality rate of less than 5% [ 131. However, patients with severe risk factors have an operative mortality reported to be between 20 and 66% [6]. Risks identified by Leather et al. include severe cardiac, renal, and pulmonary disorders, as well as morbid obesity [ 111. Advocates of the nonresective treatment of aneurysms in this high risk group have published series with acceptable morbidity and mortality rates [ 1, 8, 9, 111, but controversy ’ To whom reprint requests should be addressed: Surgical Service (112), Providence VA Medical Center, Davis Park, Providence, R.I. 02908.
MATERIALS
AND METHODS
Polyurethane prostheses were constructed from biomedical grade elastomeric polyurethane and stainless-steel and/or NITINOL wire frames (Fig. 1). NITINOL is an alloy consisting of nickel and titanium, with shape-
305
0022-4804186 $1 SO Copyright 0 I986 by Academic FESS, Inc. All rigbu of reproduction in any form resewed.
306
JOURNAL OF SURGICAL RESEARCH: VOL. 40, NO. 4, APRIL 1986
FIG. 1. I&alumina1 polyurethane prosthesis in fully expanded form (dimensions: length-8 cm; diameter10 mm).
memory properties. The design of the wire frame allowed the prosthesis to be compressed into a 15 F catheter, and when released from the catheter, the prosthesis expanded back to its original shape. Adult sheep, weighing 50-60 kg, were anesthetized with Surital 750 mg iv, and general endotracheal anesthesia with halothane and O2 was utilized during the operation. Sheep were placed on the operating table with their right side down. A long left-sided paraspinal incision provided a retroperitoneal approach to the abdominal aorta. Following heparinization and aortic clamping, a long aortotomy was made, starting from 1 cm below the level of the renal arteries and ending 1 cm above the aortic bifurcation. All bleeding lumbar arteries were ligated. A 6 X 9 cm knitted Dacron patch was then sewn onto the aortotomy (Fig. 2). Four to six weeks of healing time was allowed prior to transfemoral placement of the intraluminal prosthesis. For placement of the prosthesis, each animal was anesthetized, and the aortic aneurysm was exposed. A femoral cutdown was performed and the prosthesis was introduced
FIG. 2. Abdominal aortic aneurysm model with knitted Dacron patch sewn onto the aorta.
BALK0
ET AL.: INTRALUMINAL
307
PROSTHESIS
through a 15 F catheter to the level of the in excluding the aneurysm from the aorta aneurysm. Proper placement of the prosthesis proper. Postmortem examination demon-
was monitored by palpating the catheter tip at the neck of the aneurysm since fluoroscopy
strated directly that the prosthesis was open and that its two ends were fixed in the aorta
was not available. The catheter was slowly withdrawn, and the prosthesis was ejected so as to extend from just above the aneurysm to the aortic bifur-
above and below the aneurysm (Fig. 3). The polyurethane prosthesis was tested for bursting strength and tolerated static pressures in excess of 300 Torr.
cation. In this short term model the aneurysma1 wall was opened shortly after graft insertion, and the prosthesis and its placement were carefully evaluated. The care and use of animal subjects followed guidelines as established by AAALAC. RESULTS
Three adult sheep had satisfactory placement of the intraluminal prosthesis under direct control. Once the prosthesis expanded within the aneurysm, pulsation of the aneurysm immediately ceased in each case. Pulsation in the iliac arteries indicated the presence of aortic flow through the expanded prosthesis. A laceration was produced in the aneurysmal wall, and no bleeding developed which confirmed the integrity of the prosthesis
DISCUSSION
Our concept of intraluminal aneurysm exclusion seems the least invasive method of treating aneurysms, which makes its application for the high risk patient appealing. Angiographic visualization of the aneurysm would be a requirement both prior to and during insertion of the intraluminal prosthesis. Once dimensions of the aneurysm and suitability of this technique are determined, a properly sized prosthesis would be inserted by the angiographer working together with the vascular surgeon. Besides the high risk group, one could also consider patients who present with a ruptured aneurysm. After initial clamping is achieved, the prosthesis could be inserted in order to avoid further blood loss
FIG. 3. Excised aortic aneurysm which is excluded by the intraluminal
prosthesis.
308
JOURNAL OF SURGICAL RESEARCH: VOL. 40, NO. 4, APRIL 1986
and in order to decrease operating time in the moribund patient. Another indication for this approach could be a situation where an aneurysm was found to be inflammatory at the time of laparotomy, and further dissection deemed imprudent due to the densely adherent small bowel. Indeed, if our approach were to prove feasible in the high risk patients and shown to have a lower morbidity and mortality rate than present techniques, one could extend its use to more routine aneurysms. Abdominal aortic aneurysms smaller than 5 cm could be considered, since they tend to be more localized to the aorta, without iliac involvement, and further growth and rupture of the aneurysm would hopefully be arrested. An autopsy study of unoperated abdominal aortic aneurysms by Darling showed that aneurysms measuring between 4.1 and 5.0 cm had a similar rate of rupture when compared to those measuring between 5.1 and 7.0 cm. In addition, the vast majority of aortic ruptures occurred retroperitoneally, along the dilated portion of the lateral wall; rarely near the neck of the aneurysm or near the bifurcation [4]. A properly positioned intraluminal prosthesis could eliminate the pressure on the aneurysmal lateral walls and prevent subsequent rupture. Although our results demonstrated that insertion of an intraluminal polyurethane prosthesis transfemorally is feasible, there remain many questions and long term considerations. Short and long term biologic interactions between prosthesis and aortic wall need further investigation. Potential adversities include embolization of the gelatinous debris lining the aneurysm during insertion of the prosthesis, migration of the prosthesis, and erosion through the aortic wall. Polyurethane deterioration and calcification have to be studied. One significant disadvantage of using NITINOL is its potential premature expansion inside the catheter, and therefore constant cold saline irrigation is required during insertion. Aortic aneurysms not suitable for this technique would include the following characteristics: (a) renal artery involvement or neck just distal to the renals, (b) patent inferior mes-
enteric artery, (c) presence of iliac aneurysmal disease, and (d) iliac occlusive disease or tortuosity precluding insertion of the catheter. In order to determine whether our technique could be applied to a specific AAA, angiography would be a requirement, with particular attention to the previously mentioned factors. The nonresective management of abdominal aortic aneurysms involves thrombosis of the aneurysm and axillo-bifemoral bypass. Its advantages over the standard treatment in high risk patients include the avoidance of a major laparotomy, general anesthesia, large fluid shifts, and blood loss. Despite several favorable series [ 1, 8, 9, 1 I], others have reported aneurysmal ruptures [2, 7, 10, 121, specifically at the aneurysmal neck. This led Kwaan to adopt the total aneurysm exclusion technique [9]. However, laparotomy is required and partially defeats the original intent of this approach. Several groups have reported the placement of NITINOL coils inside the dog aorta and iliac arteries [3, 51; however, in the process of transforming its shape from a straight wire to a coil, considerable whipping motion occurs and results in endothelial damage with a highly thrombogenic surface. This wire movement would lead to significant embolization, since the human aneurysm is lined with gelatinous debris. On the other hand, the intraluminal prosthesis expands with the NITINOL or stainless steel to a predetermined diameter and would tend to displace the aneurysmal lining laterally, rather than mobilizing it. In summary, our results demonstrate that insertion of an intraluminal polyurethane prosthesis transfemorally is feasible, and that intraluminal aneurysm exclusion can be achieved acutely. Studies are in progress in order to determine the long term effectiveness. This technique may become applicable for treating abdominal aortic aneurysms, especially in high risk patients, since this approach is less invasive than current methods. ACKNOWLEDGMENT The authors thank George T. Donnelly for his expert technical assistance throughout the study.
BALK0
ET AL.: INTRALUMINAL
REFERENCES 1. Berguer, P., Scheider, J., and Wilner, H. I. Induced thrombosis of inoperable abdominal aortic aneurysm. Surgery 84: 425, 1978. 2. Cho, S. I., Johnson, W. C., Bush, M. L., Jr., Widrich, W. C., Muse, J. B., and Nabseth, D. C. Lethal complications associated with nonresective treatment of abdominal aortic aneurysm. Arch. Surg. 117: 1214, 1982. 3. Cragg, A. H., Lund, G., Rysavy, J., Salomonowitz, R., Castaneda-Zuniga, W., and Amplatz, K. Percutaneous arterial grafting. Radiology 150: 45, 1984. 4. Darling, R. C., Messina, C. R., Brewster, D. C., and Ottinger, L. W. Autopsy study of unoperated abdominal aortic aneurysms. Curdiovas. Surg. 56(3): 161, 1977. 5. Dotter, C. T., Buschmann, R. W., McKinney, M. K., and Rosch, J. Transluminal expandable NITINOL coil stent grafting: Preliminary report. Radiology 147: 259, 1983. 6. Gardner, R. J., Gardner, N. L., Tamay, T. J., Warden, H. E., James, E. D., and Watne, A. L. The surgical experience and a one to sixteen year follow-up of 277 abdominal aortic aneurysms. Amer. J. Surg. 135: 226, 1978. 7. Inahara, T., Geary, G. L., Mukhejee, D., and Egan,
8.
9.
10.
11.
12.
13.
PROSTHESIS
309
J. M. The contrary position to the nonresective treatment for abdominal aortic aneurysm. J. Vas. Surg. 2: 42, 1985. Kannody, A. M., Leather, R. P., Goldman, M., Corson, J. D., and Shah, D. M. The current position of nonresective treatment for abdominal aortic aneurysm. Surgery 94: 591, 1983. Kwaan, J. H., Khan, R. J., and Connolly, J. E. Total exclusion technigue for the management of abdominal aortic aneurysm. Amer. J. Surg. 146: 93, 1983. Kwaan, J. H. M., and Dahl, R. K. Fatal rupture after successfulsurgical thrombosis of an abdominal aortic aneurysm. Surgery 95: 235, 1984. Leather, R. P., Shah, D. M., Goldman, M., Rosenberg, M., and Karmody, A. M. Nonresective treatment of abdominal aortic aneurysm. Arch. Surg. 144: 1402, 1979. Schanzer, H., Papa, M. C., and Miller, C. M. Rupture of surgically thrombosed abdominal aortic aneurysm. J. Vas. Surg. 2: 278, 1985. Thompson, J. E., Garrett, W. V., Patman, R. D., Talkington, C. M., and Williams, S. J., III. Elective surgery for abdominal aortic aneurysms. In J. J. Bergan, and Yao, J. S. T. Eds. Aneurysms: Diagnosis and Treatment. New York: Grune & Stratton, 1982. Pp. 287-301.