Anastomotic Aneurysms Following Arterial Grafting: A 10-Year Experience JAMES V. RICHARDSON, M.D., HOLT A. McDOWELL, JR., M.D.
A multi-faceted pathogenesis of vascular anastomotic aneurysms encompassing both the earlier and modern eras of vascular surgery has been proposed. A review of the clinical records of patients with such aneurysms suggests that while silk sutures were an important causative factor in the earlier era, this complication continues to occur with the more recent use of synthetic suture material. Further examination of the data suggests that the location of the anastomosis remains important in the development of these aneurysms. Moreover, operative findings suggest that graft tension, shearing and vibration forces along the suture line and degeneration of the host vessel are the more important causative factors today.
THE DEVELOPMENT of vascular anastomotic aneurysms is one of the most common complications following arterial grafting when prosthetic grafts are used. The approximate incidence ranges from 3 to 24%.5,6,9,12,15 The earlier era of vascular surgery saw the deterioration of silk sutures as the most important causative factor.8 The work of Cutler and Dunphy,4 illustrating engulfment of silk suture fragments by macrophages, provided scientific proof that silk was, therefore, unsuitable as vascular suture material; the use of synthetic material was begun some years later. More recently, disproportion of compliance between synthetic grafts and host artery,13 shearing forces along the anastomotic line,12 vibratory fatigue of the anastomosis,13 the position of the graft and postoperative anticoagulation2 have been implicated as more important causative factors. Whatever the cause(s) of the evolution of these Submitted for publication November 11, 1975. Reprint requests: Holt A. McDowell, Jr., M.D., Department of Surgery, University Station, University ofAlabama Hospitals, Birmingham, Alabama 35294.
From the Department of Surgery, University of Alabama Hospitals, Birmingham, Alabama
aneurysms, all of them appear to begin when blood escapes from the vessel via dehiscence of the suture line.10 The hematoma, to some extent confined by surrounding tissues, then seals the arterial leak and a cup-shaped depression forms as a result of the swirling action of the nearby blood. Endothelialization of the inner surface of the sac from the host artery then occurs.3 The aneurysm, termed a false or pseudoaneurysm by most authors, is then composed of an organized clot, surrounding fibrosis and an inner endothelial lining; it differs from true aneurysms by lacking the outer elements of the arterial
wall.10 Clinical Material The clinical records of all patients with vascular anastomotic aneurysms admitted to the University and Veteran's Administration Hospitals from 1965-1975 were reviewed. Data were obtained concerning original operation performed, type of graft and suture material used and concomitant diseases. In addition, the time interval between the original operation and reoperation for anastomotic aneurysm(s), operative findings, procedure performed at reoperation and eventual results of all patients were reviewed. Case Reports Case 1. A 43-year-old man underwent an aorto-bifemoral by-pass graft (Dacron and silk) for severe peripheral occlusive disease in 1965. He did
179
180
RICHARDSON AND McDOWELL
Ann. Surg.
August
1976
TABLE 1. Clinical Data of Patients With Anastomotic Aneurysms
Patient 1
2
Age/Sex 70/F 69/M
Original Operation A-SG
CE-VP
Concurrent Diseases ASHD
ASHD
Interval Onset (Yrs)
Operative Findings
Operation Performed
Results
10
Proximal suture line dehiscence;
Aorto-BI
8
sutures intact Patch and suture line aneurysm;
Ligation of C.C.
Alive, healthy Alive, well
7
occluded I.C. Patch aneurysm
Tube graft
Alive, well
Bilateral femoral dehiscence; sutures intact Vein patch aneurysm
Interposition graft Dacron patch
Well
Femoral aneurysm, disruption of anastomosis, aneurysm of femoral
Excision of an-
3
77/F
CE-VP
4
61/M
A-BF
ASHD Hypertension ASHD
5
67/M
CE-VP
ASHD, AAA
6
6
59/M
AX-F
AAA, CVI
2
1
artery 7
78/M
A-SG
ASHD
14
8
61/M
A-BF
None
I
9
64/M
A-BF
ASHD
6
Fragmented sutures of proximal suture line Disruption of femoral anastomosis Disruption of femoral anastomosis torn vessel
Expired Ruptured AAA Alive
graft profunda
eurysm,
to
Interposition graft Resuturing of anastomosis Ligation of graft, femoral artery
Alive
Alive Claudication in effected
leg 10
70/M
A-SG
ASHD
8
Disruption of femoral anastomosis torn vessel
11
60/M
F-F
ASHD Hypertension SLE ASHD Hypertension
I
Disruption of suture line, rupture of
12
64/M
13
60/M
14
79/M
A-BF F-P A-BI
A-SG
ASHD
aneurysm 1
4 5 8
Popliteal disruption vessel quite friable Disruption left iliac Proximal aortic and right iliac disruption, vessel torn Total disruption of graft from aorta
Femoro-popliteal bypass excision of aneurysm Ligationresection Resuturing
Alive, viable limb
Alive Alive
Interposition Ruptured aortoduodenal fistula Interposition
Expired Survived
graft 15
64/M
A-BF
Hypertension
4
16
59/M
A-BF
Hypertension
1
17
43/M
A-BF
Hypertension ASHD
7 9 10
18
58/M
A-BF
None
3 8
Partial dehiscence of both femoral Resuturing, interanastomoses; grafts under excessive position graft tension Total disruption of proximal anastomosis Bilateral femoral disruption Interposition Proximal aortic disruption, tears in Interposition vessel graft Bilateral femoral Bilateral femoral anastomotic disruption Bilateral recurrence
19
76/M
FP
Hypertension
0.5
20
64/M
A-BF
7
21
57/M
A-BF
Hypertension ASHD ASHD
Occluded graft, disruption of suture line, tears in vessel, graft under excessive tension Femoral dehiscence, vessel torn
6
Femoral disruption
22 23
70/M 66/M
A-BF A-SG
ASHD None
6 4.5
Partial femoral disruption Proximal aortic dehiscence
Interposition Direct resuturing and followed Ligation of graft, Dacron angioplasty Interposition graft Interposition graft Direct resuturing Interposition graft
Alive
Expired Recurred Alive
Being followed Recurred Stable Viable limb
Alive
Alive Alive Alive
Note: AAA, abdominal aortic aneurysms; A-BF, aorto-bifemoral bypass graft; A-BI, aorto-bi-iliac bypass graft; ASHD, atherosclerotic heart disease; A-SG, aortic straight graft; Ax-F, axillo-femoral bypass graft; CE-VP, carotid endarterectomy with vein patch; CVI, cerebrovascular insufficiency; F-F, femoro-femoral bypass graft; F-P, femoro-popliteal bypass graft; SLE, systemic lupus erythematosis.
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ANASTOMOTIC ANEURYSMS
well until 1974 when he began experiencing severe mid-abdominal pain and a pulsatile mass was palpated in the supraumbilical area. He underwent reoperation for suspected proximal aortic anastomotic aneurysm, at which time a huge false aneurysm, several broken sutures and multiple tears in the aorta were found. A Dacron interposition graft was performed (Prolene® suture), and he recovered after a prolonged ileus. He was seen in followup several months later and large bilateral femoral anastomotic aneurysms were noted. At reoperation, both suture lines were dehisced and interposition grafts were performed between existing grafts and common femoral arteries using Dacron and Proleneg. He has now developed recurrences of both femoral anastomotic aneurysms which are small (1 cm) and asymptomatic. At none of his operations was evidence of infection present and cultures of the aneurysm contents were sterile. Comment: This patient illustrates the role of nonsynthetic suture material, degenerative changes in the host vessel and graft tension in the development of anastomotic aneurysms which, in the case of the femoral aneurysms, has not been corrected by the use of synthetic sutures and lengthening of grafts. Case 2. A 76-year-old man underwent a left femoro-popliteal bypass graft (reversed saphenous vein and Proleneg) in 1975 for severe claudication and rest pain. Six months later, a 4 cm left femoral aneurysm was noted. At operation, the graft was found to be occluded while the sutures were within the vein graft, but dehisced from the artery; the operator noted that the graft was under excessive tension. The graft was ligated and a Dacron patch angioplasty was performed on the common femoral artery. Although he has done well, reports no rest pain and has a viable leg, his severe claudication has retumed. Comments: Anastomotic aneurysms of saphenous vein femoropopliteal grafts are unusual as only two other reports are found in the literature.7"10 This case also illustrates the apparent role of graft position and tension and weakness of the arterial wall in the evolution of such aneurysms.
TABLE 2. Location of Anastomotic Aneurysms
Femoral Proximal aortic Carotid Iliac Popliteal Total
Number of
% of Total
Aneurysms
Aneurysms
21 7 3 2 1 34
61.6 20.4 9.0 6.0 3.0 100.0
the anastomosis or interposition grafts to lengthen the graft (Table 1). Operative results were generally good, although one patient died preoperatively, one died postoperatively of an unrelated problem and there were two patients with recurrent anastomotic aneurysms. Discussion The healing of suture lines between graft and artery occurs by an outer fibrin layering, which is soon replaced by connective tissue, and covering within by a pseudointima. 13,18 The tensile strength of this tissue is quite low; the integrity of the anastomosis is, therefore, dependent on the strength of the suture material. Accordingly, the use of silk sutures has correlated well with the development of anastomotic aneurysms. Indeed, Moore8 reported fragmentation of silk sutures in every case reported in 1970 and cited this as the primary causative factor in his series. The use of synthetic, knitted grafts and synthetic, permanent sutures is therefore imperative, although as seen by our data and others, this complication continues to occur significantly today despite this practice. The relationship between postoperative infection and the development of these aneurysms is definite and inescapable.4 However, many authors19 report significant numbers of nonseptic aneurysms, and in our series, none of the patients had evidence of infection.
Results Twenty-three patients with 34 anastomotic aneurysms serve as the basis for this report (Table 1). There were 21 men and two women in the population studied. The ages ranged from 43 to 80 years with a mean of 65. Eight patients had concurrent hypertension. The original operation performed was aorto-bifemoral bypass in 11 patients, straight aortic graft in 5, carotid endarterectomy with vein patch in 3, femoro-popliteal bypass in two, axillofemoral, aorto-iliac and femoro-femoral bypass in TABLE 3. Graft and Suture Material Associated one case each. The approximate time of onset of With Anastomotic Aneurysms* mean of aneurysm ranged from 6 months to 14 years with a % of % of Number of 5.4 years. There were 5 patients with multiple aneurysms. Number of Cases Grafts Aneurysms Aneurysms Two patients had two aneurysms each, one with three, one with 4 and one with 5 aneurysms. The aneurysms Grafts 73.5 15 62.6 25 were located in the femoral area in 21 cases, proximal Dacron 5 14.7 20.8 5 Teflon aortic area in 7, carotid vein patch in 3, iliac area in two 4 11.8 4 16.6 Vein and popliteal in one case (Table 2). Aneurysms were seen 34 100.0 24 100.0 Total in association with synthetic grafts in 19 patients (30 Sutures aneurysms) and with autogenous vein in 4 cases. Silk 32.4 11 37.5 Silk 9 8 23.6 6 25.0 sutures were used in 9 cases, cotton in one, while Tycrons 20.6 7 20.7 Tevdekg 5 synthetic material was used in the remaining 14 cases 1 2.9 4.2 1 Ethiflexg (Table 3). 1 1 2.9 4.2 Cotton 1 5 14.7 4.2 The predominant operative findings were dehiscence of ProleneS 1 2.9 4.2 1 Dacron the suture line, tears in the host artery and excessive 34 100.0 24 100.0 Total tension at the anastomotic site. The most common reparative procedures
performed were
direct resuturing of
*
Includes recurrent aneurysms.
RICHARDSON AND McDOWELL
Ann. Surg. * August 1976
The location of the graft anastomosis, particularly anastomotic aneurysms. The relationship between faulty across the hip joint, remains a critical factor.4'12'14 The healing of an anastomosis and deterioration of the host accentuation by joint movement, and hence graft motion, vessel, coupled with excessive forces, shearing and of the usual stress forces present in an anastomosis would vibratory, in the evolution of this complication seems certainly seem important. Indeed, over 60% of the inescapable. Secondarily important would seem position aneurysms in our series were in association with grafts of the graft in accentuation of shearing forces and made across joints. postoperative anticoagulation in initiating hematoma The importance of postoperative anticoagulation and formation. With the almost universal use of knitted grafts, the development of these aneurysms has been proposed synthetic sutures, prophylactic antibiotics and the often by Christensen3 and others.9 Fifty per cent of the patients discouraged use of endarterectomy, these factors would in his series were anticoagulated in the first postoperative seem less important today. week. Keeping in mind the initial stages of development of these aneurysms and the inherent imperfections of graft References material, this practice would seem important in the evolution of this complication. Salzman's emphasis on 1. Baird, R. J. and Doran, M. L.: The False Aneurysm. Canad. Med. platelet thrombosis in arterial occlusions being minimally Assoc. J., 91:281, 1964. affected by the use of heparin, coupled with the known 2. Benjamin, H. B., et al.: The Importance of the Vasa Vasorum ofthe Aorta. Surg. Gynecol. Obstet., 110:224, 1960. interference with normal hemostatic mechanisms, makes 3. Christensen, R. D. and Bernatz, P. E.: Anastomotic
this practice seemingly unwise.10 A number of physical factors such as disproportion of compliance between graft and host vessel, vibratory fatigue and shearing forces along the anastomosis apparently play important roles in the development of anastomotic aneurysms. Schultz et al.12 studied graft-artery compliances and found a rather significant disproportion. Such a disproportion could result in unusual stress, shearing forces, on the more compliant, although much weaker, arterial wall. The combination of rigid grafts and shearing forces, amplified by joint and graft motion would certainly seem contributory to unusual stress at an anastomotic site. Vibratory fatigue may also contribute to weakening of the suture line. The older practice of end-to-side anastomosis through a slit arteriotomy was shown by Szilagyi'7 to result in a sharp-edged orifice and diminished, turbulent flow. More importantly, energy and hydraulic gradients drop sharply as blood passes through this orifice and significant force is asserted along all diameters of the conduit and anastomosis. The most common cause of faulty healing of noninfected vascular anastomoses is degeneration of the host vessel.9 Benjamin,2 recognizing the importance of the vasa vasorum in the healing of vascular anastomoses, demonstrated that these vessels arise from branches of the host artery, rather than the lumen, and intimated that injury to these vessels leads to relative ischemia of the suture line and improper healing. Indeed, several studies,12"9 including our own report, show a significant number of arterial wall defects and degeneration of the host artery in association with anastomotic aneurysms. We would, therefore, propose that a combination of factors are of primary importance in the development of
Aneurysms Involving the Femoral Artery. Mayo Clin. Proc., 47:313, 1972. 4. Crawford, E. S., DeBakey, M. E. and Cooley, D. A.: Surgical Considerations of Peripheral Arterial Aneurysms. A.M.A. Arch. Surg., 78:226, 1959. 5. Cutler, E. C. and Dunphy, J. E.: The Use of Silk in Infected Wounds. N. Engl. J. Med., 224:101, 1941. 6. Donovan, T. J. and Bucknam, C. A.: Aortoenteric Fistula. Arch. Surg., 95:810, 1967. 7. Hem, E. and Helsingen, N.: Anastomotic False Aneurysms Following Femoro-popliteal Vein Bypass. Scand. J. Thorac. Cardiovasc. Surg., 8:56, 1974. 8. Moore, W. S. and Hall, A. D.: Late Suture Failure in the Pathogenesis of Anastomotic False Aneurysms. Ann. Surg., 1972:1064, 1970. 9. Olsen, W. R., DeWeese, M. S. and Fry, W. J.: False Aneurysm of Abdominal Aorta. Arch. Surg., 92:123, 1966. 10. Salzman, E. W.: The Limitations of Heparin Therapy after Arterial Reconstruction. Surgery, 57:131, 1965. 11. Sawyers, J. L., Jacobs, J. K. and Sutton, J. P.: Peripheral Anastomotic Aneurysms. Arch. Surg., 95:802, 1967. 12. Schultz, R. D., Hokanson, D. E. and Strandness, D. E., Jr.: Pressure-Flow and Stress-Strain Measurements of Normal and Diseased Aortoiliac Segments. Surg. Gynecol. Obstet., to be published. 13. Smith, R. F. and Szilagyi, D. E.: Healing Complications with Plastic Arterial Implants. Arch. Surg., 82:34, 1961. 14. Spratt, E. M., Doran, M. L. and Baird, R. J.: False Aneurysms in the Lower Extremity. Surg. Gynecol. Obstet., 124:562, 1967. 15. Stoney, R. J., Albo, R. J. and Wylie, E. J.: False Aneurysms Occurring after Arterial Grafting Operations. Am. J. Surg., 110:153, 1965. 16. Sumner, D. S. and Strandness, D. E.: False Aneurysms Occurring in Association with Thrombosed Prosthetic Grafts. Arch. Surg., 94:360, 1967. 17. Szilagyi, D. E., Whitcomb, J. G., Schenker, W. and Waibel, P.: The Laws of Fluid Flow and Arterial Grafting. Surgery, 47:55, 1960. 18. Szilagyi, D. E., Smith, R. F., Elliott, J. P. and Allen, H. M.: Long-Term Behavior of a Dacron Arterial Substitute: Clinical Roentgenologic and Histologic Correlations. Ann. Surg., 162:453, 1965. 19. West, J. P., Lattes, C. and Knox, W. G.: Anastomotic False Aneurysms. Arch. Surg., 103:348, 1971.
A multi-faceted pathogenesis of vascular anastomotic aneurysms encompassing both the earlier and modern eras of vascular surgery has been proposed. A review of the clinical records of patients with such aneurysms suggests that while silk sutures were an important causative factor in the earlier era, this complication continues to occur with the more recent use of synthetic suture material. Further examination of the data suggests that the location of the anastomosis remains important in the development of these aneurysms. Moreover, operative findings suggest that graft tension, shearing and vibration forces along the suture line and degeneration of the host vessel are the more important causative factors today.
THE DEVELOPMENT of vascular anastomotic aneurysms is one of the most common complications following arterial grafting when prosthetic grafts are used. The approximate incidence ranges from 3 to 24%.5,6,9,12,15 The earlier era of vascular surgery saw the deterioration of silk sutures as the most important causative factor.8 The work of Cutler and Dunphy,4 illustrating engulfment of silk suture fragments by macrophages, provided scientific proof that silk was, therefore, unsuitable as vascular suture material; the use of synthetic material was begun some years later. More recently, disproportion of compliance between synthetic grafts and host artery,13 shearing forces along the anastomotic line,12 vibratory fatigue of the anastomosis,13 the position of the graft and postoperative anticoagulation2 have been implicated as more important causative factors. Whatever the cause(s) of the evolution of these Submitted for publication November 11, 1975. Reprint requests: Holt A. McDowell, Jr., M.D., Department of Surgery, University Station, University ofAlabama Hospitals, Birmingham, Alabama 35294.
From the Department of Surgery, University of Alabama Hospitals, Birmingham, Alabama
aneurysms, all of them appear to begin when blood escapes from the vessel via dehiscence of the suture line.10 The hematoma, to some extent confined by surrounding tissues, then seals the arterial leak and a cup-shaped depression forms as a result of the swirling action of the nearby blood. Endothelialization of the inner surface of the sac from the host artery then occurs.3 The aneurysm, termed a false or pseudoaneurysm by most authors, is then composed of an organized clot, surrounding fibrosis and an inner endothelial lining; it differs from true aneurysms by lacking the outer elements of the arterial
wall.10 Clinical Material The clinical records of all patients with vascular anastomotic aneurysms admitted to the University and Veteran's Administration Hospitals from 1965-1975 were reviewed. Data were obtained concerning original operation performed, type of graft and suture material used and concomitant diseases. In addition, the time interval between the original operation and reoperation for anastomotic aneurysm(s), operative findings, procedure performed at reoperation and eventual results of all patients were reviewed. Case Reports Case 1. A 43-year-old man underwent an aorto-bifemoral by-pass graft (Dacron and silk) for severe peripheral occlusive disease in 1965. He did
179
180
RICHARDSON AND McDOWELL
Ann. Surg.
August
1976
TABLE 1. Clinical Data of Patients With Anastomotic Aneurysms
Patient 1
2
Age/Sex 70/F 69/M
Original Operation A-SG
CE-VP
Concurrent Diseases ASHD
ASHD
Interval Onset (Yrs)
Operative Findings
Operation Performed
Results
10
Proximal suture line dehiscence;
Aorto-BI
8
sutures intact Patch and suture line aneurysm;
Ligation of C.C.
Alive, healthy Alive, well
7
occluded I.C. Patch aneurysm
Tube graft
Alive, well
Bilateral femoral dehiscence; sutures intact Vein patch aneurysm
Interposition graft Dacron patch
Well
Femoral aneurysm, disruption of anastomosis, aneurysm of femoral
Excision of an-
3
77/F
CE-VP
4
61/M
A-BF
ASHD Hypertension ASHD
5
67/M
CE-VP
ASHD, AAA
6
6
59/M
AX-F
AAA, CVI
2
1
artery 7
78/M
A-SG
ASHD
14
8
61/M
A-BF
None
I
9
64/M
A-BF
ASHD
6
Fragmented sutures of proximal suture line Disruption of femoral anastomosis Disruption of femoral anastomosis torn vessel
Expired Ruptured AAA Alive
graft profunda
eurysm,
to
Interposition graft Resuturing of anastomosis Ligation of graft, femoral artery
Alive
Alive Claudication in effected
leg 10
70/M
A-SG
ASHD
8
Disruption of femoral anastomosis torn vessel
11
60/M
F-F
ASHD Hypertension SLE ASHD Hypertension
I
Disruption of suture line, rupture of
12
64/M
13
60/M
14
79/M
A-BF F-P A-BI
A-SG
ASHD
aneurysm 1
4 5 8
Popliteal disruption vessel quite friable Disruption left iliac Proximal aortic and right iliac disruption, vessel torn Total disruption of graft from aorta
Femoro-popliteal bypass excision of aneurysm Ligationresection Resuturing
Alive, viable limb
Alive Alive
Interposition Ruptured aortoduodenal fistula Interposition
Expired Survived
graft 15
64/M
A-BF
Hypertension
4
16
59/M
A-BF
Hypertension
1
17
43/M
A-BF
Hypertension ASHD
7 9 10
18
58/M
A-BF
None
3 8
Partial dehiscence of both femoral Resuturing, interanastomoses; grafts under excessive position graft tension Total disruption of proximal anastomosis Bilateral femoral disruption Interposition Proximal aortic disruption, tears in Interposition vessel graft Bilateral femoral Bilateral femoral anastomotic disruption Bilateral recurrence
19
76/M
FP
Hypertension
0.5
20
64/M
A-BF
7
21
57/M
A-BF
Hypertension ASHD ASHD
Occluded graft, disruption of suture line, tears in vessel, graft under excessive tension Femoral dehiscence, vessel torn
6
Femoral disruption
22 23
70/M 66/M
A-BF A-SG
ASHD None
6 4.5
Partial femoral disruption Proximal aortic dehiscence
Interposition Direct resuturing and followed Ligation of graft, Dacron angioplasty Interposition graft Interposition graft Direct resuturing Interposition graft
Alive
Expired Recurred Alive
Being followed Recurred Stable Viable limb
Alive
Alive Alive Alive
Note: AAA, abdominal aortic aneurysms; A-BF, aorto-bifemoral bypass graft; A-BI, aorto-bi-iliac bypass graft; ASHD, atherosclerotic heart disease; A-SG, aortic straight graft; Ax-F, axillo-femoral bypass graft; CE-VP, carotid endarterectomy with vein patch; CVI, cerebrovascular insufficiency; F-F, femoro-femoral bypass graft; F-P, femoro-popliteal bypass graft; SLE, systemic lupus erythematosis.
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ANASTOMOTIC ANEURYSMS
well until 1974 when he began experiencing severe mid-abdominal pain and a pulsatile mass was palpated in the supraumbilical area. He underwent reoperation for suspected proximal aortic anastomotic aneurysm, at which time a huge false aneurysm, several broken sutures and multiple tears in the aorta were found. A Dacron interposition graft was performed (Prolene® suture), and he recovered after a prolonged ileus. He was seen in followup several months later and large bilateral femoral anastomotic aneurysms were noted. At reoperation, both suture lines were dehisced and interposition grafts were performed between existing grafts and common femoral arteries using Dacron and Proleneg. He has now developed recurrences of both femoral anastomotic aneurysms which are small (1 cm) and asymptomatic. At none of his operations was evidence of infection present and cultures of the aneurysm contents were sterile. Comment: This patient illustrates the role of nonsynthetic suture material, degenerative changes in the host vessel and graft tension in the development of anastomotic aneurysms which, in the case of the femoral aneurysms, has not been corrected by the use of synthetic sutures and lengthening of grafts. Case 2. A 76-year-old man underwent a left femoro-popliteal bypass graft (reversed saphenous vein and Proleneg) in 1975 for severe claudication and rest pain. Six months later, a 4 cm left femoral aneurysm was noted. At operation, the graft was found to be occluded while the sutures were within the vein graft, but dehisced from the artery; the operator noted that the graft was under excessive tension. The graft was ligated and a Dacron patch angioplasty was performed on the common femoral artery. Although he has done well, reports no rest pain and has a viable leg, his severe claudication has retumed. Comments: Anastomotic aneurysms of saphenous vein femoropopliteal grafts are unusual as only two other reports are found in the literature.7"10 This case also illustrates the apparent role of graft position and tension and weakness of the arterial wall in the evolution of such aneurysms.
TABLE 2. Location of Anastomotic Aneurysms
Femoral Proximal aortic Carotid Iliac Popliteal Total
Number of
% of Total
Aneurysms
Aneurysms
21 7 3 2 1 34
61.6 20.4 9.0 6.0 3.0 100.0
the anastomosis or interposition grafts to lengthen the graft (Table 1). Operative results were generally good, although one patient died preoperatively, one died postoperatively of an unrelated problem and there were two patients with recurrent anastomotic aneurysms. Discussion The healing of suture lines between graft and artery occurs by an outer fibrin layering, which is soon replaced by connective tissue, and covering within by a pseudointima. 13,18 The tensile strength of this tissue is quite low; the integrity of the anastomosis is, therefore, dependent on the strength of the suture material. Accordingly, the use of silk sutures has correlated well with the development of anastomotic aneurysms. Indeed, Moore8 reported fragmentation of silk sutures in every case reported in 1970 and cited this as the primary causative factor in his series. The use of synthetic, knitted grafts and synthetic, permanent sutures is therefore imperative, although as seen by our data and others, this complication continues to occur significantly today despite this practice. The relationship between postoperative infection and the development of these aneurysms is definite and inescapable.4 However, many authors19 report significant numbers of nonseptic aneurysms, and in our series, none of the patients had evidence of infection.
Results Twenty-three patients with 34 anastomotic aneurysms serve as the basis for this report (Table 1). There were 21 men and two women in the population studied. The ages ranged from 43 to 80 years with a mean of 65. Eight patients had concurrent hypertension. The original operation performed was aorto-bifemoral bypass in 11 patients, straight aortic graft in 5, carotid endarterectomy with vein patch in 3, femoro-popliteal bypass in two, axillofemoral, aorto-iliac and femoro-femoral bypass in TABLE 3. Graft and Suture Material Associated one case each. The approximate time of onset of With Anastomotic Aneurysms* mean of aneurysm ranged from 6 months to 14 years with a % of % of Number of 5.4 years. There were 5 patients with multiple aneurysms. Number of Cases Grafts Aneurysms Aneurysms Two patients had two aneurysms each, one with three, one with 4 and one with 5 aneurysms. The aneurysms Grafts 73.5 15 62.6 25 were located in the femoral area in 21 cases, proximal Dacron 5 14.7 20.8 5 Teflon aortic area in 7, carotid vein patch in 3, iliac area in two 4 11.8 4 16.6 Vein and popliteal in one case (Table 2). Aneurysms were seen 34 100.0 24 100.0 Total in association with synthetic grafts in 19 patients (30 Sutures aneurysms) and with autogenous vein in 4 cases. Silk 32.4 11 37.5 Silk 9 8 23.6 6 25.0 sutures were used in 9 cases, cotton in one, while Tycrons 20.6 7 20.7 Tevdekg 5 synthetic material was used in the remaining 14 cases 1 2.9 4.2 1 Ethiflexg (Table 3). 1 1 2.9 4.2 Cotton 1 5 14.7 4.2 The predominant operative findings were dehiscence of ProleneS 1 2.9 4.2 1 Dacron the suture line, tears in the host artery and excessive 34 100.0 24 100.0 Total tension at the anastomotic site. The most common reparative procedures
performed were
direct resuturing of
*
Includes recurrent aneurysms.
RICHARDSON AND McDOWELL
Ann. Surg. * August 1976
The location of the graft anastomosis, particularly anastomotic aneurysms. The relationship between faulty across the hip joint, remains a critical factor.4'12'14 The healing of an anastomosis and deterioration of the host accentuation by joint movement, and hence graft motion, vessel, coupled with excessive forces, shearing and of the usual stress forces present in an anastomosis would vibratory, in the evolution of this complication seems certainly seem important. Indeed, over 60% of the inescapable. Secondarily important would seem position aneurysms in our series were in association with grafts of the graft in accentuation of shearing forces and made across joints. postoperative anticoagulation in initiating hematoma The importance of postoperative anticoagulation and formation. With the almost universal use of knitted grafts, the development of these aneurysms has been proposed synthetic sutures, prophylactic antibiotics and the often by Christensen3 and others.9 Fifty per cent of the patients discouraged use of endarterectomy, these factors would in his series were anticoagulated in the first postoperative seem less important today. week. Keeping in mind the initial stages of development of these aneurysms and the inherent imperfections of graft References material, this practice would seem important in the evolution of this complication. Salzman's emphasis on 1. Baird, R. J. and Doran, M. L.: The False Aneurysm. Canad. Med. platelet thrombosis in arterial occlusions being minimally Assoc. J., 91:281, 1964. affected by the use of heparin, coupled with the known 2. Benjamin, H. B., et al.: The Importance of the Vasa Vasorum ofthe Aorta. Surg. Gynecol. Obstet., 110:224, 1960. interference with normal hemostatic mechanisms, makes 3. Christensen, R. D. and Bernatz, P. E.: Anastomotic
this practice seemingly unwise.10 A number of physical factors such as disproportion of compliance between graft and host vessel, vibratory fatigue and shearing forces along the anastomosis apparently play important roles in the development of anastomotic aneurysms. Schultz et al.12 studied graft-artery compliances and found a rather significant disproportion. Such a disproportion could result in unusual stress, shearing forces, on the more compliant, although much weaker, arterial wall. The combination of rigid grafts and shearing forces, amplified by joint and graft motion would certainly seem contributory to unusual stress at an anastomotic site. Vibratory fatigue may also contribute to weakening of the suture line. The older practice of end-to-side anastomosis through a slit arteriotomy was shown by Szilagyi'7 to result in a sharp-edged orifice and diminished, turbulent flow. More importantly, energy and hydraulic gradients drop sharply as blood passes through this orifice and significant force is asserted along all diameters of the conduit and anastomosis. The most common cause of faulty healing of noninfected vascular anastomoses is degeneration of the host vessel.9 Benjamin,2 recognizing the importance of the vasa vasorum in the healing of vascular anastomoses, demonstrated that these vessels arise from branches of the host artery, rather than the lumen, and intimated that injury to these vessels leads to relative ischemia of the suture line and improper healing. Indeed, several studies,12"9 including our own report, show a significant number of arterial wall defects and degeneration of the host artery in association with anastomotic aneurysms. We would, therefore, propose that a combination of factors are of primary importance in the development of
Aneurysms Involving the Femoral Artery. Mayo Clin. Proc., 47:313, 1972. 4. Crawford, E. S., DeBakey, M. E. and Cooley, D. A.: Surgical Considerations of Peripheral Arterial Aneurysms. A.M.A. Arch. Surg., 78:226, 1959. 5. Cutler, E. C. and Dunphy, J. E.: The Use of Silk in Infected Wounds. N. Engl. J. Med., 224:101, 1941. 6. Donovan, T. J. and Bucknam, C. A.: Aortoenteric Fistula. Arch. Surg., 95:810, 1967. 7. Hem, E. and Helsingen, N.: Anastomotic False Aneurysms Following Femoro-popliteal Vein Bypass. Scand. J. Thorac. Cardiovasc. Surg., 8:56, 1974. 8. Moore, W. S. and Hall, A. D.: Late Suture Failure in the Pathogenesis of Anastomotic False Aneurysms. Ann. Surg., 1972:1064, 1970. 9. Olsen, W. R., DeWeese, M. S. and Fry, W. J.: False Aneurysm of Abdominal Aorta. Arch. Surg., 92:123, 1966. 10. Salzman, E. W.: The Limitations of Heparin Therapy after Arterial Reconstruction. Surgery, 57:131, 1965. 11. Sawyers, J. L., Jacobs, J. K. and Sutton, J. P.: Peripheral Anastomotic Aneurysms. Arch. Surg., 95:802, 1967. 12. Schultz, R. D., Hokanson, D. E. and Strandness, D. E., Jr.: Pressure-Flow and Stress-Strain Measurements of Normal and Diseased Aortoiliac Segments. Surg. Gynecol. Obstet., to be published. 13. Smith, R. F. and Szilagyi, D. E.: Healing Complications with Plastic Arterial Implants. Arch. Surg., 82:34, 1961. 14. Spratt, E. M., Doran, M. L. and Baird, R. J.: False Aneurysms in the Lower Extremity. Surg. Gynecol. Obstet., 124:562, 1967. 15. Stoney, R. J., Albo, R. J. and Wylie, E. J.: False Aneurysms Occurring after Arterial Grafting Operations. Am. J. Surg., 110:153, 1965. 16. Sumner, D. S. and Strandness, D. E.: False Aneurysms Occurring in Association with Thrombosed Prosthetic Grafts. Arch. Surg., 94:360, 1967. 17. Szilagyi, D. E., Whitcomb, J. G., Schenker, W. and Waibel, P.: The Laws of Fluid Flow and Arterial Grafting. Surgery, 47:55, 1960. 18. Szilagyi, D. E., Smith, R. F., Elliott, J. P. and Allen, H. M.: Long-Term Behavior of a Dacron Arterial Substitute: Clinical Roentgenologic and Histologic Correlations. Ann. Surg., 162:453, 1965. 19. West, J. P., Lattes, C. and Knox, W. G.: Anastomotic False Aneurysms. Arch. Surg., 103:348, 1971.
