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The Effect of Synthetic Wraps on Vascular Suture Lines and Venous Grafts
The Effect of Synthetic Wraps on Vascular Suture Lines and Venous Grafts Yale H. Zimberg, M.D.
V
ascular surgery has gone through many remarkable phases since the pioneering efforts of Carrel and Guthrie [3] at the turn of the century. The need for fine suture material and careful technique was established early. Blood conduits, naturally occurring (autologous and homologous veins and arteries) [2, 7-9, 11, 12, 14, 20-221 and tissue-fabricated (dermal, fascial, and pericardial) [ 18, 191, have received laboratory and clinical trials, with the resulting consensus that autologous arteries and veins are preferable as long-term grafts in the arterial system of man and animals. Since obvious limitations exist in the availability of autologous arterial grafts, venous autografts have received extensive clinical trials [ 121. Although autogenous veins implanted below the inguinal ligament have enjoyed a long functional life, relatively free of degenerative changes, thoracic arterial defects, bridged by autogenous veins, have frequently undergone aneurysmal dilatation [8, 9, 18, 191. The clinical application of synthetic grafts [23, 251 and the development of techniques for extensive endarterectomy [l] in the early 1950’s have, with certain industrial and technical refinements, brought us to the present state of competence in the surgical management of occlusive arterial disease of the aorta and its major branches. Although the choice of graft material or endarterectomy, or both, is not the area for discussion, the suture line and the immediately adjacent vessel do lend themselves to scrutiny and concern. T h e proximal cuff of atherosclerotic or degenerative aorta following aneurysmectomy and synthetic graft replacement is occasionally thin and holds sutures poorly. Early disruption of suture lines and late aneurysm formation or enteric fistulization is occasionally seen due to host tissue disruption, suture fracture, or poor incorporation of the graft into the adjacent host tissue [4].Extensive endarterectomies are also subject to the complicaFrom the Department of Surgery, Medical College of Virginia, and the Surgical Service, McCuire Veterans Adniinistration Hospital, Richmond, Va. Presented at the Fifteenth Annual Meeting of the Southern Thoracic Surgical Association, San Juan, P.R., Nov. 14-16, 1968. Addrcss reprint rcquests to Dr. Zimberg, 5700 Old Richmond Avenue, Richmond, Va. 23226.
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tions of suture line leak and residual wall disruption or aneurysmal dilatation. Vascular suture lines in the host artery, graft to host artery, or endarterectomized vessels have been reinforced with autogenous vein, Dacron and Teflon graft material or mesh' [6, 10, 151, dermis, and fascia lata with reported successes. The procurement of suitable autogenous material for support always poses a problem of additional surgery, time, and sterility. Laboratory and clinical reports and our own experience with poor host incorporation of woven Teflon and Dacron grafts, and occasionally even knitted Dacron [ 161 (especially within the first month), made the use of synthetic graft material undesirable to fill the early and late need of vascular suture line and vessel support. T h e reports of tissue acceptance and incorporation of knitted polypropylene [24] and our own observations of Marlex mesht used within the thorax initiated a laboratory and clinical study of the effect of Marlex mesh wrap on various vascular suture lines and blood vessels. METHODS A N D MATERIALS All animals used in this experiment were non-littermate mongrel dogs of various ages. Fifteen dogs had laparotomy under general anesthesia. T h e infrarenal abdominal aorta was freed and the lumbar vessels were divided from the renal arteries down to the bifurcation of the aorta. T h e aorta was divided in two places approximately 2 cm. apart. T h e aorta was reanastomosed using 5-0 arterial silk. T h e proximal suture line was wrapped with a single layer of Teflon-weave graft material, and the distal anastomosis was wrapped with a single layer of Marlex mesh. Selected animals were sacrificed at specified times from one month to one year following surgery, and the suture line wrapped area and adjacent aorta were observed for host incorporation and support of suture line. Aortograms were obtained on selected animals to confirm the clinical impression of patency. Photographs of the wrapped vessels were made after excision. Photomicrographs of the wrapped areas were made to delineate the histological characteristics of incorporation and support. Six dogs had left thoracotomy with freeing of the thoracic aorta from the subclavian artery to the diaphragm. Selected intercostal vessels were sacrificed to allow three separate 1 cm. transverse incisions in the aorta, separated by approximately 2 cm. T h e incisions were sutured with 5-0 arterial silk. I n each animal the proximal anastomosis was wrapped with Dacron knitted graft material, the middle anastomosis was wrapped with Marlex mesh, and the distal anastomosis was wrapped with Teflon-weave graft material. Selected animals were sacrificed at one month, three months, six months, nine months, and one year to show the difference in host incorporation of the various materials used and the support of the suture line. Photographs and photomicrographs were taken of the wrapped suture lines. Three dogs had a laparotomy, and a 2.5 cm. section of the abdominal aorta was excised with replacement by autogenous inferior vena cava. Suture lines were completed with 5-0 arterial silk, and the venous autograft was wrapped with Marlex mesh (Fig. 1). An additional 3 dogs were treated in like fashion using homologous vena caval grafts to replace the resected aortic segment. Animals in both groups were sacrificed at one year, after arteriograms had been made to test *C. R. Bard, Inc., Murray Hill, N.J. ?No. 1266 Usher's Marlex Mesh, Davol Rubber Co.,Providence, R.I.
342
THE ANNALS OF THORACIC SURGERY
Synthetic Wraps and Vascular Sutures
(-3-
FIG. 1 . Technique of Marlex wrap is shown diagrammatically. Horizontal mattress sutures are placed first to adjust tension; figure-of-eight sutures are then added. Any heavy nonabsorbable suture material may be used.
patency. Gross photographs of the grafted vessels were taken, as were photomicrographs of the wrapped vein and the host aorta. Eight dogs had left thoracotomy, with resection of a 3 cm. segment of the thoracic aorta and replacement by homologous vena cava from non-littermate animals. T h e venous homografts, approximately 3 cm. in length, were wrapped with Marlex mesh. These animals were followed with aortograms at six months and one year. One animal was sacrificed at six months and 3 animals at one year to note the gross characteristics and the histological nature of the Marlexsupported homograft. T h e 4 remaining animals will be sacrificed at 2 years, after aortography to note any further changes i n the homograft. Six dogs had left thoracotomy, with Marlex mesh wrap of a 2 cm. segment of aorta. Three dogs had the adventitia stripped from the area to be covered prior to wrap, and 3 had the aorta wrapped with as little dissection of the vessel as possible. One animal in each group was sacrificed at one week, two weeks, and four weeks. Gross photographs and photomicrographs were used to compare the two groups a n d to indicate the length of time necessary €or Marlex mesh permeation by host tissues. RESULTS
Those animals having abdominal aortic circumferential suture lines demonstrated that Marlex wrap gave an earlier firm support to the suture line than did the Teflon, without interfering with healing. Teflon could easily be peeled off the suture line as late as one year, whereas Marlex was firmly attached at one month. Histological sections showed good fibrous and capillary ingrowth through the Marlex (Fig. 2). T h e Teflon demonstrated no host tissue permeation (Fig. 3). One animal died on the fourteenth postoperative day of disruption of the Tefloncovered suture line. Despite the histological differences, both Marlex- and Tefloncovered suture lines withstood disruption with artificially induced intraluminal pressures as high as 400 mm. Hg. VOL.
7,
NO.
4,
APRIL,
1969
343
ZIMBERG
~
FZG. 2. Host fibrous tissue and capillaries have readiiy permeated the Marlex mesh around the aorta at one year postsurgery. Holes represent Marlex mesh.
Transverse incisions in the thoracic aorta healed with Dacron, Marlex, and Teflon supports. However, the knitted Dacron and the woven Teflon could easily be peeled off the suture line at one year, whereas Marlex was firmly attached at one month (Fig. 4). Histological confirmation of excellent host permeation of Marlex was again noted. Neither woven Dacron (Fig. 5) nor knitted Teflon showed ingrowth of host capillaries or fibrous tissue. Both autogenous (Fig. 6) and homologous vein grafts in the abdominal aorta showed excellent support by Marlex mesh and host tissue at one year. There was no dilatation noted at one year in either group. Endothelization was essentially
FIG. 3. Host tissue has not penetrated the Teflon woven material around the
aorta at one year postsurgery.
344
THE ANNALS OF THORACIC SURGERY
Synthetic Wraps and Vascular Sutures
FIG. 4 . Three transverse sutured incisions in the thoracic aorta, covered with Teflon weave, Marlex mesh, and Dacron knit. T h e Marlex is firmly adherent, but the Teflon and Dacron can easily be peeled ofl.
FIG. 5. Knitted Dacron around sutured aortic incision at one year. Note lack of host tissue penetration of the Dacron.
ZIMBERG
FIG. 6. Marlex-wrapped autogenous vein in abdominal aorta at one year. Marlex is firmly adherent and supports vein wall.
FIG. 7 . Autogenous vein, wrapped with Marlex, shows good host support and preseruation of endothelium and media at one year postgrafting. Holes represent Marlex mesh.
normal in the autograft vein, with good preservation of the media (Fig. 7). Elastic tissue stains confirmed the presence of elastic tissue in the media. Two of the homograft-wrapped veins showed endothelial degeneration, and only one showed preservation or regrowth of some elastic tissue at one year. Of the 8 dogs having Marlex-wrapped homograft veins in the thoracic aorta, all showed patency without dilatation at one year. Three showed definite evidence of graft narrowing due to extensive endothelial degeneration. At six months, the homograft-wrapped vein showed good endothelization adjacent to the suture line, with beginning degeneration in the center (Fig. 8). Simple wrapping of the thoracic aorta, with or without adventitia present, clearly demonstrated that Marlex afforded a firm capillary and fibrous tissuepermeated support of the artery within seven days of application (Figs, 9, 10). DISCUSSION
Although Dacron and Teflon graft and mesh materials have been described as supports for potentially weak vascular suture lines and 346
THE ANNALS OF THORACIC SURGERY
Synthetic Wraps and Vascular Sutures
F I G . 8. Marlex mesh wrap of the aorta-to-homograft anastomosis. Elastic stain shows lack of elastic tissue in the homograft. T h e closest portion of vein t o aorta looks excellent, with good endothelium and media. More distal vein shows some degeneration.
attenuated vessels, our studies would indicate that graft material, whether Teflon or Dacron knit or weave, is not as effective as Marlex mesh in quickly and firmly buttressing an anastomosis or vessel wall. The evidence of capillary and fibrous tissue ingrowth of Marlex mesh
Thoracic aorta one week after having been wrapped with a single layer of Marlex mesh.
FIG. 9.
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FIG. 10. Photomicrograph of a Marlex wrap of the canine thoracic aorta one
week postsurgery. Holes represent Marlex mesh. Note exuberant capillary and fibrous tissue growth into the interstices of the mesh.
within the first week would seem to make Marlex mesh an ideal agent for suture line and blood vessel support. That adventitia is not important in the healing noted would tend to confirm other studies [5] on stripped arteries. Pilot studies on Marlex wrapping of small peripheral vessels have shown that despite the exuberant host tissue response, thrombosis in the wrapped vessel does not occur. T h e tissue reaction seems to be limited to the outer media and adventitia, even in the thinner wrapped veins. The fact that autogenous vein can be well supported in the thorax with Marlex would allow safe use of autograft vein to bridge large vessels if a situation indicated its desirability. Although homograft veins can be incorporated in a Marlex jacket without the potentiality of dilatation in one year, the use of a long homograft vein would seem contraindicated by evidence of early endothelial degeneration and graft narrowing. Marlex, when used as a wrap, should demonstrate the same ability to withstand extrusion in infection as it has shown in abdominal wall repairs [13, 241. Teflon and Dacron graft materials withstand infection poorly, with healing rarely seen before the graft is removed. In the past eight years we have had occasion to wrap weak aortic suture lines with Marlex mesh 12 times. Eight wraps have been used around the proximal abdominal aorta to bifurcation synthetic graft anastomoses, three wraps have been placed around the proximal and distal thoracic anastomoses of a synthetic graft in the thoracic aorta, and one Marlex wrap has been used to support a very questionable suture line following repair of a coarctation in an adult with degeneration of 348
THE ANNALS OF THORACIC SURGERY
Synthetic Wraps and Vascular Sutures
the thoracic aorta. In all cases in which Marlex was used, suture lines have apparently healed well; follow-up for some cases has been as long as five years. SUMMARY
Marlex mesh appears to be an ideal synthetic material to support vascular suture lines in attenuated vessel walls following thromboendarterectomy or injury. T h e Marlex enhances early host permeation and supports the vessel and suture line without thrombogenic properties. T h e mesh can also be used to prevent dilatation of autogenous vein grafts used to replace large vessels, especially in the chest. Although Marlex will support venous homografts in the thorax, the intimal changes of the homograft vein at one year make venous homografts undesirable, even when supported. T h e use of a Marlex wrap to cover a vascular anastomosis of a synthetic graft to a sclerotic or degenerated aorta may prevent the complications of early disruption and late false aneurysm development or enteric fistulization. REFERENCES 1. Barker, W. F., Cannon, J. A., Zeldis, L. I., and Ah'Tye, P. Anatomical results of endarterectomy. Surg. Forum 6:266, 1955. 2. Barner, H. B., DeWeese, J. A., and Schenk, E. A. Fresh and frozen homologous venous grafts for arterial repair. Angiology 17:389, 1966. 3. Carrel, A., and Guthrie, C. C. Uniterminal and biterminal venous transplantations. Surg. Gynec. Obstet. 2:266, 1906. 4. Cohn, R., and Angell, W. W. Late complications from plastic replacement of aortic abdominal aneurysms. Arch. Surg. (Chicago) 97:696, 1968. 5. Dahl, E. V., Edwards, E. C., Grindley, J. H., and Edwards, J. E. Effect of removal of adventitia from arteries: An experimental study. Surgery 50:533, 1961. 6. Derrick, J. R. A technique of attaching a synthetic graft to the side of a severely arteriosclerotic aorta. Surgery 50:782, 1961. 7. Halpert, B., De Bakey, M. E., Jordan, G. L., and Henly, W. S. The fate of homografts and prostheses of the human aorta. Surg. Gynec. Obstet. 111:659, 1960. 8. Jesseph, J. E., Jones, T. W., Sauvage, L. R., Kanar, E. A., Nyhus, L. M., and Harkins, H. N. Five-year observations on unsupported fresh venous grafts of the aorta in dogs. Surg. Gynec. Obstet. 107:623, 1958. 9. Johnson, J., Kirby, C. K., Greifenstein, F. E., and Castillo, A. The experimental and clinical use of vein grafts to replace defects of large arteries. Surgery 26:945, 1949. 10. Krippaehne, W. W., Vetto, R. M., and Fletcher, W. S. Mesh wrapping in the treatment of abdominal aortic aneurysms: A preliminary report. Amer. Surg. 34:470, 1968. 11. Meade, J. W., Linton, R. R., Darling, C. R., and Menendez, C. V. Arterial homografts. Arch. Surg. (Chicago) 93:392, 1966. 12. Nunn, D. B., Chun, B., Whelan, T. J., Jr., and Martins, A. N. Autogenous veins as arterial substitutes. Ann. Surg. 160: 14, 1964. VOL.
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4,
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ZIMBERG 13. Ochsner, J. L. Marlex mesh, the surgeon’s friend. Surgery 57:343, 1965. 14. Peni, L. I., and Husni, E. A. A comparative study of autogenous vein and Dacron patch grafts in the dog. Arch. Surg. (Chicago) 96:369, 1968. 15. Peters, R. M., and Johnson, G., Jr. The surgeon at work. Surg. Gynec. Obstet. 117:363, 1963. 16. Romanoff, H., and Moran, E. The fate of arteriotomy patches of Dacron. AngioZogy 17:56, 1966. 17. Rutledge, R. H., and Cagle, J. E. Vein wrap for blowout in endarterectomized carotid artery. Arch. Surg. (Chicago) 92:94, 1966. 18. Sako, Y. Prevention of dilatation in autogenous venous and pericardial grafts in the thoracic aorta. Surgery 30:148, 1951. 19. Sako, Y., and Varco, R. L. Ten-year observations on autologous pericardial and venous grafts in the thoracic aorta. Surgery 51:465, 1962. 20. Sauvage, L. R., and Harkins, H. N. Experimental vascular grafts: An evaluation relating to types, means of preservation, and methods of suture in the growing pig. Surgery 33:587, 1953. 21. Schloss, G., and Shumacker, H. B., Jr. Studies in vascular repair: IV. T h e use of free vascular transplants for bridging arterial defects. An historical review with particular reference to histological observations. Yale J . Biol. M e d . 22:273, 1950. 22. Szilagyi, D. E., McDonald, R. T., Smith, R. F., and Whitcomb, J. G. Biologic fate of human arterial homografts. A . M . A . Arch. Surg. 75:506, 1957. 23. 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. 24. Usher, F. C. Hernia repair with knitted polypropylene mesh. Surg. Gynec. Obstet. 117:239, 1963. 25. Wesolowski, S. A. The healing of vascular prostheses. Surgery 57:319, 1965.
350
THE ANNALS OF THORACIC SURGERY
V
ascular surgery has gone through many remarkable phases since the pioneering efforts of Carrel and Guthrie [3] at the turn of the century. The need for fine suture material and careful technique was established early. Blood conduits, naturally occurring (autologous and homologous veins and arteries) [2, 7-9, 11, 12, 14, 20-221 and tissue-fabricated (dermal, fascial, and pericardial) [ 18, 191, have received laboratory and clinical trials, with the resulting consensus that autologous arteries and veins are preferable as long-term grafts in the arterial system of man and animals. Since obvious limitations exist in the availability of autologous arterial grafts, venous autografts have received extensive clinical trials [ 121. Although autogenous veins implanted below the inguinal ligament have enjoyed a long functional life, relatively free of degenerative changes, thoracic arterial defects, bridged by autogenous veins, have frequently undergone aneurysmal dilatation [8, 9, 18, 191. The clinical application of synthetic grafts [23, 251 and the development of techniques for extensive endarterectomy [l] in the early 1950’s have, with certain industrial and technical refinements, brought us to the present state of competence in the surgical management of occlusive arterial disease of the aorta and its major branches. Although the choice of graft material or endarterectomy, or both, is not the area for discussion, the suture line and the immediately adjacent vessel do lend themselves to scrutiny and concern. T h e proximal cuff of atherosclerotic or degenerative aorta following aneurysmectomy and synthetic graft replacement is occasionally thin and holds sutures poorly. Early disruption of suture lines and late aneurysm formation or enteric fistulization is occasionally seen due to host tissue disruption, suture fracture, or poor incorporation of the graft into the adjacent host tissue [4].Extensive endarterectomies are also subject to the complicaFrom the Department of Surgery, Medical College of Virginia, and the Surgical Service, McCuire Veterans Adniinistration Hospital, Richmond, Va. Presented at the Fifteenth Annual Meeting of the Southern Thoracic Surgical Association, San Juan, P.R., Nov. 14-16, 1968. Addrcss reprint rcquests to Dr. Zimberg, 5700 Old Richmond Avenue, Richmond, Va. 23226.
VOL.
7,
NO.
4, APRIL, 1969
341
ZIMBERG
tions of suture line leak and residual wall disruption or aneurysmal dilatation. Vascular suture lines in the host artery, graft to host artery, or endarterectomized vessels have been reinforced with autogenous vein, Dacron and Teflon graft material or mesh' [6, 10, 151, dermis, and fascia lata with reported successes. The procurement of suitable autogenous material for support always poses a problem of additional surgery, time, and sterility. Laboratory and clinical reports and our own experience with poor host incorporation of woven Teflon and Dacron grafts, and occasionally even knitted Dacron [ 161 (especially within the first month), made the use of synthetic graft material undesirable to fill the early and late need of vascular suture line and vessel support. T h e reports of tissue acceptance and incorporation of knitted polypropylene [24] and our own observations of Marlex mesht used within the thorax initiated a laboratory and clinical study of the effect of Marlex mesh wrap on various vascular suture lines and blood vessels. METHODS A N D MATERIALS All animals used in this experiment were non-littermate mongrel dogs of various ages. Fifteen dogs had laparotomy under general anesthesia. T h e infrarenal abdominal aorta was freed and the lumbar vessels were divided from the renal arteries down to the bifurcation of the aorta. T h e aorta was divided in two places approximately 2 cm. apart. T h e aorta was reanastomosed using 5-0 arterial silk. T h e proximal suture line was wrapped with a single layer of Teflon-weave graft material, and the distal anastomosis was wrapped with a single layer of Marlex mesh. Selected animals were sacrificed at specified times from one month to one year following surgery, and the suture line wrapped area and adjacent aorta were observed for host incorporation and support of suture line. Aortograms were obtained on selected animals to confirm the clinical impression of patency. Photographs of the wrapped vessels were made after excision. Photomicrographs of the wrapped areas were made to delineate the histological characteristics of incorporation and support. Six dogs had left thoracotomy with freeing of the thoracic aorta from the subclavian artery to the diaphragm. Selected intercostal vessels were sacrificed to allow three separate 1 cm. transverse incisions in the aorta, separated by approximately 2 cm. T h e incisions were sutured with 5-0 arterial silk. I n each animal the proximal anastomosis was wrapped with Dacron knitted graft material, the middle anastomosis was wrapped with Marlex mesh, and the distal anastomosis was wrapped with Teflon-weave graft material. Selected animals were sacrificed at one month, three months, six months, nine months, and one year to show the difference in host incorporation of the various materials used and the support of the suture line. Photographs and photomicrographs were taken of the wrapped suture lines. Three dogs had a laparotomy, and a 2.5 cm. section of the abdominal aorta was excised with replacement by autogenous inferior vena cava. Suture lines were completed with 5-0 arterial silk, and the venous autograft was wrapped with Marlex mesh (Fig. 1). An additional 3 dogs were treated in like fashion using homologous vena caval grafts to replace the resected aortic segment. Animals in both groups were sacrificed at one year, after arteriograms had been made to test *C. R. Bard, Inc., Murray Hill, N.J. ?No. 1266 Usher's Marlex Mesh, Davol Rubber Co.,Providence, R.I.
342
THE ANNALS OF THORACIC SURGERY
Synthetic Wraps and Vascular Sutures
(-3-
FIG. 1 . Technique of Marlex wrap is shown diagrammatically. Horizontal mattress sutures are placed first to adjust tension; figure-of-eight sutures are then added. Any heavy nonabsorbable suture material may be used.
patency. Gross photographs of the grafted vessels were taken, as were photomicrographs of the wrapped vein and the host aorta. Eight dogs had left thoracotomy, with resection of a 3 cm. segment of the thoracic aorta and replacement by homologous vena cava from non-littermate animals. T h e venous homografts, approximately 3 cm. in length, were wrapped with Marlex mesh. These animals were followed with aortograms at six months and one year. One animal was sacrificed at six months and 3 animals at one year to note the gross characteristics and the histological nature of the Marlexsupported homograft. T h e 4 remaining animals will be sacrificed at 2 years, after aortography to note any further changes i n the homograft. Six dogs had left thoracotomy, with Marlex mesh wrap of a 2 cm. segment of aorta. Three dogs had the adventitia stripped from the area to be covered prior to wrap, and 3 had the aorta wrapped with as little dissection of the vessel as possible. One animal in each group was sacrificed at one week, two weeks, and four weeks. Gross photographs and photomicrographs were used to compare the two groups a n d to indicate the length of time necessary €or Marlex mesh permeation by host tissues. RESULTS
Those animals having abdominal aortic circumferential suture lines demonstrated that Marlex wrap gave an earlier firm support to the suture line than did the Teflon, without interfering with healing. Teflon could easily be peeled off the suture line as late as one year, whereas Marlex was firmly attached at one month. Histological sections showed good fibrous and capillary ingrowth through the Marlex (Fig. 2). T h e Teflon demonstrated no host tissue permeation (Fig. 3). One animal died on the fourteenth postoperative day of disruption of the Tefloncovered suture line. Despite the histological differences, both Marlex- and Tefloncovered suture lines withstood disruption with artificially induced intraluminal pressures as high as 400 mm. Hg. VOL.
7,
NO.
4,
APRIL,
1969
343
ZIMBERG
~
FZG. 2. Host fibrous tissue and capillaries have readiiy permeated the Marlex mesh around the aorta at one year postsurgery. Holes represent Marlex mesh.
Transverse incisions in the thoracic aorta healed with Dacron, Marlex, and Teflon supports. However, the knitted Dacron and the woven Teflon could easily be peeled off the suture line at one year, whereas Marlex was firmly attached at one month (Fig. 4). Histological confirmation of excellent host permeation of Marlex was again noted. Neither woven Dacron (Fig. 5) nor knitted Teflon showed ingrowth of host capillaries or fibrous tissue. Both autogenous (Fig. 6) and homologous vein grafts in the abdominal aorta showed excellent support by Marlex mesh and host tissue at one year. There was no dilatation noted at one year in either group. Endothelization was essentially
FIG. 3. Host tissue has not penetrated the Teflon woven material around the
aorta at one year postsurgery.
344
THE ANNALS OF THORACIC SURGERY
Synthetic Wraps and Vascular Sutures
FIG. 4 . Three transverse sutured incisions in the thoracic aorta, covered with Teflon weave, Marlex mesh, and Dacron knit. T h e Marlex is firmly adherent, but the Teflon and Dacron can easily be peeled ofl.
FIG. 5. Knitted Dacron around sutured aortic incision at one year. Note lack of host tissue penetration of the Dacron.
ZIMBERG
FIG. 6. Marlex-wrapped autogenous vein in abdominal aorta at one year. Marlex is firmly adherent and supports vein wall.
FIG. 7 . Autogenous vein, wrapped with Marlex, shows good host support and preseruation of endothelium and media at one year postgrafting. Holes represent Marlex mesh.
normal in the autograft vein, with good preservation of the media (Fig. 7). Elastic tissue stains confirmed the presence of elastic tissue in the media. Two of the homograft-wrapped veins showed endothelial degeneration, and only one showed preservation or regrowth of some elastic tissue at one year. Of the 8 dogs having Marlex-wrapped homograft veins in the thoracic aorta, all showed patency without dilatation at one year. Three showed definite evidence of graft narrowing due to extensive endothelial degeneration. At six months, the homograft-wrapped vein showed good endothelization adjacent to the suture line, with beginning degeneration in the center (Fig. 8). Simple wrapping of the thoracic aorta, with or without adventitia present, clearly demonstrated that Marlex afforded a firm capillary and fibrous tissuepermeated support of the artery within seven days of application (Figs, 9, 10). DISCUSSION
Although Dacron and Teflon graft and mesh materials have been described as supports for potentially weak vascular suture lines and 346
THE ANNALS OF THORACIC SURGERY
Synthetic Wraps and Vascular Sutures
F I G . 8. Marlex mesh wrap of the aorta-to-homograft anastomosis. Elastic stain shows lack of elastic tissue in the homograft. T h e closest portion of vein t o aorta looks excellent, with good endothelium and media. More distal vein shows some degeneration.
attenuated vessels, our studies would indicate that graft material, whether Teflon or Dacron knit or weave, is not as effective as Marlex mesh in quickly and firmly buttressing an anastomosis or vessel wall. The evidence of capillary and fibrous tissue ingrowth of Marlex mesh
Thoracic aorta one week after having been wrapped with a single layer of Marlex mesh.
FIG. 9.
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FIG. 10. Photomicrograph of a Marlex wrap of the canine thoracic aorta one
week postsurgery. Holes represent Marlex mesh. Note exuberant capillary and fibrous tissue growth into the interstices of the mesh.
within the first week would seem to make Marlex mesh an ideal agent for suture line and blood vessel support. That adventitia is not important in the healing noted would tend to confirm other studies [5] on stripped arteries. Pilot studies on Marlex wrapping of small peripheral vessels have shown that despite the exuberant host tissue response, thrombosis in the wrapped vessel does not occur. T h e tissue reaction seems to be limited to the outer media and adventitia, even in the thinner wrapped veins. The fact that autogenous vein can be well supported in the thorax with Marlex would allow safe use of autograft vein to bridge large vessels if a situation indicated its desirability. Although homograft veins can be incorporated in a Marlex jacket without the potentiality of dilatation in one year, the use of a long homograft vein would seem contraindicated by evidence of early endothelial degeneration and graft narrowing. Marlex, when used as a wrap, should demonstrate the same ability to withstand extrusion in infection as it has shown in abdominal wall repairs [13, 241. Teflon and Dacron graft materials withstand infection poorly, with healing rarely seen before the graft is removed. In the past eight years we have had occasion to wrap weak aortic suture lines with Marlex mesh 12 times. Eight wraps have been used around the proximal abdominal aorta to bifurcation synthetic graft anastomoses, three wraps have been placed around the proximal and distal thoracic anastomoses of a synthetic graft in the thoracic aorta, and one Marlex wrap has been used to support a very questionable suture line following repair of a coarctation in an adult with degeneration of 348
THE ANNALS OF THORACIC SURGERY
Synthetic Wraps and Vascular Sutures
the thoracic aorta. In all cases in which Marlex was used, suture lines have apparently healed well; follow-up for some cases has been as long as five years. SUMMARY
Marlex mesh appears to be an ideal synthetic material to support vascular suture lines in attenuated vessel walls following thromboendarterectomy or injury. T h e Marlex enhances early host permeation and supports the vessel and suture line without thrombogenic properties. T h e mesh can also be used to prevent dilatation of autogenous vein grafts used to replace large vessels, especially in the chest. Although Marlex will support venous homografts in the thorax, the intimal changes of the homograft vein at one year make venous homografts undesirable, even when supported. T h e use of a Marlex wrap to cover a vascular anastomosis of a synthetic graft to a sclerotic or degenerated aorta may prevent the complications of early disruption and late false aneurysm development or enteric fistulization. REFERENCES 1. Barker, W. F., Cannon, J. A., Zeldis, L. I., and Ah'Tye, P. Anatomical results of endarterectomy. Surg. Forum 6:266, 1955. 2. Barner, H. B., DeWeese, J. A., and Schenk, E. A. Fresh and frozen homologous venous grafts for arterial repair. Angiology 17:389, 1966. 3. Carrel, A., and Guthrie, C. C. Uniterminal and biterminal venous transplantations. Surg. Gynec. Obstet. 2:266, 1906. 4. Cohn, R., and Angell, W. W. Late complications from plastic replacement of aortic abdominal aneurysms. Arch. Surg. (Chicago) 97:696, 1968. 5. Dahl, E. V., Edwards, E. C., Grindley, J. H., and Edwards, J. E. Effect of removal of adventitia from arteries: An experimental study. Surgery 50:533, 1961. 6. Derrick, J. R. A technique of attaching a synthetic graft to the side of a severely arteriosclerotic aorta. Surgery 50:782, 1961. 7. Halpert, B., De Bakey, M. E., Jordan, G. L., and Henly, W. S. The fate of homografts and prostheses of the human aorta. Surg. Gynec. Obstet. 111:659, 1960. 8. Jesseph, J. E., Jones, T. W., Sauvage, L. R., Kanar, E. A., Nyhus, L. M., and Harkins, H. N. Five-year observations on unsupported fresh venous grafts of the aorta in dogs. Surg. Gynec. Obstet. 107:623, 1958. 9. Johnson, J., Kirby, C. K., Greifenstein, F. E., and Castillo, A. The experimental and clinical use of vein grafts to replace defects of large arteries. Surgery 26:945, 1949. 10. Krippaehne, W. W., Vetto, R. M., and Fletcher, W. S. Mesh wrapping in the treatment of abdominal aortic aneurysms: A preliminary report. Amer. Surg. 34:470, 1968. 11. Meade, J. W., Linton, R. R., Darling, C. R., and Menendez, C. V. Arterial homografts. Arch. Surg. (Chicago) 93:392, 1966. 12. Nunn, D. B., Chun, B., Whelan, T. J., Jr., and Martins, A. N. Autogenous veins as arterial substitutes. Ann. Surg. 160: 14, 1964. VOL.
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THE ANNALS OF THORACIC SURGERY