Surgical Treatment of ortic Dissection: pplication of Ivalon Sponge to the Dissected Lumen Tatsuzo Tanabe, M.D., Masahito Hashimoto, M.D., Keisuke Sakai, M.D., Keishu Yasuda, M.D., Tetsuro Takeoka, M.D., Osamu Matsunami, M.D., Makoto Sakuma, M.D., and Toshihiro Gohda, M.D. STRCT With canine disease models for aortic dissection, we performed comparative evaluations of several surgical procedures for the management of this dissection. From these experimental procedures, we developed a new operative technique, the Ivalon sponge occlusion method, designed to promote thrombus formation and to mesh (organize) effectively with the tissue ingrowth of the peripheral dilated, dissected aortic lumen. The details of the technique are described. It has been used successfully in 12 patients with Deakey type I and type I11 aortic dissection. ased on our experimental and clinical evaluations, although the results are preliminary, we believe this operative technique is a simple, effective approach for the management of extended aortic dissection. Dissecting aneurysm of the aorta has been recognized as a life-threatening cardiovascular disease because of rupture of the aorta with ischemic occlusion of the main arterial branches. lthough various operative techniques have been introduced, surgical treatment of this disease is still considered most difficult because of the complexity of the disease and the structural destruction of the aorta. We have performed basic studies using experimental disease models in dogs and have analyzed the results of these experiences. From these studies, a new and relatively simple technique has been developed. The technique is called the Ivalon sponge occlusion method and has been employed successfully in 12 patients since July, 1982. Materials and Method Experimental Studies It is difficult to create a naturally developed dissection based on medical degeneration of the aorta in dogs. Thus, we [l] modified the method of lanton and associates [la] to create a surgical dissection in the canine aorta. The model, the prognosis of acute aortic dissection, and the development of aortic dilation or rupture of aneurysms from chronic dissection have been described previously [2]. We studied the details of various surgical techniques (3-51 and the results of drug therapy using these experimental disease models. From the Second Department of Surgery, Hokkaido University School of Medicine, Sapporo, Japan. ccepted for publication Mar 29, 1985. ddress reprint requests to Dr. Tanabe, Hokkaido University Hospital, Kita 14, Nishi 5, Sapporo, Japan 060. Our review of the experimental studies suggested that suture closure of the entry immediately after creation of the dissection could be a radical procedure resulting in thrombus formation and healing of the dissected lumen. However, constant occlusion of the dissected lumen could not be achieved in the chronic stage of the model with application of the various reported operative techniques. It seemed that other procedures for closure of the extended dissected lumen were necessary to heal the aortic dissection in the chronic stage. We decided to try to inject or insert various thrombogenic materials into the dissected lumen to promote thrombus formation. It is well known that the Ivalon sponge has unique Fig 1. Sticks of lvalon sponge: (top) original size of prepared sponge; (middle) compressed, molding sponge; (lower) sponge expanded by contact with blood (measurement in cm). Fig 2. t autopsy, the dissected lumen was filled with thrombosed lvalon sponge at two weeks postoperatively (measurement in cm). 169 nn Thorac Surg 41:169-175, Feb 1986
170 The nnals of Thoracic Surgery Vol 41 No 2 February 1986 Fig 3. t histological examination, complete organization had occurred throughout the dissected lumen with Zvalon sponge at 3 months postoperatively. compressibility, flexibility, moldability, and tissue ingrowth into the body. ecause of these properties, we inserted a piece of Ivalon sponge into the dissected lumen. The sponge, corresponding to the length and width of the dissected lumen, was compressed into a small, sticklike shape for easy insertion (Fig 1). The stick was placed into the dissected lumen, which had been incised for closure of the entry toward the periphery, thus preventing reflux bleeding. The compressed Ivalon sponge expanded immediately on contact with blood and filled the dissected lumen. thrombus formed Summary of Results Obtained with Ivalon Sponge Occlusion Method Patient No., Type of ge (Y4t Dissection Follow-up Sex (Deakey) (mo) Results 1. 49, F I 27 Good; slight neurological sequelae 2. 56, M I 21 Excellent 3. 60, M IIIb 33 Excellent 4. 60, M IIIb 31 Excellent 5. 61, F IIIa 21 Excellent 6. 61, M 11% 17 Fair 7. 64, M 11% 4 Renal failure; died 8. 44, M 11% 19 Good; renal failure 9. 50, M IIIb 14 Excellent 10. 65, M IIIb 11 Excellent 11. 69, M 11% 8 Excellent 12. 48, M IIIb 4 Excellent around the sponge, and subsequent growth of connective tissues was expected to surround the sponge and mesh completely with the dissected lumen. Using 20 dogs in the chronic stage of the experimental model, we inserted a strip of Ivalon sponge and closed the entry of the lumen with sutures. utopsies were performed two weeks, 1 month, and 3 months postoperatively. The dissected lumen was filled with thrombosed Ivalon sponge at two weeks postoperatively (Fig 2). The thrombosed sponge adhered to the wall of the dissected lumen at 1 month postoperatively. Complete organization and obstruction occurred throughout the dissected lumen with the Ivalon sponge by 3 months postoperatively (Fig 3). No apparent complications or drawbacks of this procedure, such as destruction of blood cells, infection, destructive changes in the entire aortic wall, or damage to liver or kidney function, were evident throughout the observation periods. We considered that the rationale for the procedure was confirmed by the satisfactory results obtained from these studies. Clinical Experience On the basis of our successful experimental studies, we used the Ivalon sponge occlusion method in 12 patients with aortic dissection. OPERTION FOR DEKEY TYPE I ORTIC DISSECTION. fter median sternotomy, standard cardiopulmonary bypass was instituted. With the aorta clamped proximal to the innominate artery, the dilated aorta containing the entry was opened. When the entry was small and lineal, it was closed with sutures. When the entry was large and complex, patch closure or graft replacement of the involved aorta was accomplished using a low-porosity, veri-soft Dacron graft. If prolapse of the aortic valve was found, the valve was resuspended with pledgeted sutures.
171 Tanabe et al: Ivalon Sponge as Treatment of ortic Dissection Fig 4. (Patient 2.) Computed tomographic scans with contrast infusion, Deakey type 1: () preoperative scan at a level of the thoracic aorta and () postoperative scan. (TL = true lumen; DL = dissected lumen; IT = intraluminul thrombus.) Fig 5. (Patient 3.) Computed tomographic scans with contrast infusion, Deakey type Illb: () preoperative scan at a level of the thoracic aorta and () postoperative scan. (TL = true lumen; DL = dissected lumen; IT = intraluminal thrombus.) The proximal and distal aortic stumps were oversewn as follows: 2-0 Ti-Cron sutures with pledgets were passed from the inside of the true aortic lumen through the Teflon felt inserted into the dissected lumen and through the Teflon felt attached on the outside of the dissected wall. When the sutures were ligated about halfway around the distal aorta, extracorporeal circulation was temporarily suspended for about a minute. stick of Ivalon sponge, 1 cm wide and 30 cm long, was inserted into the distal portion of the dissected lumen. The circulation was then resumed. fter approximation of the aortic stumps, a graft was secured and both stumps were sutured with a continuous suture. Complete hemostasis at the sutured portion was observed at completion. OPERTION FOR DEKEY TYPE 111 ORTIC DISSECTION. The descending thoracic aorta was exposed through a left posterolateral thoracotomy. vinyl chloride shunt tube was placed between the left subclavian artery and the left common femoral artery for temporary aortic bypass. The aorta was clamped, and the dissected lumen was opened to find the entry of the dissection. This incision, including the entry, was carefully closed in the following manner: 2-0 Ti-Cron sutures with pledgets were passed from the inside of the true aortic lumen through the Teflon felt inserted into the dissected lumen and the Teflon felt attached on the outside of the dissected wall. efore these sutures were ligated, the strip of Ivalon sponge, 1 cm wide and 20 cm long, was in-
172 The nnals of Thoracic Surgery Vol 41 No 2 February 1986 C Fig 6. (Patient 2.) Repeated uortogrurns, Deakey type I: () preoperative uortogrum; () postoperative aortogram made at 1 month; and (0 postoperative aortogram at one yeur. serted into the distal dissected lumen while the distal aortic clamp was temporarily released. ll sutures were then ligated. Results The 10 men and 2 women in the clinical study ranged in age from 44 to 69 years. The aortic dissection was a type I in 2 patients, type IIIa in 1 patient, and type IIIb in 9 patients. ll patients were hospitalized in the acute stage of dissection. complete aortogram was obtained to reveal the exact site of entry and reentry, the circulation of the arterial branches, and the precise configuration of the dissected lumen. summary of the operative results is shown in the Table. There were no hospital deaths, and the postoperative course was satisfactory in most patients. Two patients whose renal function was impaired prior to the operation required hemodialysis postoperatively. One of them died of renal failure 4 months following the operation. Immediately after the operation, 1 patient had an episode of disseminated intravascular coagulation and slight neurological sequelae related to the technique of cardiopulmonary bypass, but currently is taking no medication. ortography at about 1 month postoperatively revealed complete disappearance of the dissected lumen of the thoracic aorta in all but 1 patient in whom the entry closed incompletely. The patients have been followed carefully with periodic repeat computed tomographic (CT) imaging and aortography (Figs 4-7). Long-term follow-up (average, 18 months) has been gratifying, and there have been no late deaths. lthough most of the dissections extending
173 Tanabe et al: Ivalon Sponge as Treatment of ortic Dissection Fig 7. (Patient 3.) Repeat aortograms, Deakey type Illb: () preoperative aortogram; () postoperative aortogram made at I month; and (C) postoperative aortograrn made at two years. into the abdominal aorta were not treated with insertion of the Ivalon sponge, gradual occlusion and disappearance of the dissected lumen were observed during follow-up (Fig 8). No disturbance of the main arterial blood supply, such as paraplegia or abdominal ischemia, was observed. We believe the effectiveness of the operative procedure was confirmed. Comment Surgical treatment of dissecting aneurysm was introduced by Deakey and co-workers [6, 71. Despite extensive efforts, however, satisfactory operative results have been difficult to obtain because of the relatively high incidence of postoperative complications, such as heart failure, renal failure, bleeding from anastomotic C suture lines, and rupture of the remaining dissected lumen. Various new operative techniques have been introduced, such as closure of the entry with sutures, insertion of a ringed vascular prosthesis [3, 41, wrapping of mesh around the dissected aorta, thromboexclusion with bypass flow reversal [5], and replacement of the entire dissected aorta. Using experimental disease models of dogs, we performed extensive basic studies on each modified technique. The results of these studies showed that every technique had advantages and disadvantages. In our past clinical experience involving 30 patients with dissecting aneurysm, we also employed these techniques. In general, however, the operative results were not favorable because of bleeding from anastomotic suture lines, and persistence or dilatation of the remaining dissected lumen [2]. Furthermore, the outcome after operative repair of aortic dissection is not clear [8-111. Several reports indicate that a double aortic lumen persists for a long time
174 The nnals of Thoracic Surgery Vol 41 No 2 February 1986 Type I Type IIIb Patients 1 and 2 Patients 3,4, 7-12 Patient 6 Patient 5 Fig 8. Summary of aortographic findings. Substantial disappearance of the dissected lumen of the thoracic aorta was observed in all but 1 patient whose entry closed incompletely. Dotted area indicates lvalon sponge with thrombus formation, and darkened area indicates extension of thrombus formation. following operation. Deakey and colleagues [12] analyzed their experience with 527 patients treated surgically. One of the most important observations was the subsequent formation of an aneurysm and its effect on survival. The development and rupture of such an aneurysm was the most common cause of late death, accounting for 29.3% of all late deaths. The authors emphasized the need for careful follow-up studies and suggested the desirability of modifying the surgical procedure by extending the operation into the abdomen to remove the entire dissecting process. Crawford (131 reviewed his experience with Marfan s syndrome and pointed out that 50% of 41 patients required one or more operations after the first operation. The most common groups of lesions requiring later operation were aortic dissection and recurrent problems associated with the first operation. Crawford and his associates [14, 151 obtained excellent results by treating aneurysms involving the thoracic and abdominal aorta at one operation and in 1984, they [16] reported successful total aortic replacement in 2 patients with a chronic dissecting aortic aneurysm. However, this experience is small and long-term results are not yet available for comparison with less extensive procedures. The new operative technique that we have developed-the Ivalon sponge occlusion method-is simple to employ and has many advantages, such as prompt occlusion of the extended dissected lumen by a relatively small incision of the aorta, and progressive organization with the tissue ingrowth mechanism around the Ivalon sponge. In the case of a dissection in which the blood supply to the main arterial branches came from the true lumen of the aorta, the Ivalon sponge could be inserted into the entire dissected lumen, thereby representing a radical operative technique. However, the majority of the dissections involved one or two arterial branches of the abdominal visceral vessels. To date, we have inserted the Ivalon sponge to the level of the diaphragm in most patients to prevent postoperative paraplegia and abdominal ischemia. Gradual obstruction of the remaining dissected lumen was observed during follow-up, as shown in the repeat CT scans and angiograms. The key goals of our technique are to close the entry of the aortic dissection completely and to fill the dissected lumen with the Ivalon sponge, thereby promoting thrombus formation in the state of blood stagnation. It is quite reasonable to promote thrombus formation and the healing mechanism with insertion of the strip of Iva- Fig 9. Descending aortic dissection and repair. Dotted area indicates lvalon sponge with thrombus formation, and lined area in same drawing indicate; extension of thrombus formation into abdominal aorta.
175 Tanabe et al: Ivalon Sponge as Treatment of ortic Dissection lon sponge with minimal intervention, rather than try to repair the entire aortic dissection completely. For these purposes, the Ivalon sponge has three major advantages: excellent compressibility, flexibility, and moldability. These advantages allow easy insertion of the stick of sponge through the small aortic incision, thereby filling up the dissected lumen. It is also said that the Ivalon sponge enables tissue ingrowth to organize the dissected lumen. These excellent properties have been confirmed by our experimental studies. The clinical results are alsc excellent. t present, we are continuing our studies of this technique to improve and refine it and to make it a simple, safe, and effective operative procedure for aortic dissection. With periodic CT imaging and aortography, we have observed progressive occlusion and organization with tissue ingrowth into the remaining peripheral dissected lumen of the abdominal aorta. Follow-up ranges from 4 to 33 months with a mean of 18 months. The true lumen appears to reexpand to its normal shape with no apparent evidence of postoperative paraplegia or abdominal ischemia. ased on these results, we are confident that placement of an Ivalon sponge into the dissected lumen is another efficient procedure for the surgical treatment of dissecting aneurysm (Fig 9). Supported in part by a grant from the Japanese Ministry of Health and Welfare. References 1. Hashimoto M, Gohda T, Tanabe T, et al: Surgical treatment of experimental dissecting aneurysm. Rinsho Kyobu Geka 1:260, 1981 la. lanton FS Jr, Muller WH Jr, Warren WD: Experimental production of dissecting aneurysms of the aorta. Surgery 45:81, 1959 2. Tanabe T, Kawakami T, Hashimoto M, et al: Evaluation of various surgical techniques for dissecting aneurysm from the experimental and clinical standpoints. Nippon Kyobu Geka Gakkai Zasshi 30:678, 1982 3. Dureau G, Ward J, George M, et al: New surgical technique for operative management of acute dissections of the ascending aorta: report of two cases. J Thorac Cardiovasc Surg 76:385, 1978 4. blaza SGG, Ghosh SC, Grana VP, et al: Use of the ringed intraluminal graft in the surgical treatment of dissecting aneurysms of the thoracic aorta: a new technique. J Thorac Cardiovasc Surg 76:390, 1978 5. Carpentier, Deloche, Fabiani JN, et al: New surgical approach to aortic dissection: flow reversal and thromboexclusion. J Thorac Cardiovasc Surg 81:659, 1981 6. Deakey ME, Cooley D, Creech DJ. et al: Surgical considerations of dissecting aneurysm of the aorta. nn Surg 142:586, 1955 7. Deakey ME, Menly WS, Cooley D, et al: Surgical treatment of dissecting aneurysm of the aorta: analysis of seventy-two cases. Circulation 24:290, 1961 8. Thomas CS Jr, lford WC Jr, ums GR, et al: The effectiveness of surgical treatment of acute aortic dissection. nn Thorac Surg 2642, 1978 9. Guthaner DF, Miller DC, Silverman JF, et al: Fate of the false lumen following surgical repair of aortic dissections: an angiographic study. Radiology 133:1, 1979 10. Miller DC, Stinson E, Oyer PE, et al: Operative treatment of aortic dissections: experience with 125 patients over a sixteen-year period. J Thorac Cardiovasc Surg 78:365, 1979 11. Egloff L, Rothlin M, Kugelmeier J, et al: The ascending aortic aneurysm: replacement or repair? nn Thorac Surg 34:117, 1982 12. Deakey ME, McCollum CH, Crawford ES, et al: Dissection and dissecting aneurysms of the aorta: twenty-year followup of five hundred twenty-seven patients treated surgically. Surgery 92:1118, 1982 13. Crawford ES: Marfan s syndrome: broad spectral surgical treatment cardiovascular malformations. nn Surg 198:487, 1983 14. Crawford ES, Walker HSJ, Saleh S, et al: Graft replacement of aneurysm of descending thoracic aorta: results without bypass or shunting. Surgery 89:73, 1981 15. Crawford ES, Snyder DM: Treatment of aneurysms of the aortic arch: a progress report. J Thorac Cardiovasc Surg 85:237, 1983 16. Crawford ES, Crawford JL, Stowe CL, et al: Total aortic replacement for chronic aortic dissection occurring in patients with and without Marfan s syndrome. nn Surg 199:358, 1984