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Ann Thorac Surg 1997;64:399-403
© 1997 The Society of Thoracic Surgeons
First Department of Surgery, Shimane Medical University, and Department of Thoracic and Cardiovascular Surgery, Shimane Central Hospital, Shimane, Japan
Accepted for publication January 29, 1997.
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Abstract |
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 TopFootnotes Abstract IntroductionMaterial and MethodsResultsCommentReferences |
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Methods. Forty-four patients underwent graft replacement (group 1) and 14, the thromboexclusion operation (group 2). We reviewed the long-term results of the thromboexclusion operation and compared them with those of graft replacement in our institutions.
Results. The hospital mortality rate in groups 1 and 2 was 29.5% (13 patients) and 35.7% (4 patients), respectively. In group 1, the one late death (2.3%) was due to heart failure and in group 2, three of the four late deaths (28.6%) were due to rupture of the excluded thoracic aorta, and one late death was due to heart failure. Long-term follow-up was possible for 23 patients in group 1 and 5 patients in group 2. Survival 3 years after operation was significantly better in group 1 than in group 2 (p < 0.05). Long-term follow-up with blood pressure measurements, chest roentgenograms, electrocardiograms, and echocardiograms showed no significant differences between the preoperative and postoperative findings. However, in group 2, left ventricular hypertrophy and hypertension, which had not been present preoperatively, were found in all of the patients. Also, 1 patient has had persistent hemoptysis.
Conclusions. The thromboexclusion operation has introduced unanticipated problems that were recognized at long-term follow-up.
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Introduction |
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TopFootnotesAbstractIntroductionMaterial and MethodsResultsCommentReferences |
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In 1981, Carpentier and associates [1] described the thromboexclusion operation for aortic dissection. Since then, this technique has been used not only for aortic dissections but also some nondissected aneurysms [1, 2]. The thromboexclusion procedure has the following advantages: the operation is performed on nondissected aorta, a permanent clamp is placed across the aorta distal to the left subclavian artery to reverse the flow in the descending aorta, and gradual thrombosis of the descending aorta will occur in the excluded blind segment, which may allow a period of circulatory adaptation of the spinal cord and decrease the incidence of paraplegia [1, 3]. Some investigators [3, 4] have reported that with thromboexclusion, paraplegia and rupture can occur, the mortality rate may not be reduced, and the clamp can migrate. In addition, surgical techniques of graft replacement for aortic aneurysms have been developed to overcome these complications, and today the thromboexclusion procedure is rarely used.
There are very few reports of the results of long-term follow-up of survivors of the thromboexclusion operation. Here we present a retrospective review of our experience with the thromboexclusion operation. We discuss our selection criteria and the early and long-term outcomes. We compare the postoperative course of patients who underwent thromboexclusion with that of patients who underwent graft replacement.
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Material and Methods |
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TopFootnotesAbstractIntroductionMaterial and MethodsResultsCommentReferences |
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Graft Replacement
Between July 1982 and December 1989, we performed graft replacement of the descending aorta on 44 patients who had either a dissected thoracic aortic aneurysm (28 patients) or a true aortic aneurysm (16 patients: 7 with aortic arch aneurysm, 6 with descending aortic aneurysm, and 3 with thoracoabdominal aneurysm). The age of the patients ranged from 19 to 81 years (average age, 62 years). There were 32 men and 12 women. Woven Dacron grafts 22 to 26 mm in diameter (USCI DeBakey woven vascular prosthesis; C.R. Bard Inc, Billerica, MA) were used.
Thromboexclusion Operation
Between May 1982 and November 1988, 14 patients who had either a dissected thoracic aortic aneurysm (7 patients) or a true aortic aneurysm (6 patients with thoracic aneurysm and 1 patient with thoracoabdominal aneurysm) underwent the thromboexclusion operation (Table 1
). The age of the patients ranged from 39 to 72 years (average age, 57.8 years). There were 13 men and 1 woman. Twelve patients had bypass of the proximal intrapericardial ascending aorta to the nondissected segment of the abdominal aorta; 1 patient had bypass of the proximal descending thoracic aorta to the distal descending thoracic aorta; and 1 patient had bilateral axillary–iliac artery bypass grafting. Gore-Tex reinforced expanded polytetrafluoroethylene vascular grafts 10 to 22 mm in diameter (W.L. Gore & Associates Inc, Flagstaff, AZ) were used in 7 patients, woven Dacron grafts 16 to 20 mm in diameter (USCI DeBakey woven vascular prosthesis; C.R. Bard Inc) were used in 5 patients, and knitted Dacron grafts 18 and 22 mm in diameter (USCI DeBakey Vasculour II Dacron velour prosthesis; C.R. Bard Inc) were used in 2 patients. Five patients had permanent aortic occlusion (permanent aortic clamp SHM 50 mm, Matsuda Ika Kogyo Co, Ltd, Tokyo, Japan) both proximally and distally, and 9 patients had permanent aortic closure only proximally. The Ivalon sponge occlusion technique was performed in patient 13.
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The diagnosis of hypertension was based on repeated blood-pressure measurements on two screening occasions. On each occasion, blood pressure was taken three times with an appropriately sized cuff after the patient had been seated for more than 5 minutes. Patients whose average blood pressure on both occasions exceeded 140 mm Hg systolic or 90 mm Hg diastolic were considered hypertensive [5]. A cardiothoracic ratio exceeding 0.50 was considered enlargement of the cardiac contour. The ECG was obtained with a model FCP-4301 (Fukuda Denshi Co. Ltd, Tokyo, Japan). If the SV1 + RV5 exceeded 37 mV and ST strain was present in V5 and V6, the pattern was considered one of left ventricular hypertrophy (LVH). Echocardiographic examination was performed with a Toshiba model SSH-160A (Toshiba Medical System Co, Ltd, Tokyo, Japan). On the echocardiogram, LVH was diagnosed if the thickness of the left ventricular posterior wall and of the interventricular septum was greater than 13 mm.
Statistical Analysis
Data are expressed as the mean ± the standard deviation. Paired Student's t test was used to assess differences between mean values of continuous variables. Postoperative survival was calculated using the Kaplan-Meier method. The generalized Wilcoxon test was used to compare survival between groups. Significance was defined as a p value of less than 0.05.
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Results |
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TopFootnotesAbstractIntroductionMaterial and MethodsResultsCommentReferences |
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. The hospital mortality rate in groups 1 and 2 was 29.5% (13 patients) and 35.7% (5 patients), respectively. In group 1, 6 patients died of postoperative bleeding, 4 of low-output syndrome, and 3 of infection. There was no instance of paraplegia in group 1. In group 2, 2 patients died of aneurysmal rupture, and 1 patient each died of low-output syndrome, cerebral infarction, and hepatorenal insufficiency. Three of them had emergency operation for impending rupture and were in hypovolemic shock in the operating room; all 3 died, 2 of perioperative aneurysmal rupture and 1 of cerebral infarction resulting from hypotension of long duration.
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Long-term follow-up included 23 patients in group 1 and 5 patients in group 2. The mean survival after operation was 8.8 ± 3.0 years (range, 6.4 to 12.0 years) in group 1 and 13.3 ± 3.9 years (range, 8.2 to 17.2 years) in group 2. Mean age at follow-up was 65.1 ± 8.6 years (range, 29 to 76 years) in group 1 and 66.6 ± 13.7 years (range, 47 to 85 years) in group 2. The actuarial survival rate at 1 year, 5 years, and 10 years in groups 1 and 2 was 70% ± 9% and 50% ± 9%, 68% ± 2% and 36% ± 16%, and 68% ± 0% and 36% ± 0%, respectively. Survival 3 years after operation was significantly better in group 1 than in group 2 (p < 0.05).
Current Status of Long-Term Survivors
The mean preoperative values for systolic and diastolic blood pressures, cardiothoracic ratio, SV1 + RV5 on the ECG, and thickness of the interventricular septum and the left ventricular posterior wall in groups 1 and 2 were 126 ± 7 mm Hg and 123 ± 2 mm Hg, 80 ± 7 mm Hg and 69 ± 7 mm Hg, 0.52 ± 0.04 and 0.48 ± 0.02, 33 ± 8 mV and 29 ± 3 mV, 10.2 ± 0.6 mm and 9.8 ± 0.6 mm, and 9.9 ± 0.6 mm and 9.8 ± 0.4 mm, respectively. There were no significant differences in these variables between groups 1 and 2.
In group 1 at the time of admission, 5 patients (11.4%) were on a regimen of at least one antihypertensive agent (4 patients, a calcium-channel blocker, and 1 patient, a calcium-channel blocker and an angiotensin-converting enzyme inhibitor), and 3 of these patients (6.8%) had systolic and diastolic hypertension. The mean postoperative values for systolic and diastolic blood pressures, cardiothoracic ratio, SV1 + RV5 on the ECG, and thickness of the interventricular septum and the left ventricular posterior wall were 123 ± 8 mm Hg, 78 ± 6 mm Hg, 0.52 ± 0.02, 31 ± 6 mV, 10.2 ± 0.5 mm, and 10.4 ± 0.6 mm. There were no significant differences between the mean preoperative and postoperative values.
In group 2, thrombotic occlusion of the excluded thoracic aorta was documented by computed tomographic scan, magnetic resonance imaging, or digital subtraction angiography in all patients (see Table 1
). There were no neurologic complications postoperatively. Although at the time of admission, 1 patient was on a regimen of one antihypertensive drug (calcium-channel blocker), all 5 long-term survivors were normotensive after operation. However, all had both systolic and diastolic hypertension postoperatively and were on a regimen of at least one antihypertensive medication. The mean postoperative values for systolic and diastolic blood pressures, cardiothoracic ratio, SV1 + RV5 on the ECG, and thickness of the interventricular septum and of the left ventricular posterior wall were 154 ± 5 mm Hg, 94 ± 5 mm Hg, 0.58 ± 0.02, 48 ± 5 mV, 14.1 ± 0.6 mm, and 13.8 ± 0.5 mm. The postoperative values were higher than those obtained before operation, (p < 0.05).
Although thrombotic occlusion affected the celiac artery, superior mesenteric artery, and left renal artery in patient 1, there were no symptoms of paraplegia, abdominal organ ischemia, or limb ischemia.
In patient 13, although the excluded lumen of the descending aorta was filled with thrombosed Ivalon sponge, the patient had persistent hemoptysis for 2 years after operation. We decided to reoperate to remove collateral branches of the excluded aorta to the adherent lung, as they seemed to be causing the hemoptysis. At reoperation, the lumen of the excluded aorta into which the Ivalon sponge had been inserted was found to have been closed by organization, and there was no bleeding from inside the excluded aorta. We closed the distal descending aorta with sutures and resected the proximal portion of the excluded aorta with a part of the adherent lung. The patient continued to expectorate blood at times. We performed digital subtraction angiography of the left subclavian artery and found many collateral branches to the adjacent lung. Recently, coil embolization of the collateral vessels successfully controlled the hemoptysis.
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Comment |
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TopFootnotesAbstractIntroductionMaterial and MethodsResultsCommentReferences |
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Carpentier and associates [1] described flow reversal and thromboexclusion for both ascending and descending aortic dissections. There are several advantages to this procedure: the operation is performed on nondissected areas of the aorta; it is possible to perform the operation without considering the problems of cardiac unloading, lower-body perfusion, and spinal cord protection; thrombosis of the excluded descending aorta occurs gradually, which allows the body to adapt by collateral formation, thus decreasing the incidence of paraplegia; and thrombosis of the excluded descending aorta will prevent rupture or extension of the dissection [1, 3]. However, Patra and co-workers [4] reported retrograde dissections of the aortic arch after exclusion-bypass of the descending thoracic aorta.
From May 1982 to November 1988, 14 patients underwent the thromboexclusion operation in our hospitals. Five (35.7%) died perioperatively and 4 (28.6%) during follow-up. Causes of death were aortic rupture, low-output syndrome, and hepatorenal insufficiency resulting from disseminated intravascular coagulation. The long-term survival rate was 35.7% (5 patients). The mean follow-up was 14.8 years. We compared the postoperative course of these patients with that of patients having graft replacement. There was no significant difference in hospital mortality, although survival was significantly better for the patients who underwent graft replacement. There were no significant differences in the mean preoperative and postoperative values for blood pressures, cardiothoracic ratio, and SV1 + RV5 on the ECG for the patients having graft replacement. On the other hand, after the thromboexclusion operation, hypertension, enlargement of the cardiac contour on the chest roentgenogram, a pattern indicative of LVH on the ECG, and a concentric LVH pattern on the echocardiogram were present in the survivors, none of whom had had these findings before operation. In addition, 1 patient has experienced persistent hemoptysis.
Elefteriades and associates [3] reported that after thromboexclusion, thrombosis of the excluded descending aorta occurs within days and might prevent rupture or extension of the dissection. Robicsek [2] and others [3] occluded the excluded descending aorta both proximally and distally, and there was no late rupture or further dilatation of the completely occluded segment.
In this study, we used permanent aortic occlusion (permanent aortic clamp, SHM 50 mm) and found that there was neither migration of the clamp nor compression of surrounding tissues such as the pulmonary artery or bronchus [6]. Five of our patients underwent permanent aortic occlusion both proximally and distally, and 9 had permanent aortic proximal closure only. Although thrombotic occlusion of the excluded thoracic aorta occurred, three late deaths were related to rupture of the excluded aorta, and 1 of these patients had received permanent aortic occlusion both proximally and distally. Either the distal pressure on the clot or the increased collateral blood supply to the excluded aneurysm seems to be able to cause expansion and late aneurysmal rupture. Thrombosis of the excluded descending aorta may not necessarily prevent rupture or expansion of the aneurysm.
Occlusion of both parts of the excluded descending aorta may also not always be a safe procedure. One patient underwent the operation successfully and had thrombosis of the excluded descending aorta within days; he died of hepatorenal insufficiency caused by disseminated intravascular coagulation. The rapid formation of excessive thrombus in the excluded descending aorta can cause coagulopathy. We used Ivalon sponge [7] to occlude the excluded descending aorta in 1 patient, and at reoperation, we found that the sponge was occluding the excluded aorta completely. There was no paraplegia in our experience, although the possibility of paraplegia may increase with occlusion of both parts of the excluded descending aorta compared with that for proximal closure only. The Ivalon sponge occlusion technique can be regarded as the procedure of choice for achieving gradual thrombosis of the excluded segment and hopefully will result in a decrease in the incidence of paraplegia [3, 7].
There are some reports [1, 8, 9] that a long aortic bypass graft does not cause problems. However, we reviewed the long-term follow-up of the 5 survivors and found LVH and hypertension in all of them. Changes in the hemodynamics of the thoracic vascular beds after placement of a long graft have to be taken into account [10]. The follow-up in those reports [1, 8, 9] is shorter than that of our study. A long aortic bypass graft may cause excessive overloading of the left ventricle and lead to LVH, hypertension, or both in long-term survivors. The size of the graft in our study tends to be smaller in diameter than that in the other reports [1, 8, 9]. There was one late death caused by heart failure that might have been due to excessive overloading of the left ventricle. Larger-sized grafts may be necessary to the thromboexclusion technique.
One patient had persistent hemoptysis. The excluded segment in this patient thrombosed completely, although there were many collateral branches to the adjacent lung. The thromboexclusion technique may increase collateral circulation, which allows a period of circulatory adaptation of the spinal cord, but it may also cause unknown hazards such as bleeding through a perforation into the bronchus from these abundant collaterals.
In the present study, we performed bilateral axillary–femoral artery bypass grafting in 1 patient because of a dissected aneurysm that extended to the abdominal aorta and could not be bypassed. We chose a descending–descending bypass for another patient because of a severely calcified ascending aorta that was unsuitable for aortic clamping. Although descending–descending and the axillary–femoral artery bypass grafts are not in keeping with standard thromboexclusion techniques, we found thrombosis of the excluded aortas.
In conclusion, the thromboexclusion technique used in this study has introduced unanticipated problems, which are especially apparent in the long-term follow-up. Thrombosis of the excluded segment may not necessarily prevent rupture or extension of the aneurysm. In long-term survivors, a long bypass graft can lead to left ventricular overload and hypertension. Nevertheless, total exclusion of the thoracic aneurysm with a graft reaching from the ascending to the infrarenal aorta is still occasionally necessary. Our current policy is to use this technique only in the following cases: a large aneurysm with impending rupture; an aneurysm that is closely adherent to the adjacent lung and cannot be approached directly; and a severely calcified thoracoabdominal aneurysm that is unsuitable for aortic clamping.
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Footnotes |
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TopFootnotesAbstractIntroductionMaterial and MethodsResultsCommentReferences |
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References |
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TopFootnotesAbstractIntroductionMaterial and MethodsResultsCommentReferences |
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