Asian Cardiovasc Thorac Ann 2004;12:69-74
© 2004 Asia Publishing EXchange Ltd
Extensive Thoracoabdominal Aortic Aneurysm Repair Using Deep Hypothermic Bypass and Circulatory Arrest
Hiroyuki Nishi, MD,
Satoru Miyamoto, MD,
Hirokazu Minamimura, MD,
Takumi Ishikawa, MD,
Yasuyuki Kato, MD,
Hideki Arimoto, MD,
Kensuke Ohue, MD,
Yoshihiro Shimizu, MD
Department of Cardiovascular Surgery, Osaka General City Hospital, Osaka, Japan
For reprint information contact: Hiroyuki Nishi, MD Tel: 81 6 6929 1221 Fax: 81 6 6929 1091 Email: nishi24{at}jc4.so-net.ne.jp Department of Cardiovascular Surgery, Osaka City General Hospital 2-13-22, Miyakojimahondori, Miyakojima-ku, Osaka, 534-0021, Japan.
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ABSTRACT
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We sought to evaluate the safety and usefulness of deep hypothermic cardiopulmonary bypass with intervals of circulatory arrest for extensive thoracoabdominal aortic aneurysms. Between March 1994 and December 2002, 17 patients with Crawford type I and II were reviewed retrospectively. The patients were divided into two groups: group H (hypothermic circulatory arrest, n = 8) and group N (normothermic cardiopulmonary bypass, n = 9). In group H, in-hospital mortality was 12.5%, and that in group N was 11.1%. Operation times were similar between the two groups though the cardiopulmonary bypass time was significantly shorter in group N than in group H (p < 0.05). Postoperative paraplegia occurred in 1 patient of group N. Postoperative renal dysfunction occurred in none of group H except in 1 preoperative dialysis case, whilst it occurred in 6 patients of group N. Postoperative creatinine levels were significantly higher in group N than in group H. Three cases in group H required tracheostomy. Our experience with hypothermic cardiopulmonary bypass and circulatory arrest for diffuse type thoracoabdominal aortic aneurysm confirms the safety and efficacy of this technique. Although respiratory complications remain a problem, the technique is considered to be effective for renal protection.
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INTRODUCTION
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Although improvements in operative techniques and perioperative management have reduced the overall mortality and morbidity associated with thoracoabdominal aortic aneurysm (TAAA) repair,1–3 surgical repair of extensive (Crawford types I and II) TAAA remains a surgical challenge.2–5 Operation to repair extensive TAAA is associated with significant perioperative morbidity, mainly because of ischemic damage of the spinal cord, malperfusion of the abdominal organs during crossclamping and cerebrovascular events. Distal aortic perfusion, established via partial cardiopulmonary bypass (CPB) 6,7 or left heart bypass (LHB),5,8–10 is generally used as an adjunct during surgery. Deep hypothermic circulatory arrest (DHCA) has been employed less in the surgical treatment of extensive TAAA because of the increased risk of coagulopathy and pulmonary complications due to the prolonged time on CPB. However, hypothermia has been shown experimentally to have a marked protective effect on the spinal cord and visceral organs during periods of aortic occlusion, and DHCA is useful when aortic crossclamping distal to the subclavian artery is difficult or hazardous.9,11,12 We sought to evaluate the safety and usefulness of deep hypothermic cardiopulmonary bypass with intervals of circulatory arrest for extensive TAAA in comparison with those in patients operated on using partial CPB with normothermia.
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PATIENTS AND METHODS
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Between March 1994 and December 2002, 35 consecutive patients with aortic disease involving the thoracoabdominal aorta underwent resection and graft replacement of the diseased aortic segments. Extensive aneurysms (Crawford types I and II) were repaired in 17 patients. The patients ranged in age from 43 to 73 years (mean, 62 years) and 11 (65%) were male. A comparative analysis was performed on two series of the patients. Group H included 8 patients operated on using deep hypothermic CPB and circulatory arrest during construction of the proximal anastomosis, whereas the distal anastomosis was performed during proximal perfusion. Group N included 9 patients operated with normothermic partial CPB and crossclamping of the aorta. The characteristics of the patients and extent of the aortic disease are summarized in Table 1
. Blood samples were drawn before the operation and on postoperative days 1, 3, 7 and 14. The laboratory parameters examined included serum creatinine (Cr), total bilirubin (T-bil), and alanine aminotransferase (ALT). Operative results were compared between the two groups.
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SURGICAL TECHNIQUE WHEN DHCA WAS USED
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Routine conventional hemodynamic monitoring and double-lumen endotracheal intubation were performed. A spinal drainage tube was not used. The temperature of the bladder and forehead were monitored routinely and electroencephalographic monitoring was performed. In the Stoney’s spiral position, the left common femoral artery and vein were exposed, and a 19 to 21 F long cannula was inserted into the vein and positioned in the right atrium. The femoral artery was cannulated with a 20 to 22 F short cannula. Posterolateral thoracotomy was performed and the chest was entered in the fourth or fifth intercostal space. In order to expose the entire TAAA, the incision was extended from the costal margin to the abdominal midline and thoracotomy was also performed at the seventh intercostal space. The diaphragm was incised circumferentially to minimize injury to the phrenic nerve until the celiac axis was exposed. The abdominal cavity was opened for type II TAAAs. CPB was established after the chest was entered and cooling was started immediately.
Alternatively, the distal aorta was sometimes used for arterial cannulation and the pulmonary artery for venous cannulation. During the period of cooling, the abdominal organs and the kidney were retracted medially after the peritoneum was incised in the left gutter. The left lung was collapsed and gently retracted anteriorly to minimize manipulation and injury. After ventricular fibrillation, we did not use a venting catheter. The ascending aorta was not clamped and cardioplegic solution was not administered to any patient. The patient was cooled until electroencephalographic silence was achieved, and forehead temperature of 22°C and bladder temperature of 20°C were reached. Thiopental (600 mg) was administered a few minutes before DHCA. After circulatory arrest was established, the proximal anastomosis was performed in an open fashion at the level of the distal arch, the proximal descending aorta, or the aortic arch. While doing this, the aneurysm was clamped distally to the proximal anastomosis site when feasible and low flow distal perfusion was started. Surgical repair was accomplished with woven Dacron grafts in all patients. After the proximal anastomosis was completed, an arterial line cannula was inserted directly into the vascular graft. Thereafter, the vascular prosthesis was clamped immediately distal to the anastomosis and flow was established to the cerebral and coronary circulation. The aneurysm was repaired segment by segment in proximal to distal order thereby maintaining perfusion to the spinal cord for all but the time required for direct anastomosis. Intercostal attachment was carried out while with the renal-visceral segment of the aorta was perfused. A clamp was then placed on the graft distal to the intercostal anastomosis, allowing the heart to perfuse the spinal cord during visceral and renal artery attachment. If necessary, cold solution was administered to both renal arteries for kidney protection. Rewarming was initiated as the lowest intercostal was being attached to the graft. During rewarming, spontaneous defibrillation usually occurred and CPB was discontinued when normothermia was reached, and the cannulas were then removed.
In group N, we used left heart bypass or partial femoro-femoral CPB with normothermia. The surgical procedures were similar to those of DHCA, except the proximal aortic crossclamping was performed distal to the left subclavian artery. Cold solution for renal protection was used more frequently and spinal evoked potentials were often monitored. We did not perform cerebrospinal fluid (CSF) drainage or selective perfusion of visceral organs.
All data in the text and tables are presented as mean ± standard deviation. Changes in baseline and postoperative laboratory values of each group were compared by two-way repeated-measures ANOVA. Patient characteristics and postoperative clinical course were compared by using t tests for continuous variables and the 
2 or the Fisher exact test for categorized variables. The Statview program (Statview 4.5, Abacus Concepts, Berkeley, California) was used for statistical analysis.
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RESULTS
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There were no significant differences in the main demographic factors between groups H and N (Table 1
). Both groups showed a similar incidence of aortic dissection and degenerative aortic aneurysmal disease. The incidence of Crawford types I and II was also similar in both groups of patients. Cardiopulmonary bypass time was significantly longer in group H than in group N. Other important CPB data are given in Table 2.
The hospital mortality of group H was 12.5% and that of group N 11.1%. A 66-year-old man with acute type B (Crawford type II) dissection in group H had ischemic heart disease, disseminated idiopathic coagulopathy (DIC) and paraplegia before surgery. DIC developed in the early postoperative period. A 64-year-old man in group N died of pneumonia on the 25th postoperative day.
In a 55-year-old man with degenerative aortic aneurysm (Crawford type II) in group N, paraplegia occurred postoperatively. No patients in group H showed postoperative paraplegia except the patient in whom it had occurred before surgery. A tendency toward less renal complications was found in the group operated on using DHCA. Postoperative renal dysfunction (max Cr > 2.0 mg·dL-1) occurred in none of group H except in 1 preoperative dialysis case, whilst it occurred in 6 patients of group N and 1 of these patients required dialysis. There were no significant differences of postoperative liver dysfunction, re-exploration for bleeding or cerebrovascular accident between the 2 groups. Pulmonary complications occurred more frequently in group H. Three cases in group H required prolonged ventilation and tracheostomy. Only 1 case in group N developed pneumonia.
Creatinine levels were higher in group N than in group H (Figure 1). Although the level of creatinine had returned to baseline by the 14th postoperative day in group H, it was still higher than normal in group N. There was a significant difference of creatinine level between group H and group N (p < 0.05). In both groups, the serum levels of T-bil and ALT rose to levels 3 times the normal but they normalized within 14 days. There was no significant difference in liver function between group H and group N (Figures 2 and 3).
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Figure 1. Serum creatinine level before and after operation in group H and group N. The difference between the two study groups was statistically significant ( p < 0.05 by analysis ANOVA).
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Figure 2. The course of serum total bilirubin level before and after surgery. There was no significant difference.
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Figure 3. The course of serum alanine aminotransferase level before and after surgery. There was no significant difference.
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DISCUSSION
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Since the first successful report of TAAA repair by Etheridge and Rob in 1955,13 numerous studies aimed at reducing the operative mortality rate for TAAA have been made. As a result, the outcome of surgery for TAAA improved remarkably over the past decade.1–3 Nevertheless, operations for extensive TAAA (Crawford types I and II) still remain a surgical challenge, because such extensive TAAA is an independent risk factor for mortality and its mortality is higher than that for other types of TAAA.2–5 The main reason is high morbidity such as paraplegia and dysfunction of visceral organs. Over the past decade, extensive TAAA repairs have consistently been associated with high levels of paraplegia (24% to 32%)2,5,14 and renal dysfunction (16% to 26%).15,16 In order to reduce these problems, various adjuncts such as distal perfusion with arterial bypass,5–10 CSF drainage,17 sequential aortic clamping,7,8 selective perfusion of intercostal arteries6 or visceral arteries3,7 and reattachment of critical intercostal arteries have been used.3 Most reported studies have used left heart bypass5,8–10 or partial CPB6,7 as mechanical support for extensive TAAA operations. On the other hand, profound hypothermia is a widely accepted technique for the protection of the central nervous system as well as other organs in various fields of cardiovascular surgery.18 In contrast with the frequent use of DHCA in aortic arch operations, this technique has received less attention in the surgical treatment of extensive TAAA because of the prolonged time of CPB and the risk of coagulopathy.
Paraplegia or paraparesis is the most serious complication because it is a major cause of morbidity19 in the patient and may shorten the long-term survival after surgery. Recent studies have documented permanent spinal dysfunction in 10% to 30% of high-risk patients whose adjuncts were LHB or partial CPB, and only a few institutes have reported an incidence of paraplegia less than 5%.3 Even in large institutions, paraplegia occurred in 7.8% of cases of extensive TAAA.4 On the other hand, some institutes in which DHCA was used as the main adjunct reported a lower incidence (less than 3%) of paraplegia in surgery to repair descending and thoracoabdominal aneurysms.2,9 Not only large institutions2 but also moderate-sized institutions reported a 3% incidence of paraplegia even for surgery to repair extensive TAAA.9 In our cases, there was no postoperative paraplegia when DHCA was used as the adjunct, while one patient (12.5%) whose adjunct was normothermic CPB developed postoperative spinal cord dysfunction.
In order to reduce the duration and degree of decreased blood flow to the spinal cord, several adjuncts have been developed. Although some reports showed protective qualities of these adjuncts in patients who had more than 45 minutes of crossclamp time,19 it is generally considered that the ischemic tolerance of the spinal cord may be less than 40 minutes, and that it is preferable to reconstruct critical spinal cord arteries within 30 minutes.6 This still remains a problem for the repair of extensive TAAA, which sometimes requires longer aortic crossclamping time due to the complexity of the procedure. In a primate study employing proximal and distal hypothermic perfusion with circulatory arrest, hypothermia adequately protected spinal cord function after double aortic clamping for 60 minutes.20 Thus DHCA is more useful when extensive TAAA is present, and when the risk for development of ischemic spinal cord injury is judged to be increased.
Renal failure after TAAA continues to be a significant and potentially lethal complication. This adversely affects both short-term and long-term survival.4 In order to reduce postoperative renal failure and its associated mortality, several techniques and intraoperative strategies have been used, including intraoperative administration of diuretics, minimization of ischemic time, renal hypothermia and renal artery perfusion with oxygenated blood.8 Coselli and colleagues have demonstrated that reduced kidney temperature was associated with renal protection, and that the use of cold crystalloid was an independent predictor of preserved renal function.4 Morishita and colleagues reported that selective visceral and renal perfusion during thoracoabdominal aortic aneurysm repair had greatly contributed to the lower occurrence of kidney failure and to the maintenance of hepatorenal function.8 However, despite the use of adjuvant techniques, the incidence of renal failure after TAAA repair still ranges from 5.5% to 10%. The incidence after repair of type II TAAA still remains especially high (from 16% to 20%).4 On the other hand, DHCA is considered to provide substantial protection of not only the spinal cord but also visceral organs. In fact, lower incidence (from 1% to 7%) of renal failure was reported when DHCA was used for visceral organ protection.2,9,12 Although we used various adjuncts for renal protection, including administration of cold solution to the renal artery, distal aortic perfusion and sequential aortic crossclamping, in group N, renal dysfunction occurred in 66.7% of the cases and 1 patient (11.1%) required postoperative dialysis. In contrast, when we use DHCA for renal protection, no patient developed postoperative renal dysfunction, except for one patient who had required preoperative dialysis. There was a significant difference in the changes of postoperative serum creatinine levels between group H and group N. Thus, for renal protection, DHCA clearly appears to be more effective than normothermic CPB.
DHCA offers some other advantages compared with other techniques such as simple aortic crossclamping or the use of distal aortic perfusion with atriofemoral or femoro-femoral bypass, absence of dissection of the proximal aorta (minimizing the risk of recurrent paresis), elimination of the need for proximal aortic crossclamping, excellent and easy access to the aortic arch and a bloodless field. Furthermore, it is not necessary to use other complex adjuncts, such as monitoring of CSF pressure, CSF drainage, monitoring of evoked potentials, selective perfusion of visceral arteries, or insertion of epidural catheters. Although DHCA is a simple method and it provides effective protection for various organs, it also has some disadvantages. One of these is a high incidence of pulmonary complications (19% to 67%). Pulmonary complications remain the most common source of morbidity associated with TAAA repair, and they occur more frequently in the repair of type II TAAA (35.7%) than of other types of TAAA.4 DHCA was not useful for preventing pulmonary dysfunction even in large institutes.2,12 In our series, a high incidence of pulmonary complications was observed. Another disadvantage of DHCA is increased blood use because low temperature induces coagulopathy, which sometimes makes it difficult to control intraoperative bleeding. As a result, mortality still remained high4 (15.6%) when DHCA was used for the repair of extensive II TAAA. Therefore, some surgeons warn against the routine use of this technique because of the high mortality rate and pulmonary complications.11 They also recommend DHCA only if crossclamping of the distal arch or proximal descending aorta is hazardous because of rupture, excessive aortic size, or atheromatous plaque and debris.
Our results compare very favorably with those of other series. Although pulmonary complications occurred in 37.5% of DHCA cases, these patients recovered and were discharged. The early mortality rate (12.5%) was acceptable and the rates of paraplegia and renal dysfunction were low. We have found deep hypothermic CPB and circulatory arrest to be safe adjuncts for extensive TAAA operations even in a small institution. The major limitation of this study is that the present work was a retrospective analysis of a non-randomized small group of patients. In order to clarify whether DHCA is really effective for extensive TAAA, or whether it replaces decreased morbidity with increased mortality, a prospective randomized study of a large number of patients will be needed.
In conclusion, our experience with hypothermic cardiopulmonary bypass and circulatory arrest for surgical repair of extensive thoracoabdominal aortic aneurysm confirms the safety and efficacy of this technique. Although respiratory complications remain a problem, the technique is considered to be effective for renal protection.
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REFERENCES
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- Svensson LG, Crawford ES, Hess KR, Coselli JS, Safi HJ. Experience with 1509 patients undergoing thoracoabdominal aortic operations. J Vasc Surg
1993;17:357–70.[Medline]
- Kouchoukos NT, Masetti P, Rokkas CK, Murphy SF. Hypothermic cardiopulmonary bypass and circulatory arrest for operations on the descending thoracic and thoracoabdominal aorta. Ann Thorac Surg
2002;74:S1885–7.[Abstract/Free Full Text]
- Coselli JS, Conklin LD, LeMaire SA. Thoracoabdominal aortic aneurysm repair: review and update of current strategies. Ann Thorac Surg
2002;74:S1881–4.[Abstract/Free Full Text]
- Coselli JS, LeMaire SA, Conklin LD, Koksoy C, Schmittling ZC. Morbidity and mortality after extent II thoracoabdominal aortic aneurysm repair. Ann Thorac Surg
2002;73:1107–16.[Abstract/Free Full Text]
- Safi HJ, Miller CC 3rd. Spinal cord protection in descending thoracic and thoracoabdominal aortic repair. Ann Thorac Surg
1999;67:1937–9.[Abstract/Free Full Text]
- Sueda T, Morita S, Okada K, Orihashi K, Shikata H, Matsuura Y. Selective intercostal arterial perfusion during thoracoabdominal aortic aneurysm surgery. Ann Thorac Surg
2000;70:44–7.[Abstract/Free Full Text]
- Morishita K, Yokoyasa H, Inoue S, Koshino T, Tamiya Y, Abe T. Selective visceral and renal perfusion in thoracoabdominal aneurysm repair. Eur J Cardiothorac Surg
1999;15:502–7.
- Frank SM, Parker SD, Rock P, Gorman RB, Kelly S, Beattie C, et al. Moderate hypothermia, with partial bypass and segmental sequential repair for thoracoabdominal aortic aneurysm. J Vasc Surg
1994;19:687–97.[Medline]
- Carrel TP, Berdat PA, Robe J, Gysi J, Nguyen T, Kipfer B, et al. Outcome of thoracoabdominal aortic operations using deep hypothermia and distal exsanguination. Ann Thorac Surg
2000;69:692–5.[Abstract/Free Full Text]
- Coselli JS, LeMaire SA. Left heart bypass reduces paraplegia rates after thoracoabdominal aortic aneurysm repair. Ann Thorac Surg
1999;67:1931–4.[Abstract/Free Full Text]
- Safi HJ, Miller CC 3rd, Subramanian MH, Campbell MP, Iliopoulos DC, O’Donnell JJ, et al. Thoracic and thoracoabdominal aortic aneurysm repair using cardiopulmonary bypass, profound hypothermia, and circulatory arrest via left side of the chest incision. J Vasc Surg
1998;28:591–8.[Medline]
- Kouchoukos NT, Masetti P, Rokkas CK, Murphy SF, Blackstone EH. Safety and efficacy of hypothermic cardiopulmonary bypass and circulatory arrest for operations on the descending thoracic and thoracoabdominal aorta. Ann Thorac Surg
2001;72:699–708.[Abstract/Free Full Text]
- Etheredge SN, Yee J, Smith JV, Schonberger S, Goldman MJ. Successful resection of a large aneurysm of the upper abdominal aorta and replacement with homograft. Surgery
1955;38:1071–81.[Medline]
- Gilling-smith GL, Worswick L, Knight PF, Wolfe JH, MansfieldAO. Surgical repair of thoracoabdominal aortic aneurysm: 10 years’ experience. Br J Surg
1995;82:624–9.[Medline]
- Grabitz K, Sandmann W, Stuhmeier K, Mainzer B, Godehardt E, Ohle B, et al. The risk of ischemic spinal cord injury in patients undergoing graft replacement for thoracoabdominal aortic aneurysms. J Vasc Surg
1996;23:230–40.[Medline]
- Safi HJ, Harlin SA, Miller CC, Iliopoulos DC, Joshi A, Mohasci TG, et al. Predictive factors for acute renal failure in thoracic and thoracoabdominal aortic aneurysm surgery. J Vasc Surg
1996;24:338–45.[Medline]
- Coselli JS, LeMaire SA, Koksoy C, Schmittling ZC, Curling PE. Cerebrospinal fluid drainage reduces paraplegia after thoracoabdominal aortic aneurysm repair: results of a randomized clinical trial. J Vasc Surg
2002;35:631–9.[Medline]
- Coselli JS, Crawford ES, Beall AC Jr, Mizrahi EM, Hess KR, Patel VM. Determination of brain temperature for safe circulatory arrest during cardiovascular operations. aorta. Ann Thorac Surg
1988;45:638–42.[Abstract]
- LeMaire SA, Miller CC 3rd, Conklin LD, Schmittling ZC, Koksoy C, Coselli JS. A new predictive model for adverse outcomes after elective thoracoabdominal aortic aneurysm repair. Ann Thorac Surg
2001;71:1233–8.[Abstract/Free Full Text]
- Rokkas CK, Sundaresan S, Shuman TA, Palazzo RS, Nitta T, Despotis GJ, et al. Profound systemic hypothermia protects the spinal cord in a primate model of spinal cord ischemia. J Thorac Cardiovasc Surg
1993;106:1024–35.[Abstract]
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ABSTRACT
INTRODUCTION
