Clinical Outcome of Emergency Surgery for Complicated Acute Type B Aortic Dissection

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1 Circulation Journal Official Journal of the Japanese Circulation Society ORIGINAL ARTICLE Cardiovascular Surgery Clinical Outcome of Emergency Surgery for Complicated Acute Type B Aortic Dissection Takashi Murashita, MD; Hitoshi Ogino, MD; Hitoshi Matsuda, MD; Hiroaki Sasaki, MD; Hiroshi Tanaka, MD; Yutaka Iba, MD; Keitaro Domae, MD; Tatsuki Fujiwara, MD Background: The aim of the present study was to review the clinical profile and outcome of emergency surgery for complicated acute type B aortic dissection. Methods and Results: A total of 34 consecutive patients requiring surgical treatment for complicated acute type B aortic dissection between 2003 and 2010 were examined. The median age was 64.0 years (range, years). Indication for emergency surgery was aortic rupture in 11 patients, rapid expansion of the dissecting aorta in 5, dissection involving a non-dissecting aneurysm in 6, and organ malperfusion in 12. All of 3 patients with open aortic rupture died during surgery. Operative mortality was 9.7% (central operation, 14.2%; peripheral operation, 7.1%; thoracic endovascular aneurysm repair, 0%). There were 2 aortic ruptures within 1 week after operation. Two patients suffered from persistent organ malperfusion after emergency surgical relief of ischemia and died. The 1- and 5-year survival rates were 74.1±8.1% and 64.8±11.2%. The actual rate of freedom from aortic events at 1- and 5- years was 83.0±7.0% and 58.7±11.4%. Conclusions: Emergency surgery for complicated acute type B dissection still has a high mortality rate for patients with open rupture and critical visceral ischemia. Medical treatment is best given immediately after admission, and adequate surgical treatment without delay is crucial. (Circ J 2012; 76: ) Key Words: Acute type B aortic dissection; Clinical outcome; Complicated aortic dissection; Open surgical treatment With advances in diagnosis and perioperative care, 1 excellent early- and long-term outcomes for emergency surgery for acute type A aortic dissection have been reported. 2 Meanwhile, the current primary treatment for acute type B aortic dissection without major complications remains medical with wide acceptance. Indications for surgical treatment are limited to prevention or relief of lifethreatening complications such as aortic rupture or aortic branch compromise of dissection. Previous studies have demonstrated that emergency surgery is associated with significant mortality and morbidity, despite recently improved surgical techniques and perioperative care. 3 5 Meanwhile, there is growing interest in catheter interventions including stent-graft repair for aortic rupture and stent insertion for aortic branch compromise for complicated acute B dissection. 6 The optimal treatment for complicated B dissection, however, remains controversial. The aim of the present study was to review the early and intermediate results of recent surgical treatment for complicated acute type B dissection in a single Japanese center to clarify the impact of emergency surgical intervention. Methods Subjects Between June 2003 and December 2010, 245 patients with acute type B aortic dissection were admitted to National Cerebral and Cardiovascular Center. Surgical treatment was indicated immediately after admission for 17 patients due to aortic rupture in 5 patients, dissection involving a non-dissecting aneurysm in 4 and critical organ malperfusion in 8. Another 228 patients were treated with anti-hypertensive medication. Among them, 17 patients (7.5%) required emergency surgery due to the following reasons: aortic rupture in 6 patients, rapid expansion of the dissecting aorta in 5, newly developed dissection in 2, and organ malperfusion in 4. Three patients developed critical open aortic rupture suddenly and required cardiopulmonary resuscitation (CPR). We examined the clinical outcomes of 34 patients who underwent emergency surgical treatment. They consisted of 17 patients who underwent emergency surgery immediately after admission, and 17 patients who required emergency surgery during medical treatment. The median age was 64.0 years Received September 1, 2011; revised manuscript received November 6, 2011; accepted November 7, 2011; released online December 17, 2011 Time for primary review: 32 days Department of Cardiovascular Surgery, Kobe City Medical Center General Hospital, Kobe (T.M.); Department of Cardiovascular Surgery, National Cerebral and Cardiovascular Center, Suita (H.O., H.M., H.S., H.T., Y.I., K.D., T.F.), Japan Mailing address: Takashi Murashita, MD, Department of Cardiovascular Surgery, Kobe City Medical Center General Hospital, Minatozimaminami, Chuo-ku, Kobe , Japan. tmurashita@kcho.jp ISSN doi: /circj.CJ All rights are reserved to the Japanese Circulation Society. For permissions, please cj@j-circ.or.jp

2 Surgery for Type B Aortic Dissection 651 Table 1. Operative Procedure Operation type No. patients Central operation Descending aortic replacement 13 Total arch replacement 3 Thoracoabdominal replacement 1 Peripheral operation Fenestration of abdominal aorta 2 Replacement of abdominal aorta 4 Fenestration and replacement of abdominal aorta 3 Fenestration of abdominal aorta and bypass to SMA 1 Extra-anatomical bypass 4 Thoracic endovascular aneurysm repair 3 SMA, superior mesenteric artery. (range, years). There were 25 men and 9 women. Six patients (17.6%) had connective tissue disorders: Marfan syndrome in 5 patients and Ehlers-Danlos syndrome in 1 patient. We evaluated computed tomography (CT) in the acute (<2 weeks) and subacute (2 4 weeks) phases. Emergency surgery was performed during the acute phase in 29 patients (85.2%) and in the subacute phase in 5 (14.7%). The median duration between onset of aortic dissection and operation was 12 h (range, 0.5 h 25 days). Data analysis was approved by the Institutional Review Board of National Cerebral and Cardiovascular Center, and the Board waived the need for patient consent. Surgical Procedure Operative procedure and perioperative findings are listed in Tables 1,2. Central operations were performed in 17 patients and peripheral procedures in 14 patients. Thoracic endovascular aneurysm repair (TEVAR) was performed in 3 recent patients since December in In the 17 patients requiring central operation, 3 patients (17.6%) preoperatively required CPR for serious open rupture. For 3 patients having retrograde dissection involving the distal aortic arch, an entire arch-proximal descending aortic replacement was carried out. With regard to the peripheral operations, which were carried out for 14 patients who suffered from critical organ malperfusion caused by aortic branch compromise, we performed aortic fenestration in the infrarenal abdominal aorta in 6 patients, replacement of abdominal aorta due to a coexisting abdominal aortic aneurysm in 7, axillo-femoral bypass in 3, and femoro-femoral cross-over bypass in 1. In contrast, for the 3 recent patients, urgent TEVAR was performed to occlude the main intimal tear of aortic dissection. In all, clinical condition was relatively stable, and adequate landing zone for TEVAR was achievable. No critical rupture or organ malperfusion had been included. The devices used were MK stent (Kitamura, Kanazawa, Japan), Talent (Medtronic, Santa Rosa, CA, USA), and Excluder (W.L. Gore & Associates, Sunnyvale, CA, USA) in each patient. Table 2. Preoperative Findings Central (n=17) Peripheral (n=14) TEVAR (n=3) Median age (years) M/F 13/4 10/4 2/1 Preoperative CPR Operative indication Aortic rupture Rapid expansion Involving aneurysm Malperfusion TEVAR, thoracic endovascular aneurysm repair; CPR, cardiopulmonary resuscitation. Table 3. Operative Outcome Central operation (n=17) Peripheral operation (n=14) TEVAR (n=3) Operative death In-hospital death Postoperative complications Aortic rupture Cerebral dysfunction Respiratory failure Renal failure Bleeding Paraplegia Bowel ischemia Graft infection TEVAR, thoracic endovascular aneurysm repair. Definition of Complications Cerebral dysfunction was defined as cerebral infarction, cerebral bleeding, coma, convulsion, serious cognitive disorder and delirium. Respiratory failure was defined as need for mechanical ventilation for >1 week postoperatively, or tracheostomy. Renal failure was defined as new need for hemodialysis. Bleeding was defined as need for re-exploration for postoperative bleeding. Bowel ischemia was defined as need for bowel resection due to bowel necrosis. Graft infection was diagnosed on CT or on drainage of pus around the inserted prosthesis. Follow-up and Statistical Analysis We followed the patients at the outpatient clinic or via telephone survey. Follow-up with regular CT was completed in all patients. The mean duration of follow-up was 11.5 months (range, 1 77 months). Continuous data are expressed as mean ± SD or median (range). Survival and freedom from aortic events were calculated using the Kaplan-Meier method and expressed as mean ± SE. Statistical analysis was performed with StatView (SAS Institute, Cary, NC, USA). Results Three patients who did not recover cardiac beating after cardiopulmonary arrest despite CPR for massive open descending aortic rupture, died during operation. Overall operative and in-hospital mortality were 17.6% and 23.5%, respectively. Excluding the outcomes of these 3 patients, the operative and in-hospital mortality were 9.7% and 16.1%, respectively (Table 3). In the central operation for 14 patients without CPR, there were 2 operative deaths (14.2%). One patient requiring concomitant entire arch replacement through a median sternotomy died from descending aortic open rupture 4 days after operation. Another patient having descending aortic replacement died from brain damage 5 days after operation.

3 652 MURASHITA T et al. Figure 1. Kaplan-Meier survival rate. Figure 2. Actual rate of freedom from aortic events (Kaplan-Meier method). In the 14 patients requiring peripheral operation, 1 patient died within 30 days and 2 patients died after long hospital stay. One patient having axillo-femoral bypass died from rupture of the dissecting descending aorta 2 days after peripheral operation. Another patient having abdominal aorta fenestration for bowel ischemia developed respiratory failure requiring tracheostomy and renal failure. He died from rupture of the dissecting descending aorta on postoperative day 248. Another obese patient with systemic infection already had complications due to paraplegia before surgery and underwent palliative axillo-femoral bypass for ischemia of the lower half body. He suffered from respiratory failure requiring tracheostomy, renal failure, and graft infection. He died from rupture of the dissecting descending aorta on postoperative day 240. In the 3 recent relatively stable patients having TEVAR, there were no deaths, although 1 developed paraplegia (33.3%). Among the 17 patients who were treated with medication first after admission, there were 4 operative deaths (23.5%), involving 3 patients with CPR. Another patient died after prolonged hospital stay. As a result, the operative and in-hos-

4 Surgery for Type B Aortic Dissection 653 pital mortality were 23.5% and 29.4% for this patient group. During the follow-up period, there were 2 (7.7%) late deaths from alcoholic hepatitis and from massive bleeding during the abdominal debranching bypass before TEVAR for dilation of residual dissection on the thoraco-abdominal aorta. In the latter patient the etiology of aortic pathology was Ehlers-Danlos syndrome. The 1- and 5-year survival rates using the Kaplan- Meier method were 74.1±8.1% and 64.8±11.2%, respectively (Figure 1). Four patients underwent replacement of the thoracoabdominal aorta, 1 patient underwent total arch replacement, and 1 underwent elective replacement of the descending aorta for expansion of the dissecting aorta. Including the perioperative aortic rupture, freedom from aortic events at 1 year and at 5 years using the Kaplan-Meier method was 83.0±7.0% and 58.7±11.4%, respectively (Figure 2). Discussion It is widely accepted that the primary management for uncomplicated acute type B dissection is medication, due to the lower mortality rate, ranging from 0% to 7.4%. 3 5 Consequently, emergency surgical treatment has been limited for complicated acute type B dissection, including aortic rupture or critical organ malperfusion caused by aortic branch compromise. A report from the International Registry of Aortic Dissection (IRAD) noted that the overall in-hospital mortality was 29.3% among 82 patients requiring emergency surgery for acute type B dissection. 7 Furthermore, it was also reported by IRAD that patients with severe hypotension or shock on admission and at surgery had the worst prognosis, in that 85.0% of patients died in the first week after admission. 8 In the present study, although all of 3 patients requiring CPR before surgery due to serious open rupture died, the mortality in the other patients without CPR prior to surgery was 9.7%. Even with aortic rupture, the mortality rate was only 12.5% in the 8 patients not requiring CPR before surgery. The 3 catastrophic patients requiring CPR due to open rupture were treated medically at first after admission. During the medical treatment, however, which involved poor management of blood pressure, 2 developed fatal open aortic rupture at 3 h and at 72 h after admission, respectively. Consequently, careful medical treatment with meticulous control of blood pressure is necessary immediately after admission. Also, 1 of these 2 patients had Marfan syndrome and the other had partially thrombosed dissection with systemic infection by methicillin-resistant Staphylococcus aureus. Given that the risk of open repair is relatively low and the risk of rupture is high in patients with dilatation or partial thrombosis of the false channel 9 and connective tissue disorder, more aggressive surgical treatment under relatively stable conditions should have been performed without delay. In terms of surgery for organ malperfusion, aortic grafting, aortic fenestration, or extra-anatomical bypass are selected to restore organ or limb perfusion. Panneton et al reported on the effectiveness of aortic fenestration for organ or limb ischemia. 10 Lauterbach et al demonstrated that aortic fenestration through either the open or endovascular approach provided good results, but that the results of extra-anatomical bypass were unclear. 11 In the present study, 3 patients suffered from persistent organ malperfusion even after emergency surgical treatment involving abdominal aortic fenestration in 1 patient and extra-anatomical bypass in 2. They suffered from critical bowel, renal, spinal cord, and leg ischemia, which led to lethal multiple organ failure and immunocompromise. They died from infection or infection-caused aortic rupture. In this patient group also, 2 of 3 suffered from organ malperfusion during initial medical treatment. We should have arranged emergency surgical treatment without delay for these patients. Recently, the percutaneous catheter-based technique of stent-grafting has been reported for its potential advantages over invasive surgery. 6 Desai et al recently reported excellent long-term results for TEVAR. 12 Early mortality after TEVAR for complicated type B dissection was 7.7%. Serious complications of stent implantation, however, such as occlusion of the left subclavian artery, inadequate device placement, and type I endoleak, have also been reported. 13 Such complications can be difficult to treat via a percutaneous catheter approach and make surgical intervention more complex. We have used TEVAR in only 3 recent patients. There was no mortality, but 1 patient developed paraplegia. Considering the reported excellent results of TEVAR for complicated type B aortic dissection, we consider that TEVAR can be indicated more aggressively. Under compromised hemodynamic conditions such as open rupture, however, we still think that open surgical interventions are necessary. Further investigation including close follow-up is required to clarify the impact of lessinvasive TEVAR. There were some limitations in the present study. First, the size of the cohort was small and the follow-up period was relatively short. Second, this study was a single-institution retrospective study. Randomized controlled studies between conventional surgery and newly developed catheter interventions are desirable to assess the best strategy for complicated acute type B dissection. In conclusion, upon review of the surgical results for acute type B dissection, the clinical results were acceptable despite the high risk. The mortality was relatively low even in patients with aortic rupture. Peripheral operation could be effective, but in some cases organ malperfusion progressed to multiple organ failure. Timely, aggressive surgical intervention is essential. Because postoperative aortic rupture is fatal and reoperation for residual dissection occurs frequently, persistent medical treatment and careful follow-up with regular CT are crucial during the postoperative course. References 1. Kurabayashi M, Okishige K, Azegami K, Ueshima D, Sugiyama K, Shimura T, et al. Reduction of the PaO2/FiO2 ratio in acute aortic dissection: Relation between the extent of dissection and inflammation. Circ J 2010; 74: Kimura N, Tanaka M, Kawahito K, Itoh S, Okamura H, Adachi H, et al. Early- and long-term outcomes after surgery for acute type A aortic dissection in patients aged 45 years and younger. Circ J 2011; 75: Hsu RB, Ho YL, Chen RJ, Wang SS, Lin FY, Chu SH. Outcome of medical and surgical treatment in patients with acute type B aortic dissection. Ann Thorac Surg 2005; 79: Estrera AL, Miller CC 3rd, Safi HJ, Goodrick JS, Keyhani A, Porat EE, et al. Outcomes of medical management of acute type B aortic dissection. Circulation 2006; 114(Suppl): I384 I Nienaber CA, Eagle KA. Aortic dissection: New frontiers in diagnosis and management: Part II: Therapeutic management and followup. Circulation 2003; 108: Dake MD, Kato N, Mitchell RS, Semba CP, Razavi MK, Shimono T, et al. Endovascular stent-graft placement for the treatment of acute aortic dissection. N Engl J Med 1999; 340: Trimarchi S, Nienaber CA, Rampoldi V, Myrmel T, Suzuki T, Bossone E, et al; IRAD Investigators. Role and results of surgery in acute type B aortic dissection: Insights from the International Registry of Acute Aortic Dissection (IRAD). Circulation 2006; 114: Suzuki T, Mehta RH, Ince H, Nagai R, Sakomura Y, Weber F, et al; International Registry of Aortic Dissection. Clinical profiles and outcomes of acute type B aortic dissection in the current era: Lessons from the International Registry of Acute Aortic Dissection (IRAD). 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