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a Second Cardiac Surgical Department, Evangelismos General Hospital, Athens, Greece
b Unit of Interventional Radiology, Evangelismos General Hospital, Athens, Greece
c Thoracic Surgery Department, Sismanoglio, General Hospital, Athens, Greece
Accepted for publication July 23, 2007.
* Address correspondence to Dr Misthos, 16-18 Markou Avgeri St, 15343 Agia Paraskevi, Athens, 15343, Greece (Email: panmisthos{at}yahoo.gr).
| Abstract |
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Methods: A review of a tertiary trauma center registry identified all patients who suffered blunt thoracic aortic injury from 2002 to 2006. All patients underwent either open repair with synthetic graft interposition or endovascular stent grafting (EVS) of the descending thoracic aorta. Type and severity of injury, concomitant injuries, clinical factors, and outcome were compared between groups. Univariate and multivariate analysis was performed.
Results: Endovascular stent grafting was performed in 22 patients, and 10 patients underwent open surgical repair. In the open group, the 30-day mortality rate was 10%, the paraplegia rate was 10%, and incidence of major complications was 30%, which were comparable with the incidences observed in the EVS group of 4.5%, 4.5%, and 13.6%, respectively. No statistically significant differences were demonstrated. Multivariate regression analysis identified associated thoracic injury as the main independent predictor of hospital length of stay (p = 0.03, 95% confidence interval: 0.53 to 18.85). In the EVS group, 1 patient died in the short-term follow-up period and 2 cases of endovascular leak required additional treatment.
Conclusions: Although postoperative mortality and morbidity between open and endovascular repair were comparable, EVS can be considered a safe alternative treatment modality in the therapeutic algorithm of blunt thoracic aortic injury particularly for the higher risk multitrauma patients.
| Introduction |
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Several reports have recently emphasized the efficacy of endovascular stent grafting (EVS) as a therapeutic modality for the management of thoracic aortic disease. There are several limitations in the published literature in that the vast majority of these studies are not comparative, they are referred to patients undergoing elective interventions, and finally, they are primarily focusing on immediate postoperative morbidity and mortality [8–16].
Endovascular stent grafting is a less invasive approach, and although simpler, faster, and safer in unstable patients, it is also associated with stent-related complications, including leakage and migration, that can potentially affect its long-term efficacy.
The aim of this study is to evaluate the short-term performance of EVS repair in emergency thoracic aortic trauma compared with traditional surgical repair to assess the assumption that EVS can be considered as a safe alternative treatment modality in the management of BAI.
| Patients and Methods |
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Inclusion and Exclusion Criteria
Inclusion criteria of the study population consisted of the following: blunt injury, age more than 17 years, and injury to the thoracic aorta requiring intervention. Patients who died before arrival at the hospital or in the emergency department were excluded from analysis. Initially, until June 2005, the indications for EVS were the following: critically unstable patient, surgical priority for other major associated injuries, and contraindication to systematic heparin therapy. Owing to overcoming the learning curve and increasing experience in thoracic stenting techniques in the elective setting, several changes in our selection criteria occurred, and EVS became the method of choice for BAI management. Endovascular stent grafting was contraindicated in case of aortic arch anomalies [17] and proximal extension of the injury.
Diagnosis and Management
The diagnosis was established by spiral computed tomography (CT) with contrast enhancement.
Initial management included strict monitoring of blood pressure, fluid resuscitation, and treatment of other life-threatening associated injuries. All patients emergently underwent either open repair with graft interposition or EVS of the BAI. The patients were classified into two groups: the first group included all cases that were managed with open surgical repair (using or not extracorporeal circulatory assistance), and the second one included all cases of BAI that were managed with EVS repair.
Surgical treatment
The thoracic aorta was approached through left posterolateral thoracotomy. After the pericardium was opened, the aortic arch was controlled with positioning of aortic cross-clamp either between the left commmon carotid and the left subclavian artery or distal to the left subclavian artery. The descending thoracic aorta was controlled distally immediatelly after the traumatic injury to avoid compromise of the intercostal arteries. Two surgical techniques were used: either with the use of full cardiopulmonary bypass or without (clamp-and-sew method). Two surgeons (J.K., A.L.) involved making the choice to repair the aorta with graft interposition.
Endovascular treatment
All of the endovascular procedures were performed in the angiographic suite under local anesthesia and sedation. The vertebrobasilar circulation was routinely evaluated in all patients.
Thirteen patients received Tallent stent grafts, 4 Valiant (World Medical Corporation, Sunrise, Florida) and 5 Relay stent grafts (Bolton Medical, Sunrise, Florida). The common femoral artery was exposed, and stent grafts were delivered through the femoral artery with a 22F to 25F delivery system. A digital aortic angiography was obtained to guide stent graft placement (left brachial artery). The actual stent graft upsizing was as much as 15% on the basis of the aortic diameter on the CT scan (Table 1). In 1 case (patient no. 7), however, upsizing of 20% was used because of shortage of a smaller size that time. No immediate anticoagulation was ever used.
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Major complication was defined as any of the following: acute respiratory distress syndrome, pneumonia, pulmonary embolism, life-threatening postoperative bleeding, myocardial infarction, renal failure, hepatic failure, and cerebrovascular accident.
Protocol of follow-up
The treatment response was assessed on follow-up contrast-enhanced spiral CT at the second day, at 3 to 6 months, and 12 months after the implantation and yearly thereafter.
Statistical Analysis
Patient demographic and epidemiologic characteristics as well as preoperative, intraoperative, and postoperative variables were collated for analysis. Data are expressed as mean ± SD, median and interquartile range (IQR [25th to 75th centile]). Categorical variables were compared using Fishers exact test or
2 test where appropriate, and continuous variables were compared using Students t test or the Mann-Whitney test as appropriate. All tests were two-sided. All p values of 0.05 or less were considered significant. No adjustments were made for multiple testing.
To elucidate associated causative factors to the outcomes of interest (hospital length of stay), a multivariable regression analysis was performed. Initially univariate regression analysis was used to determine all significant confounding variables (covariables). Those associated confounding variables were subsequently included in the multivariable regression model. Only statistically or clinically significant (p
0.05) causative factors from the univariable analysis were adjusted for (included) in the multivariable model. Model fit was evaluated using the Hosmer and Lemeshow goodness-of-fit statistic. All statistical analysis was performed using SPSS 14.0 (SPSS, Chicago, Illinois).
| Results |
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Endovascular stent grafting was performed in 22 patients, and 10 patients underwent open surgical repair with graft interposition. Six of these patients were operated on with extracorporeal cardiopulmonary support (mean aortic cross-clamp time: 26.9 ± 4.7 minutes; median, 25).
Successful stent graft deployment was achieved in all patients with complete exclusion of the pseudoaneurysm (mean procedure time, 63 ± 8 minutes). In no case was conversion to open repair required. In 2 patients (9%), the left subclavian artery was intentionally covered with the device without any long-term sequelae. In 2 cases (9%), endovascular leak was recorded. In the first one, the distal leak was managed with the deployment of a second stent graft. In the second one, proximal endovascular leak took place, which was managed with balloon dilatation of the proximal landing zone (Figs 1 and 2).
Computed tomography scans obtained 6 months after endovascular showed disappearance of pseudoaneurysm in all patients.
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The open group had a 10% 30-day mortality rate (n = 1), a paraplegia rate of 10% (n = 1), and a 30% incidence of major complications (n = 3). These findings are comparable to a 4.5% rate of 30-day mortality (n = 1, died intraoperatively owing to associated injuries; portal vein rupture found at autopsy), and of mortality rate at midterm follow-up (n = 1 at the 40th postoperative day, of pulmonary insufficiency), and of paraplegia. However, in the stent group, the patient had paraplegia by admission due to spine injury, which remained after stent grafting. The incidence of major complications in the endovascular group was 13.6% (Table 3). The details of the single death in the open group were as follows. This patient was transferred to our institution almost 30 hours after the accident in a critical condition with paraplegia, renal failure, intestinal ischemia, and lower limb ischemia due to the aortic injury. He was immediately managed with open repair. A complicated rupture extending to the proximal arch along with complete obstruction of the mid-descending aorta were the operative findings. The patient suffered intraoperative cardiac arrest twice and finally died of abdominal reperfusion injury and multiple organ failure 8 hours after the end of the operation [18].
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| Comment |
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Once the diagnosis of BAI is established, a multidisciplinary decision for further management with surgery or endovascular stenting should be undertaken. Several factors need to be taken into account, including the patients risk factors, patients status (stable or unstable), evidence in the literature, and institutional factors (availability, resources and expertise of different treatment modalities).
The time-honored treatment for BAI is open surgical repair through a left posterolateral thoracotomy, which can be performed with or without cardiopulmonary bypass support. Despite the recent advances in surgical and circulatory assistance techniques, postoperative mortality ranges from 15% to 30%, and the incidence of paraplegia is reported to be 13% to 14% in contemporary studies [1, 2]. A recent meta-analysis showed that the risk of postoperative paraplegia can be minimized if active distal perfusion is used [2].
Recent reports have demonstrated favorable outcome in patients managed with EVS for BAI but failed to disclose a clear advantage of EVS over traditional open surgical repair in terms of survival [8–16, 23, 24]. However, few studies have compared the outcomes of EVS to open repair for BAI in an emergency setting [10, 12–14, 16, 24, 25]. Although there is a clear trend toward better results for the EVS group in all these studies, these two primary outcomes of interest mortality and paraplegia were not significantly different between open and EVS groups. Our results are in accordance with these comparative studies. It is important to note that our study included the largest number of EVS cases for BAI in an emergency setting (n = 22) in comparison with these previous studies (n = 5 to 16).
Cardiopulmonary bypass has a protective effect on the heart and provides distal perfusion to the spinal cord and the kidneys. However, this procedure requires heparin therapy, which can result in bleeding complications, and is clearly a major disadvantage in the presence of other associated serious injuries such as closed head injury. Thus, it increases the risk of conventional surgery in terms of bleeding, and on some occasions, BAI repair is postponed until other serious injuries are repaired [26–28].
On the other hand, the main potential limitations to stent graft treatment for BAI are the site of the laceration, the vascular access, and the availability of a stent graft in the emergency setting. The success of the endovascular procedure greatly depends on the presence of a straight and long neck proximal and distal to the aortic injury. The main EVS prerequisites are proximal and distal landing zone of at least 1 to 2 cm length; aorta diameter less than of the biggest available stent (46 mm); and iliac artery diameter of at least 8 mm.
We deliberately covered the left subclavian artery in 2 patients to increase the length of the proximal landing zone. Although the site of injury is usually in the isthmus of the descending thoracic aorta, at a short distance distal to the left subclavian artery, occlusion of the left subclavian artery usually does not cause significant damage because the basilar artery is usually supplied by both vertebral arteries, and perfusion to the left upper limb is maintained through collaterals from the other arterial branches.
Longer length of hospital stay for the EVS group was attributed to associated thoracic injuries. In our study, prolonged airleak, flail chest, pulmonary infection, severe lung contusions, and multiple ribs fractures were the main causes of prolonged hospital stay.
Delayed repairs have given satisfactory results. However, it is not entirely risk free as 4% of the patients who are candidates for delayed repair die of a ruptured aorta within 1 week from the traumatic injury [29, 30]. To avoid possible catastrophic or even fatal complications of a blunt aortic injury, our team gave priority to aortic EVS repair.
Study Limitations
The limitations of this study are following: firstly, the design of the study, which is not randomized and allows selection bias to occur; secondly, the extent of follow-up available yet to make a more valid comparison; and thirdly, the fact that open operations were performed by two surgeons but stenting by the same team. Finally, the relatively low power of the present study was not able to demonstrate a statistically significant difference in death and paraplegia outcomes. However, the fact that a less invasive method for BAI repair offered the same results with open surgery is of great clinical significance. There has been no evidence of stent graft migration, pseudoaneurusm, reperfusition injury, or other aortic complications. The presence of an aortic stent graft does not seem to have significant effect on secondary surgery for repair of associated injuries.
In conclusion, this preliminary experience has pointed out that early endovascular repair of blunt aortic injury had at least equal short-term results in comparison with those of traditional open surgical repair. For these reasons, although at the beginning our indications for EVS were very narrow (in case systemic heparinization therapy is contraindicated; aortic repair should be delayed; unstable patient), after the initial satisfactory results, EVS became the standard method of BAI repair in our institution. We recommend endovascular stent grafting as a safe alternative treatment modality for BAI in the therapeutic algorithm of the unstable or high-risk patient.
| References |
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