Ann Thorac Surg 2002;73:1618-1620
© 2002 The Society of Thoracic Surgeons
Case report
Hybrid management of aortic rupture and lung failure: pumpless extracorporeal lung assist and endovascular stent-graft
Franz X. Schmid, MD*a,
Alois Philipp, MDa,
Johann Link, MDb,
Markus Zimmermann, MDc,
Dietrich E. Birnbaum, MDa
a Department of Cardiothoracic and Vascular Surgery, University of Regensburg, Regensburg, Germany
b Department of Diagnostic Radiology, University of Regensburg, Regensburg, Germany
c Department of Anaesthesiology, University of Regensburg, Regensburg, Germany
Accepted for publication October 17, 2001.
* Address reprint requests to Dr Schmid, Department of Cardiothoracic and Vascular Surgery, University of Regensburg, Franz-Josef-Strauss-Allee 11, D-93053 Regensburg, Germany
e-mail: franz-xaver.schmid{at}klinik.uni-regensburg.de
 |
Abstract
|
|---|
Acute traumatic aortic rupture represents a potentially life-threatening situation. Because of the extremely high early mortality, emergency surgical repair used to be the preferred method of treatment. This group of patients usually is seen with a wide variety of injuries and comorbid conditions, all of which have a major impact on surgical outcome. We present an alternative hybrid approach that combines on-site placement of pumpless extracorporeal lung assist, subsequent patient transfer, and endovascular stent-graft implantation. This procedure may be a potentially useful strategy to reduce the comorbidity and the mortality of both lesions.
|
Introduction
|
|---|
Acute traumatic rupture of the thoracic aorta is mainly a consequence of blunt thoracic or deceleration trauma. Because the majority of these patients are seen with multiple injuries, the most frequent being major fractures, head injury, and blunt thoracic trauma, surgical treatment on an emergency basis has a high mortality rate of 15% to 21% [1]. Given the principle that thoracic aortic injuries are best treated early, defining the strategy for a treatment protocol presents a difficult interdisciplinary challenge.
A 20-year-old man was involved in a head-on car collision. When the emergency physician arrived, the patient was awake and responsive but complained of breathlessness and chest pain. Arterial pressure was stable at 100/60 mm Hg, and heart rate was 112 beats per minute. Because of respiratory deterioration, the patient was intubated and ventilated in the field and transferred to the nearest regional hospital.
The chest radiograph and computed tomographic scan demonstrated bilateral hemopneumothorax with contusional patchy lung disease and rupture of the descending aorta in the isthmian region just distal to the origin of the left subclavian artery (Fig 1A).
Despite placement of chest tubes on both sides and maximum ventilatory support, oxygenation deteriorated dramatically; the arterial oxygen tension to inspired oxygen fraction ratio was 36 and the oxygen saturation, 65%. The patient was deemed to be in too unstable condition to undergo transportation or surgical intervention. Consultation by telephone prompted a team of our specialized facility to move to the patient using a rescue helicopter.
View larger version (129K):
[in this window]
[in a new window]
|
Fig 1. (A) Preoperative angiogram locates the rupture at the aortic isthmus. (B) Immediate postoperative angiogram shows the stent-graft with complete sealing of the rupture without compromising the subclavian artery.
|
|
Shortly after arrival of the team, extracorporeal lung assist (ECLA) without a pump was initiated (Fig 2).
Vascular cannulation was achieved by percutaneous introduction of wire-reinforced heparin sodium-coated cannulas into the right femoral artery and the left femoral vein (model BE-FCSA17V; Jostra AG, Hirrlingen, Germany). The arteriovenous shunt was established by connecting a prefilled membrane oxygenator with low flow resistance (Novabreath; Jostra AG) to the cannulas. Oxygen inflow to the oxygenator was 12 L/min. Technical details of the implantation procedure and the setup have been published previously [2]. The arteriovenous pressure gradient provided an extracorporeal flow across the membrane oxygenator of 2.1 L/min, which represented 25% of the patient’s cardiac output. Oxygen saturation immediately improved to 96%. Cardiac output remained stable at 8 to 10 L/min with moderate inotropic support (dopamine hydrochloride, 20 µg · kg-1 · min-1, and norepinephrine, 5 µg · kg-1 · min-1). A continuous heparin infusion was administered through the arterial cannula to achieve an activated clotting time of 130 to 150 seconds. While receiving extracorporeal support, the patient was transferred to our institution in the rescue helicopter.
View larger version (124K):
[in this window]
[in a new window]
|
Fig 2. Pumpless extracorporeal lung assist system is placed between the patient’s legs. The completely heparin-coated arteriovenous shunt includes a low-resistance membrane oxygenator.
|
|
The next day oxygenation improved gradually, and the decision was made to perform endovascular stent-graft implantation. Informed consent was obtained from the patient’s parents. After surgical exposure of the arterial access vessel, namely, the left femoral artery, a 5F graduated catheter was positioned in the aortic arch for angiographic evaluation of the false aneurysm and its proximal and distal neck. Subsequently, the introducer system of the stent device was advanced under fluoroscopic guidance. After deployment of the stent at the target position, the leading and trailing parts of the graft were modeled to the aortic wall. Adenosine or other measures to induce bradycardia or to reduce blood flow or pressure were not used, as the highly flexible stent allowed quick delivery of the prosthesis. At completion angiography, the rupture was shown to be completely sealed (Fig 1B). The stent-graft used was constructed from a self-expanding 26 x 10-mm stent and a soft polytetrafluoroethylene graft (Thoracic Excluder; W. L. Gore & Associates, Flagstaff, AZ).
Lung assist was in continuous use for a total of 7 days. During pumpless ECLA support, the respirator settings were modified to achieve low pressure, low frequency, and low oxygen ventilation including a normalized inspiration to expiration (I:E) ratio. Monitoring of hemodynamics and extracorporeal flow was performed by serial measurements (Table 1).
Discontinuation of extracorporeal support was undertaken when the patient had a stable arterial oxygen pressure of greater than 80 mm Hg at an inspired oxygen fraction of 0.5 for more than 24 hours during weaning. After manual extraction of both cannulas in association with a compressive bandage, the patient made an uneventful postoperative recovery. One month and 5 months later, he was readmitted for postoperative two-dimensional reconstruction by magnetic resonance imaging. Perfect stent-graft placement with no signs of leakage or migration was noted.
|
Comment
|
|---|
Emergency surgical repair of traumatic rupture of the thoracic aorta used to be the preferred method of treatment. On the other hand, caution should be exercised in the application of surgical techniques to a group of patients in whom transthoracic graft replacement of the aorta portends excessively high morbidity and mortality, for instance, patients with severe respiratory failure or bleeding complications from pelvic fractures or head injury. Operation for traumatic aortic rupture accounts for a mortality rate of 15% to 21% [1]. Recent advances in endovascular techniques have enabled nonsurgical treatment of aortic aneurysm [3], complications of aortic dissection [4], and bleeding complications of traumatic aortic rupture [5]. Experience with endovascular treatment is still limited, but reports in the literature are encouraging [6]. In this regard, we obtained a good result using such a strategy in our patient. There was no procedure-related morbidity. Our result compares well with promising results of others.
Recently, we [2] introduced pumpless ECLA into clinical practice. Compared with conventional pump-driven ECLA, pumpless ECLA offers a number of advantages. The most common problems, such as mechanical- and foreign surface-induced blood trauma, hemorrhagic complications, and bleeding from the surgical site, are at least partly pump-dependent. By avoiding a pump head, minimizing the length of the total extracorporeal circuit (120 cm; see Fig 2), and using a completely heparin-bonded setup, heparin requirements and thus target levels for activated clotting time were reduced. In our patient, neither thrombus formation at the cannulation sites or within the oxygenator nor bleeding from the groin incisions or from other injured body compartments (lungs, or fractures of the pelvic bones) was recognized. However, our experience with more than 60 patients told us that thrombus formation in the venous cannula or the oxygenator resulting in decreased extracorporeal flow can become a problem in long-term pumpless ECLA use. The pumpless ECLA circuit was placed between the patient’s legs to allow nursing care and kinetic therapy. In comparison to maximum flow rates of 4 to 6 L/min with pump-driven ECLA, extracorporeal flow in our patient was limited to about 2 L/min. Nevertheless, relevant oxygenation and carbon dioxide elimination were achieved. There were no echocardiographic or serological findings suggestive of blunt myocardial injury. Inotropic support was given to maintain adequate pumpless ECLA flow in this patient who was in a hypotensive circulatory state, which in our experience is necessary in up to 50% of patients.
Use of pumpless ECLA in our patient preceded endovascular stenting of the aorta. An alternative approach, not suitable in this patient for logistic reasons, would have been combined stenting and commencement of pumpless ECLA therapy in the catheterization laboratory. The possibility of using pumpless ECLA on an ambulatory basis, namely, to render the patient’s transfer possible, emphasizes the feasibility and efficiency of our ECLA system. The site of aortic rupture with a 1-cm distance to the left subclavian artery was ideally suited to stenting. However, concomitant pumpless ECLA use requires skilled methods reserved for centers with experience in interventional techniques. In our opinion, indications for surgical intervention are complete circular disruption of the aorta, major bronchopleural fistulas, major bleeding, and lack of a minimum length of the proximal landing zone for secure stent fixation.
In conclusion, pumpless ECLA and endovascular stent-graft placement as a combined procedure proved to be extremely useful in managing a difficult problem and obviated the heightened risks of operation. It is simple, safe, and particularly suitable for patients with multiple injuries. The combined procedure offers an effective treatment option for a group of carefully selected patients seen with complex lung and aortic pathologic conditions.
|
References
|
|---|
-
Von Oppell U.O., Dunne T.T., De Groot M.K., Zilla P. Traumatic aortic rupture: twenty-year metaanalysis of mortality and risk of paraplegia. Ann Thorac Surg 1994;58:585-593.[Abstract]
-
Philipp A., Behr R., Reng M.C., et al. Pumpless extracorporeal lung assist. J Extracorpor Technol 1998;30:3-7.
-
Dake M.D., Miller D.C., Mitchell R.S., Semba C.P., Moore K.A., Sakai T. The "first generation" of endovascular stent-grafts for patients with aneurysms of the descending thoracic aorta. J Thorac Cardiovasc Surg 1998;116:689-704.[Abstract/Free Full Text]
-
Walker P.J., Dake M.D., Mitchell R.S., Miller D.C. The use of endovascular techniques for the treatment of complications of aortic dissection. J Vasc Surg 1993;18:1042-1051.[Medline]
-
Dorweiler B., Dueber C., Neufang A., et al. Endovascular treatment of acute bleeding complications in traumatic aortic rupture and aortobronchial fistula. Eur J Cardiothorac Surg 2001;19:739-745.[Abstract/Free Full Text]
-
Nienaber C.A., Fattori R., Lund G., et al. Nonsurgical reconstruction of thoracic aortic dissection by stent-graft placement. N Engl J Med 1999;340:1539-1545.[Abstract/Free Full Text]
This article has been cited by other articles:
|
|
|
|
 
M. Foltan, A. Philipp, and D. Birnbaum
Extended use of ECC
Perfusion,
May 1, 2007;
22(3):
173 - 178.
[PDF]
|
|
|
|
|
|
|
G. Matheis
New technologies for respiratory assist
Perfusion,
July 1, 2003;
18(4):
245 - 251.
[Abstract]
[PDF]
|
|
|
Top
Abstract
Introduction
