Ann Thorac Surg 2006;81:345-347
© 2006 The Society of Thoracic Surgeons
Case report
Successful Repair of Iatrogenic Acute Aortic Dissection With Cerebral Malperfusion
R
za Türköz, MD
a
,
*
,
Oner Gulcan, MD
a
,
Levent Oguzkurt, MD
b
,
Esra Calskan, MD
c
,
Ayda Turkoz, MD
c
a Department of Cardiovascular Surgery, Adana Teaching and Medical Research Center, Baskent University, Adana, Turkey
b Department of Radiology, Adana Teaching and Medical Research Center, Baskent University, Adana, Turkey
c Department of Anesthesiology, Adana Teaching and Medical Research Center, Baskent University, Adana, Turkey
Accepted for publication October 4, 2004.
* Address correspondence to Dr Türköz, Baskent Universitesi, Tp Fakültesi, Adana Uygulama ve Ara
trma Hastanesi, Dadalo
lu mah, 39 sok, No 6, PK 01250, Adana, Turkey (Email: rturkoz{at}yahoo.com).
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Abstract
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We describe the successful treatment of a patient with iatrogenic acute aortic dissection including cerebral malperfusion as a complication of coronary artery surgery. After beginning cardiopulmonary bypass, a retrograde ascending aortic dissection associated with cerebral malperfusion was recognized. Systemic circulation was immediately arrested at 31°C. After aortotomy, hypothermic selective antegrade cerebral perfusion was established. Replacement of the ascending aorta with coronary artery bypass grafting was performed without neurologic complications.
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Introduction
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Iatrogenic acute aortic dissection (IAAD) is a potentially fatal complication of cardiac surgery. Its prevalence has been estimated at between 0.16% and 0.35% [1, 2]. The frequency of IAAD is high in patients with severe atherosclerotic disease of the aorta, long-standing hypertension, thin, dilated aortic walls, cystic medial necrosis, and collagen vascular disease [1, 2]. Successful management of IAAD depends on immediate recognition and appropriate surgical repair. The mortality rate is approximately 20% after recognition and management in the operating room. However, mortality increases dramatically to 50% if discovered postoperatively [1]. Aortic cannulation, aortic cross-clamps, partial-occlusion clamps, proximal aortic anastomosis, and retrograde dissection from femoral cannulation are responsible for most of the dissections.
Here, we present the case of a patient with cerebral malperfusion due to a retrograde dissection of the ascending aorta after cardiopulmonary bypass (CPB) after femoral artery cannulation. The patient was successfully managed by selective antegrade cerebral perfusion at 31°C owing to the inability to wait for induction of deep hypothermia.
A 70-year-old woman with unstable angina and dizziness was admitted to our hospital. The patient had a 20-year history of systemic arterial hypertension. Coronary angiogram revealed severe stenosis of the left anterior descending, first diagonal branch, intermediate branch, circumflex marginal branches, and complete obstruction of the right coronary artery. Ventriculogram showed severe hypokinesis of the anterior and inferior wall; the ejection fraction was 30%. Preoperative carotid angiography revealed a significant lesion with 90% stenosis of the right internal carotid artery and 80% of the left internal carotid artery with ulceration.
Computed tomography scan of the great vessels showed heavy calcification of the entire thoracic aorta and brachiocephalic arteries (Fig 1). In view of the seriousness of the findings, an approach using simultaneous intervention of both carotid arteries plus off-pump myocardial revascularization with a no-touch aorta technique was chosen. After general anesthesia, endarterectomy of both carotid arteries was performed, first on the right side and then on the left. After bilateral carotid endarterectomy, a median sternotomy was performed.
Owing to the advanced cardiomegaly, it was determined that the circumflex system would not tolerate off-pump myocardial revascularization. Intraoperative examination revealed that the entire wall of the ascending aorta had severe calcification and was therefore considered unsuitable for arterial cannulation or aortic clamping. Cardiopulmonary bypass was established, using the right common femoral artery after femoral exploration and arteriotomy and the right atrium for venous cannulation.
Within a few minutes after beginning CPB, the right radial artery pressure decreased suddenly, and the pressure waveform became flat. We recognized a retrograde dissection (occurring from the cannulation site through the right femoral artery) with the appearance of a tense, circumferential dilatation with bluish discoloration of the exposed aorta. We immediately began cooling to perform the repair under deep hypothermic circulatory arrest. At the same time, we noted that the radial artery pressure was less than 25 mm Hg, and that there was too much strain on the ascending aorta. For these reasons, a diagnosis of cerebral malperfusion was made. Without waiting for further cooling to deep hypothermic circulatory arrest, systemic circulation was arrested at 31°C, and the aorta was transected with the patient in the Trendelenburg position.
Aortotomy showed that there was no intimal tear in the ascending aorta. Immediately after aortotomy, hypothermic selective antegrade cerebral perfusion was administered through cannulation of the innominate artery and the left common carotid artery using two 15F retrograde coronary sinus perfusion cannulas with a manual-inflating cuff (Medtronic DLP, Grand Rapids, Michigan). In addition, the left subclavian artery was occluded with a Fogarty catheter (Baxter Healthcare, Irvine, California). Under selective antegrade cerebral perfusion at 10°C, flow rate of 10 mL · kg–1 · min–1, and cerebral perfusion pressures were adjusted to maintain a right radial artery pressure of 55 to 70 mm Hg. Teflon felt was applied to the distal ascending aorta internally and externally. A distal aortic graft (28 mm, Hemashield Woven Double Velour Vascular Graft; Medox Medicals, Oakland, New Jersey) anastomosis was performed under selective antegrade cerebral perfusion. Then, selective antegrade cerebral perfusion was stopped, the graft was cross-clamped proximally, and antegrade extracorporeal circulation was reinstituted through the arterial cannula inserted into the graft. Circulatory arrest with selective antegrade cerebral perfusion lasted 31 minutes. The proximal aortic reconstruction was performed in a manner similar to that used in the distal ascending aorta, with application of two strips of Teflon felt during rewarming. Then, five distal coronary anastomoses were constructed with two sequential vein grafts and the left internal thoracic artery. Two proximal anastomoses using saphenous vein grafts were performed in the aortic graft.
Postoperatively, there were no neurologic complications. The patient recovered uneventfully; however, early postoperative computed tomography scans showed a patent false lumen (Fig 2).
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Fig 2. The false lumen of the descending aorta was patent in the enhanced computed tomography scan taken in the third month after the operation.
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Comment
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During cardiac surgery, IAAD of the ascending aorta is a rare but potentially fatal complication, particularly with cerebral malperfusion [3]. In these patients, cerebral protection remains a challenge while inducing circulatory arrest during the cooling period. In the current case, we dealt with this challenge as follows: To prevent possible neurologic complications, systemic circulation was arrested at 31°C, and selective antegrade cerebral perfusion was administered at 10°C through cannulation of the cerebral branches. Replacement of the ascending aorta by coronary artery bypass graft was performed with no neurologic complications.
Iatrogenic acute aortic dissection can originate anywhere including the sites of aortic cannulation, aortic cross-clamping, partial lateral clamping, cardioplegic site, the vein anastomosis site, aortotomy site, or at the site of a retrograde dissection of the ascending aorta associated with femoral artery cannulation, as was the case in our patient. Prompt recognition of the IAAD and rapid repair are essential for successful surgical outcome.
Recently, selective antegrade cerebral perfusion has proved to be a reliable method of brain protection during surgery of acute type A aortic dissections [4]. Di Eusanio and coworkers [5] have demonstrated that selective antegrade cerebral perfusion time is not associated with increased hospital mortality or adverse neurologic outcome. However, deep systemic hypothermia or a temperature lower than 26°C has been used for selective antegrade cerebral perfusion [4, 5]. Totally normothermic aortic arch replacement has been described without circulatory arrest, but in this technique innominate artery and the left common carotid artery had been selectively cannulated [6]. Our current policy is to use an open distal anastomosis technique with deep hypothermic circulatory arrest with retrograde cerebral perfusion if it is anticipated that the time for deep hypothermic circulatory arrest will last less than 50 minutes. Selective antegrade cerebral perfusion with deep hypothermia (less than 18°C) is preferred if the period will last longer than 50 minutes.
In our patient, retrograde dissection of the ascending aorta associated with femoral artery cannulation existed, and it was not possible to provide antegrade perfusion of the true lumen to induce deep hypothermic circulatory arrest. Because of this, systemic circulation was stopped at 31°C, and selective antegrade cerebral perfusion was applied immediately to provide cerebral perfusion and hypothermia.
In IAAD, if cerebral malperfusion is diagnosed, waiting for deep hypothermic circulatory arrest may lead to irreversible brain damage. Therefore, in these cases, it is preferable to open the aorta very quickly and apply selective antegrade cerebral perfusion without waiting for occurrence of hypothermia. We believe this approach provides safer and more controlled cerebral perfusion, and we believe that this strategy should be considered in cases of cerebral malperfusion.
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References
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- Still RJ, Hilgenberg AD, Akins CW, Daggett WM, Buckley MJ. Intraoperative aortic dissection Ann Thorac Surg 1992;53:374-379.[Abstract]
- Murphy DA, Craver JM, Jones EL, Bone DK, Guyton RA, Hatcher Jr CR. Recognition and management of ascending aortic dissection complicating cardiac surgical operations J Thorac Cardiovasc Surg 1983;85:247-256.[Abstract]
- Ruchat P, Hurni M, Stumpe F, Fischer AP, von Segesser LK. Acute ascending aortic dissection complicating open heart surgerycerebral perfusion defines the outcome. Eur J Cardiothorac Surg 1998;14:449-452.
- Di Eusanio M, Tan ME, Schepens MA, et al. Surgery for acute type A dissection using antegrade selective cerebral perfusionexperience with 122 patients. Ann Thorac Surg 2003;75:514-519.[Abstract/Free Full Text]
- Di Eusanio M, Schepens MA, Morshuis WJ, et al. Separate grafts or en bloc anastomosis for arch vessels reimplantation to the aortic arch Ann Thorac Surg 2004;77:2021-2028.[Abstract/Free Full Text]
- Touati GD, Roux N, Carmi D, et al. Totally normothermic aortic arch replacement without circulatory arrest Ann Thorac Surg 2003;76:2115-2117.[Abstract/Free Full Text]
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Abstract
Introduction
