J Thorac Cardiovasc Surg 2008;135:229-230
© 2008 The American Association for Thoracic Surgery
Reply to the Editor
Heinz Jakob, MDa,
Eva Assenmacher, MDb,
Konstantinos Tsagakis, MDa,
Ulf Herold, MDa
a Department of Thoracic and Cardiovascular Surgery, West German Heart Center Essen, University Hospital Essen, Essen, Germany
b Department of Anesthesiology, West German Heart Center Essen, University Hospital Essen, Essen, Germany
We appreciate Dr Augoustides’ important and meaningful questions regarding brachiocephalic dissection and cerebral malperfusion in the surgical treatment of patients with acute type A aortic dissection.
To provide specific answers, we follow his questions as raised after specifying the baseline situation in our 8 patients: All patients came in with a computed tomographic scan diagnosis obtained elsewhere. Six patients demonstrated dissection of the brachiocephalic trunk, 2 of them hemodynamically in highly unstable condition with tamponade. In 2 patients, no dissection of the truncus was seen, but severe instability and cardiac tamponade was observed in 1 patient. Five patients had clinical signs of cerebral malperfusion, and 1 patient was found unconscious and was intubated before arrival. Thus, brachiocephalic malperfusion was present before surgery in at least 5 patients, confirmed in all by computed tomographic scan.
- 1 Intraoperative monitoring to detect brachiocephalic malperfusion consisted of bilateral monitoring of radial artery pressure in all but 1 of the highly unstable patients, forcing immediate surgery. To date, no transcranial Doppler or transcutaneous scanning of the carotid arteries has been used.
- 2 No intraoperative episodes of new brachiocephalic malperfusion were detected. Validation of this simplistic statement can be given in part by the open approach we used: After exsanguination and opening of the ascending aorta, including the retracted intimal sac, the aortic arch could be inspected directly with both head vessels exposed for some seconds. By placement of the aortic cannula in the mid arch position within the true lumen under direct vision and controlled deairing followed by clamping of the ascending aorta adjacent to the cannula, we were able to immediately exclude the primary tear in the ascending aorta, including the blown up false lumen, which primarily caused the obstruction of the brachiocephalic trunk.
- Distal repair was performed after the target temperature had been reached and after a short period of circulatory arrest and selected cannulation of the brachiocephalic trunk. Backflow via the left carotid artery gave additional information of patency of the right carotid artery. The left carotid artery was cannulated immediately thereafter.
- 3 The aforementioned surgical strategy of immediate exclusion of the primary aortic tear, including the blown up false lumen, obviated any intimal fenestration above the aortic clamp, even in the presence of a re-entry site in the aortic arch. In the 7 patients with bilateral radial artery pressure monitoring, identical pressures were seen throughout cooling.
- 4 Occasional dismal experience has been incurred with "blind" direct ascending aortic cannulation in emergency situations, with thrombotic material from the false lumen being dispersed, especially in patients with ongoing dissection beyond 24 hours. We are therefore concerned that even placement of the cannula into the true lumen under epiaortic scanning could result in the same dilemma of potentially dispersing thrombi via the wide open connection to the false lumen in the ascending aorta.1
Thus, we do believe that our new approach might be a safer way toward adequate antegrade perfusion of the cerebrum during the cooling phase.
References
- Inoue Y, Ueda T, Taguchi S, Kashima I, Koizumi K, Takahashi R, et al. Ascending aorta cannulation in acute type A aortic dissection. Eur J Cardiothorac Surg 2007;31:976-979.[Abstract/Free Full Text]
Related Article
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Ascending aortic cannulation in acute type A aortic dissection: Is intraoperative brachiocephalic malperfusion a possibility?
- John G.T. Augoustides
J. Thorac. Cardiovasc. Surg. 2008 135: 229.
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