Ann Thorac Surg 2006;81:790
© 2006 The Society of Thoracic Surgeons
Correspondence
Reply
Leonard N. Girardi, MD,
Karl H. Krieger, MD,
Charles A. Mack, MD,
Leonard Y. Lee, MD,
Anthony J. Tortolani, MD,
Ottis Wayne Isom, MD
Department of Cardiothoracic Surgery, Weill Medical College of Cornell University, 525 E 68th St, M-424, New York, NY 10021
(Email: lngirard{at}med.cornell.edu).
To the Editor:
We would like to thank Morishita and colleagues [1] for their insightful analysis of our article examining the effects of aortic arch cross clamping on the incidence of neurologic injury after repair of descending and thoracoabdominal aortic aneurysms [2]. Their concern for the cause of aneurysms is understandable. In their series of 81 patients who had their arch clamped proximal to the left subclavian artery, those patients with degenerative aneurysms had a sixfold increased risk of stroke when compared with patients who had aneurysms secondary to aortic dissections.
Of the 272 patients in our report, 165 were "degenerative," whereas 107 were secondary to either chronic (82) or acute (25) aortic dissection. The number of atherosclerotic aneurysms was similar between group I (ie, those who had arch clamping proximal to the left subclavian artery) and group II (ie, those who had the aorta clamped distal to the left subclavian artery). In our experience, aneurysm etiology did not alter the incidence of stroke, paralysis, renal failure, or mortality. These data suggest that the cause of aneurysms is not a critical predictor of neurologic injury. Rather, intimal topography and the presence of significant aortic calcification, as determined by a combination of epiaortic echocardiography and preoperative imaging, should alert the surgeon to the increased risk of stroke with arch clamping. As long as the proposed site of cross clamping is free of mobile debris and circumferential calcification, we believe that arch clamping is safe and preferable to more extensive operations requiring cardiopulmonary bypass. However, this does not mean that profound hypothermic circulatory arrest (PHCA) should be abandoned.
In our report, approximately 10% of patients (29 of 301) with aneurysms arising in the distal arch required repair utilizing PHCA. Cross clamping proximal to the left subclavian artery was contraindicated in these patients with mobile atheromatous debris at the clamp site, a porcelain aortic arch, or extensive aneurysmal involvement of the proximal arch. In our opinion, PHCA in these situations is mandatory and may help reduce the 25% incidence of stroke seen in Kawaharada and colleagues' [3] experience with degenerative aneurysms undergoing arch clamping. However, it is important to keep in mind that the risk of stroke in these high-risk patients is not eliminated regardless of the surgical technique. Our experience with PHCA in this high-risk cohort of patients was disappointing with a 10% incidence of stroke and an operative mortality of 17%. As we stated in our conclusions, perhaps this type of aneurysm would be better treated with less conventional methods of aortic reconstruction in the hopes of further reducing the incidence of this often fatal complication.
Finally, we do not agree that the increased incidence of left recurrent nerve palsy in those who have had arch clamping translates into more arch manipulation and stroke. Proximal control of the arch between the great vessels is fraught with danger and should be performed in a gentle and meticulous fashion. Debris dislodgement can occur with either chronic dissections or degenerative aneurysms and should not occur because of the "usual arch manipulations."
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References
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- Morishita K, Kawaharada N, Fukada J, Abe T. Does arch clamping increase stroke rates? (letter) Ann Thorac Surg 2006;81:789-790.[Free Full Text]
- Girardi LN, Krieger KH, Mack CA, Lee LY, Tortolani AJ, Isom OW. Does cross-clamping the arch increase the risk of descending thoracic and thoracoabdominal aneurysm repair? Ann Thorac Surg 2005;79:133-138.[Abstract/Free Full Text]
- Kawaharada N, Morishita K, Fukada J, et al. Stroke in surgery of the arteriosclerotic descending thoracic aortic aneurysmsinfluence of cross-clamping technique of the aorta. Eur J Cardiothorac Surg 2005;27:622-625.[Abstract/Free Full Text]
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