ARTICLE IN PRESS doi:10.1510/icvts.2007.171819
Interactive CardioVascular and Thoracic Surgery 7 (2008) 720–721 www.icvts.org
Case report - Vascular thoracic
High resolution computed tomography imaging for individualized allograft replacement of an infected Dacron aortic arch prosthesis Mathias H. Wilhelmi*, Omke E. Teebken, Maximilian A. Pichlmaier, Axel Haverich Divison for Cardiothoracic-, Transplantations- and Vascular Surgery, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany Received 27 November 2007; received in revised form 27 March 2008; accepted 27 March 2008
Abstract We report on the case of a young woman with a history of intravenous drug abuse and the development of an infection of a prosthetic supracoronary-, total arch and partial descending aortic allograft prosthesis following acute aortic dissection type Stanford-A two years previously. For surgical treatment we implanted an allograft prosthesis obtained from a local tissue bank. Particular variations in this setting and in comparison to conventional surgical planning were that high resolution computed tomography imaging was applied to determine and subsequently order the optimal allograft prosthesis in this individual patient and anatomical situation. 䊚 2008 Published by European Association for Cardio-Thoracic Surgery. All rights reserved. Keywords: Aortic surgery; Homograft; Infection; Aortic arch; Computed tomography
1. Case report We report on the case of a 44-year-old woman who was referred to our Department because of recurrent mediastinitis with purulent secretion through a sternal fistula. History revealed an intravenous drug abuse, and prosthetic supracoronary-, total arch and partial descending aortic replacement performed in so-called ‘elephant trunk technique’ following acute aortic dissection type Stanford-A two years previously. Although letters revealed that clinical symptoms and laboratory data had been improved following surgical debridement, drainage of the mediastinum and antimicrobial treatment according to resistogram (Cefotaxim and Ciprofloxacin) over an eight-week course, blood and previous wound specimen cultures were still positive for Clebsiella pneumoniae. A primarily initiated conventional chest X-ray and computed tomography evaluations showed a broadened mediastinum with enlarged lymphatic nodes and a fistula affecting the Dacron prosthesis. Due to these clinical and radiological findings we decided to replace the infected prosthesis by an aortic allograft. However, threedimensional rendered CT-scans further revealed strong anatomic alterations showing that the aortic bulbus was dilated (48.7 mm) and the ascending aorta was elongated and showed a kinked stenosis prior to the dilated brachiocephalic branch (Fig. 1). Thus, to determine optimal dimensions of the desired aortic allograft, we were confronted with three major problems: (1) to measure all crucial vascular dimensions in the pathological situation; (2) to transfer these findings in a virtually corrected *Corresponding author. Tel.: q49-511-532-3448; fax: q49-511-532-5404. E-mail address:
[email protected] (M.H. Wilhelmi). 䊚 2008 Published by European Association for Cardio-Thoracic Surgery
anatomy; and (3) to be able to characterize and identify an individually, suitable allograft prosthesis. Using a 64-row-multislice scanner (GE LightSpeed VCT, Milwaukee), all further imaging evaluations were obtained contrast enhanced with intravenous bolus injection of 80 ml non-ionic contrast media (iomeprol, 350 mgyml iodine) via an antecubital vein (4 mlys flow rate). The scanning protocol consisted of an aortic bolus triggering with a start delay of 5 s. After data acquisition the scan was assessed on a post-processing workstation (GE Advantage Workstation 4.3) to get a multiplanar three-dimensional-rendered imaging. Now it was possible to distinctively view and measure all dimensions and distances of interest and to locate pathological extensions three-dimensionally. Furthermore, analyses such as center line calculations now allowed for diameter determinations of the aortic root, the descending aorta, and the supra-aortic branches, as well as the measurement of distances between the aortic root and the supra-aortic branches (Fig. 1) in a virtually corrected anatomy. Based on this information we precisely characterized the optimal allograft for this patient, asked our local tissue bank for such a graft and subsequently obtained it from our local tissue bank. Surgically the infected prosthesis was totally removed and the ascending aorta and the aortic arch were replaced by an aortic allograft. The whole procedure was performed under conditions of extra-corporal circulation, applied to the vessels of the left groin (total bypass time: 204 min, body temperature minimum 21 8C). Anastomoses of the supra-aortic vessels were sewn in cardiac arrest (45 min) and cross-clamped (CC) carotid arteries (CA) (right: CCs9 minyantegrade brain perfusions71 min; left: CCs10 minyantegrade brain perfusions45 min). The intra-
ARTICLE IN PRESS M.H. Wilhelmi et al. / Interactive CardioVascular and Thoracic Surgery 7 (2008) 720–721
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Fig. 2. Three-dimensional-rendered imaging to view the post-operative situation with the allograft in place and corrected anatomy.
Fig. 1. (a,b) Rotational views of three-dimensional-rendered CT images of the patholgical situation revealing a strongly altered anatomy with elongation of the ascending aorta, a kinked stenosis prior to the dilated brachiocephalic branch and a dissection of the descending aorta; (c) two-dimensional distance measurements in oblique reformational view of the heart, the aorta and the supra-aortic vessels.
and postoperative course of the patient was uneventful, so that she could be discharged from hospital on post-operative day 16. Another CT-scan initiated prior to discharge gave no further hints for graft infection or other structural complications, lymphatic nodes became smaller and the pre-operatively strongly altered anatomy was now corrected (Fig. 2). The patient’s neurological status was inconspicuous, laboratory values were within normal range and the chest X-ray gave no further hints for infectious complications. This patient remains well without signs of local or systemic infection eighteen months after surgery. To the authors’ knowledge, this is the first report on a computed tomography calculated total allograft aortic arch replacement in an infected prosthetic graft situation.
Although this is a rare case we must stress four considerations: (1) the impact of high-resolution and three-dimensional-rendered computed tomography imaging especially in complex anatomical situations for definite localization of pathological extension; (2) the possibility for a thoroughly and ‘guided’ strategic preoperative surgical planning, permitting the exact assessment of crucial dimensions necessary for individual(ized) graft selection; (3) the usefulness of an allograft prosthesis in the situation of an infected alloplastic aortic arch prosthesis; and (4) the importance of a precisely preoperative planning in a surgical situation with no alternative to the one and only available graft in theatre. Although current strategies of surgical planning seem to be sufficient in general and many decisions still have to be made intra-operatively, we experienced that, utilizing the whole spectrum of technical options of high resolution computed tomography imaging, many decisions, especially in complex anatomical situations, can be made preoperatively. Thus, high end imaging may help to further improve surgical strategy and decision making, which may save surgical time and also help to further reduce complication rates.
