Ann Thorac Surg 2007;84:2138. doi:10.1016/j.athoracsur.2007.07.077
© 2007 The Society of Thoracic Surgeons
Correspondence
Internal Thoracic Artery Grafts and Upper Extremity Arteriovenous Fistula
Yoshiyuki Tokuda, MD,
Min-Ho Song, MD, PhD
Department of Cardiovascular Surgery, Gifu Prefectural Tajimi Hospital, 5-161 Maehata, Tajimi, Gifu 507-8522, Japan
(Email: tokuda{at}mxb.mesh.ne.jp).
To the Editor:
Rahbar and colleagues [1] recently published an article regarding the hemodynamic effects of an upper extremity arteriovenous (AV) fistula on the native internal thoracic artery (ITA). The principal conclusion of this study was that changes in AV fistula flow did not alter the Doppler flow hemodynamics of the ipsilateral ITA. Although this study provided valuable information, it analyzed the Doppler flow effects on the native in-situ ITA and not on ITAs used as pedicled grafts. We consider this a major weakness of the study.
We recently treated 8 patients with patent left upper extremity AV fistulas in our hospital. These patients underwent coronary artery bypass grafting (CABG) with pedicled left ITA grafts to the left anterior descending artery (LAD). In addition, these patients underwent intraoperative transit time flow measurements (TTFM) and early postoperative coronary angiography. The angiography confirmed that all grafts were patent without stenosis, with grade A flow (ie, adequate graft flow without significant competition) according to the classification of Nakajima and colleagues [2].
In these 8 patients, the intraoperative TTFM of ITA grafts revealed mean flow (Qmean) of 34.0 ± 11.2 mL/min (range, 21–56), pulsatile index (PI) of 2.73 ± 0.60 (range, 2.1–3.7), and percentage of backward flow (%BF) of 2.50 ± 2.65 (range, 0–8) [3]. The %BF describes the backward-directed flow through the graft across the anastomotic site compared with the total forward flow of the same cardiac cycle, and is therefore a measure of competition flow. As a control group, we reviewed the TTFM of 91 ITA grafts to the LAD without ipsilateral AV fistula, which were confirmed to be fully patent by early postoperative angiography. In this group, Qmean was 41.2 ± 25.3 mL/min, PI was 2.73 ± 1.78, and %BF was 2.41 ± 4.26. There were no significant differences in measurements between the patients with AV fistula and the control group. These results suggest that the presence of ipsilateral AV fistula had no effect on the TTFM hemodynamics of pedicled ITA grafts. In particular, the similar %BF in both groups confirmed that the degree of competition was similar, despite the patent AV fistula. Although we only observed a small number of patients, our observations agree with the conclusions of Rahbar and colleagues [1]. We support the use of the left ITA as a pedicled graft for patients with a left upper extremity AV fistula. However, further clinical experience is required to draw definitive conclusions.
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References
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- Rahbar R, McGee WR, Birdas TJ, Muluk S, Magovern J, Maher T. Upper extremity arteriovenous fistulas induce modest hemodynamic effect on the in situ internal thoracic artery Ann Thorac Surg 2006;81:145-147.[Abstract/Free Full Text]
- Nakajima H, Kobayashi J, Tagusari O, et al. Angiographic flow grading and graft arrangement of arterial conduits J Thorac Cardiovasc Surg 2006;132:1023-1029.[Abstract/Free Full Text]
- Di Giammarco G, Pano M, Cirmeni S, Pelini P, Vitolla G, Di Mauro M. Predictive value of intraoperative transit-time flow measurement for short-term graft patency in coronary surgery J Thorac Cardiovasc Surg 2006;132:468-474.[Abstract/Free Full Text]
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