| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
J Thorac Cardiovasc Surg 2007;134:789-791
© 2007 The American Association for Thoracic Surgery
Brief Communication |
a Department of Thoracic and Cardiovascular Surgery, Wakayama Medical University School of Medicine, Wakayama, Japan
b Department of Thoracic and Cardiovascular Surgery, Minami Wakayama Medical Center, Wakayama, Japan
c Department of Cardiovascular Surgery, Hashimoto Municipal Hospital, Wakayama, Japan.
Received for publication March 22, 2007; accepted for publication April 19, 2007. * Address for reprints: Atsutoshi Hatada, MD, Department of Thoracic and Cardiovascular Surgery, Wakayama Medical University School of Medicine, 811-1 Kimiidera, Wakayama 641-8509, Japan. (Email: hatada{at}mail.wakayama-med.ac.jp).
Graft patency is the major factor limiting the initial clinical benefits of revascularization and patient survival; however, it is not easy to anticipate. Transit-time flow measurement (TTFM) has been the common method of assessing intraoperative coronary artery bypass grafting (CABG) patency because it is a noninvasive and easy method. TTFM provides a mean graft flow (MGF), a flow waveform, and derived values such as the pulsatility index (PI). D’Ancona and colleagues1
reported the necessity to revise 3% of grafts on the basis of TTFM and emphasized the crucial feature of flow value interpretation as an index of graft patency. Takami and Ina2 reported the relation between the graft flow waveform and the anastomotic quality of CABG using a fast Fourier transformation (FFT) analysis. However, there have been no reports that graft patency can be anticipated using analysis of the graft flow waveform.
We demonstrate that graft patency can be assessed with FFT analysis of TTFM waveform.
The present study included 29 patients who underwent isolated CABG with cardiopulmonary bypass and a postoperative cardiac catheterization (the term after CABG; 3–6 months). The patients received 29 saphenous vein grafts, all aortocoronary bypass grafts, including 24 patent grafts in the future and 5 occluded grafts. All anastomoses were performed by 1 surgeon (Y. O.) in the same fashion.
Graft flow tracing was obtained intraoperatively using a transit-time flowmeter (BF 1000; Medi-Stim AS, Oslo, Norway). A flow probe to fit each saphenous vein graft (3–4 mm) was placed around the graft when hemodynamic conditions were stable after weaning from CABG. On the basis of the obtained flow profile, the following variables were calculated: MGF, PI, and FFT of the flow waveform. Harmonics of FFT analysis by the flowmeter existed at frequencies that were multiplies of the frequency of the original waveform and were described in terms of an amplitude and a phase. In the present study, we defined F0 as a power of the fundamental frequency, H1 as a power of the first harmonic, H2 as a power of the second harmonic, and sequentially as H3, H4, H5, H6, H7, H8, H9, and H10. Ha (=H5 + H6 + H7 + H8 + H9 + H10) was calculated.
All data were expressed as mean ± standard division. Comparison of the data between the patent and occluded grafts was performed using the Student t test.
Figure 1 shows the PI and MGF of each group (patent grafts and occluded grafts). There was no significant difference between the patent grafts and occluded grafts (PI: 27.2 ± 16.6 vs 21.0 ± 10.9, respectively, P = .181; MGF: 3.60 ± 2.23 vs 4.91 ± 4.69, respectively, P = .155). Figure 2 shows the power of Ha. In the spectrum from H5 to H10, the power in the group of patent grafts was significantly higher than that in the group of occluded grafts. Ha in the group of patent grafts was significantly higher than that in the group of occluded grafts (0.352 ± 0.0517 vs 0.485 ± 0.402, respectively, P = .04).
|
|
D’Ancona and colleagues1 emphasized the reliance on correct analysis of TTFM flow patterns to correct abnormalities and reported a predominantly systolic flow in 34 of 37 grafts, which had altered to a diastolic pattern after revision. The flow pattern was useful to confirm graft patency in conjunction with adequate MGF and PI values. In this study, MGF and PI values were not significantly different between the patent grafts and the nonpatent grafts. Some reports3,4 demonstrated that graft flow waveform was more important in relation to graft patency than graft flow volume, because graft flow waveform affects the perfusion area of target vessels, coronary resistance, graft resistance, and quality of anastomosis. We did not consider the quality of anastomosis because our study did not include the grafts with anastomotic stenosis.
In contrast, although it was reported that the diastolic filling pattern was a good graft flow waveform,5 no study has reported that pattern expressed as the numeric value. We demonstrated graft flow waveform expressed as the numeric value using FFT analysis, and harmonics of FFT analysis may become the parameter to express graft patency when comparing patent grafts with nonpatent grafts.
We did not report the cutoff value of the parameter including H5, H6, H7, H8, H9, H10, and Ha. Because the graft flow waveform was different in each kind of graft, including the internal thoracic artery, gastroepiploic artery, radial artery, and saphenous vein, we should investigate the parameters in each kind of graft in the future.
We demonstrated that graft patency may be anticipated using FFT analysis of TTFM waveform.
Acknowledgments
We acknowledge the technical assistance of Ryota Tsubaki, a graduate student of Kobe University.
References
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |
