JTCS KCI
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to Personal Folders
Right arrow Download to citation manager
Right arrow Permission Requests
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kulik, A.
Right arrow Articles by Ruel, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kulik, A.
Right arrow Articles by Ruel, M.
Related Collections
Right arrowRelated Article

J Thorac Cardiovasc Surg 2007;133:592-593
© 2007 The American Association for Thoracic Surgery

Letter to the Editor

Intraoperative indocyanine green angiography: Ready for prime time?

Alexander Kulik, MDa, Fraser D. Rubens, MD, MSca, Marc Ruel, MD, MPHa,b

a Division of Cardiac Surgery, University of Ottawa, Ottawa, Ontario, Canada
b Department of Epidemiology, University of Ottawa, Ottawa, Ontario, Canada

To the Editor:

We read with interest the report by Desai and associates1Go comparing intraoperative graft evaluation using indocyanine green (ICG) angiography and transit-time ultrasound flow (TTF) measurements. Our group also shared in the enthusiasm for ICG angiography when it was introduced,2Go and we congratulate the authors on their efforts to validate this novel technology as a quality improvement initiative in coronary surgery.3Go In our opinion, maximizing coronary artery bypass graft patency is a highly relevant issue.

In our experience, we found an important learning curve with ICG angiography, and we noted difficulty in the assessment of coronary anastomoses involving arterial pedicles, such as nonskeletonized internal thoracic artery (ITA) and radial artery grafts. We routinely skeletonized the distal portion of arterial grafts, and yet the images created by ICG angiography were still unclear at the anastomotic level. We would be interested to learn of the authors’ experience with the evaluation of ITA grafts using ICG angiography and whether they now skeletonize their ITA grafts for this purpose. Another issue that was not addressed in this study relates to ICG costs, including the capital investment necessary to acquire the imaging device and the per-case costs. Can the authors comment on the cost effectiveness of the two techniques for the intraoperative assessment of graft patency?

More important, however, we are concerned with the analysis of sensitivity and specificity in Desai and colleagues’ article. In the evaluation of sensitivity and specificity of a new diagnostic test, the validity of the analysis is intimately dependent on the definitions chosen for "positives" and "negatives." We disagree with the definition of "normal" used by the authors for TTF assessment, and we could not find any previous studies to support the authors’ use of greater than 10 mL/min as a cutoff for "normal." Applying the definitions of Desai and associates, a vein graft to a large obtuse marginal coronary artery with high-grade proximal stenosis measured to have a pulsatility index of 4.9, diastolic flow fraction of 60%, and mean flow of 12 mL/min would be considered "normal." In our view, such a graft is abnormal because flow would be expected to be much higher than 12 mL/min, and we would consider graft revision. It is not surprising that such a graft would be seen as abnormal or even occluded by postoperative x-ray angiography. Applying the study’s definition, this would constitute a false negative (normal by TTF, abnormal by x-ray angiography) and thus would contribute to an artificially low sensitivity of TTF measurement. Did the authors consider performing a post hoc exploratory analysis to evaluate their results with alternative definitions for "abnormal?" For example, had greater than 15 mL/min4Go or greater than 20 mL/min5Go been the cutoff for "normal" by TTF instead of greater than 10 mL/min, different conclusions may have been drawn regarding the sensitivity and specificity of TTF measurement.

In summary, we commend Desai and associates for their comparative assessment of TTF and ICG angiography. However, we have identified limitations in their analysis and other logistical challenges that may constitute important barriers to the generalizability of their conclusions.

Footnotes

Dr Marc Ruel reports consulting fees from Medtronic, Inc, the manufacturer of the transit-time ultrasonic flowmeter.

References

  1. Desai ND, Miwa S, Kodama D, Koyama T, Cohen G, Pelletier MP, et al. A randomized comparison of intraoperative indocyanine green angiography and transit-time flow measurement to detect technical errors in coronary bypass grafts. J Thorac Cardiovasc Surg 2006;132:585-594.[Abstract/Free Full Text]
  2. Rubens FD, Ruel M, Fremes SE. A new and simplified method for coronary and graft imaging during CABG. Heart Surg Forum 2002;5:141-144.[Medline]
  3. Desai ND, Miwa S, Kodama D, Cohen G, Christakis GT, Goldman BS, et al. Improving the quality of coronary bypass surgery with intraoperative angiography: validation of a new technique. J Am Coll Cardiol 2005;46:1521-1525.[Abstract/Free Full Text]
  4. 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]
  5. Walpoth BH, Bosshard A, Genyk I, Kipfer B, Berdat PA, Hess OM, et al. Transit-time flow measurement for detection of early graft failure during myocardial revascularization. Ann Thorac Surg 1998;66:1097-1100.[Abstract/Free Full Text]

Related Article

Reply to the Editor
Nimesh Desai and Stephen E. Fremes
J. Thorac. Cardiovasc. Surg. 2007 133: 1396-1397. [Extract] [Full Text] [PDF]



This article has been cited by other articles:


Home page
 J Am Coll Cardiol ImgHome page
H. B. Ward, R. F. Kelly, and E. K. Weir
Assessment of graft patency during coronary artery bypass graft surgery mitigating the risk.
J. Am. Coll. Cardiol. Img., May 1, 2009; 2(5): 613 - 615.
[Full Text] [PDF]

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to Personal Folders
Right arrow Download to citation manager
Right arrow Permission Requests
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kulik, A.
Right arrow Articles by Ruel, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kulik, A.
Right arrow Articles by Ruel, M.
Related Collections
Right arrowRelated Article

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