Letter by Nežić et al Regarding Article, “The Impact of Diabetic Status on Coronary Artery Bypass Graft Patency: Insights From the Radial Artery Patency Study”

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HomeCirculationVol. 119, No. 22Letter by Nežić et al Regarding Article, “The Impact of Diabetic Status on Coronary Artery Bypass Graft Patency: Insights From the Radial Artery Patency Study” Free AccessLetterPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessLetterPDF/EPUBLetter by Nežić et al Regarding Article, “The Impact of Diabetic Status on Coronary Artery Bypass Graft Patency: Insights From the Radial Artery Patency Study” Duško Nežić, MD, PhD, FETCS, Aleksandar Knežević, MD, BcS, Miomir Jović, MD, PhD and Petar Vuković, MD, BcS Duško NežićDuško Nežić “Dedinje” Cardiovascular Institute, Belgrade, Serbia Search for more papers by this author , Aleksandar KneževićAleksandar Knežević “Dedinje” Cardiovascular Institute, Belgrade, Serbia Search for more papers by this author , Miomir JovićMiomir Jović “Dedinje” Cardiovascular Institute, Belgrade, Serbia Search for more papers by this author and Petar VukovićPetar Vuković “Dedinje” Cardiovascular Institute, Belgrade, Serbia Search for more papers by this author Originally published9 Jun 2009https://doi.org/10.1161/CIRCULATIONAHA.108.832063Circulation. 2009;119:e559To the Editor:We read with great interest the article by Singh and associates1 that was recently published in Circulation. We respect all subsequent analysis arising from an excellent, prospective, randomized basic study presented by Desai and colleagues2 a few years ago that compared the angiographic patency of radial artery (RA) grafts with that of saphenous vein (SV) grafts 1 year after surgery. Although that study demonstrated significantly better angiographic patency of RA conduits compared with SV grafts (occlusion rate of 8.2% for RA conduits versus 13.6% for SV conduits), the existence of a string sign was assigned to 7% of RA grafts and to only 0.9% of SV grafts. Subsequent analysis of those data3 showed that 48.4% (15 out of 31) of the RA conduits with a string sign presented with thrombolysis in myocardial infarction (TIMI) 1 flow. A significantly higher rate of postoperative angina has been registered in patients whose RA conduits were found to have a string sign and TIMI 1 flow.3The primary end point of the study by Singh et al1 was to determine overall study graft failure, and the secondary objective was to compare graft failure of the study RA conduits versus the study SV conduits within nondiabetic and diabetic patients. All RA conduits with a string sign were considered to be patent. In our opinion, if we are discussing the failure and occlusion of study grafts, RA grafts with an angiographic string sign should be included in the category of failed conduits (at least those with TIMI 1 flow because TIMI 1 flow has been defined as some penetration of contrast material beyond the point of obstruction but without perfusion of the distal coronary bed4). Although only the perioperative use of α-adrenergic agonists and target vessels stenosis <90% were pointed out as significant factors for a string sign3 appearance of RA conduits, we assume that RA conduits with a string sign and TIMI 1 flow were similarly distributed among diabetic and nondiabetic patients. Some of the authors’ conclusions are based on the border level of statistical significance (ie, RA protectiveness against graft failure compared with SV grafting in both diabetic and nondiabetic cohorts). It is possible that, with the inclusion of all RA conduits that have definitely failed (36 occluded, 15 with a string sign and TIMI 1 flow), the findings of the study would no longer be statistically significant.DisclosuresNone. References 1 Singh S, Desai N, Petroff S, Deb S, Cohen E, Radhakrishnan S, Schwartz L, Dubbin J, Fremes S, for the Radial Artery Patency Study Investigators. The impact of diabetic status on coronary artery bypass graft patency: insights from the radial artery patency study. Circulation. 2008; 118: S-222–S-225.Google Scholar2 Desai N, Cohen E, Naylor D, Fremes E, for the Radial Artery Patency Study Investigators. A randomized comparison of radial artery and saphenous vein coronary bypass grafts. N Engl J Med. 2004; 351: 2302–2309.CrossrefMedlineGoogle Scholar3 Miwa S, Desai N, Koyama T, Chan E, Cohen E, Fremes S, from the Radial Artery Patency Study Investigators. Radial artery angiographic string sign: clinical consequences and the role of pharmacologic therapy. Ann Thorac Surg. 2006; 81: 112–119.CrossrefMedlineGoogle Scholar4 Appleby MA, Michaels AD, Chen M, Gibson CM. Importance of the TIMI frame count: implications for future trials. Curr Control Trials Cardiovasc Med. 2000; 1: 31–34.CrossrefMedlineGoogle Scholar Previous Back to top Next FiguresReferencesRelatedDetails June 9, 2009Vol 119, Issue 22 Advertisement Article InformationMetrics https://doi.org/10.1161/CIRCULATIONAHA.108.832063PMID: 19506121 Originally publishedJune 9, 2009 PDF download Advertisement