Basic Science Review Intravascular Ultrasound and 3D Angle Measurements of Coronary Bifurcations Eva C. van der Waal, 1 MSc, Gary S. Mintz, 2 MD, Hector M. Garcia-Garcia, 1 MD, MSc, Anh B. Bui, 3 MD, Marieta Pehlivanova, 3 BS, Chrysafios Girasis, 1 MD, Patrick W. Serruys, 1 MD, Wim J. van der Giessen, 1 * MD, and Neil J. Weissman, 3 MD Objective: To standardize the intravascular ultrasound (IVUS) analysis of coronary bifur- cations. Background: Percutaneous treatment of bifurcation lesions is difficult particu- larly at the side branch ostium. Imaging techniques may improve our understanding of treatment options. There is no established IVUS methodology to assess the bifurcation. The present study aims to develop standards for bifurcation imaging. Methods: Quanti- tative IVUS analysis and 3D bifurcation angle measurements were performed in 34 patients who were selected from the Washington Hospital Center Database. Patients were included if both left anterior descending (LAD) and first diagonal (DX) pullbacks in the same procedure were done. Angiograms were available in 27 patients to measure the 3D bifurcation angle using specialized software. Pullbacks were analyzed proximal and distal to the bifurcation, and at the bifurcation. Results: Prox LAD versus Prox LAD(DX) were similar for vessel area (15.5 6 4.6 mm 2 vs. 15.9 6 4.0 mm 2 , P 5 0.19), lumen area (8.3 6 3.6 mm 2 vs. 8.6 6 3.3 mm 2 , P 5 0.25), and plaque area (7.2 6 2.0 mm 2 vs. 7.3 6 1.9 mm 2 , P 5 0.55). However, Bifurcation LAD was larger than Bifurcation DX for vessel area (17.3 6 4.0 mm 2 vs. 16.6 6 3.9 mm 2 , P 5 0.0083). The 3D angiographic bifurcation angle was 508 6 138 (range of 268–848), and did not affect the IVUS measurements. IVUS analysis showed that bifurcation lesions did obey Murray’s Law, as Prox LAD lumen area measured 36.7 6 25.1 mm 3 versus Dist LAD /Dist DX measured 38.0 6 29.1 mm 3 , P 5 0.56. Conclu- sions: Two IVUS pullbacks should be performed for a complete assessment of the bifur- cation and comparison with Murray’s Law. The proposed IVUS analysis was not influ- enced by the bifurcation angle. ' 2009 Wiley-Liss, Inc. Key words: intravascular ultrasound; percutaneous coronary intervention; angiography; bifurcation INTRODUCTION Coronary bifurcations are often difficult and incom- pletely assessed angiographically because of vessel overlap, limited visualization of only the lumen, and the requirement for multiple views. Intravascular ultra- sound (IVUS) is routinely used to clarify angiographic ambiguity in many clinical scenarios. IVUS gives a better understanding of the normal and diseased vessel wall by displaying tomographic views. However, there has been limited application of IVUS in bifurcations. One reason for this is that there is no established IVUS method to assess the bifurcation. A second rea- son is that prestenting IVUS of both main branch (MB) and side branch (SB) is uncommon and post- stenting advancement of the IVUS probe through a stent into the sidebranch can be problematic. Even if Conflict of interest: Nothing to report. 1 Department of Cardiology, Thoraxcenter, Erasmus MC Rotter- dam, The Netherlands 2 Cardiovascular Research Foundation, New York, New York 3 MedStar Research Institute, Washington Hospital Center, Washington DC *Correspondence to: Wim van der Giessen, MD, Erasmus MC, Thoraxcenter, ’s Gravendijkwal 230, 3015 CE Rotterdam, The Neth- erlands. E-mail: w.j.vandergiessen@erasmusmc.nl Received 22 September 2008; Revision accepted 19 December 2008 DOI 10.1002/ccd.21965 Published online 19 March 2009 in Wiley InterScience (www. interscience.wiley.com). ' 2009 Wiley-Liss, Inc. Catheterization and Cardiovascular Interventions 73:910–916 (2009)