Intravascular ultrasound and 3D angle measurements of coronary bifurcations
Objective: To standardize the intravascular ultrasound (IVUS) analysis of coronary bifurcations. Background: Percutaneous treatment of bifurcation lesions is difficult particularly 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: Quantitative 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: ProxLADversus ProxLAD(DX)were similar for vessel area (15.5 ± 4.6 mm2vs. 15.9 ± 4.0 mm2, P 5 0.19), lumen area (8.3 ± 3.6 mm2vs. 8.6 ± 3.3 mm2, P = 0.25), and plaque area (7.2 ± 2.0 mm2vs. 7.3 ± 1.9 mm2, P = 0.55). However, BifurcationLADwas larger than BifurcationDXfor vessel area (17.3 ± 4.0 mm2vs. 16.6 ± 3.9 mm2, P = 0.0083). The 3D angiographic bifurcation angle was 50° ± 13° (range of 26°-84°), and did not affect the IVUS measurements. IVUS analysis showed that bifurcation lesions did obey Murray's Law, as ProxLADlumen area measured 36.7 ± 25.1 mm3versus DistLAD/DistDXmeasured 38.0 ± 29.1 mm3, P = 0.56. Conclusions: Two IVUS pullbacks should be performed for a complete assessment of the bifurcation and comparison with Murray's Law. The proposed IVUS analysis was not influenced by the bifurcation angle.