Author + information
- Received November 4, 2015
- Revision received December 17, 2015
- Accepted December 18, 2015
- Published online April 11, 2016.
- Bill D. Gogas, MD, PhDa,d,
- Boyi Yang, PhDb,d,
- Marina Piccinelli, PhDc,d,
- Yasir H. Bouchi, BSd,
- Spencer B. King III, MDa,d,e,
- Nabil Dib, MD, MSf,
- Don P. Giddens, PhDd,g,
- Alessandro Veneziani, PhDb,d and
- Habib Samady, MDa,d,∗ ()
- aAndreas Gruentzig Cardiovascular Center, Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
- bDepartment of Mathematics and Computer Science, Emory University School of Medicine, Atlanta, Georgia
- cDepartment of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Georgia
- dEmory Cardiovascular Imaging & Biomechanics Core Laboratory, Emory University School of Medicine, Atlanta, Georgia
- eSaint Joseph’s Heart and Vascular Institute, Atlanta, Georgia
- fUniversity of Arizona College of Medicine, Phoenix, Arizona
- gWallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
- ↵∗Reprint requests and correspondence:
Dr. Habib Samady, Emory University School of Medicine, 1364 Clifton Road NE, Suite F622, Atlanta, Georgia 30322.
A 72-year-old male patient presented with stable angina, and coronary angiography showed a heavily calcified mid left anterior descending coronary artery lesion (diameter stenosis ≈ 75%). Optical coherence tomographic (OCT) assessment (C7-XRsystem, C7 Dragonfly catheter; LightLab Imaging, St. Jude Medical, St. Paul, Minnesota) demonstrated a minimal luminal area of 1.80 mm2, with severe circumferential calcification proximal to the minimal luminal area (Figures 1A1 and 1A2). Lesion “preparation” was performed to optimize stent deployment using the 1.25-mm classic crown Diamondback 360 Coronary Orbital Atherectomy System (OAS) (Cardiovascular Systems, St. Paul, Minnesota) (1). Three runs of 25 s were performed, using a rotational speed of 80,000 rpm. Repeat OCT assessment post-OAS deployment demonstrated a numeric gain in the luminal area of the selected cross sections, with the most significant circumferential calcification from 4.10 ± 0.98 to 4.27 ± 1.07 mm2 (p = 0.80), a relative change of 3.8%. Thereafter, a 3.0 × 12 mm Xience stent (Abbott Vascular, Santa Clara, California) was deployed at 12 atm, followed by post-dilation with a noncompliant balloon at 16 atm.
A novel methodological approach to assess the potential effects of OAS in vessel compliance is the application of computational fluid dynamics analysis using finite-element methods in the treated segments. This post-processing analysis fuses angiographic with OCT acquisitions, including the following steps: 1) automatic luminal extraction following stacking of the OCT cross sections over the patient-specific anatomy (curvature) obtained from angiography; 2) extraction of the patient-specific computational fluid dynamics domain; 3) implementation of realistic inflow boundary conditions; and 4) computational fluid dynamics analysis using finite-element methods over the reconstructed domain. A recent analysis indicated that 3-dimensional optical coherence tomography–derived wall shear stress assessment was in close agreement with earlier techniques using intravascular ultrasound and angiographically derived shear values (2).
In this assessment, following evaluation of circumferential wall shear stress over the selected cross sections with the largest burden of calcium, a numeric increase from 7.05 ± 0.73 to 7.30 ± 0.46 dynes/cm2 (p = 0.73), was observed. This preliminary feasibility analysis addresses the change of local fluid mechanics following OAS application; meanwhile, further studies are needed to evaluate if these observations are associated with changes in vessel compliance after reducing the circumferential burden of calcium.
Dr. Dib has served as a consultant for Cardiovascular Systems, Inc. and has received grant support from Cardiovascular Systems, Inc. The other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received November 4, 2015.
- Revision received December 17, 2015.
- Accepted December 18, 2015.
- American College of Cardiology Foundation