Author + information
- Received March 18, 2008
- Revision received May 12, 2008
- Accepted June 10, 2008
- Published online September 1, 2008.
- Craig M. Gardner, PhD⁎,⁎ (, )
- Huwei Tan, PhD⁎,
- Edward L. Hull, PhD⁎,
- Jennifer B. Lisauskas, MS⁎,
- Stephen T. Sum, PhD⁎,
- Thomas M. Meese, BS⁎,
- Chunsheng Jiang, PhD⁎,
- Sean P. Madden, PhD⁎,
- Jay D. Caplan, BS, MBA⁎,
- Allen P. Burke, MD†,
- Renu Virmani, MD‡,
- James Goldstein, MD§ and
- James E. Muller, MD⁎
Reprint requests and correspondence:
Dr. Craig M. Gardner, InfraReDx, Inc., 34 Third Avenue, Burlington, Massachusetts 01803
Objectives This study sought to assess agreement between an intravascular near-infrared spectroscopy (NIRS) system and histology in coronary autopsy specimens.
Background Lipid core plaques cannot be detected by conventional tests, yet are suspected to be the cause of most acute coronary syndromes. Near-infrared spectroscopy is widely used to determine the chemical content of substances. A NIRS system has been developed and used successfully in 99 patients.
Methods Scanning NIRS was performed through blood in 212 coronary segments from 84 autopsy hearts. One histologic section was analyzed for every 2 mm of artery. Lipid core plaque of interest (LCP) was defined as a lipid core >60° in circumferential extent, >200-μm thick, with a mean fibrous cap thickness <450 μm. The first 33 hearts were used to develop the algorithm; the subsequent 51 validation hearts were used in a prospective, double-blind manner to evaluate the accuracy of NIRS in detecting LCP. A NIRS-derived lipid core burden index for an entire artery was also validated by comparison to histologic findings.
Results The LCPs were present in 115 of 2,649 (4.3%) sections from the 51 validation hearts. The algorithm prospectively identified LCP with a receiver-operator characteristic area of 0.80 (95% confidence interval [CI]: 0.76 to 0.85). The lipid core burden index detected the presence or absence of any fibroatheroma with an area under the curve of 0.86 (95% CI: 0.81 to 0.91). A retrospective analysis of lipid core burden index conducted in extreme artery segments with either no or extensive fibroatheroma yielded an area under the curve of 0.96 (95% CI: 0.92 to 1.00), confirming the accuracy of spectroscopy in identifying plaques with markedly different lipid content under ideal circumstances.
Conclusions This novel catheter-based NIRS system accurately identified lipid core plaques through blood in a prospective study in coronary autopsy specimens. It is expected that this novel capability will be of assistance in the management of patients with coronary artery disease.
- coronary artery disease
- intravascular imaging
- near-infrared spectroscopy
- ex vivo validation
InfraReDx was the sole source of financing for this study. Drs. Gardner, Tan, Hull, Sum, Jiang, Madden, and Muller, and Ms. Lisauskas, Mr. Meese, and Mr. Caplan are current employees of InfraReDx or were employees at the time of this study. Dr. Goldstein is an InfraReDx consultant and equity owner. Drs. Burke and Virmani were consultants to InfraReDx for histologic studies.
- Received March 18, 2008.
- Revision received May 12, 2008.
- Accepted June 10, 2008.
- American College of Cardiology Foundation