Detection of Lipid Pool, Thin Fibrous Cap, and Inflammatory Cells in Human Aortic Atherosclerotic Plaques by Near-Infrared Spectroscopy

Background—A method is needed to identify nonstenotic, lipid-rich coronary plaques that are likely to cause acute coronary events. Near-infrared (NIR) spectroscopy can provide information on the chemical composition of tissue. We tested the hypothesis that NIR spectroscopy can identify plaque composition and features associated with plaque vulnerability in human aortic atherosclerotic plaques obtained at the time of autopsy. Methods and Results—A total of 199 samples from 5 human aortic specimens were analyzed by NIR spectroscopy. Features of plaque vulnerability were defined by histology as presence of lipid pool, thin fibrous cap (<65 &mgr;m by ocular micrometry), and inflammatory cell infiltration. An InfraAlyzer 500 spectrophotometer was used. Spectral absorbance values were obtained as log (1/R) data from 1100 to 2200 nm at 10-nm intervals. Principal component regression was used for analysis. An algorithm was constructed with 50% of the samples used as a reference set; blinded predictions of plaque composition were then performed on the remaining samples. NIR spectroscopy sensitivity and specificity for histological features of plaque vulnerability were 90% and 93% for lipid pool, 77% and 93% for thin cap, and 84% and 89% for inflammatory cells, respectively. Conclusions—NIR spectroscopy can identify plaque composition and features associated with plaque vulnerability in postmortem human aortic specimens. These results support efforts to develop an NIR spectroscopy catheter system to detect vulnerable coronary plaques in living patients.

[1]  S E Nissen,et al.  Extent and direction of arterial remodeling in stable versus unstable coronary syndromes : an intravascular ultrasound study. , 2000, Circulation.

[2]  R. Virmani,et al.  Coronary risk factors and plaque morphology in men with coronary disease who died suddenly. , 1997, The New England journal of medicine.

[3]  W. O’Connor,et al.  A combination Verhoeff's elastic and Masson's trichrome stain for routine histology. , 1982, Stain technology.

[4]  M. Naghavi,et al.  New developments in the detection of vulnerable plaque , 2001, Current atherosclerosis reports.

[5]  Robert A. Lodder,et al.  Biological and Medical Applications of Near-Infrared Spectrometry , 1996 .

[6]  G. Bearman,et al.  Thermal detection of cellular infiltrates in living atherosclerotic plaques: possible implications for plaque rupture and thrombosis , 1996, The Lancet.

[7]  J. Muller,et al.  Triggers, acute risk factors and vulnerable plaques: the lexicon of a new frontier. , 1994, Journal of the American College of Cardiology.

[8]  P. Libby.  Molecular bases of the acute coronary syndromes. , 1995, Circulation.

[9]  Samin K. Sharma,et al.  Macrophages, smooth muscle cells, and tissue factor in unstable angina. Implications for cell-mediated thrombogenicity in acute coronary syndromes. , 1996, Circulation.

[10]  R A Shaw,et al.  Multianalyte Serum Analysis Using Mid-Infrared Spectroscopy , 1998, Annals of clinical biochemistry.

[11]  W Jaross,et al.  Determination of cholesterol in atherosclerotic plaques using near infrared diffuse reflection spectroscopy. , 1999, Atherosclerosis.

[12]  Y. Uchida,et al.  Prediction of acute coronary syndromes by percutaneous coronary angioscopy in patients with stable angina. , 1995, American heart journal.

[13]  R. Alfano,et al.  Intracerebral hemodynamics probed by near infrared spectroscopy in the transition between wakefulness and sleep , 2000, Brain Research.

[14]  J. G. Fujimoto,et al.  Assessing atherosclerotic plaque morphology: comparison of optical coherence tomography and high frequency intravascular ultrasound. , 1997, Heart.

[15]  I. Gabriely,et al.  Transcutaneous glucose measurement using near-infrared spectroscopy during hypoglycemia. , 1999, Diabetes care.

[16]  H Rijsterborgh,et al.  Histopathologic validation of intracoronary ultrasound imaging. , 1994, Journal of the American Society of Echocardiography : official publication of the American Society of Echocardiography.

[17]  L A Cassis,et al.  Near‐Infrared Imaging and Spectroscopy in Stroke Research: Lipoprotein Distribution and Disease a , 1997, Annals of the New York Academy of Sciences.

[18]  S L Jacques,et al.  Optical properties of rat liver between 350 and 2200 nm. , 1989, Applied optics.

[19]  J. Willerson,et al.  Role of inflammation in coronary plaque disruption. , 1994, Circulation.

[20]  A F van der Steen,et al.  Intravascular ultrasound combined with Raman spectroscopy to localize and quantify cholesterol and calcium salts in atherosclerotic coronary arteries. , 2000, Arteriosclerosis, thrombosis, and vascular biology.

[21]  M. Davies.  Detecting vulnerable coronary plaques , 1996, The Lancet.

[22]  J. Fujimoto,et al.  Index Matching to Improve Optical Coherence Tomography Imaging Through Blood , 2001, Circulation.

[23]  P Toutouzas,et al.  Thermal heterogeneity within human atherosclerotic coronary arteries detected in vivo: A new method of detection by application of a special thermography catheter. , 1999, Circulation.

[24]  V. Fuster,et al.  Characterization of Atherosclerotic Plaques by Magnetic Resonance Imaging , 2000, Annals of the New York Academy of Sciences.

[25]  R A Shaw,et al.  In vivo optical/near-infrared spectroscopy and imaging of metalloproteins. , 2000, Journal of inorganic biochemistry.

[26]  E Falk,et al.  Techniques characterizing the coronary atherosclerotic plaque: influence on clinical decision making? , 2000, Journal of the American College of Cardiology.

[27]  V. Fuster,et al.  Coronary plaque disruption. , 1995, Circulation.

[28]  Emil W. Ciurczak,et al.  Handbook of Near-Infrared Analysis , 1992 .

[29]  R. Virmani,et al.  Lessons from sudden coronary death: a comprehensive morphological classification scheme for atherosclerotic lesions. , 2000, Arteriosclerosis, thrombosis, and vascular biology.

[30]  L A Cassis,et al.  Near-IR imaging of atheromas in living arterial tissue. , 1993, Analytical chemistry.

[31]  C. Cocanour,et al.  Tissue hemoglobin O2 saturation during resuscitation of traumatic shock monitored using near infrared spectrometry. , 2000, The Journal of trauma.