Near-infrared spectroscopy for the detection of lipid core coronary plaques

Near-infrared spectroscopy-intravascular ultrasound: scientific basis and clinical applications

Coronary angiography underestimates the magnitude of the atherosclerotic burden and cannot detect the presence of disease in the early phases. Recognition of these inherent limitations of angiography has been an impetus for the development of other coronary imaging techniques. The novel near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS) catheters can detect and quantify the presence of lipid core in the atherosclerotic plaque and associate it with other features such as lumen size and plaque architecture. Lipid-rich plaques are known to pose a higher risk of distal embolization during interventions and plaque disruption. The aim of this manuscript is the review of the potential clinical and research applications of this technology as highlighted by recent studies.

Association of coronary lipid core plaque with intrastent thrombus formation: a near-infrared spectroscopy and optical coherence tomography study

BACKGROUND

Optical coherence tomography (OCT) and near-infrared spectroscopy (NIRS) allow assessment of the anatomy (OCT) and composition (NIRS) of coronary lesions. We sought to examine the association between pre-stenting lipid core plaque (LCP), as assessed by NIRS and post-stenting thrombus formation, as assessed by OCT.

METHODS

We reviewed the angiograms of nine patients who underwent coronary stenting in association with NIRS and OCT imaging. A large LCP by NIRS was defined as at least three 2-mm yellow blocks on the NIRS block chemogram with >200° angular extent. Intracoronary thrombus was defined as a mass of medium reflectivity protruding into the vessel lumen, discontinuous from the surface of the vessel wall.

RESULTS

Mean age was 67 ± 7 years, and all patients were men, presenting with stable angina (56%), unstable angina (11%), or acute myocardial infarction (33%). The mean vessel lipid core burden index (LCBI) was 120 ± 45, and the mean highest 6-mm LCBI was 386 ± 190. Three patients had a large LCP and two of them (66%) developed intrastent thrombus after stent implantation compared to none of six patients without large LCPs (0%, P = 0.02). The thrombus resolved after intracoronary glycoprotein IIb/IIIa administration and balloon postdilation. Postprocedural myocardial infarction occurred in 33% versus 17% of patients with and without large LCP, respectively (P = 0.57).

CONCLUSION

Stenting of large LCPs may be associated with intrastent thrombus formation, suggesting that more intensive anticoagulant and/or antiplatelet therapy may be beneficial in such lesions. © 2012 Wiley Periodicals, Inc.

Waterproof AlInGaP optoelectronics on stretchable substrates with applications in biomedicine and robotics

Inorganic light-emitting diodes and photodetectors represent important, established technologies for solid-state lighting, digital imaging and many other applications. Eliminating mechanical and geometrical design constraints imposed by the supporting semiconductor wafers can enable alternative uses in areas such as biomedicine and robotics. Here we describe systems that consist of arrays of interconnected, ultrathin inorganic light-emitting diodes and photodetectors configured in mechanically optimized layouts on unusual substrates. Light-emitting sutures, implantable sheets and illuminated plasmonic crystals that are compatible with complete immersion in biofluids illustrate the suitability of these technologies for use in biomedicine. Waterproof optical-proximity-sensor tapes capable of conformal integration on curved surfaces of gloves and thin, refractive-index monitors wrapped on tubing for intravenous delivery systems demonstrate possibilities in robotics and clinical medicine. These and related systems may create important, unconventional opportunities for optoelectronic devices.