Near-infrared Spectroscopy Guided Percutaneous Coronary Intervention in Patients With Acute Myocardial Infarction

Background Myocardial infarction (MI) secondary to atherosclerotic coronary artery disease is mainly due to plaque-rupture with formation of a luminal thrombogenic material. Lesions responsible for MI are more frequently composed of lipid-rich plaques (LRP) in both culprit and in non-culprit lesions compared to lesions in patients with stable angina.

LRP is thought to be main precursor for future coronary events and may also have an impact on complications following percutaneous coronary intervention (PCI). It has been previously indicated that stent thrombosis (ST) and restenosis often occur when stenting a lipid-rich plaque. And if using angiography guidance only during PCI, there is a potential risk of implantation of a stent edge on a lipid pool, which can result in incomplete stent coverage of a lesion. The incidence of restenosis and ST may be related to the lesion characteristics, clinical presentation, antithrombotic treatment and stent design. Other factors may include inflammatory reaction to the polymer coating containing drug that delays vascular healing, insufficient stent strut coverage and incomplete stent apposition (ISA).

Invasive imaging modality can contribute to better understanding of the changes that occur in the vessel wall during stent implantation.

Intravascular ultrasound (IVUS) combined with a new imaging modality called near-infrared spectroscopy (NIRS) can identify LRP and provide a semi-quantitative estimate of amount of LRP present within selected region of interest. The method is excellent to identify ISA and improve stent implantation technique.

Optical coherence tomography (OCT) is a high resolution imaging modality that can analyze healing pattern after stent implantation such as stent strut coverage.