Association Between IVUS and OCT Parameters and Invasive Physiologic Indices

1. to evaluate diagnostic accuracy and performance of IVUS and OCT-derived quantitative parameters to predict functional significance of stenosis defined using all the available physiologic indices.
2. to explores the association between intravascular imaging-derived plaque characteristics and invasive physiologic indices.

Given the inherent limitations of coronary angiography to depict the presence of functionally significant epicardial coronary stenosis and discrepancy between angiographic stenosis severity and the presence of myocardial ischemia, invasive physiologic indices such as fractional flow reserve (FFR) or instantaneous wave-free ratio (iFR) has been a standard method to guide decision of revascularization.

Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) are an intracoronary imaging method able to provide information about lumen area, vessel area, plaque burden, and plaque characteristics that can be used for the guidance of revascularization procedure. Several previous studies explored the diagnostic performance of intravascular imaging-defined quantitative parameters to predict functional significance defined by FFR, however, quantitative parameter derived from intravascular imaging showed only moderate diagnostic accuracy and the optimal cut-off value of intravascular imaging-derived minimal lumen area (MLA) or minimal lumen diameter (MLD) were varied according to the patient population, interrogated vessels, and the location of target lesions, suggesting limited clinical relevance of judging functional significance of target stenosis using intravascular imaging alone. Nevertheless, the adoption rate of FFR-guided decision has been limited due to various reasons and intravascular image-guided decision has been still used in substantial proportion of the patients.

Recently, new resting pressure-derived indices including resting full-cycle ratio (RFR) or diastolic pressure ratio (dPR) have been introduced as other substitutes for iFR, which does not require administration of hyperemic agents, therefore, possess more convenient in daily practice. Recent study with the largest sample size demonstrated identical diagnostic property and prognostic implication among iFR, RFR, and dPR. As those resting pressure-derived indices might have more generalizability for daily practice, it is expected to raise the adoption rate of physiologic interrogation. Therefore, understanding the association between all the available physiologic indices and intravascular imaging-derived quantitative and qualitative parameters might be important in clinical decision for patient who underwent invasive coronary angiography.

In this regard, the investigators sought to evaluate diagnostic accuracy and performance of intravascular imaging-derived quantitative parameters to predict functional significance of stenosis defined using all the available physiologic indices and further explores the association between IVUS and OCT-derived plaque characteristics and invasive physiologic indices.

Eligibility Criteria:
Inclusion Criteria:

* Patients who suspected ischemic heart disease, and underwent invasive physiologic assessment and intravascular ultrasound

Exclusion Criteria:

* Cardiogenic shock
* Graft vessel
* In-stent restenosis