Optical coherence tomography versus intravascular ultrasound for culprit lesion assessment in patients with acute myocardial infarction

Intracoronary Imaging of Vulnerable Plaque-From Clinical Research to Everyday Practice

The introduction into clinical practice of intravascular imaging, including intravascular ultrasound (IVUS), optical coherence tomography (OCT) and their derivatives, allowed for the in vivo assessment of coronary atherosclerosis in humans, including insights into plaque evolution and progression process. Intravascular ultrasound, the most commonly used intravascular modality in many countries, due to its low resolution cannot assess many features of vulnerable plaque such as lipid plaque or thin-cap fibroatheroma. Thus, novel methods were introduced to facilitate this problem including virtual histology intravascular ultrasound and later on near-infrared spectroscopy and OCT. Howbeit, none of the currently used modalities can assess all known characteristics of plaque vulnerability; hence, the idea of combining different intravascular imaging methods has emerged including NIRS-IVUS or OCT-IVUS imaging. All of those described methods may allow us to identify the most vulnerable plaques, which are prone to cause acute coronary syndrome, and thus they may allow us to introduce proper treatment before plaque destabilization.

Factors associated with aorto-ostial stent coverage during intravascular ultrasound-guided percutaneous coronary intervention to severely narrowed non-ostial right coronary artery lesions

Introduction

In percutaneous coronary intervention (PCI) to atherosclerotic lesions in the right coronary artery (RCA), coronary artery dissection in the ostium of the RCA is a rare but fatal complication. Stent implantation to the ostium of RCA may be selected for the prevention of aorto-ostial dissection.

Aim

To find factors associated with aorto-ostial stent coverage to mild to moderate ostial stenosis during the treatment of severely narrowed non-ostial RCA lesions.

Material and methods

The primary interest was to find factors associated with ostial stent coverage using multivariate regression analysis. We included 236 patients who underwent intravascular ultrasound (IVUS)-guided PCI to severely narrowed RCA lesions with mild to moderate ostial stenosis, and divided those into the ostial-coverage group (n = 52) and the non-coverage group (n = 184).

Results

The prevalence of continuous ostial plaque detected by intravascular ultrasound (IVUS) was significantly greater in the ostial-coverage group (84.6%) than in the non-coverage group (52.9%) (p < 0.001). Multivariate logistic regression analysis revealed that continuous ostial plaque detected by IVUS (OR = 5.398, 95% CI: 2.322–12.553, p < 0.001) was significantly associated with ostial stent coverage after controlling confounding factors. Ischaemia-driven target vessel revascularization was less frequently observed in the ostial-coverage group than in the non-coverage group, without reaching statistical significance (p = 0.069).

Conclusions

Continuous ostial plaque detected by IVUS was significantly associated with ostial stent coverage to the mild to moderate stenosis when PCI to non-ostial, severely narrowed RCA lesions was performed. The use of IVUS may enhance the safety but may increase the total stent length in PCI to RCA.

OCT Findings in MINOCA

Myocardial infarction with non-obstructive coronary artery disease (MINOCA) is a working diagnosis for patients presenting with acute myocardial infarction without obstructive coronary artery disease on coronary angiography. It is a heterogenous entity with a number of possible etiologies that can be determined through the use of appropriate diagnostic algorithms. Common causes of a MINOCA may include plaque disruption, spontaneous coronary artery dissection, coronary artery spasm, and coronary thromboembolism. Optical coherence tomography (OCT) is an intravascular imaging modality which allows the differentiation of coronary tissue morphological characteristics including the identification of thin cap fibroatheroma and the differentiation between plaque rupture or erosion, due to its high resolution. In this narrative review we will discuss the role of OCT in patients presenting with MINOCA. In this group of patients OCT has been shown to reveal abnormal findings in almost half of the cases. Moreover, combining OCT with cardiac magnetic resonance (CMR) was shown to allow the identification of most of the underlying mechanisms of MINOCA. Hence, it is recommended that both OCT and CMR can be used in patients with a working diagnosis of MINOCA. Well-designed prospective studies are needed in order to gain a better understanding of this condition and to provide optimal management while reducing morbidity and mortality in that subset patients.