Qualitative and quantitative evaluation of dynamic changes in non-culprit coronary atherosclerotic lesion morphology: a longitudinal OCT study

Plasma asymmetric dimethylarginine is associated with vulnerable plaque and long-term outcomes in stable coronary artery disease

Asymmetric dimethylarginine (ADMA) is considered to be an atherogenic molecule. We aimed to investigate the relationship between ADMA and plaque vulnerability assessed by optical coherence tomography (OCT) in patients with stable coronary artery disease (CAD). Two hundred and forty-five patients with stable CAD undergoing OCT-guided percutaneous coronary intervention were included in this study and were divided into two groups according to their ADMA levels. Micro-vessel, macrophage accumulation, thin-cap fibroatheroma, intra-plaque calcium and lipid core content, and vulnerable score (VS) were evaluated by OCT analysis. The patients with higher ADMA levels had significantly higher calcium and lipid content (p < 0.001, respectively). There were significantly more micro-vessel and macrophage (32.8%, p = 0.004 and 52.5%, p < 0.001, respectively) and higher VS (87.7 ± 17.6, p < 0.001) in the higher ADMA group. Moreover, plasma ADMA level was significantly correlated with the intra-plaque lipid, calcium content and VS (p < 0.001, respectively). Plasma ADMA level was identified as an independent predictor of future adverse cardiovascular events, following OCT-guided PCI. In patients with stable CAD, higher plasma ADMA levels were significantly associated with the presence of intra-plaque lipid, calcification, vulnerable plaque, and poor long-term outcomes.

The clinical impact of serum 1,5-anhydro-D-glucitol levels on coronary artery calcification and adverse outcomes assessed by coronary optical coherence tomography in diabetic patients

Background

Serum 1,5-anhydro-D-glucitol (1,5-AG) is a novel biomarker for short-term glycemic status and postprandial hyperglycemia. The association between serum 1,5-AG levels and coronary artery calcification (CAC) through a quantitative assessment using optical coherence tomography (OCT) is unclear. We aimed to evaluate this association using OCT in patients with diabetes mellitus (DM).

Methods

From June 2016 to December 2019, we prospectively enrolled 256 patients who underwent OCT-guided percutaneous coronary intervention (PCI). Half of the patients had diabetes. Patients were followed up for a mean period of 1.8 ± 0.8 years (median: 2.2 years). The relative calcium index and relative lipid core index measured by quantitative OCT analysis were used to evaluate the intra-plaque calcium and lipid levels of culprit plaques. We also analyzed the correlation between serum 1,5-AG levels and long-term major adverse cardiovascular events.

Results

Serum 1,5-AG levels were significantly lower in diabetic patients than in non-diabetic patients (DM vs. non-DM: 55.6 ± 27.9 μg/mL vs. 63.7 ± 26.1 μg/mL, p = 0.016), and lower in fibrocalcified lesions than in fibrotic or fibrolipidic lesions (fibrocalcified vs. fibrotic or fibrolipidic: 42.8 ± 19.1 vs. 72.9 ± 25.2 or 66.4 ± 27.5 μg/mL, p &lt; 0.001, respectively). In addition, we found a significant inverse correlation between serum 1,5-AG levels and relative calcium index (r = −0.729, p &lt; 0.001). In multivariate Cox regression analysis, low serum 1,5-AG level was identified as an independent predictor for major adverse cardiovascular events in diabetic patients (p = 0.043), but not in non-diabetic patients (p = 0.748) after adjusting for age and sex.

Conclusion

This study revealed that low serum 1,5-AG levels were associated with an increased risk of CAC as assessed by OCT, especially in diabetic patients. Low serum 1,5-AG levels may predict future major adverse cardiovascular events in diabetic patients undergoing OCT-guided PCI.

Identification of coronary calcifications in optical coherence tomography imaging using deep learning

Coronary calcifications are an obstacle for successful percutaneous treatment of coronary artery disease patients. The optimal method for delineating calcifications extent is coronary optical coherence tomography (OCT). To identify calcification on OCT and subsequently tailor the appropriate treatment, requires expertise in both image acquisition and interpretation. Image acquisition consists from system calibration, blood clearance by a contrast agent along with synchronization of the pullback process. Accurate interpretation demands careful review by the operator of a segment of 50-75 mm of the coronary vessel at steps of 5-10 frames per mm accounting for 375-540 images in each OCT run, which is time consuming and necessitates some expertise in OCT analysis. In this paper we developed a new deep learning algorithm to assist the physician to identify and quantify coronary calcifications promptly, efficiently and accurately. Our algorithm achieves an accuracy of 0.9903 ± 0.009 over the test set at size of 1500 frames and even managed to find calcifications that were not recognized manually by the physician. For the best knowledge of the authors our algorithm achieves high accuracy which was never achieved in the past.

Predictive value of spiral shape in coronary plaque progression: an intraindividual comparative study

OBJECTIVE

We conducted a pilot study to explore the value of spiral-shaped sign of plaque from coronary computed tomographic angiography (CCTA) in predicting plaque progression by intraindividual comparison.

METHODS

A total of 30 patients with a total of 60 plaques who received serial CCTA were retrospectively included and intraindividual compared. The spiral shape was defined as plaques coursing along the long axis of a coronary artery and encircling it at an angle of ≥ 180 degrees. The high-risk and other plaque signs were recorded.

RESULTS

On baseline CCTA, the spiral shape (P < 0.01) and length (P < 0.05) of plaques were more frequently seen in the progression group than in the nonprogression group; however, there was no difference between two groups in terms of high-risk plaque signs. In the progression group, plaque length, volume, and napkin-ring sign on follow-up CCTA were significantly greater than at baseline (P < 0.05). In the nonprogression group, there were fewer low-attenuation and positive remodeling plaques on follow-up CCTA than at baseline (P < 0.05). The spiral shape (standardized β = -4.55; P < 0.01) was an independent risk factor for plaque progression. There were 24 spiral plaques in the progression group, of which 16 (66.7%) had progression below the twist point of the spiral shape.

CONCLUSIONS

The baseline spiral shape is more frequently found in those lesions that progress than in those that do not in patients with multiple coronary lesions, and the spiral shape is an independent predictor of which plaques will progress.

Intravascular Polarimetry in Patients With Coronary Artery Disease

OBJECTIVES

The aims of this first-in-human pilot study of intravascular polarimetry were to investigate polarization properties of coronary plaques in patients and to examine the relationship of these features with established structural characteristics available to conventional optical frequency domain imaging (OFDI) and with clinical presentation.

BACKGROUND

Polarization-sensitive OFDI measures birefringence and depolarization of tissue together with conventional cross-sectional optical frequency domain images of subsurface microstructure.

METHODS

Thirty patients undergoing polarization-sensitive OFDI (acute coronary syndrome, n = 12; stable angina pectoris, n = 18) participated in this study. Three hundred forty-two cross-sectional images evenly distributed along all imaged coronary arteries were classified into 1 of 7 plaque categories according to conventional OFDI. Polarization features averaged over the entire intimal area of each cross section were compared among plaque types and with structural parameters. Furthermore, the polarization properties in cross sections (n = 244) of the fibrous caps of acute coronary syndrome and stable angina pectoris culprit lesions were assessed and compared with structural features using a generalized linear model.

RESULTS

The median birefringence and depolarization showed statistically significant differences among plaque types (p < 0.001 for both, one-way analysis of variance). Depolarization differed significantly among individual plaque types (p < 0.05), except between normal arteries and fibrous plaques and between fibrofatty and fibrocalcified plaques. Caps of acute coronary syndrome lesions and ruptured caps exhibited lower birefringence than caps of stable angina pectoris lesions (p < 0.01). In addition to clinical presentation, cap birefringence was also associated with macrophage accumulation as assessed using normalized SD.

CONCLUSIONS

Intravascular polarimetry provides quantitative metrics that help characterize coronary arterial tissues and may offer refined insight into coronary arterial atherosclerotic lesions in patients.