Background: Local hemodynamics are known to play an important role in the development of plaque erosion. Recent studies showed that erosion patients might be treated conservatively without stent... Show moreBackground: Local hemodynamics are known to play an important role in the development of plaque erosion. Recent studies showed that erosion patients might be treated conservatively without stent implantation. We investigated evolution of hemodynamic parameters on the plaque erosion site in conservatively treated patients. Methods: Computational fluid dynamics (CFD) simulations were performed using the coronary angiogram and optical coherence tomography (OCT) images of non-stent treated erosion patients who had serial OCT studies. Calculated CFD parameters included endothelial shear stress (ESS), ESS gradient (ESSG), and oscillatory shear index (OSI).Results: The CFD parameters at the erosion and non-erosion sites were compared among baseline (n = 23), and 1-month (n = 20) and 12-month (n = 16) follow-ups. The erosion site had higher ESS and ESSG values than the non-erosion sites at baseline (mean ESS: 3.00 vs 1.36 Pa, p < 0.01; mean ESSG: 1.71 vs. 0.65 Pa/mm, p = 0.01), 1-month (mean ESS: 2.89 vs 1.19 Pa, p < 0.01; mean ESSG: 1.71 vs. 0.60 Pa/mm, p < 0.01), and 12-month (mean ESS: 3.26 vs 1.59 Pa, p < 0.01; mean ESSG: 1.87 vs. 0.78 Pa/mm, p < 0.01). OSI was not different between erosion and and non-erosion sites. Conclusions: ESS and ESSG values were higher at the plaque erosion sites compared to non-erosion sites. Elevated ESS and ESSG at the erosion site persisted up to 12 months. These data indicate that a local thrombogenic milieu related to hemodynamic perturbation persists up to 12 months at the plaque erosion sites following conservative treatment. Show less
Araki, M.; Park, S.J.; Dauerman, H.L.; Uemura, S.; Kim, J.S.; Mario, C. di; ... ; Jang, I.K. 2022
Optical coherence tomography (OCT) has been widely adopted in research on coronary atherosclerosis and adopted clinically to optimize percutaneous coronary intervention. In this Review, Jang and... Show moreOptical coherence tomography (OCT) has been widely adopted in research on coronary atherosclerosis and adopted clinically to optimize percutaneous coronary intervention. In this Review, Jang and colleagues summarize this rapidly progressing field, with the aim of standardizing the use of OCT in coronary atherosclerosis.Since optical coherence tomography (OCT) was first performed in humans two decades ago, this imaging modality has been widely adopted in research on coronary atherosclerosis and adopted clinically for the optimization of percutaneous coronary intervention. In the past 10 years, substantial advances have been made in the understanding of in vivo vascular biology using OCT. Identification by OCT of culprit plaque pathology could potentially lead to a major shift in the management of patients with acute coronary syndromes. Detection by OCT of healed coronary plaque has been important in our understanding of the mechanisms involved in plaque destabilization and healing with the rapid progression of atherosclerosis. Accurate detection by OCT of sequelae from percutaneous coronary interventions that might be missed by angiography could improve clinical outcomes. In addition, OCT has become an essential diagnostic modality for myocardial infarction with non-obstructive coronary arteries. Insight into neoatherosclerosis from OCT could improve our understanding of the mechanisms of very late stent thrombosis. The appropriate use of OCT depends on accurate interpretation and understanding of the clinical significance of OCT findings. In this Review, we summarize the state of the art in cardiac OCT and facilitate the uniform use of this modality in coronary atherosclerosis. Contributions have been made by clinicians and investigators worldwide with extensive experience in OCT, with the aim that this document will serve as a standard reference for future research and clinical application. Show less
Patient-specific coronary endothelial shear stress (ESS) calculations using Newtonian and non-Newtonian rheological models were performed to assess whether the common assumption of Newtonian blood... Show morePatient-specific coronary endothelial shear stress (ESS) calculations using Newtonian and non-Newtonian rheological models were performed to assess whether the common assumption of Newtonian blood behavior offers similar results to a more realistic but computationally expensive non-Newtonian model. 16 coronary arteries (from 16 patients) were reconstructed from optical coherence tomographic (OCT) imaging. Pulsatile CFD simulations using Newtonian and the Quemada non-Newtonian model were performed. Endothelial shear stress (ESS) and other indices were compared. Exploratory indices including local blood viscosity (LBV) were calculated from non-Newtonian simulation data. Compared to the Newtonian results, the non-Newtonian model estimates significantly higher time-averaged ESS (1.69 (IQR 1.36)Pa versus 1.28 (1.16)Pa, p < 0.001) and ESS gradient (0.90 (1.20)Pa/mm versus 0.74 (1.03)Pa/mm, p < 0.001) throughout the cardiac cycle, under-estimating the low ESS (<1Pa) area (37.20 +/- 13.57% versus 50.43 +/- 14.16%, 95% CI 11.28-15.18, p < 0.001). Similar results were also found in the idealized artery simulations with non-Newtonian median ESS being higher than the Newtonian median ESS (healthy segments: 0.8238Pa versus 0.6618Pa, p < 0.001 proximal; 0.8179Pa versus 0.6610Pa, p < 0.001 distal; stenotic segments: 0.8196Pa versus 0.6611Pa, p < 0.001 proximal; 0.2546Pa versus 0.2245Pa, p < 0.001 distal) On average, the non-Newtonian model has a LBV of 1.45 times above the Newtonian model with an average peak LBV of 40-fold. Non-Newtonian blood model estimates higher quantitative ESS values than the Newtonian model. Incorporation of non-Newtonian blood behavior may improve the accuracy of ESS measurements. The non-Newtonian model also allows calculation of exploratory viscosity-based hemodynamic indices, such as local blood viscosity, which may offer additional information to detect underlying atherosclerosis. Show less
Thondapu, V.; Mamon, C.; Poon, E.K.W.; Kurihara, O.; Kim, H.O.; Russo, M.; ... ; Jang, I.K. 2021
Aims To investigate local haemodynamics in the setting of acute coronary plaque rupture and erosion.Methods and results Intracoronary optical coherence tomography performed in 37 patients with... Show moreAims To investigate local haemodynamics in the setting of acute coronary plaque rupture and erosion.Methods and results Intracoronary optical coherence tomography performed in 37 patients with acute coronary syndromes caused by plaque rupture (n=19) or plaque erosion (n=18) was used for three-dimensional reconstruction and computational fluid dynamics simulation. Endothelial shear stress (ESS), spatial ESS gradient (ESSG), and oscillatory shear index (OSI) were compared between plaque rupture and erosion through mixed-effects logistic regression. Lipid, calcium, macrophages, layered plaque, and cholesterol crystals were also analysed. By multivariable analysis, only high ESSG [odds ratio (OR) 5.29, 95% confidence interval (CI) 2.57-10.89, P<0.001], lipid (OR 12.98, 95% CI 6.57-25.67, P<0.001), and layered plaque (OR 3.17, 95% CI 1.82-5.50, P<0.001) were independently associated with plaque rupture. High ESSG (OR 13.28, 95% CI 6.88-25.64, P<0.001), ESS (OR 2.70, 95% CI 1.34-5.42, P=0.005), and OSI (OR 2.18, 95% CI 1.33-3.54, P=0.002) independently associated with plaque erosion. ESSG was higher at rupture sites than erosion sites [median (interquartile range): 5.78 (2.47-21.15) vs. 2.62 (1.44-6.18) Pa/mm, P=0.009], OSI was higher at erosion sites than rupture sites [1.04 x 10(-2) (2.3 x 10(-3)-4.74 x 10(-2)) vs. 1.29 x 10(-3) (9.39 x 10(-5)-3.0 x 10(-2)), P<0.001], but ESS was similar (P=0.29).Conclusions High ESSG is independently associated with plaque rupture while high ESSG, ESS, and OSI associate with plaque erosion. While ESSG is higher at rupture sites than erosion sites, OSI is higher at erosion sites and ESS was similar. These results suggest that ESSG and OSI may play critical roles in acute plaque rupture and erosion, respectively. Show less
