Three-Dimensional Fluid Dynamical Features of Coronary Plaque Rupture Provoking Acute Coronary Syndrome.

AIM: Coronary plaque rupture is the main cause of acute coronary syndrome (ACS), but the role of blood flow features around plaque rupture for ACS is still unknown. The present study aimed to assess the relationship between the geometric configuration of ruptured plaque and ACS occurrence using computational fluid dynamics (CFD) by moving particle method in patients with coronary artery disease. METHODS: In this study, 45 patients with coronary artery disease who underwent three-dimensional intravascular ultrasound (IVUS) and had a coronary ruptured plaque (24 plaques with provoked ACS, 21 without) were included. To compare the difference in blood flow profile around ruptured plaque between the patients with and without ACS, the IVUS images were analyzed via the novel CFD analysis. RESULTS: There were no significant differences in localized flow profile around ruptured plaque between the two groups when the initial particle velocity was 10.0 cm/s corresponded to a higher coronary flow velocity at ventricular diastole. However, when it was 1.0 cm/s corresponded to lower coronary flow velocity at ventricular systole, particles with lower velocity (0 ≤ V ≤ 5 cm/s) were more prevalent around ACS-PR ( p=0.035), whereas particles with higher velocity (10 ≤ V ≤ 20 cm/s) were more often detected in silent plaque ruptures (p=0.018). CONCLUSIONS: Three-dimensional IVUS revealed that coronary plaque rupture was a complex one with a wide variety of its stereoscopic configuration, leading to various patterns of the local coronary flow profile. A novel CFD analysis suggested that the local flow was more stagnant around ACS-provoked ruptures than in silent ones.

Macrophage accumulation within coronary arterial wall in diabetic patients with acute coronary syndrome: a study with in-vivo intravascular imaging modalities.

BACKGROUND AND AIMS: Macrophage accumulation in arteriosclerotic plaque of coronary arteries is involved in plaque destabilization. Atherosclerosis has been known to be progressive in patients with type 2 diabetes mellitus (DM). This study compared the features of 3-dimensional (3D) spatial distribution of macrophage accumulation within coronary artery wall between acute coronary syndrome (ACS) patients with DM (n = 20) and those without (non-DM, n = 20) by using intravascular ultrasound (IVUS) and optical coherence tomography (OCT). METHODS: The OCT-derived macrophage accumulation was measured within the proximal left anterior-descending artery. This measurement was performed for the whole vessel segment of interest, higher shear stress region (flow divider side) and lower shear stress region (the opposite side). RESULTS: Normalized macrophage accumulation per unit length of the whole segment of interest was significantly larger in ACS patients with DM than without. In non-DM patients, macrophage density per IVUS-derived plaque volume was significantly higher in high shear stress region compared to low shear stress region, however, there was no significant difference between the two regions in DM patients. The macrophage density in the low shear stress region was significantly higher in the DM group than in the non-DM group. A multivariate analysis showed that the presence of DM was a major determinant for macrophage distribution. CONCLUSIONS: Macrophage accumulation was more abundant and homogeneous within coronary arterial wall in DM patients with ACS compared to non-DM patients, suggesting that plaque destabilization may occur more widely throughout coronary wall in DM patients.

Angioscopic differences of coronary intima between diffuse and focal coronary vasospasm: Comparison of optical coherence tomography findings.

BACKGROUND: Coronary artery vasospasm (CS) can be identified as either a diffuse type or focal type; however, the difference in endothelial characteristics between these spasm types remains unclear. The features of coronary intima associated with diffuse spasm and focal spasm using coronary angioscopy (CAS) were evaluated and the optical coherence tomography (OCT) findings were compared. METHODS: CAS and/or OCT observational analysis was performed in 55 patients (mean age: 61.4 years, 31 men) who had acetylcholine-provoked CS (diffuse CS, 31 patients; focal CS, 24 patients). The yellowness of the intima, presence of thrombus in CAS, and intimal characteristics based on the OCT results were evaluated. RESULTS: CAS showed more atherosclerotic yellow plaques at the focal spasm segment than at the diffuse spasm segment (p=0.032). Moreover, there were more thrombi at the focal spasm segment (p=0.039). In addition, OCT results revealed that the intima area, maximum intima thickness, and lipid content in the focal CS group were larger than the diffuse CS group (4.22±1.67mm2 vs. 3.45±2.36mm2; 0.71±0.29mm vs. 0.53±0.30mm; 55.9% vs. 32.0%, p<0.001, respectively). CONCLUSIONS: These results indicate that the presence of atherosclerotic plaques at the spasm site is likely to be related to the occurrence of a focal vasospasm. This may support the difference of features between focal CS and diffuse CS and contribute to precise treatment for each spasm type.

Effect of Aggressive lipid-lowering treatment with Rosuvastatin on vascular endoTHelium function: evaluation of vascular endothelium function (EARTH study).

Vascular endothelial dysfunction plays an important role in the process of atherosclerosis up to the final stage of plaque rupture. Vascular endothelial dysfunction is reversible, and can be recovered by medications and life-style changes. Improvement in endothelial function may reduce cardiovascular events and improve long-term prognosis. A total of 50 patients with stable angina and dyslipidemia were enrolled, including patients who had not received prior treatment with statins and had serum LDL-C levels ≥ 100 mg/dL, and patients who had previously received statin treatment. All agreed to register regardless of their LDL-C level. Rosuvastatin was initially administered at a dose of 2.5 mg and appropriately titrated up to the maximum dose of 20 mg or until LDL-C levels lower than 80 mg/dL were achieved, for 24 weeks. Endothelial function was assessed by the reactive hyperemia peripheral arterial tonometry (RH-PAT) index in the radial artery by Endo-PAT® 2000 (Endo-PAT®2000, software version 3.0.4, Itamar Medical Ltd., Caesarea, Israel). RH-PAT data were digitally analyzed online by Endo-PAT®2000 at baseline and at 24 weeks. LDL-C and MDA-LDL-C decreased from 112.6 ± 23.3 to 85.5 ± 20.2 mg/dL and from 135.1 ± 36.4 to 113.9 ± 23.5 mg/dL respectively (p < 0.0001). However, HDL-C, hs-CRP and TG did not change significantly after treatment. RH-PAT index levels significantly improved, from 1.60 ± 0.31 to 1.77 ± 0.57 (p = 0.04) after treatment, and the percent change of the RH-PAT index was 12.8 ± 36.9%. Results of multivariate analysis show that serum LDL-C levels over 24 weeks did not act as a predictor of improvement of the RH-PAT index. However, HbA1c at baseline was an independent predictor which influenced the 24-week RH-PAT index level. The RH-PAT index of patients with high HbA1c at baseline did not improve after administration of rosuvastatin but it did improve in patients with low HbA1c at baseline. Aggressive lowering of LDL-C with rosuvastatin significantly improved the RH-PAT index, suggesting that it may improve endothelial function in patients with coronary artery disease.Clinical Trial Registration No: UMIN-CTR, UMIN000010040.