Influence of myocardial bridge on atherosclerotic plaque distribution and characteristics evaluated by near-infrared spectroscopy intravascular ultrasound

Fractal geometry of culprit coronary plaque images within optical coherence tomography in patients with acute coronary syndrome vs stable angina pectoris

The main cause of acute coronary syndrome (ACS) is plaque rupture and thrombus formation. However, it has not been fairly successful to identify vulnerable plaque to rupture using conventional parameters of intravascular imaging modalities. Fractal analysis is one of the mathematical models to examine geometrical features of picture image using a specific parameter called as fractal dimension (FD) which suggests geometric complexity of the image. This study examined FD of the optical coherence tomography (OCT)-derived images of the culprit plaque in patients with ACS vs stable angina pectoris (SAP) to evaluate the feasibility of FD for identifying vulnerable coronary plaques prone to provoke ACS distinguished from stable plaques only provoking SAP. We examined 65 cases (34 ACS patients, 31 SAP patients) in which the culprit lesion was imaged by OCT before percutaneous coronary intervention in patients with ACS and SAP. The culprit plaque lesion in the ACS group had a significantly larger mean lipid arc (203.8 ± 39.4° vs 152.3 ± 34.5°, p < 0.001) and a larger lipid plaque length (12.6 ± 5.1 mm vs 7.7 ± 2.7 mm, p < 0.001) and a thinner fibrous cap thickness (75.3 ± 22.3 μm vs 134.8 ± 53.2 μm, p < 0.001) than those in the SAP group. The prevalence of OCT-derived macrophage infiltration (Mph) in the entire culprit coronary vessel as well as that of the OCT-derived thin-cap fibroatheroma (TCFA) at the culprit lesion were significantly greater in the ACS group than those in the SAP group, respectively (Mph: 61.8% vs 35.5%, p = 0.048; TCFA: 44.1% vs 6.4%, p < 0.001). The FD of culprit plaque in the ACS group was significantly greater than in the SAP group (2.401 ± 0.073 vs 2.341 ± 0.051, p < 0.001). In multivariate regression analysis, the presence of Mph was a significant determinant of FD (regression coefficient estimate 0.049, CI 0.018-0.079, p = 0.002). The FD of OCT-derived image of culprit coronary plaque in the ACS group was significantly greater than that in the SAP group, indicating that the culprit plaque in ACS were structurally more complex. Therefore, fractal analysis of coronary OCT images might be clinically useful for identifying coronary plaques prone to provoke ACS.

Plaque morphology and distribution in patients with and without myocardial bridge - an intravascular ultrasound study

BACKGROUND

Myocardial bridging (MB) is a common congenital cardiovascular anomaly. There are reported associations of MB with different clinical presentations like effort angina, acute coronary syndromes (ACS) and sudden cardiac death. Acceleration of atherosclerosis in proximal vessel is reported in patients with MB, while bridged segments are reported to be free of atherosclerosis.

METHODS

We assessed patients who underwent intravascular ultrasound (IVUS) guided percutaneous intervention (PCI) of left anterior descending (LAD) artery. Plaque characteristics derived from IVUS analysis were compared between those who displayed myocardial bridge versus those who did not harbour the anomaly.

RESULTS

One hundred and forty-seven (147) patients underwent IVUS guided PCI. Incidence of MB was 44/147 (29.9%). Mean age of patients who had MB {+} was higher (62.1 ± 10.3 vs. 57.8 ± 11.2 (p = .03). 142/147 (96.6%) patients presented with ACS. ST elevation myocardial infarction (STEMI) was the most common presenting diagnosis (110/147 to 74.8%). There were no differences in qualitative plaque characteristics - attenuated plaque, calcification or calcium score between two groups. Plaque burden and length of the lesion in the proximal vessel were not different. Among patients with MB {+}, atheromatous extension to segments underlying the bridge was seen in 31/44 (70.5%) cases.

CONCLUSIONS

In a series of patients who presented with advanced clinical atherosclerosis, plaque characteristics were not different in patients who harboured myocardial bridge vs. those who did not have the anomaly. Atheromatous involvement was seen extending into bridged segment contrary to previous reports.

Prognostic value of 1,5-anhydro-D-glucitol incorporating syntax score in acute coronary syndrome

The utility of adding information on 1,5-anhydro-D-glucitol (1,5-AG), a marker for postprandial hyperglycemia, to a pre-existing scoring system in acute coronary syndrome (ACS) patients is unknown. This retrospective cohort study included 266 ACS patients. The end point was major adverse cardiac and cerebral events (MACCE) through 5 years of follow-up. To evaluate incremental benefits of combining 1,5-AG with the syntax score, we applied time-dependent receiver operating curve (ROC) analysis, net reclassification improvement (NRI), integrated discrimination improvement (IDI) and decision curve analysis (DCA). Temporal changes to the area under time-dependent ROC curves showed that addition of 1,5-AG parameters to syntax score did not provide any incremental value (area under the curve for syntax alone, 0.673 (95% confidence interval (CI), 0.599-0.747) vs. with 1,5-AG combined, 0.671 (95%CI 0.596-0.746; Delong p = 0.65). Incorporating 1,5-AG into syntax score yielded a significant NRI of 0.291 (95%CI 0.015-0.567) and IDI of 0.055 (95%CI 0.018-0.093), while DCA analysis showed the limited net benefit in combination with 1,5-AG and syntax score. 1,5-AG values exhibited significant discriminatory utility for detecting MACCE within the ACS population. However, 1,5-AG levels contributed limited utility beyond syntax score based on time-dependent ROC and DCA analyses.Trial registration: UMIN000023837.

The Impact of Myocardial Bridging on the Coronary Functional Test in Patients with Ischaemia with Non-Obstructive Coronary Artery Disease

Background: The possibility of myocardial bridging (MB) causing chest pain has been widely reported; however, the effect of MB on coronary microvessels has not been thoroughly investigated. Therefore, this study evaluated the effects of MB on epicardial coronary artery and coronary microvascular function during coronary angiography (CAG) and coronary function test (CFT) in patients with ischaemia with non-obstructive coronary artery disease (INOCA). Methods: This study included 62 patients with INOCA who underwent CAG and CFT for the left anterior descending coronary artery (LAD) to evaluate chest pain. In the CFT, acetylcholine was first administered intracoronarily in a stepwise manner, followed by chest symptoms, electrocardiographic ST-T changes and CAG. Positive coronary spasm was defined as coronary vasoconstriction of >90% on CAG accompanied by chest symptoms or electrocardiographic ST-T changes. After nitroglycerin administration, CAG was performed to assess MB, which was defined as systolic narrowing of the coronary artery diameter by >20% compared with that in diastole. Coronary flow reserve (CFR) and index of microcirculatory resistance (IMR) were subsequently obtained via transvenous adenosine triphosphate infusion using a pressure wire. Coronary microvascular vasodilatory dysfunction (CMD) was defined as a CFR of <2.0 or an IMR of ≥25 units. Results: Of the 62 patients, 15 (24%) had MB. The patients’ characteristics did not differ between the two groups. Regarding the CAG and CFT results, the presence of coronary spasm in the LAD was higher in the MB (+) group (87%) than in the MB (−) group (53%, p = 0.02), whereas the values of CFR (MB (+): 2.7 ± 1.4, MB (−): 2.8 ± 1.1) and IMR (MB (+): 26.9 ± 1.0, MB (−): 30.0 ± 17.3) and the presence of CMD (MB (+): 53%, MB (−): 60%) were similar in the two groups. Conclusions: The findings suggest that MB predisposes patients with INOCA to coronary spasms. Conversely, MBs may have a limited effect on microvessels, particularly in such patients.