Viewpoint: Recent Advances in Intracoronary Imaging for Vasa Vasorum Visualisation

Optical coherence tomography of the pulmonary arteries in children with congenital heart diseases: A systematic review

Importance

Optical coherence tomography (OCT) is a high-resolution intravascular imaging tool and has shown promise for providing real-time quantitative and qualitative descriptions of pulmonary vascular structures in vivo in adult pulmonary hypertension (PH), while not popular in pediatric patients with congenital heart diseases (CHD).

Objective

The aim of this review is to summarize all the available evidence on the use of OCT for imaging pulmonary vascular remodeling in pediatric patients.

Methods

We conducted the systematic literature resources (Cochran Library database, Medline via PubMed, EMBASE, and Web of Knowledge) from January 2010 to December 2021 and the search terms were "PH", "child", "children", "pediatric", "OCT", "CHD", "pulmonary vessels", "pulmonary artery wall". Studies in which OCT was used to image the pulmonary vessels in pediatric patients with CHD were considered for inclusion.

Results

Five studies met the inclusion criteria. These five papers discussed the study of OCT in the pulmonary vasculature of different types of CHD, including common simple CHD, complex cyanotic CHD, and Williams-Beuren syndrome. In biventricular anatomy, pulmonary vascular remodeling was primarily reflected by pulmonary intima thickening from two-dimensional OCT. In single-ventricle anatomy, due to the state of hypoxia, the morphology of pulmonary vessels was indirectly reflected by the number and shape of nourishing vessels from three-dimensional OCT.

Interpretation

OCT may be an adequate imaging procedure for the demonstration of pulmonary vascular structures and provide additional information in pediatric patients.

Acute diffuse thickening like 'halo' of the coronary tunica adventitia after rotational atherectomy

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Three-dimensional imaging of pulmonary arterial vasa vasorum using optical coherence tomography in patients after bidirectional Glenn and Fontan procedures

AIMS

We evaluated pulmonary arterial (PA) vasa vasorum (VV) in Fontan candidate patients with a novel three-dimensional (3D) imaging technique using optical coherence tomography (OCT).

METHODS AND RESULTS

This prospective study assessed the development of adventitial VV in the distal PA of 10 patients with bidirectional Glenn circulation (BDG group, 1.6 ± 0.3 years) and Fontan circulation (Fontan group, 3.3 ± 0.3 years), and in 20 children with normal PA haemodynamics and morphology (Control group, 1.5 ± 0.3 years). We assessed the PA VV with two-dimensional (2D) cross-sectional, multi-planar reconstruction (MPR), and volume rendering (VR) imaging. VV development was evaluated by the VV area/volume ratio, defined as the VV area/volume divided by the adventitial area/volume. Compared to the control group, the observed VV number and diameter on 3D images of MPR and VR were significantly higher, and curved and torturous-shaped VV were more frequently observed in the BDG and Fontan groups (P < 0.001, all). The median VV volume ratio was significantly greater in the BDG than in the control group (3.38% vs. 0.61%; P < 0.001). Although the VV volume ratio decreased significantly after the Fontan procedure (2.64%, P = 0.005 vs. BDG), the ratio remained higher than in the control group (P < 0.001 vs. control).

CONCLUSION

3D OCT imaging is a novel method that can be used to evaluate adventitial PA VV and may provide pathophysiological insight into the role of the PA VV in these patients.

Role of Inflammation in Coronary Epicardial and Microvascular Dysfunction

There is accumulating evidence highlighting a close relationship between inflammation and coronary microvascular dysfunction (CMD) in various experimental and clinical settings, with major clinical implications. Chronic low-grade vascular inflammation plays important roles in the underlying mechanisms behind CMD, especially in patients with coronary artery disease, obesity, heart failure with preserved ejection fraction and chronic inflammatory rheumatoid diseases. The central mechanisms of coronary vasomotion abnormalities comprise enhanced coronary vasoconstrictor reactivity, reduced endothelium-dependent and -independent coronary vasodilator capacity and increased coronary microvascular resistance, where inflammatory mediators and responses are substantially involved. How to modulate CMD to improve clinical outcomes of patients with the disorder and whether CMD management by targeting inflammatory responses can benefit patients remain challenging questions in need of further research. This review provides a concise overview of the current knowledge of the involvement of inflammation in the pathophysiology and molecular mechanisms of CMD from bench to bedside.

Clinicopathological complexity in the application of the universal definition of myocardial infarction

A universal definition of myocardial infarction (UDMI) has been established, periodically updated, and refined over the past twenty years. The primary purpose of the UDMI is to bring uniformity and accuracy to clinical diagnosis. Herein, a review and analysis of the UDMI is presented with emphasis on clinicopathological correlation. Determination of the presence of myocardial injury is based on the detection of abnormal serum cardiac biomarkers, particularly cardiac troponin (cTn), and in the current fourth iteration of the UDMI, high sensitivity (hs)-cTn. Differentiation of myocardial infarction from other causes of myocardial injury requires the documentation of clinical evidence of myocardial ischemia. In this review, difficulties in applying the UDMI in actual practice are discussed, based on the experience and perspective of those of us who face these problems as part of our own practice of pathology. The complexity in application of the UDMI is highlighted by the presentation of five illustrative cases involving the differential diagnosis of myocardial injury and myocardial infarction due to atherothrombotic and nonatherothrombotic coronary artery disease. The cases include myocardial infarction due to severe coronary atherosclerosis, supply-demand mismatch, coronary artery dissection associated with an eosinophilic coronary periarteritis, and coronary thromboembolism, and a case with a differential diagnosis of myocarditis and myocardial infarction. These cases illustrate how pathological findings can contribute to more accurate application of the UDMI and how, when critically applied, the UDMI can be used to better characterize myocardial infarcts in clinical practice.