Radial artery intima-media ratio predicts presence of coronary thin-cap fibroatheroma: A frequency domain-optical coherence tomography study

Application of ultrasound in cardiovascular intervention via the distal radial artery approach: New wine in old bottles?

The distal radial artery (DRA) approach has emerged as a new approach in cardiovascular intervention. In recent years, ultrasound has been widely used in cardiovascular intervention via the DRA approach. This article systematically discusses the progress of ultrasound in the preoperative vascular assessment, intraoperative guided puncture and postoperative observation of complications via the DRA approach.

Assessment of radial artery atherosclerosis in acute coronary syndrome patients: an in vivo study using optical coherence tomography

Background

Radial artery (RA) atherosclerosis in acute coronary syndrome (ACS) patients has not been systematically observed in vivo. The study aims to characterize plaque morphology and intimal hyperplasia of the RA in patients with ACS, using optical coherence tomography (OCT).

Methods

In this retrospective study involving 239 ACS patients underwent RA OCT without guidewire shadow, 3 groups were divided according to the following criteria: radial artery plaque (RAP) group included patients with fibrous, lipid or calcified plaque; patients without RAP were further classified into radial intimal hyperplasia (RIH) group (intima media thickness ratio [IMR] ≥ 1) or normal group (IMR < 1). The presence and characteristics of RAP and its related risk factors were identified.

Results

The RAP, RIH and normal groups included 76 (31.8%), 69 (28.9%) and 94 (39.3%) patients, respectively. Patients in RAP group were the oldest, compared with those in the RIH and normal groups (p < 0.001), and more frequently had triple vessel disease (p = 0.004). The percentage of plaque rupture (72.4% vs. 56.4%, p = 0.018) and calcification (42.1% vs. 27.6%, p = 0.026) at culprit lesion were significantly higher in patients with RAP than those without RAP. A total of 148 RAP were revealed by OCT, including fibrous (72, 48.6%), lipid (50, 33.8%) and calcified plaques (26, 17.6%). The microvessels were also frequently observed in the RAP group than that in RIH and normal groups (59.2% vs. 8.7% vs. 9.6%, p < 0.001). Multivariate logistic regression analysis showed that age, diabetes, and smoking history (all p < 0.05) were independent risk factors for RAP.

Conclusions

In terms of insights gained from OCT, RA atherosclerosis is not uncommon in ACS patients by OCT, sharing several morphological characters with early coronary atherosclerosis. Aging, diabetes, and smoking are risk factors for RAP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02561-5.

Proof-of-Concept Study for an Enhanced Surrogate Marker of Endothelial Function in Diabetes

Diabetes mellitus affects distal small vessels earlier and to a greater extent than proximal vessels. Vascular disease starts from activation of the endothelial cells, which if prolonged may lead to reduced distensibility of the vessel when maximally stimulated. Hence a device which measures distensibility of a distal vessel should be a good biomarker for subclinical disease. We have developed a device capable of measuring reactive hyperaemia induced changes in the radial artery flow, volumetric changes and accompanying effects on the vessel wall. The measurement is based on the magnetic flux disturbance upon haemodynamic modulation as blood flows through a uniformly applied magnetic field, and generates what we have termed the radial artery maximum distensibility index (RA-MDI). In a proof-of-concept study we found significant correlations between RA-MDI and cardiovascular risk factors, scoring systems and carotid artery intima-media thickness. Further large scale prospective studies need to be conducted to ascertain the correlations with cardiovascular events.

Nonlinear dynamics of early atherosclerotic plaque formation may determine the efficacy of high density lipoproteins (HDL) in plaque regression

We use a computational model to explore the effect of foam cell accumulation on plaque regression following an increase in high density lipoprotein (HDL) influx into the plaque. Atherosclerotic plaque formation is the outcome of cellular and cytokine responses to low density lipoproteins (LDL) that penetrate the artery wall following an injury to the endothelium and become modified. We modelled the cells and cytokines that are most important in plaque formation using partial differential equations. The model includes monocytes and macrophages, foam cells, macrophage chemoattractants, endothelium-stimulating cytokines, modified low density lipoproteins (mod LDL) and HDL. We included interactions both at the endothelium surface and inside the artery wall. The model predicts that when HDL influx into a well-established plaque with large numbers of foam cells is increased, the plaque may not regress but may continue to grow at a slower rate. If HDL influx is increased when a model plaque is recently established and has fewer foam cells, then the plaque does regress. If modLDL influx into the plaque is lowered at the same time that HDL influx increased or the capacity of the HDL to remove cholesterol from foam cells is increased, then the plaque is more likely to regress. The predictions of the model are in qualitative agreement with experimental studies in mice and rabbits. The results suggest that the intrinsic dynamics of reverse cholesterol transport by HDL are important in determining the success of HDL raising in promoting plaque regression.

Pre-existing arterial pathologic changes affecting arteriovenous fistula patency and cardiovascular mortality in hemodialysis patients

The radiocephalic arteriovenous fistula (AVF) provides optimal vascular access for hemodialysis; it has a higher long-term patency rate and fewer complications than other vascular access methods. However, the AVF has a high primary failure rate. The presence of small-diameter vessels at anastomosis sites is an important risk factor for AVF failure. However, in a recent study, despite selecting an adequate artery and vein for creating an AVF by routine preoperative vascular mapping, AVF maturation and primary failure occurred. Thus, pre-existing arteriosclerosis at AVF anastomosis sites likely contributes to AVF failure. In this review, we discuss the relationship between pathologic changes and AVF patency in hemodialysis patients. Because arteriosclerosis of the major arteries such as the coronary and carotid arteries is associated with cardiovascular mortality, we also review the impact of arteriosclerosis of upper arm arteries at AVF anastomosis sites on cardiovascular mortality in hemodialysis patients.

Bifurcation and dynamics in a mathematical model of early atherosclerosis: How acute inflammation drives lesion development

We present here a mathematical model describing the primary mechanisms that drive the early stages of atherosclerosis. This involves the interactions between modified low density lipoprotein (LDL), monocytes/macrophages, cytokines and foam cells. This model suggests that there is an initial inflammatory phase associated with atherosclerotic lesion development and a longer, quasi-static process of plaque development inside the arterial wall that follows the initial transient. We will show results that show how different LDL concentrations in the blood stream and different immune responses can affect the development of a plaque. Through numerical bifurcation analysis, we show the existence of a fold bifurcation when the flux of LDL from the blood is sufficiently high. By analysing the model presented in this paper, we gain a greater insight into this inflammatory response qualitatively and quantitatively.

Morphological and functional consequences of transradial coronary angiography on the radial artery: implications for its use as a bypass conduit

OBJECTIVES

To assess the degree of damage to the radial artery (RA) in coronary artery bypass grafting (CABG) patients who underwent preoperative transradial coronary angiography (RA-CA).

METHODS

From May 2012 to October 2013, 50 consecutive CABG patients who underwent RA-CA were prospectively enrolled in the study. All patients underwent echo-Doppler evaluation of the RA of the catheterized arm; the contralateral RA was used as control. The distal segment of the RA was submitted to immunohistochemical assessment of endothelial integrity. Patients were divided in three groups according to the time interval from angiography to evaluation: ≤24 h, >24 h to <7 days and ≥7 days.

RESULTS

Baseline RA median diameters were 0.25 ± 0.04 cm in the cannulated arm and 0.22 ± 0.04 cm in the non-cannulated arm (P = 0.01). The flow-mediated dilatation (FMD) in the RA in the catheterized arm and in the control arm were 11.6 ± 7.9 and 14.2 ± 8.9 (P = 0.01), respectively. A statistically significant correlation was found between FMD of the catheterized RA and the time from RA-CA (Pearson's r = 0.348). Linear regression analysis confirmed that the FMD of the catheterized RA was dependent on days elapsed from the procedure (P = 0.032; OR 1.11, CI 0.009-0.203). Immunohistochemical evaluation showed extensive endothelial lesion in all examined RAs, with a trend towards reduction of the damage with time. Endothelial function and integrity of the cannulated arm did not reach those of the control arm in any of the study patients.

CONCLUSIONS

RA-CA produces extensive damage to the RA. The lesions tend to heal with time but incomplete recovery of endothelial integrity and function is still present more than 30 days after the procedure. After RA-CA, the cannulated RA should not be used for CABG.

Carotid intima media thickness and coronary atherosclerosis linkage in symptomatic intermediate risk patients evaluated by coronary computed tomography angiography

BACKGROUND

There is a growing evidence that carotid intima media thickness (CIMT) is associated with coronary artery disease (CAD) and it should be used as a predictor of atherosclerotic burden of coronary arteries. However, these studies have been performed by using invasive coronary angiography (ICA) and in high-risk patients for CAD. The purpose of this study was to evaluate the correlation between CIMT by ultrasound and coronary atherosclerosis in symptomatic intermediate risk patients by coronary computed tomography angiography (CCTA).

METHODS

We enrolled 204 consecutive symptomatic patients (mean age: 61±10; men: 118) and intermediate risk for CAD. All patients underwent CIMT ultrasound evaluation and CCTA. Coronary artery calcium score (CACS), characteristics of plaques, severity of CAD, segment involvement score (SIS) and Gensini's score were assessed and compared with CIMT values.

RESULTS

CIMT has been proved as an independent predictor of a number of coronary artery plaques, overall number of mixed and remodeled plaques, presence of obstructive CAD, high SIS and Gensini's score (HR 1.2, CI 1.05-1.42, p 0.01; HR 1.2, CI 1.01-1.41, p 0.03; HR 9.0, CI 1.37-59.7, p 0.02; HR 21.0, CI 2.40-184, p<0.01; HR 1.2, CI 1.08-1.42, p<0.01; HR 1.2, CI 1.08-1.42, p<0.01, respectively). A cut-off value>1.3 was associated with a better positive and negative predictive value (100% and 69%) to predict the combined endpoint of presence and mixed and/or remodeled coronary artery plaques.

CONCLUSIONS

CIMT is an independent predictor of coronary atherosclerotic burden as detected by CCTA in symptomatic intermediate risk patients.