Intramural location and size of arterial calcification are associated with stenosis at carotid bifurcation

Relationship between annular calcification of plaques in the carotid sinus and perioperative hemodynamic disorder in carotid angioplasty and stenting

OBJECTIVE

To investigate the correlation between annular plaque calcification in the carotid sinus and perioperative hemodynamic disorder (HD) in carotid angioplasty and stenting (CAS).

METHODS

The clinical data of 49 patients undergoing CAS due to narrowing of the carotid sinus were retrospectively analyzed. All patients had preoperative carotid computed tomography angiography (CTA) and were divided into HD and non-HD groups based on the occurrence of HD in the perioperative period of CAS. HD was defined as persistent bradycardia (heart rate < 60 beats per min) or persistent hypotension (systolic blood pressure < 90 mmHg) in the perioperative period and lasting for at least 1 h. The baseline data, including the degree of carotid artery stenosis, plaque length, plaque thickness, calcified plaque morphologies (i.e., plaque circumferential angle: < 90° defined as dotted calcification; 90°-180° defined as arcuate calcification; > 180° defined as annular calcification), contralateral carotid artery conditions, balloon diameter, and stent types, were compared between the two groups. Binary logistic regression was used to analyze the risk factors for the occurrence of HD.

RESULTS

Among the 49 patients undergoing CAS, 14 (28.57%) developed perioperative HD, and 35 did not. Annular calcification was more common in the patients in the HD group than in the non-HD group. No significant differences in the probabilities of dotted and arcuate calcifications were found between the two groups (p > 0.05). The duration of continuous dopamine consumption in the HD group was 9-71 h. The average hospital stay of the HD group (10.14 ± 4.17 days) was significantly longer than that of the non-HD group (6.57 ± 1.9 days; p < 0.001). Patients in the HD group had significantly more pronounced lumen stenosis (p = 0.033) and longer plaque length (p = 0.034) than those in the non-HD group. After adjusting for age and sex, multivariate regression analysis showed that the presence of annular plaque calcification was an independent predictor of HD (odds ratio: 7.68, 95% confidence interval: 1.46-40.37, p = 0.016).

CONCLUSIONS

The occurrence of annular plaque calcification in the carotid sinus was an independent risk factor for perioperative HD in CAS. Preoperative carotid CTA assists with the early identification of high-risk patients who may develop HD.

Circumferential degree of carotid calcification is associated with new ischemic brain lesions after carotid artery stenting

Background

The relationship between plaque calcification and new ischemic brain lesions after carotid artery stenting (CAS) remains controversial. The purpose of this study was to determine if the circumferential degree of carotid calcification is associated with new ischemic brain lesions on diffusion-weighted imaging (DWI) after CAS.

Methods

A total of 96 patients with carotid stenosis of ≥50% who underwent CAS were enrolled in the study. All patients underwent preoperative carotid computed tomography (CT), and preoperative and postoperative brain MRI. The brain MRI sequences included T1WI, T2WI, T2-fluid-attenuated inversion recovery (FLAIR), and DWI. The location, circumferential degree, volume, percentage volume, maximum density, mean density, Agatston score of carotid calcification, and total plaque volume were assessed and compared between patients with and without new ischemic brain lesions after CAS. Univariate and multivariate analyses were performed to evaluate predictors of new ischemic brain lesions.

Results

All of the 96 patients (67.8±6.8 years of age, 83.3% men) were included in the analysis. New ischemic brain lesions on DWI were observed in 40 patients (41.7%). Patients with new ischemic brain lesions after CAS had a larger circumferential degree of calcification than those without new ischemic brain lesions (P<0.001). There was only a possible trend toward significance for the percentage volume of calcification between the two groups with and without new brain ischemic lesions (P=0.07). No significant differences were found regarding the location (P=0.18), volume (P=0.37), maximum density (P=0.44), mean density (P=0.39), Agatston score (P=0.28), and total plaque volume (P=0.33) of carotid calcification between the DWI+ and DWI- groups. In the multivariate analysis, an increased risk of new ischemic brain lesions was observed in patients with a high score for the circumferential degree of calcification [score 3; odds ratio (OR): 10.7, P<0.001; score 4, OR: 11.7, P=0.038].

Conclusions

The circumferential degree of carotid calcification was associated with new ischemic brain lesions after CAS. CAS should be avoided if possible for carotid stenosis with large circumferential calcified plaques.

Superficial Calcification With Rotund Shape Is Associated With Carotid Plaque Rupture: An Optical Coherence Tomography Study

Background: Plaque rupture is an important etiology for symptomatic carotid stenosis. The role of calcification in the plaque vulnerability has been controversial. We aimed to detect the geometric features of calcifications in carotid plaque and to examine its association with plaque rupture. Methods: Optical coherence tomography assessment of carotid plaque was performed in 88 patients. Calcification shape was evaluated through quantitative measurements of the long and short axis, area size, circumference, calcification arc, and longitudinal length. Calcification location was analyzed through the distance to the lumen. Furthermore, we developed idealized fluid-structure interaction models to investigate the association of calcification shape and plaque stress. Results: A total of 33 ruptured plaques and 30 non-ruptured plaques were recognized. Ruptured plaques had more multiple calcifications and protruded calcifications. The calcifications in the ruptured plaques displayed a remarkably lower long-axis/short-axis (L/S) ratio than in the non-ruptured plaques (p = 0.001). We classified calcification shape into crescentic calcification (L/S > 2.5) and rotund calcification (L/S ≤ 2.5). Rotund-shaped calcifications were more common in ruptured plaques than in non-ruptured plaques (p = 0.02). Superficial calcifications with minimal distance to the lumen ≤ 50 μm accounted for 79.4% of all calcifications in the ruptured plaques, and only 7.7% in the non-ruptured plaques (p < 0.001). Biomechanical analysis showed that the plaque with rotund-shaped calcification developed 7.91-fold higher von Mises stress than the plaque with crescentic calcification. Conclusions: Superficial calcifications and rotund-shaped calcifications are associated with carotid plaque rupture, suggesting that calcification location and shape may play a key role in plaque vulnerability.

Calcification in Atherosclerotic Plaque Vulnerability: Friend or Foe?

Calcification is a clinical marker of atherosclerosis. This review focuses on recent findings on the association between calcification and plaque vulnerability. Calcified plaques have traditionally been regarded as stable atheromas, those causing stenosis may be more stable than non-calcified plaques. With the advances in intravascular imaging technology, the detection of the calcification and its surrounding plaque components have evolved. Microcalcifications and spotty calcifications represent an active stage of vascular calcification correlated with inflammation, whereas the degree of plaque calcification is strongly inversely related to macrophage infiltration. Asymptomatic patients have a higher content of plaque calcification than that in symptomatic patients. The effect of calcification might be biphasic. Plaque rupture has been shown to correlate positively with the number of spotty calcifications, and inversely with the number of large calcifications. There may be certain stages of calcium deposition that may be more atherogenic. Moreover, superficial calcifications are independently associated with plaque rupture and intraplaque hemorrhage, which may be due to the concentrated and asymmetrical distribution of biological stress in plaques. Conclusively, calcification of differential amounts, sizes, shapes, and positions may play differential roles in plaque homeostasis. The surrounding environments around the calcification within plaques also have impacts on plaque homeostasis. The interactive effects of these important factors of calcifications and plaques still await further study.

Arterial location-specific calcification at the carotid artery and aortic arch for chronic kidney disease, diabetes mellitus, hypertension, and dyslipidemia

Several risk factors for arterial calcification have been reported but controversial. The aim of this study was to clarify the interactions among chronic kidney disease (CKD), diabetes mellitus (DM), hypertension, and dyslipidemia in altering the risk of arterial calcification in the three different arterial locations and the intramural location at the internal carotid artery (ICA) origins. Calcified burdens at the ICA origins, the aortic arch, and its orifices were evaluated in a retrospective fashion by using computed tomography angiography in 397 patients. The multivariate analyses were adjusted for age, gender, CKD, DM, hypertension, dyslipidemia, and current smoking status. Additionally, subgroup analyses in each variable were conducted. Our multivariate logistic regression analyses revealed that CKD was significantly associated with the outside-wall calcification at the ICA origins, whereas DM was only associated with the inside-ICA-wall calcification. Additionally, we found that DM increased the association between CKD and arterial calcification at the aortic arch and its orifices, and the outside-wall at the ICA origins. Hypertension was significantly associated with the calcification at the orifices of the aortic arch branches synergistically with CKD. Dyslipidemia did not have any significant association with calcification in any of the three vascular beds. CKD had the highest prevalence risk of calcification in common with the three different vascular beds. CKD in combination with DM, as well as hypertension in combination with CKD, were key relationships affecting the risk of arterial calcification, especially at the aortic arch and its orifices.

Computed tomography of aortic wall calcifications in aortic dissection patients

Objectives

To investigate the frequency of aortic calcifications at the outer edge of the false lumen and the frequency of fully circular aortic calcifications in a consecutive series of patients with aortic dissection who underwent contrast-enhanced CT.

Methods

The study population compromised of 69 consecutive subjects aged 60 years and older with a contrast-enhanced CT scan demonstrating an aortic dissection. All CT scans were evaluated for the frequency of aortic calcifications at the outer edge of the false lumen and the frequency of fully circular aortic calcifications by two experienced observers. Between observer reliability was evaluated by using Cohen’s Kappa. Differences between groups were tested using unpaired T test and Chi-square test.

Results

Presumed media calcifications were observed in 22 (32%) patients of 60 years and older and were found more frequently in chronic aortic dissection (N = 12/23, 52%) than in acute aortic dissection (N = 10/46, 22%).

Conclusion

As the intima has been torn away by the aortic dissection it is highly likely that CT scans can visualize the calcifications in the tunica media of the aorta.