The prognostic impact of vascular calcification on abdominal aortic aneurysm progression

OBJECTIVE

The maximal aortic diameter is currently the only clinically applied predictor of abdominal aortic aneurysm (AAA) progression. It is known that risk of rupture is associated with aneurysm size, hence accurate monitoring of AAA expansion is crucial. Aneurysmal vessel wall calcification and its implication on AAA expansion are insufficiently explored. We evaluated the vascular calcification using longitudinal computed tomography angiographies (CTA) of AAA patients and its association with AAA growth.

METHODS

We conducted a retrospective study of 102 AAA patients with a total number of 389 abdominal CTAs at six-month intervals, treated and followed-up at the Division of Vascular Surgery, Department of General Surgery, Medical University of Vienna. Digitally stored CTAs were reviewed for vascular calcification (volume and score) of the infrarenal aorta and common iliac arteries as well as for morphometric AAA analysis. In the prognostic setting, slow versus fast AAA progression was defined as < 2 or ≥ 2 mm increase in AAA diameter over six months. In addition, to analyze the association of vascular calcification and AAA growth rate with longitudinal monitoring data, a specifically tailored log-linear mixed model was employed.

RESULTS

An inverse relation of increased abdominal vessel wall calcification and short-term AAA progression was detected. Compared to fast progressing AAA, the median calcification volume of the infrarenal aorta (1225.3 vs 519.8 mm³, P = 0.003), the median total calcification volume (2014.1 vs 1434.9 mm³, P = 0.008) and the median abdominal total customized Agatston calcium (cAC) score (1663.5 vs 718.4, P = 0.003) were significantly increased in slow progressing AAA. Importantly, a log-linear mixed model efficiently predicted AAA expansion based on current diameter and abdominal total cAC score (P = 0.042).

CONCLUSION

We assessed the prognostic value of CTA-measured vascular calcification for AAA progression. Increased vascular calcification stabilizes the aortic aneurysmal wall and likely protects against progressive AAA expansion, resulting in a significant decrease of aneurysm growth over time. As a consequence, this may have implications for rupture risk, mortality, morbidity, and cost.

Advances in CT Techniques in Vascular Calcification

Vascular calcification, a common pathological phenomenon in atherosclerosis, diabetes, hypertension, and other diseases, increases the incidence and mortality of cardiovascular diseases. Therefore, the prevention and detection of vascular calcification play an important role. At present, various techniques have been applied to the analysis of vascular calcification, but clinical examination mainly depends on non-invasive and invasive imaging methods to detect and quantify. Computed tomography (CT), as a commonly used clinical examination method, can analyze vascular calcification. In recent years, with the development of technology, in addition to traditional CT, some emerging types of CT, such as dual-energy CT and micro CT, have emerged for vascular imaging and providing anatomical information for calcification. This review focuses on the latest application of various CT techniques in vascular calcification.

Carotid artery calcification score and its association with cognitive impairment

Purpose

To retrospectively investigate the possible association between carotid artery calcification score (CS) and cognitive impairment in carotid artery stenosis (CAS) patients.

Patients and methods

Carotid artery was measured in 102 patients with cervical carotid arteries using Color Doppler ultrasound, multi-detector row spiral CT angiography and MRI scanning. Correlation analysis between CSs obtained by MD CT and cognitive scores was performed, and the correlation between CSs and vascular stenosis degree and MRI-measured plaque histological (lipid-rich necrotic nucleus [LRNC], intraplaque hemorrhage and fibrous cap surface rupture) and morphological parameters (lumen area [LA], wall area [WA], total area of blood vessels [TVA], plaque burden [PB]) was analyzed. Follow-up review analysis was conducted on 38 postoperative patients.

Results

Significant negative correlation was discovered between CS value and cognitive scores in CAS patients (R=-0.359, P<0.001), which did not exist in postoperative patients (P=0.348); CS value also showed significant correlation with WA (R=0.521, P=0.042), TVA (R=0.215, P=0.017) and PB (R=0.237, P=0.003) and had a certain predictive value for the occurrence probability of carotid plaque LRNC (P=0.029, AUC =0.780) in preoperative patients.

Conclusion

Carotid artery CSs have significant correlation with cognitive scores, which could be used as risk factor for early screening of cognitive impairment in CAS patients. The possible mechanism may be related to the calcification impact on the plaque burden.

Expression of bone-related proteins in vascular calcification and its serum correlations with coronary artery calcification score

Since vascular calcification is considered a process regulated similar to that of bone tissue mineralization, we investigated the participation of bone formation proteins. We analyzed the correlation of serum circulating bone markers, osteoprotegerin (OPG) and receptor activator of nuclear factor ĸB ligand (RANKL) in chronic kidney disease (CKD) patients, to coronary artery calcification score. We also considered the effect of inorganic phosphate on pro- and anti-calcifying tissue factors. We confirmed that circulating OPG is an independent calcium score predictor with its high serum concentration favoring high coronary artery calcification. In tissue samples of non-diseased human renal arteries, the expression of OPG and receptor activator of nuclear factor ĸB (RANK) was positive, while expression of RANKL was absent. In atherosclerotic specimens and arteries with medial calcification, the most upregulated was expression of bone morphogenetic proteins, BMP-2 and BMP-7, as well as expression of RANK and RANKL. In the diseased arteries, OPG expression was present only in areas where bone structures were formed. In atherosclerotic and medial calcification arteries, loss of alpha-smooth muscle actin (α-SMA) expression was observed. These data suggest a possible regulatory role of the examined proteins, especially OPG and RANKL, in vascular calcification, as well as their possible clinical significance as circulating predictors of vascular calcification.

Calcification score versus arterial stenosis grading: comparison of two CT-based methods for risk assessment of anastomotic leakage after esophagectomy and gastric pull-up

Purpose

Anastomotic leakage is a major surgical complication following esophagectomy and gastric pull-up. Specific risk factors such as celiac trunk (TC) stenosis and high calcification score of the aorta have been identified, but no data are available on their relative prognostic values. This retrospective study aimed to compare and evaluate calcification score versus stenosis quantification with regards to prognostic impact on anastomotic leakage.

Patients and methods

Preoperative contrast-enhanced computed tomography scans of 164 consecutive patients with primary esophageal cancer were evaluated by two radiologists to apply a calcification score (0–3 scale) assessing the aorta, the celiac axis and the right and left postceliac arteries. Concurrently, the presence and degree of stenosis of TC and superior mesenteric artery were recorded for stenosis quantification.

Results

Anastomotic leakage was noted in 14/164 patients and 12/14 showed stenosis of TC (n=11). The presence of TC stenosis was found to have a significant impact on anastomotic healing (p=0.004). The odds ratio for the prediction of anastomotic leakage by the degree of stenosis was 1.04 (95% CI, 1.02–1.07). Ten of 14 patients had aortic calcification scores of 1 or 2, but calcification scores of the aorta, the celiac axis and the right and left postceliac arteries did not correlate with the corresponding TC stenosis values and showed no influence on patient outcome as defined by the occurrence of anastomotic insufficiency (p=0.565, 0.855, 0.518 and 1.000, respectively). Inter-reader reliability of computed tomography analysis and absolute agreement on calcium scoring was mostly over 90%. No significant differences in preoperative comorbidities and patient characteristics were found between those with and without anastomotic leakage.

Conclusion

Measurement of TC stenosis in preoperative contrast-enhanced computed tomography scans proved to be more reliable than calcification scores in predicting anastomotic leakage and should, therefore, be used in the risk assessment of patients undergoing esophagectomy and gastric pull-up.

The role of CT in predicting the need for surgery in patients diagnosed with mesenteric phlebosclerosis

To determine if imaging findings on computed tomography (CT) can predict the need of surgery in patients with idiopathic mesenteric phlebosclerosis (IMP).This retrospective study included 28 patients with IMP. Abdominal CT images were reviewed to determine the extent and severity of mesenteric calcifications and the presence of findings related to colitides. We compared the number of colonic segments with mesenteric venous calcification, a total calcification score, and the rate of colonic wall thickening, pericolic fat stranding, and bowel loop dilatation between patients undergoing surgery (surgery group) and patients without surgery (nonsurgery group). Comparisons were made using the Mann-Whitney U test and Fisher exact test. Receiver operating characteristic analysis was also performed. Inter-reader agreement for the calcification scores was analyzed using kappa statistics.The number of colonic segments with mesenteric venous calcification and the total calcification scores were both significantly higher in the surgery group than the nonsurgery group (4.33 vs 2.96, P = 0.003; and 15.00 vs 8.96, P <0.001). The areas under the receiver operating characteristics to identify patients who need surgery were 0.96 and 0.92, respectively. The prevalence of bowel loop dilatation in the surgery group was also significantly higher than that in the nonsurgery group (16% vs 100%, P = 0.011).Evaluation of the severity and extent of IMP based on the total mesenteric venous calcification score, number of involved colonic segments, and the presence bowel loop dilatation on CT may be useful to indicate the outcomes of conservative treatment and need for surgery.

Correlation of serum 25-hydroxyvitamin D level with vascular calcification in hemodialysis patients

OBJECTIVE

The aim of this study was to analyze the correlation of serum 25-hydroxyvitamin D level with vascular calcification in patients treated with hemodialysis.

METHODS

As a cross-sectional study, 126 patients receiving maintenance hemodialysis (MHD) in our hospital were enrolled in this study. According to the serum 25-hydroxyvitamin D level, the patients were divided into 25-hydroxyvitamin D deficiency group (30 ηg/ml or less than 30 ηg/ml) and 25-hydroxyvitamin D normal level group (>30 ηg/ml). All of the subjects underwent lateral lumbar, pelvis and hands X-ray examination to score the degree of calcification (Kauppila score).

RESULTS

Among the 126 patients treated with MHD, there were 110 patients with 25-hydroxyvitamin D deficiency and 16 patients with normal 25-hydroxyvitamin D level. There was no significant difference found in gender, age, age of dialysis, active vitamin D treatment, blood calcium, blood phosphorus, blood parathyroid hormone (PTH) and other related indicators between the two groups. The incidence of vascular calcification in patients with 25-hydroxyvitamin D deficiency was significantly higher than that in patients with normal 25-hydroxyvitamin D level (P = 0.001). Serum 25-hydroxyvitamin D level had a negative correlation with the calcification score (r = 0.193, P = 0.193). Logistic regression showed that 25-hydroxyvitamin D was not a risk factor for vascular calcification in MHD patients. Serum 25-hydroxyvitamin D level is generally low in patients with MHD.

CONCLUSIONS

Patients with 25-hydroxyvitamin D deficiency have a higher incidence of vascular calcification with a markedly negative correlation. Thus, for the patients treated with MHD, vitamin D deficiency should be actively treated.