Comparative Analysis of Vascular Calcification Risk Factors in Pre-Hemodialysis and Prevalent Hemodialysis Adult Patients: Insights into Calcification Biomarker Associations and Implications for Intervention Strategies in Chronic Kidney Disease

This retrospective study aimed to compare risk factors for vascular calcification (VC) between pre-hemodialysis (HD) and prevalent HD adult patients while investigating associations with calcification biomarkers. Baseline data from 30 pre-HD and 85 HD patients were analyzed, including iPTH, vitamin D, FGF 23, fetuin-A, sclerostin, and VC scores (Adragao method). Prevalence of VC was similar in both groups, but HD patients had more frequent VC scores ≥ 6. Pre-HD patients were older, with higher prevalence of hypertension and less frequent use of calcium phosphate binders. Both groups showed similar patterns of hyperphosphatemia, low vitamin D, and iPTH. Fetuin-A and sclerostin levels were higher in pre-HD, while FGF 23 was elevated in HD patients. Higher VC risk in pre-HD patients was associated with male gender, older age, lower fetuin-A and higher sclerostin, lower ferritin, and no vitamin D treatment, while in HD patients with higher sclerostin, FGF 23 and urea, and lower iPTH. Conclusion: Biomarkers could be measurable indicators of biological processes underlying VC in CKD patients that may serve as a potential guide for considering personalized therapeutic approaches. Further studies are needed to elucidate the underlying pathways.

A Peculiar Presentation of a Debilitating Condition: Calciphylaxis

Calciphylaxis is a debilitating condition associated with significant morbidity and mortality, often associated with patients with end-stage renal disease, in which the calcification of cutaneous arterioles and small arteries occurs, leading to subsequent ischemia and cutaneous infarction. Herein, we report the case of a diabetic patient with end-stage kidney disease on dialysis, presenting multiple intensely painful necrotic plaques on the lower extremities. The suspicion of calciphylaxis was raised based on the patient's medical history and clinical presentation, subsequently confirmed by radiological examination, which revealed calcifications along vascular pathways. Diagnosis can be established based on clinical and paraclinical grounds alone, and some clinicians may forego skin biopsy and initiate treatment presumptively. The management of calciphylaxis remains a challenge and requires a multidisciplinary approach since most patients experience intense pain that is often unresponsive to conventional analgesics, leading to a reduced quality of life.

Hyperparathyroidism and Peripheral Arterial Disease

Primary hyperparathyroidism (PHPT) is presented in various forms, including classic PHPT, characterised by increased parathyroid hormone (PTH) secretion, normohormonal PHPT, and normocalcaemic PHPT. Secondary hyperparathyroidism is characterised by increased PTH secretion triggered by factors such as vitamin D deficiency and kidney failure. This review aims to discuss the involvement of hyperparathyroidism (HPT) in atherosclerosis, including peripheral arterial disease (PAD). The increased level of PTH is involved in developing subclinical and overt vascular diseases, encompassing endothelial dysfunction, vascular stiffness, hypertension, and coronary and peripheral arterial diseases. It has been consistently associated with an augmented risk of cardiovascular morbidity and mortality, independent of classical risk factors for atherosclerosis. Chronic hypercalcemia associated with increased levels of PTH contributes to the development of calcification of vessel walls and atherosclerotic plaques. Vascular calcification can occur in the intima or media of the arterial wall and is associated with stiffness of peripheral arteries, which the formation of atherosclerotic plaques and narrowing of the vessel lumen can follow. For treating hyperparathyroidism, particularly SHPT, calcimimetics, novel phosphorus binders and novel vitamin D receptor activators are used. However, they are ineffective in severe PHPT. Therefore, parathyroidectomy remains the primary therapeutic option of PHPT.

Real-world usage of Chronic Kidney Disease - Mineral Bone Disorder (CKD-MBD) biomarkers in nephrology practices

Background

Chronic kidney disease mineral bone disorder (CKD-MBD) is a condition characterized by alterations of calcium, phosphate, parathyroid hormone (PTH), and fibroblast growth factor 23 (FGF-23) metabolism that in turn promote bone disorders, vascular calcifications, and increase cardiovascular (CV) risk. Nephrologists' awareness of diagnostic, prognostic, and therapeutic tools to manage CKD-MBD plays a primary role in adequately preventing and managing this condition in clinical practice.

Methods

A national survey (composed of 15 closed questions) was launched to inquire about the use of bone biomarkers in the management of CKD-MBD patients by nephrologists and to gain knowledge about the implementation of guideline recommendations in clinical practice.

Results

One hundred and six Italian nephrologists participated in the survey for an overall response rate of about 10%. Nephrologists indicated that the laboratories of their hospitals were able to satisfy request of ionized calcium levels, 105 (99.1%) of both PTH and alkaline phosphatase (ALP), 100 (94.3%) of 25(OH)D, and 61 (57.5%) of 1.25(OH)2D; while most laboratories did not support the requests of biomarkers such as FGF-23 (intact: 88.7% and c-terminal: 93.4%), Klotho (95.3%; soluble form: 97.2%), tartrate-resistant acid phosphatase 5b (TRAP-5b) (92.5%), C-terminal telopeptide (CTX) (71.7%), and pro-collagen type 1 N-terminal pro-peptide (P1NP) (88.7%). As interesting data regarding Italian nephrologists' behavior to start treatment of secondary hyperparathyroidism (sHPT), the majority of clinicians used KDOQI guidelines (n = 55, 51.9%). In contrast, only 40 nephrologists (37.7%) relied on KDIGO guidelines, which recommended referring to values of PTH between two and nine times the upper limit of the normal range.

Conclusion

Results point out a marked heterogeneity in the management of CKD-MBD by clinicians as well as a suboptimal implementation of guidelines in Italian clinical practice.

Vitamin K supplementation impact in dialysis patients: a systematic review and meta-analysis of randomized trials

Vitamin K supplementation has been considered recently as a potential treatment for addressing vascular calcification in chronic kidney disease patients. We conducted a systematic review and meta-analysis to summarize the impact of vitamin K supplementation in dialysis patients. Electronic databases were searched for clinical randomized trials among patients treated with vitamin K. Random effects models were performed and risk of bias was evaluated with Cochrane tools and the search was conducted until 15 of September 2023. Eleven trials comprising 830 patients (both adult and pediatric, mainly hemodialysis) compared vitamin K with different controls: lower doses of vitamin K, standard care or placebo. Vitamin K supplementation had no effect on mortality. Vitamin K administration improved vitamin K levels and led to lower levels of dp-uc-MGP and moderately increased calcium levels [0.18 (0.04-0.32)]. Vitamin K1 proved more potency in reducing dp-uc-MGP [SMD -1.64 (-2.05, -1.23) vs. -0.56 (-0.82, -0.31)] and also raised serum vitamin K levels in comparison with vitamin K2 [5.69 (3.43, 7.94) vs. 2.25 (-2.36, 6.87)]. While it did not have a proved benefit in changing calcification scores [-0.14 (-0.37 ± 0.09)], vitamin K proved to be a safe product. There was some concern with bias. Vitamin K supplementation has no impact on mortality and did not show significant benefit in reversing calcification scores. Vitamin K1 improved vitamin K deposits and lowered dp-uc-MGP, which is a calcification biomarker more than vitamin K2. As it proved to be a safe product, additional randomized well-powered studies with improved treatment regimens are needed to establish the true impact of vitamin K in dialysis patients.

Hypomagnesemia: a potential underlooked cause of persistent vitamin D deficiency in chronic kidney disease

Magnesium and vitamin D play important roles in most cells of the body. These nutrients act in a coordinated fashion to maintain physiologic functions of various organs, and their abnormal balance could adversely affect these functions. Therefore, deficient states of both nutrients may lead to several chronic medical conditions and increased cardiovascular and all-cause mortality. Chronic kidney disease (CKD) patients have altered metabolism of both magnesium and vitamin D. Some studies indicate that magnesium could have a role in the synthesis and metabolism of vitamin D, and that magnesium supplementation substantially reversed the resistance to vitamin D treatment in some clinical situations. Recent observational studies also found that magnesium intake significantly interacted with vitamin D status and, particularly with the risk of cardiovascular mortality. It is therefore essential to ensure adequate levels of magnesium to obtain the optimal benefits of vitamin D supplementation in CKD patients. In this review, we discuss magnesium physiology, magnesium and vitamin D metabolism in CKD, potential metabolic interactions between magnesium and vitamin D and its clinical relevance, as well as the possible role of magnesium supplementation to assure adequate vitamin D levels.

Association between intracranial vessel calcifications, structural brain damage, and cognitive impairment after minor strokes: a prospective study

Background

Vascular calcifications are a hallmark of atherosclerosis, and in the coronary arteries are routinely used as a prognostic marker. Calcifications of intracranial vessels (ICC) are frequently observed on non-contrast CT (NCCT) and their effect on post-stroke cognitive impairment (PSCI) remains unclear. Our aim was to explore the association of ICC with prospective long-term cognitive function and advanced MRI-measures in a large prospective cohort of cognitively intact mild stroke survivors.

Methods

Data from the Tel-Aviv brain acute stroke cohort (TABASCO) study [ClinicalTrials.gov #NCT01926691] were analyzed. This prospective cohort study (n = 575) aimed to identify predictors of PSCI, in cognitively intact mild stroke survivors. A quantitative assessment of the intracranial calcium content - The ICC score (ICCS) was calculated semi-automatically on NCCT using a validated calcium quantification application. Participants underwent a 3 T-MRI and prospective comprehensive cognitive clinical and laboratory assessments at enrollment, 6, 12, and 24-months.

Results

Data were available for 531 participants (67.4 years, 59.5% males). The incidence of PSCI at two-years doubled in the high ICCS group (26% vs. 13.7%, p < 0.001). The high ICCS group had significantly greater small-vessel-disease (SVD) tissue changes and reduced microstructural-integrity assessed by Diffusion-Tensor-Imaging (DTI) maps (p < 0.05 for all). In multivariate analysis, a higher ICCS was independently associated with brain atrophy manifested by lower normalized white and gray matter, hippocampal and thalamic volumes (β = -0.178, β = -0.2, β = -0.137, β = -0.157; p < 0.05) and independently predicted PSCI (OR 1.83, 95%CI 1.01-3.35).

Conclusion

Our findings suggest that the ICCS, which is a simple and readily available imaging marker on NCCT, is associated with brain atrophy, microstructural damage, the extent of SVD, and may predict PSCI. This finding has implications for identifying individuals at risk for PSCI and implementing targeted interventions to mitigate this risk.

Relationship between Muscle Mass, Bone Density and Vascular Calcifications in Elderly People with SARS-CoV-2 Pneumonia

BACKGROUND

Little is known about the changes in organs and tissues that may make elder patients more vulnerable to acute stressors such as SARS-CoV-2 infection.

METHODS

In 80 consecutive elderly patients with SARS-CoV-2 infection, we evaluated the association between the descending thoracic aorta calcium score, L1 bone density and T12 skeletal muscle density measured on the same scan by high-resolution computed tomography.

RESULTS

At median regression, the ln-transformed DTA calcium score was inversely associated with L1 bone density (-0.02, 95%CI -0.04 to -0.01 ln-Agatston units for an increase of 1 HU) and with T12 muscle density (-0.03, -0.06 to -0.001 ln-Agatston units for an increase of 1 HU). At penalized logistic regression, an increase of 1 ln-Agatston unit of DTA calcium score was associated with an OR of death of 1.480 (1.022 to 2.145), one of 1 HU of bone density with an OR of 0.981 (0.966 to 0.996) and one of 1 HU of muscle density with an OR of 0.973 (0.948 to 0.999). These relationships disappeared after correction for age and age was the stronger predictor of body composition and death.

CONCLUSIONS

Age has a big effect on the relationship between vascular calcifications, L1 bone density and T12 muscle density and on their relationship with the odds of dying.

Automatic measurement of vascular calcifications in patients with aorto-iliac occlusive disease to predict the risk of re-intervention after endovascular repair

OBJECTIVE

There is currently a lack of consensus and tools to easily measure vascular calcification using computed tomography angiography (CTA). The aim of this study was to develop a fully automatic software to measure calcifications and to evaluate the interest as predictive factor in patients with aorto-iliac occlusive disease.

METHODS

This study retrospectively included 171 patients who had endovascular repair of an aorto-iliac occlusive lesion at the University Hospital of Nice between January 2011 and December 2019. Calcifications volumes were measured from CT-angiography (CTA) using an automatic method consisting in 3 sequential steps: image pre-processing, lumen segmentation using expert system and deep learning algorithms and segmentation of calcifications. Calcification volumes were measured in the infrarenal abdominal aorta and the iliac arterial segments, corresponding to the common and the external iliac arteries.

RESULTS

Among 171 patients included with a mean age of 65 years, the revascularization was performed on the native external and internal iliac arteries in respectively: 83 patients (48.5%); 107 (62.3%) and 7 (4.1%). The mean volumes of calcifications were 2759 mm³ in the infrarenal abdominal aorta, 1821 mm³ and 1795 mm³ in the right and left iliac arteries. For a mean follow up of 39 months, TLR was performed in 55 patients (32.2%). These patients had higher volume of calcifications in the right and left iliac arteries, compared with patients who did not have a re-intervention (2274 mm³ vs 1606 mm³, p=0.0319 and 2278 vs 1567 mm³, p=0.0213).

CONCLUSION

The development of a fully automatic software would be useful to facilitate the measurement of vascular calcifications and possibly better inform the prognosis of patients.

HAP-Multitag, a PET and Positive MRI Contrast Nanotracer for the Longitudinal Characterization of Vascular Calcifications in Atherosclerosis

Vascular microcalcifications are associated with atherosclerosis plaque instability and, therefore, to increased mortality. Because of this key role, several imaging probes have been developed for their in vivo identification. Among them, [¹⁸F]FNa is the gold standard, showing a large uptake in the whole skeleton by positron emission tomography. Here, we push the field toward the combined anatomical and functional early characterization of atherosclerosis. For this, we have developed hydroxyapatite (HAP)-multitag, a bisphosphonate-functionalized ⁶⁸Ga core-doped magnetic nanoparticle showing high affinity toward most common calcium salts present in microcalcifications, particularly HAP. We characterized this interaction in vitro and in vivo, showing a massive uptake in the atherosclerotic lesion identified by positron emission tomography (PET) and positive contrast magnetic resonance imaging (MRI). In addition, this accumulation was found to be dependent on the calcification progression, with a maximum uptake in the microcalcification stage. These results confirmed the ability of HAP-multitag to identify vascular calcifications by PET/(T₁)MRI during the vulnerable stages of the plaque progression.

Intravascular shockwave lithotripsy as a treatment modality for symptomatic mesenteric ischemia

Chronic mesenteric ischemia has traditionally been treated with either open surgical revascularization or endovascular therapy. Endovascular surgery has typically been preferred due to the lower rates of peri-procedural and post-procedural morbidity, yet this comes at the expense of long-term durability. Intravascular shockwave lithotripsy is a technique utilized to modify intimal and medial calcified plaque in order to improve vessel expansion and patency. Intravascular lithotripsy has been investigated as both primary and adjunctive treatment for peripheral arterial and coronary arterial lesions, however, its use in the treatment of chronic mesenteric ischemia requires further investigation. We present a case of a 75-year-old woman with symptomatic mesenteric ischemia who underwent intravascular shockwave lithotripsy of a 99% stenosis superior mesenteric artery with an excellent outcome.

Computed tomography findings of metabolic syndrome in patients with acute colonic diverticulitis

INTRODUCTION

Many factors associated with colonic diverticulitis are also part of the clinical definition of the metabolic syndrome. Computed tomography (CT) is commonly performed in symptomatic patients, such as those with suspected or known acute diverticulitis, and could add additional value for the health of these patients by identifying and reporting CT biomarkers of metabolic syndrome, if present and detectable. The purpose of this study was to identify CT biomarkers of metabolic syndrome in patients with acute colonic diverticulitis.

METHODS

We retrospectively reviewed 243 patients (mean-60 yrs, M:F:126:117) diagnosed with colonic diverticulitis on CT between March 2015 and March 2017 for hepatic steatosis, vascular calcifications, abdominal diameters and fat volumes. Criteria of metabolic syndrome were obtained from medical records. Differences in imaging biomarkers were compared using chi-square comparisons stratified by metabolic syndrome, abdominal diameter and fat volume.

RESULTS

Of 243 patients, 33% demonstrated hepatic steatosis and 71% atherosclerotic vascular calcifications on CT. 28% met criteria for metabolic syndrome. Patients with metabolic syndrome had higher occurrence of hepatic steatosis, sagittal diameter ≥ 35 cm, visceral fat > 5000 cm³ and subcutaneous fat > 8300 cm³ (P < 0.05), but not vascular calcifications (P > 0.05).

CONCLUSIONS

CT biomarkers of metabolic syndrome are commonly encountered in patients with acute diverticulitis. Recognizing and reporting these findings can guide towards further evaluation for metabolic syndrome.

Biomarkers of bone and mineral disorders (FGF-23, fetuin-A) and vascular calcification scores as predictive tools for cardiovascular death in dialysis patients, at 10 years of follow-up

Cardiovascular disorders represent the leading cause of death in dialysis patients. Alterations of bone and mineral metabolism (BMM) and vascular calcifications play a fundamental role in it. The objective of this study was to evaluate the predictive role on cardiovascular mortality of the measurement of biomarkers of BMM and vascular calcifications. A prospective cohort study was performed. All prevalent patients on chronic dialysis in September 2009 at our institution, who completed the total of the complementary studies, were studied. BMM biomarkers were measured (FGF 23, fetuin A, PTH, calcium and phosphorus) and the vascular calcifications were evaluated using the Kauppila and Adragao scores. Follow-up was carried out until 1/1/2019, death or transplant. Of the 30 patients included, 7 (23.3%) died due to cardiovascular causes. The follow-up time was 44.1 ± 30.4 (range = 1.4-112) months. The Adragao score was the only predictive variable of long-term cardiovascular mortality (area under the curve = 0.82; 95% CI 0.64-0.94; p < 0.001). The best cut-off point was 5 (sensitivity = 85.7%; specificity = 78.3%). It was also an independent risk factor for cardiovascular mortality adjusted for age, diabetes mellitus, coronary heart disease, aortic calcifications, time spent on dialysis and follow-up time (adjusted OR = 1.77; 95% CI = 1.06-2.96; p = 0.028). The vascular calcifications quantified from the Adragao score were the only independent predictor of long-term cardiovascular mortality. This score represents a simple, useful and superior tool to the biomarkers of BMM.

Fluorescent Arylphosphonic Acids: Synergic Interactions between Bone and the Fluorescent Core

Herein, we report the third generation of fluorescent probes (arylphosphonic acids) to target calcifications, particularly hydroxyapatite (HAP). In this study, we use highly conjugated porphyrin-based arylphosphonic acids and their diesters, namely 5,10,15,20-tetrakis[m-(diethoxyphosphoryl)phenyl]porphyrin (m-H8 TPPA-OEt8 ) and 5,10,15,20-tetrakis [m-phenylphosphonic acid]porphyrin (m-H8 TPPA), in comparison with their positional isomers 5,10,15,20-tetrakis[p-(diisopropoxyphosphoryl)phenyl]porphyrin (p-H8 TPPA-iPr8 ) and 5,10,15,20-tetrakis [p-phenylphosphonic acid]porphyrin (p-H8 TPPA), which have phosphonic acid units bonded to sp2 carbon atoms of the fluorescent core. The conjugation of the fluorescent core is thus extended to the (HAP) through sp2 -bonded -PO3 H2 units, which generates increased fluorescence upon HAP binding. The resulting fluorescent probes are highly sensitive towards the HAP in rat bone sections. The designed probes are readily taken up by cells. Due to the lower reported toxicity of (p-H8 TPPA), these probes could find applications in monitoring bone resorption or adsorption, or imaging vascular or soft tissue calcifications for breast cancer diagnosis etc.

Synergistic effect of sclerostin and angiotensin II receptor 1 polymorphism on arterial stiffening

Aim: We aimed to establish the association between sclerostin (a glycoprotein involved in bone metabolism) and development of pulse wave velocity (PWV) in the general population. Methods: A prospective cohort study with a total of 522 subjects. Aortic PWV was measured twice (at baseline and after approximately 8 years of follow-up) and intraindividual change in PWV per year (ΔPWV/year) was calculated. Results: ΔPWV/year increased across the sclerostin quintiles, but generally in a strong age-dependent manner. However, a significant independent positive association between sclerostin and ΔPWV/year was observed exclusively in C allele carriers of rs5186 polymorphism for the angiotensin II receptor 1 (n = 246). Conclusion: Sclerostin concentrations were associated with an accelerated natural course of arterial stiffening, but only in interaction with renin-angiotension system.

Dual Roles of the Mineral Metabolism Disorders Biomarkers in Prevalent Hemodilysis Patients: In Renal Bone Disease and in Vascular Calcification

Background

Vascular calcification (VC) is highly prevalent in dialysis (HD) patients, and its mechanism is multifactorial. Most likely that systemic or local inhibitory factor is overwhelmed by promoters of VC in these patients. VC increased arterial stiffness, and left ventricular hypertrophy. Thus, the present study aimed to investigate the association of VC and myocardial remodeling and to analyze their relationship with VC promoters (fibroblast growth factor 23-FGF23, Klotho, intact parathormon-iPTH, vitamin D) in 56 prevalent HD patients (median values: age 54 yrs, HD vintage 82 months).

Methods

Besides routine laboratory analyzes, serum levels of FGF 23, soluble Klotho, iPTH, 1,25-dihydroxyvitamin D3; pulse wave velocity (PWV); left ventricular (LV) mass by ultrasound; and VCs score by Adragao method were measured.

Results

VC was found in 60% and LV concentric or eccentric hypertrophy in 50% patients. Dialysis vintage (OR 1.025, 95%CI 1.007–1.044, p=0.006) FGF23 (OR 1.006, 95% CI 0.992–1.012, p=0.029) and serum magnesium (OR 0.000, 95%CI 0.000–0.214, p=0.04) were associated with VC. Changes in myocardial geometry was associated with male sex (beta=-0.273, 95% CI -23.967 1.513, p=0.027), iPTH (beta 0.029, 95%CI -0.059–0.001, p=0.027) and vitamin D treatment (beta 25.49, 95%CI 11.325–39.667, p=0.001). Also, patients with the more widespread VC had the highest LV remodeling categories. PWV was associated patient’s age, cholesterol, diastolic blood pressure, LV mass (positively) and serum calcium (negatively), indicating potential link with atherosclerotic risk.

Conclusions

Despite to different risk factors for VC and myocardial remodeling, obtained results could indicate that risk factors intertwine in long-term treatment of HD patients and therefore careful and continuous correction of mineral metabolism disorders is undoubtedly of the utmost importance.

Feasibility of Image Fusion for Concurrent MRI Evaluation of Vessel Lumen and Vascular Calcifications in Peripheral Arterial Disease

OBJECTIVE

With MR angiography of peripheral arterial disease, calcifications are unapparent, so a separate calcification-sensitive pulse sequence (proton density-weighted in-phase 3D stack-of-stars [PDIP-SOS]) is needed for complete assessment. We hypothesized that, despite being acquired separately, MR angiography and PDIP-SOS images could be coregistered and fused without loss of significant diagnostic information.

CONCLUSION

In a prospective study of 15 patients, MR image fusion enabled the simultaneous display of vessel lumen and vascular calcifications similarly to CT angiography.

Non-uraemic calciphylaxis successfully treated with pamidronate infusion

Calciphylaxis is a rare and potentially fatal disease that affects the subcutaneous layer of the skin. It is a calcific vasculopathy induced by a systemic process that causes occlusion of small blood vessels. The mortality rate for individuals diagnosed with calciphylaxis is estimated between 52% and 81% with sepsis being the leading cause of death. Uraemic calciphylaxis and its known effective treatments are well documented in the literature. Unfortunately, there is no known effective treatment for non-uraemic calciphylaxis. Most of the current treatments for non-uraemic calciphylaxis are derived from uraemic calciphylaxis treatment protocols. We report a case of a 75-year-old female with calciphylaxis on the right lower extremity who was successfully treated with four pamidronate infusions in addition to local wound care. This case represents a non-uraemic calciphylaxis wound successfully treated with pamidronate infusions and standard wound care, and suggests that IV pamidronate can be an effective treatment option.

[ASSOCIATION BETWEEN VERTEBRAL FRACTURES AND VASCULAR CALCIFICATIONS]

Several cross-sectional and prospective studies highlight the existence of an association between bone fractures and abdominal aortic calcifications, especially if particularly severe and independent from confounders such as aging, smoking habits and diabetes. This phenomenon affects not only the general population but also patients with chronic kidney disease in which cortical bone lesions are prevalent. Moreover, bone fractures and aortic calcifications have been proved to be linked to increased cardiovascular morbidity and mortality, both in the general populations and in patients with chronic kidney disease, who notoriously show elevated cardiovascular risks. Therefore, diagnostic investigations about bone fractures and abdominal aortic calcifications, particularly in patients with chronic kidney disease, may represent a useful tool for identification of patients with a higher cardiovascular risk in order to optimize therapies for bone metabolism disorders.

Metabolic acidosis of chronic kidney disease and subclinical cardiovascular disease markers: Friend or foe?

The effect of chronic metabolic acidosis (MA) on cardiovascular disease (CVD) in the setting of chronic kidney disease (CKD) is largely unknown. Therefore, we aimed to study this relationship in nondialysis CKD patients.This cross-sectional, single-center study prospectively enrolled 95 clinically stable CKD patients (median age 61 (58, 65) years, 60% male, median eGFR 27 (22, 32) mL/min). Data on CKD etiology, CVD history, CVD traditional, and nontraditional risk factors were obtained. Also, markers of subclinical CVD were assessed: intima-media thickness (IMT), abdominal aortic calcifications (Kauppila score-AACs), cardio-ankle vascular index (CAVI), ankle-brachial index (ABI), ejection fraction, and interventricular septum thickness. Using the serum bicarbonate cutoff value of 22 mEq/L, comparisons between MA (<22 mEq/L; 43 patients) and non-MA (≥22 mEq/L; 52 patients) groups were performed.Vascular (40%), tubulointerstitial (24%), and glomerular (22%) nephropathies were the main causes of CKD. Twenty-three percent of patients had diabetes mellitus, but only 5% were considered to have diabetic nephropathy. Patients with chronic MA had lower eGFR (P < .01), higher iPTH (P = .01), higher serum phosphate (P < .01), and increased serum cholesterol (P = .04) and triglycerides (P = .01).Higher ABI (P = .04), lower IMT (P = .03), CAVI (P = .05), and AACs (P = .03) were found in patients with chronic MA.Separate binomial logistic regression models were performed using ABI (cutoff 0.9), CAVI (cutoff 9), IMT (cutoff 0.1 cm), and AACs (cutoff 1) as dependent variables. MA was used as independent variable and adjustments were made for iPTH, serum phosphate, eGFR, proteinuria, cholesterol, triglycerides, CVD score. The absence of MA was retained as an independent predictor only for the presence of AACs.In conclusion, the present study shows a potential advantageous effect of MA on vascular calcifications in predialysis CKD patients. Thus, a guideline relaxation of the serum bicarbonate target might prove to be beneficial in CKD patients at high risk of vascular calcifications. However, one should always consider the negative effects of MA. Therefore, additional research is warranted before any clear clinical recommendation.

Isolated intrasplenic vascular calcifications in a child with type 1 diabetes mellitus---A case report

We report a case of vascular calcifications in the spleen of a 7-year-old girl who was diagnosed with type 1 diabetes mellitus (DM). The possible etiology for vascular calcifications might be medial sclerosis associated with DM. To the best of our knowledge, this finding has not yet been reported in the literature. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:438-440, 2017.

[Matrix Gla protein as natural inhibitor of vascular calcification and potential treatment target]

Vascular calcification was once regarded as an advanced stage of atherosclerosis only. However, calcification is currently considered as highly regulated and potentially reversible process.Matrix Gla protein (MGP) represents natural inhibitor of vascular calcification, whereas vitamin K is key co-factor of its maturation to the active form. There is accumulating evidence that vitamin K status and corresponding MGP activity may influence cardiovascular risk. This review summarizes pathophysiological mechanism and recent evidence relative to MGP. Moreover, available data concerning vitamin K supplementation are depicted.

[Vascular calcifications in subjects with and without chronic renal failure: types, sites and risk factors]

Vascular calcifications worse outcomes in the general population and in patients on dialysis. We investigated 146 patients on chronic hemodialysis and 63 healthy controls with normal renal function under 65 years of age. All subjects underwent B-mode ultrasonography of common and internal carotid artery, abdominal aorta, common and superficial femoral artery and posterior tibial artery to assess the presence of intimal and medial calcifications. Intimal and media calcifications were present at the level of the carotid vessel, the abdominal aorta, the common femoral artery, the superficial femoral artery and the posterior tibial artery, respectively in 45%, 50%, 45%, 50%, 42% of patients on dialysis and in 5%, 15%, 24%, 5%, 2% of controls (p <0,01). On multivariate logistic analysis of regression, after adjustment for potential confounders, carotid intimal calcification, abdominal aortic calcification, medial calcification of the superficial femoral artery and posterior tibial artery calcification were associated with dialysis and with cardiovascular disease. Only intimal arterial calcification were associated with older age and smoking. Vascular calcifications are extremely common in middle-aged patients on chronic hemodialysis. Ultrasonography currently available in Nephrology, is a sensitive, reproducible, inexpensive imaging technique to identify arterial intimal and medial calcification in high-risk cardiovascular subjects.

[Imaging in CKD]

Imaging has contributed to the successful reduction of cardiovascular morbidity and mortality in the general population and it has demonstrated excellent potential among patients with chronic kidney disease (CKD). The well-known severity of cardiovascular disease in patients suffering from CKD requires an accurate risk stratification of these patients in several clinical situations. Alterations of both structure and function of the myocardium as well as severe vasculopathy are highly prevalent in patients with advanced CKD. Hence sophisticated imaging techniques are at times necessary to make an accurate assessment of risk. Two main forms of arterial pathology develop in patients with CKD: atherosclerosis, with accumulation of inflammatory cells, lipids, fibrous tissue and calcium in the sub-intimal space of the artery, and arteriosclerosis. The latter is characterized by thickening and calcification of the muscular layer of the arterial wall and it is not necessarily associated with typical atherosclerotic changes. This review explores the indications, strengths and weaknesses of several invasive and non-invasive imaging modalities employed to evaluate myocardial and vascular disease in CKD.

MR imaging of iliofemoral peripheral vascular calcifications using proton density-weighted, in-phase three-dimensional stack-of-stars gradient echo

PURPOSE

The presence of vascular calcifications helps to determine percutaneous access for interventional vascular procedures and has prognostic value for future cardiovascular events. Unlike CT, standard MRI techniques are insensitive to vascular calcifications. In this prospective study, we tested a proton density-weighted, in-phase (PDIP) three-dimensional (3D) stack-of-stars gradient-echo pulse sequence with approximately 1 mm³ isotropic spatial resolution at 1.5 Tesla (T) and 3T to detect iliofemoral peripheral vascular calcifications and correlated MR-determined lesion volumes with CT angiography (CTA).

METHODS

The study was approved by the Institutional Review Board. The prototype PDIP stack-of-stars pulse sequence was applied in 12 patients with iliofemoral peripheral vascular calcifications who had undergone CTA.

RESULTS

Vascular calcifications were well visualized in all subjects, excluding segments near prostheses or stents. The location, size, and shape of the calcifications were similar to CTA. Quantitative analysis showed excellent correlation (r²  = 0.84; P < 0.0001) between MR- and CT-based measures of calcification volume. In one subject in whom three pulse sequences were compared, PDIP stack-of-stars outperformed cartesian 3D gradient-echo and point-wise encoding time reduction with radial acquisition (PETRA).

CONCLUSION

In this pilot study, a PDIP 3D stack-of-stars gradient-echo pulse sequence with high spatial resolution provided excellent image quality and accurately depicted the location and volume of iliofemoral vascular calcifications. Magn Reson Med 77:2146-2152, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Vascular Calcifications on the Preoperative Radiograph: Predictor of Ischemic Complications in Total Knee Arthroplasty?

BACKGROUND

Vascular calcifications seen on the preoperative radiograph of patients scheduled for total knee arthroplasty (TKA) are intuitively seen as a risk factor for ischemic complications though there is no empiric evidence to support this assumption. The aim of this study was the correlation of perioperative ischemic complications and vascular calcifications of patients undergoing TKA.

METHODS

In this retrospective analysis, all 825 patients who had undergone primary TKA in the period 2009-2011 with intraoperative use of a tourniquet were included. Patients with pathologic pulse status and history of vascular intervention were excluded. Vascular calcifications seen on the preoperative radiograph were classified as intimal-type and medial-type calcifications and were correlated to perioperative ischemic complications.

RESULTS

Vascular calcifications were seen in 268 patients (medial type: n = 54, intimal type: n = 214). Major ischemic complications such as arterial thrombosis were seen in 2 patients, one of them with intimal-type calcifications and one without (complication rate 0.5% vs 0.2%, P = .715). The rate of minor ischemic complications such as protracted wound healing was significantly elevated in patients with intimal-type calcifications (6.1%) when compared to patients with medial-type calcifications (1.9%) and those without (1.6%, P = .003) even when multiple regression analysis was performed taking into account 2 potential influencing factors "age" and "diabetes mellitus" (P = .008).

CONCLUSION

Owing to the significantly increased risk of ischemic complications in patients with intimal-type calcifications undergoing TKA, we recommend high alertness to the presence of calcifications on preoperative radiographs, careful intraoperative soft tissue management, and postoperative monitoring of the vascular status.

The effects of vitamin K supplementation and vitamin K antagonists on progression of vascular calcification: ongoing randomized controlled trials

Background

The extent and the progression of vascular calcification (VC) are independent predictors of cardiovascular risk in the haemodialysis population. Vitamin K is essential for the activation of matrix gla protein (MGP), a powerful inhibitor of tissue calcification. Functional vitamin K deficiency may contribute to the high VC burden in haemodialysis patients. In addition, haemodialysis patients are frequently treated with vitamin K antagonists, mainly to prevent stroke in atrial fibrillation, potentially compounding the cardiovascular risk in these already vulnerable patients. New oral anticoagulants (NOACs) are valuable alternatives to vitamin K antagonists in the general population, but their use in dialysis has been encumbered by substantial renal clearance. However, a recent pharmacokinetic study provided information on how to use rivaroxaban in haemodialysis patients.

Methods

We conduct a randomized, prospective, multicentre, open-label interventional clinical trial that will include 117 chronic haemodialysis patients with non-valvular atrial fibrillation, treated with or candidates for treatment with vitamin K antagonists. Patients will be randomized to a vitamin K antagonist titrated weekly to an international normalized ratio between 2 and 3, a daily dose of rivaroxaban of 10 mg, or a daily dose of rivaroxaban 10 mg with a thrice weekly supplement of 2000 µg vitamin K2. Cardiac computed tomography, pulse wave velocity (PWV) measurements and MGP sampling will be performed at baseline, 6 months, 12 months and 18 months. Primary endpoints include progression of coronary artery and thoracic aorta calcification and changes in PWV. Secondary endpoints are progression of aortic and mitral valve calcification, all-cause mortality, major adverse cardiovascular events, stroke and bleeding. The ClinicalTrials.gov database was searched to retrieve related trials.

Results

Seven trials, three of which are performed in the haemodialysis population, evaluate whether pharmacological doses of vitamin K1 or K2 retard progression of VC. Five studies compare the effect of warfarin and NOACs on progression of VC, the present study being the only conducted in the dialysis population.

Conclusion

Vitamin K deficiency may be a modifiable cardiovascular risk factor in the haemodialysis population. Conversely, vitamin K antagonists may aggravate VC burden in haemodialysis patients. Several ongoing trials may provide an answer to these questions in the near future.

The role of bone in CKD-mediated mineral and vascular disease

Cardiovascular disease is the leading cause of death in pediatric patients with chronic kidney disease (CKD), and vascular calcifications start early in the course of CKD. Based on the growing body of evidence that alterations of bone and mineral metabolism and the therapies designed to treat the skeletal consequences of CKD are linked to cardiovascular calcifications, the Kidney Disease, Improving Global Outcomes (KDIGO) working group redefined renal osteodystrophy as a systemic disorder of mineral and bone metabolism due to CKD, and this newly defined disorder is now known as "chronic kidney disease-mineral bone disorder (CKD-MBD)". Elevated fibroblast growth factor 23 (FGF23), a bone-derived protein, is the first biochemical abnormality to be associated with CKD-MBD, and high FGF23 levels correlate with increased cardiovascular morbidity and mortality, suggesting that bone is central to both initiating and perpetuating the abnormal mineral metabolism and vascular disease in CKD. The current standard therapies for CKD-MBD affect FGF23 levels differently; non-calcium-based binders with or without concurrent use of dietary phosphate restriction reduce FGF23 levels, while calcium-based binders seem to either increase or have no effect on FGF23 levels. Active vitamin D sterols increase FGF23 levels, whereas therapy with calcimimetics decreases FGF23 levels. Thus, the appropriate therapy that will minimize the rise in FGF23 and prevent cardiovascular morbidity remains to be defined.

Vascular calcifications on hand radiographs in rheumatoid arthritis and associations with autoantibodies, cardiovascular risk factors and mortality

OBJECTIVE

To examine whether vascular calcifications on hand films in RA might aid in determining mortality risk.

METHODS

Hand radiographs from 906 RA patients were scored as positive or negative for vascular calcifications. Patient characteristics associated with vascular calcifications were assessed using multivariable logistic regression, and associations with mortality were examined using Cox proportional hazards regression. Cytokines and multiplex ACPA were measured in both groups.

RESULTS

A total of 99 patients (11%) demonstrated radiographic vascular calcifications. Factors independently associated with vascular calcifications included diabetes [odds ratio (OR) 2.85; 95% CI 1.43, 5.66], cardiovascular disease at enrolment (OR 2.48; 95% CI 1.01, 6.09), prednisone use (OR 1.90; 95% CI 1.25, 2.91), current smoking (OR 0.06; 95% CI 0.01, 0.23) and former smoking (OR 0.36; 95% CI 0.27, 0.48) vs never smoking. In cytokine and ACPA subtype analysis, IL-4 and anti-citrullinated apolipoprotein E were significantly increased in patients with vascular calcifications in fully adjusted multivariable models. After multivariable adjustment, vascular calcifications were associated with an increase in all-cause mortality (hazard ratio 1.41; 95% CI 1.12, 1.78; P = 0.004).

CONCLUSION

Vascular calcifications on hand radiographs were independently associated with increased all-cause mortality in RA. Mechanisms underpinning the associations of IL-4 and select ACPA with vascular calcifications and their utility as biomarkers predictive of cardiovascular disease risk in RA merit further study.

The future of phosphate binders: a perspective on novel therapeutics

Chronic kidney disease-mineral bone disorder (CKD-MBD) is a common complication of CKD. The therapeutic strategies for the treatment of CKD-MBD include phosphate binders, active vitamin D analogs and calcimimetics. The first class of drugs provided nephrologists with a range of phosphate binders that are able to decrease circulating phosphate and parathyroid hormone but involve some tolerability and safety issues. In the past 2 years, new phosphate binders have been launched and others are still under development. Serum phosphate increases only in the late stages of CKD but clinical abnormalities begin to occur earlier when multiple mechanisms try to compensate for the progressive reduced ability of the kidney to eliminate phosphorus with urine. Accordingly, starting phosphate binders when phosphatemia reaches values higher than normal may represent a late therapeutic approach. Serum phosphorus is not the ideal biomarker for the diagnosis and treatment of phosphate imbalance. This role could be better played by fibroblast growth factor 23, whose serum concentrations rise earlier in CKD. A more detailed knowledge of the mechanisms underlying CKD-MBD development will provide new therapeutic targets and then new perspectives for the treatment of phosphate imbalance in the future.

The consequences of chronic kidney disease on bone metabolism and growth in children

Growth retardation, decreased final height and renal osteodystrophy (ROD) are common complications of childhood chronic kidney disease (CKD), resulting from a combination of abnormalities in the growth hormone (GH) axis, vitamin D deficiency, hyperparathyroidism, hypogonadism, inadequate nutrition, cachexia and drug toxicity. The impact of CKD-associated bone and mineral disorders (CKD-MBD) may be immediate (serum phosphate/calcium disequilibrium) or delayed (poor growth, ROD, fractures, vascular calcifications, increased morbidity and mortality). In 2012, the clinical management of CKD-MBD in children needs to focus on three main objectives: (i) to provide an optimal growth in order to maximize the final height with an early management with recombinant GH therapy when required, (ii) to equilibrate calcium/phosphate metabolism so as to obtain acceptable bone quality and cardiovascular status and (iii) to correct all metabolic and clinical abnormalities that can worsen bone disease, growth and cardiovascular disease, i.e. metabolic acidosis, anaemia, malnutrition and 25(OH)vitamin D deficiency. The aim of this review is to provide an overview of the mineral, bone and vascular abnormalities associated with CKD in children in terms of pathophysiology, diagnosis and clinical management.

Femoral bone mineral density reflects histologically determined cortical bone volume in hemodialysis patients

We evaluated the associations between dual energy X-ray absorptiometry (DXA) and histologically determined cancellous and cortical bone volume by controlling for vascular calcifications and demographic variables in hemodialysis (HD) patients. Femoral bone mineral density (f-BMD) was associated with cortical porosity.

INTRODUCTION

Assessment of bone mass in chronic kidney disease patients is of clinical importance because of the association between low bone volume, fractures, and vascular calcifications. DXA is used for noninvasive assessment of bone mass whereby vertebral results reflect mainly cancellous bone and femoral results reflect mainly cortical bone. Bone histology allows direct measurements of cancellous and cortical bone volume. The present study evaluates the association between DXA and histologically determined cancellous and cortical bone volumes in HD patients.

METHODS

In 38 HD patients, DXA was performed for assessment of bone mass, anterior iliac crest bone biopsies for bone volume, and multislice computed tomography for vascular calcifications.

RESULTS

While lumbar bone mineral density (l-BMD) by DXA was not associated with histologically measured cancellous bone volume, coronary Agatson score showed a borderline statistically significant association (P = 0.055). When controlled for age and dialysis duration, f-BMD by DXA was associated with cortical porosity determined by histology (P = 0.005).

CONCLUSIONS

The usefulness of l-BMD for predicting bone volume is limited most probably because of interference by soft tissue calcifications. In contrast, f-BMD shows significant association with cortical porosity.

The pathogenesis of vascular calcification in the chronic kidney disease mineral bone disorder: the links between bone and the vasculature

Considerable scientific progress in the pathogenesis of vascular calcification that has accrued in recent years is reviewed in this article. Factors regulating mesenchymal cell differentiation and their role in the neointimal calcification of atherosclerosis and the vascular media calcification observed in chronic kidney disease and diabetes are discussed, as is the role of bone regulatory proteins in bone mineralization and vascular calcification. This includes recent studies related to fetuin-A, and the discovery of a new circulating hormone involved in regulating phosphate homeostasis and sensing skeletal hydroxyapatite precipitation. Finally, the relationship between skeletal mineralization and vascular mineralization is discussed in terms of their links, especially through serum phosphate concentrations.