Association of aortic stiffness with abdominal vascular and coronary calcifications in patients with stage 3 and 4 chronic kidney disease

RATIONALE AND OBJECTIVES

Increased central (aortic) arterial stiffness has hemodynamic repercussions that affect the incidence of cardiovascular and renal disease. In chronic kidney disease (CKD) there may be an increase in aortic stiffness secondary to multiple metabolic alterations including calcification of the vascular wall (VC). The objective of this study was to analyze the association of central aortic pressures and aortic stiffness with the presence of VC in abdominal aorta (AAC) and coronary arteries(CAC).

MATERIALS AND METHODS

We included 87 pacientes with CKD stage 3 and 4. Using applanation tonometry, central aortic pressures and aortic stiffness were studied. We investigated the association of aortic pulse wave velocity (Pvc-f) and Pvc-f adjusted for age, blood pressure, sex and heart rate (Pvc-f index) with AAC obtained on lumbar lateral radiography and CAC assessed by multidetector computed tomography. AAC and CAC were scored according to Kauppila and Agatston methods, respecti-vely. For the study of the association between Pvc-f index, Kauppila score, Agatston score, central aortic pressures, clinical parameters and laboratory data, multiple and logistic regression were used. We investigated the diagnosis performance of the Pvc-f index for prediction of VC using receiver-operating characteristic (ROC).

RESULTS

Pvc-f and Pvc-f index were 11.3 ± 2.6 and 10.6 m/s, respectively. The Pvc-f index was higher when CKD coexisted with diabetes mellitus (DM). AAC and CAC were detected in 77% and 87%, respectively. Albuminuria (β = 0.13, p = 0.005) and Kauppila score (β = 0.36, p = 0.001) were independently associated with Pvc-f index. In turn, Pvc-f index (β = 0.39, p = 0.001), DM (β = 0.46, p = 0.01), and smoking (β = 0.53; p = 0.006) were associated with Kauppila score, but only Pvc-f index predicted AAC [OR: 3.33 (95% CI: 1.6-6.9; p = 0.001)]. The Kauppila score was independently associated with the Agatston score (β = 1.53, p = 0.001). The presence of AAC identified patients with CAC with a sensitivity of 73%, a specificity of 100%, a positive predictive value of 100% and a negative predictive value of 38%. The Vpc-f index predicted the presence of CAC [OR: 3.35 (95% CI: 1.04-10.2, p = 0.04)]. In the ROC curves, using the Vpc-f index, the AUC for AAC and CAC was 0.82 (95%CI: 0.71-0.93, p = 0.001) and 0.81 (95% CI: 0.67-0.96, p = 0.02), respectively.

CONCLUSIONS

When stage 3-4 CKD coexists with DM there is an increase in aortic stiffness determined by the Vpc-f index. In stage 3-4 CKD, AAC and CAC are very prevalent and both often coexist. The Vpc-f index is independently associated with AAC and CAC and may be useful in identifying patients with VC in these territories.

Biochemical Clusters as Substitutes of Bone Biopsies in Kidney Transplant Patients

Bone and mineral metabolism abnormalities are frequent in kidney transplant recipients and have been associated with cardiovascular morbidity. The primary aim of this study was to analyse the association between routine clinically available biochemical evaluation, non-routine histomorphometric bone evaluation, and vascular disease in kidney transplanted patients. A cross-sectional analysis was performed on 69 patients, 1-year after kidney transplantation. Laboratory analysis, radiography of hands and pelvis, bone biopsy, bone densitometry, and coronary CT were performed. One-year post-transplantation, nearly one-third of the patients presented with hypercalcemia, 16% had hypophosphatemia, 39.3% had iPTH levels > 150 pg/mL, 20.3% had BALP levels > 40 U/L, and 26.1% had hypovitaminosis D. Evaluation of extraosseous calcifications revealed low Adragão and Agatston scores. We divided patients into three clusters, according to laboratory results routinely used in clinical practice: hypercalcemia and hyperparathyroidism (Cluster1); hypercalcemia and high BALP levels (Cluster2); hypophosphatemia and vitamin D deficiency (Cluster 3). Patients in clusters 1 and 2 had higher cortical porosity (p = 0.001) and osteoid measurements, although there was no difference in the presence of abnormal mineralization, or low volume. Patients in cluster 2 had a higher BFR/BS (half of the patients in cluster 2 had high bone turnover), and most patients in cluster 1 had low or normal bone turnover. Cluster 3 has no differences in volume, or turnover, but 60% of the patients presented with pre-osteomalacia. All three clusters were associated with high vascular calcifications scores. Vascular calcifications scores were not related to higher bone mineral density. Instead, an association was found between a higher Adragão score and the presence of osteoporosis at the femoral neck (p = 0.008). In conclusion, inferring bone TMV by daily clinical biochemical analysis can be misleading, and bone biopsy is important for assessing both bone turnover and mineralization after kidney transplantation, although hypophosphatemia combined with vitamin D deficiency is associated with abnormal mineralization. The presence of hypercalcemia with high levels of PTH or high levels of BALP, or hypophosphatemia and vitamin D deficiency should remind us to screen vascular calcification status of patients.Clinical Research: ClinicalTrials.gov ID NCT02751099.

CT analysis of aortic calcifications to predict abdominal aortic aneurysm rupture

BACKGROUND

Abdominal aortic aneurysm (AAA) rupture prediction based on sex and diameter could be improved. The goal was to assess whether aortic calcification distribution could better predict AAA rupture through machine learning and LASSO regression.

METHODOLOGY

In this retrospective study, 80 patients treated for a ruptured AAA between January 2001 and August 2018 were matched with 80 non-ruptured patients based on maximal AAA diameter, age, and sex. Calcification volume and dispersion, morphologic, and clinical variables were compared between both groups using a univariable analysis with p = 0.05 and multivariable analysis through machine learning and LASSO regression. We used AUC for machine learning and odds ratios for regression to measure performance.

RESULTS

Mean age of patients was 74.0 ± 8.4 years and 89% were men. AAA diameters were equivalent in both groups (80.9 ± 17.5 vs 79.0 ± 17.3 mm, p = 0.505). Ruptured aneurysms contained a smaller number of calcification aggregates (18.0 ± 17.9 vs 25.6 ± 18.9, p = 0.010) and were less likely to have a proximal neck (45.0% vs 76.3%, p < 0.001). In the machine learning analysis, 5 variables were associated to AAA rupture: proximal neck, antiplatelet use, calcification number, Euclidian distance between calcifications, and standard deviation of the Euclidian distance. A follow-up LASSO regression was concomitant with the findings of the machine learning analysis regarding calcification dispersion but discordant on calcification number.

CONCLUSION

There might be more to AAA calcifications that what is known in the present literature. We need larger prospective studies to investigate if indeed, calcification dispersion affects rupture risk.

CLINICAL RELEVANCE STATEMENT

Ruptured aneurysms are possibly more likely to have their calcification volume concentrated in a smaller geographical area.

KEY POINTS

• Abdominal aortic aneurysm (AAA) rupture prediction based on sex and diameter could be improved. • For a given calcification volume, AAAs with well-distributed calcification clusters could be less likely to rupture. • A machine learning model including AAA calcifications better predicts rupture compared to a model based solely on maximal diameter and sex alone, although it might be prone to overfitting.

Put out the fire: The pleiotropic anti-inflammatory action of non-vitamin K oral anticoagulants

Non-vitamin K antagonist oral anticoagulants (NOACs) should be the preferred anticoagulant strategy for preventing ischemic stroke in patients with atrial fibrillation (AF) at increased thromboembolic risk and for treating deep venous thromboembolism (DVT) in the general population. Beyond their inhibiting action on the activated factor X (FXa) or thrombin (FIIa), NOACs showed some pleiotropic anti-inflammatory effects. The present review aimed to describe the role of FXa and FIIa in the inflammation pathway and the potential anti-inflammatory effects of NOACs.

The Combined Prognostic Significance of Alkaline Phosphatase and Intracranial Arterial Calcifications in Hemodialysis Patients

INTRODUCTION

The prevalence of intracranial arterial calcification (ICAC) in maintenance hemodialysis (MHD) patients is about 90%, and its severity is correlated with age, hemodialysis vintage, and mineral bone disease. Elevated concentrations of calcium and phosphorus are not sufficient for medial calcification because of inhibition by pyrophosphate. Alkaline phosphatase (ALP) promotes calcification by hydrolyzing extracellular pyrophosphate. Epigenetic mechanisms involving ALP inhibition by apabetalone were investigated as a potential target for preventing vascular calcifications (VCs). This study assessed the combined impact of VCs and elevated serum ALP on mortality among chronic HD patients.

METHODS

VCs represented by ICAC were measured simultaneously with mineral bone disease parameters including serum ALP of MHD patients who underwent noncontrast brain computed tomography from 2015 to 2018 in our institution.

RESULTS

This retrospective study included 150 MHD patients (mean age 71.3 ± 12.1 years, 60.1% male). Of the total cohort, 12 (7.8%) had no brain calcifications and 69 (45.1%) had multiple intracranial calcifications. Considering the patients with normal ALP and no calcification as the reference group yielded adjusted odds ratios for all-cause mortality of 4.6 (95% CI: 1.7-12.7) among patients with brain calcifications and normal ALP (p = 0.003) and odds ratios for all-cause mortality of 6.1 (95% CI: 2.1-17.7) among patients with brain calcifications and elevated ALP (p= 0.001).

CONCLUSION

We found an independent association between ICAC and the risk of death among MHD patients. The combined effect of ICAC and elevated ALP was associated with a higher odds ratio for all-cause mortality in MHD patients and may contribute to the risk stratification of these patients.

Lower Leg Arterial Calcifications Assessed by High-Resolution Peripheral Quantitative Computed Tomography in Hypoparathyroid and Pseudohypoparathyroid Patients

Hypoparathyroidism (HypoPT) and pseudohypoparathyroidism (PHP) are diseases with abnormal calcium and phosphate homeostasis and low and high PTH levels, respectively. It has been hypothesized that this could dispose to vascular calcifications and thereby perhaps also cardiovascular morbidity. The aim of this study was to assess lower leg arterial calcifications (LLAC) in patients with HypoPT or PHP. Using a cross-sectional design, we measured the LLAC using a high-resolution peripheral quantitative computed tomography (HR-pQCT) scanner in 72 patients with HypoPT and 25 patients with PHP and compared them with findings in 61 controls. LLAC were found in only two (3%) of the controls. Compared to the controls, LLAC were significantly more prevalent in patients with HypoPT (N = 12, [17%], p < 0.01) and PHP (N = 4, [16%], p < 0.04). Compared to the patients without calcifications, patients with calcifications had higher plasma calcium levels and a lower eGFR, as well as they were older and more often males. Plasma phosphate levels and the calcium-phosphate product were not associated with LLAC. In conclusion, we found that HypoPT and PHP are associated with an increased prevalence of vascular calcifications.

Frequency of biological non-skeletal materials in dry bone scenarios

In forensic anthropology, many small biological non-osseous materials may be found associated to skeletonized remains and can provide crucial information to the biological profile. Indeed, their careful recovery and correct identification can add information related to age-at-death, sex, ancestry, health, diet, migration and habits, and may be used in specific analysis such as DNA typing. However, and despite their potential, little is known about these non-osteological materials. Indeed, how frequent are they in dry bone cases? To answer this question, 100 skeletal remains with postmortem intervals ranging from 23 to 76 years from the CAL Milano Cemetery Skeletal Collection were meticulously examined for the presence of non-skeletal materials and in particular ossified cartilage, vascular calcifications, hair and nails. As a result, non-skeletal materials were found in 81 skeletal remains and showed high frequencies of recovery, despite the less-than-optimal conditions of exhumation of the skeletons. The high frequencies of non-skeletal materials obtained demonstrate the need for additional training and research given their informative power in forensic cases.

Hyperphosphatemia and Chronic Kidney Disease: A Major Daily Concern Both in Adults and in Children

Hyperphosphatemia is common in chronic kidney disease (CKD). Often seen as the "silent killer" because of its dramatic effect on vascular calcifications, hyperphosphatemia explains, at least partly, the onset of the complex mineral and bone disorders associated with CKD (CKD-MBD), together with hypocalcemia and decreased 1-25(OH)₂ vitamin D levels. The impact of CKD-MBD may be immediate with abnormalities of bone and mineral metabolism with secondary hyperparathyroidism and increased FGF23 levels, or delayed with poor growth, bone deformities, fractures, and vascular calcifications, leading to increased morbidity and mortality. The global management of CKD-MBD has been detailed in international guidelines for adults and children, however, with difficulties to obtain an agreement on the ideal PTH targets. The clinical management of hyperphosphatemia is a daily challenge for nephrologists and pediatric nephrologists, notably because of the phosphate overload in occidental diets that is mainly due to the phosphate "hidden" in food additives. The management begins with a dietary restriction of phosphate intake, and is followed by the use of calcium-based and non-calcium-based phosphate binders, and/or the intensification of dialysis. The objective of this review is to provide an overview of the pathophysiology of hyperphosphatemia in CKD, with a focus on its deleterious effects and a description of the clinical management of hyperphosphatemia in a more global setting of CKD-MBD.

CT calcification patterns of peripheral arteries in patients without known peripheral arterial disease

PURPOSE

In the last few years histologic studies of peripheral arteries have shown that both intimal and medial calcifications are found in patients in an early, asymptomatic stage and that differentiation between medial and intimal calcifications is possible. The aim of this study was to assess the computed tomography (CT) calcification characteristics in peripheral arteries and to explore potential patterns in subjects without peripheral arterial disease (PAD).

METHOD

Retrospectively, 204 patients without known PAD were studied. The thin slice CT-imaging characteristics severity, annularity, thickness and continuity were scored in the following arteries: plantar and dorsal, crural, femoro-popliteal, iliac and the abdominal aorta. Interrelation was assessed using linear regression and significance was tested by Chi-Square tests.

RESULTS

In the crural arteries two calcification patterns with strong associations were found. Pattern 1: continuous-annular 93.5 % (29/31), continuous-thin and thin-annular both 73 % (27/37, p < 0.001) and pattern 2: thick-discontinuous 91.7 % (44/48), thick-dotted 68.8 % (33/48), patchy-dotted 59.3 % (16/27, p < 0.001). Similar associations were found in the femoro-popliteal artery, but not in the plantar, dorsal, iliac arteries and aorta.

CONCLUSIONS

In the crural and femoropopliteal arteries at least two morphological patterns can be distinguished on CT that, compared to a CT-histologically validated score, may represent an intimal and medial calcification pattern.

Treatment of hyperphosphatemia: the dangers of high PTH levels

The control of secondary hyperparathyroidism (SHPT) in pediatric chronic kidney disease is of utmost importance. Even though parathyroid hormone (PTH) is an important biomarker of mineral and bone disorders associated to CKD (CKD-MBD), calcium, phosphate, alkaline phosphatase, and vitamin D are also crucial and should be assessed together. In pediatric dialysis, high PTH levels have been associated with impaired longitudinal growth, bone disease, cardiovascular comorbidities, left ventricular hypertrophy, anemia, and even mortality (when PTH levels were above 500 pg/mL, i.e., 8.3-fold the upper normal limit (UNL)). As such, high PTH levels are for sure deleterious, but too low PTH levels have also been shown to impair growth and to promote vascular calcifications because of the underlying adynamic bone. This manuscript is part of a pros and cons debate for keeping PTH levels within the normal range in pediatric CKD, focusing on the pros. High bone turnover lesions can occur at lower PTH levels than "current" guidelines would suggest; thus, PTH alone is not a good predictor of the underlying osteodystrophy. PTH results can vary locally depending on the assay. Existing guidelines for PTH targets are conflicting and based on a very little evidence. However, the 120-180 pg/mL (2- to 3-fold the UNL) range is common to most of the guidelines; it seems to be a reasonable target in children undergoing dialysis, even though it does not correspond to "normal" PTH levels. As always, the philosophy of PTH levels in pediatric dialysis may be balanced, i.e., "not too low, not too high, and keep phosphate under control."

Assessment of relationship between extracranial and intracranial carotid calcifications-a retrospective cone beam computed tomography study

OBJECTIVES

Cone beam CT scans in current day dental practice are highly collimated yet involve areas along the course of the extracranial carotid artery. Detecting an extracranial carotid calcification on small volume scans leaves the dentist with two questions: whether the patient is likely to have intracranial carotid calcifications and whether the patient warrants further medical attention. This study aimed to assess the presence of intracranial carotid artery calcifications (ICAC) in the presence of extracranial carotid artery calcifications (ECAC).

METHODS

450 CBCT scans were retrospectively evaluated for ECAC and ICAC. Erby et al's classification was modified to classify calcifications as mild, moderate, and severe. The presence of ICAC when ECAC were present was evaluated in all three orthogonal planes. The risk of ICAC in the presence of ECAC was calculated as odds ratio and the association between the two was calculated using a χ² test.

RESULTS

The odds ratio for bilateral ICAC in the presence of bilateral ECAC was 15.09. The odds ratio for left ICAC/right ICAC in the presence of left/ right ECAC was 0.833 and 2.564, respectively. The number and severity of calcifications increased with age. The χ² test showed that there was a strong association (p < 0.001) between bilateral ECAC with bilateral ICAC.

CONCLUSIONS

The results of this group of patients showed that there is an increased presence of ICAC in the presence of ECAC.

Atherosclerotic plaque burden evaluated from neck to groin: effect of gender and cardiovascular risk factors

We explored the impact of gender and cardiovascular risk factors (RF) in the distribution and burden of coronary and extra-coronary atherosclerotic plaques among patients undergoing ECG-gated thoracoabdominal computed tomography angiography (CTA) from the supra-aortic trunks to the femoral arteries. We included a consecutive cohort of patients who underwent ECG-gated thoracoabdominal aortic CTA from the supra-aortic trunks to the pubic symphysis. We evaluated the number of coronary segments with plaques [segment-involvement score (SIS)]; and the extra-coronary atherosclerotic plaque burden, comprising the aorta and supra-aortic trunks, iliofemoral arteries, and visceral arteries (extra-coronary SS). A total of 3400 vascular segments were evaluated in 100 patients (mean age 67.0 ± 12.6 years, 66% male). Seventy-two (72%) patients had evidence of atherosclerosis in the coronary tree (coronary SIS ≥ 1), of which 32% was extensive (coronary SIS > 5). Males had a significantly higher prevalence of coronary SIS ≥ 1 [53 (80%), vs. 19 (56%), p = 0.018], and coronary SIS > 5 [24 (36%) vs. 8 (24%), p = 0.035] than females. Extra-coronary SS was similar between genders (males 10.2 ± 5.8 vs. females 9.7 ± 5.4, p = 0.70), irrespective of the location along the different vascular beds. The number of coronary RF was significantly related to the coronary SIS (p = 0.038), and hypertension and diabetes were consistently related to coronary and extra-coronary plaque burden. In the present study involving analysis of multiple vascular beds from the supra-aortic trunks to the femoral arteries, we identified significant sex-related differences in coronary plaque burden, whereas extra-coronary plaque burden was similar between genders irrespective of the vascular bed assessed.

[Calcific uremic arteriolopathy in hemodialysis patient, review of literature through five cases reports]

Calcific uremic arteriolopathy, also called calciphylaxis, is a rare and severe disorder that presents with skin ischemia and necrosis, sometimes it presents with systemic necrosis, the process is secondary to the obliteration of the arterioles first by sub-intimal calcium deposits and then by thrombosis. These lesions can often lead to death due to infectious complications and comorbidities such as diabetes, obesity, arteritis, diffuse vascular calcifications, heart disease and undernutrition. The diagnosis is suggested by the characteristic ischemic skin lesions and their distribution, often bilateral and painful, associeted with calcific uremic arteriolopathy risk factors (phosphocalcic abnormalities, anti-vitamin K). The presence of radiological vascular calcifications is highly suggesting the diagnosis, but remains not very specific. The indication of skin biopsy is rare and reserved for difficult diagnoses. The goals of treatment are: reduce the extension of calcification and treatment of mineral and bone metabolism disorders of end-stage renal disease, dialysis adequacy, local treatment of skin lesions, tissue oxygenation, pain management, discontinuation and contraindication of medications that may contribute to the disorder. We propose to discuss it from a review of the literature and illustrate it with five clinical cases.

Calciphylaxis in patients with chronic kidney disease: A disease which is still bewildering and potentially fatal

Calciphylaxis, also known as calcific uraemic arteriolopathy, is a rare syndrome that typically causes skin necrosis and usually affects dialysis patients. Its pathogenesis is multifactorial and is the consequence of many factors causing ectopic calcifications in patients with chronic kidney disease, such as calcium-phosphate metabolism disorders, hyper- or hypo-parathyroidism, diabetes, obesity, systemic inflammation and the use of vitamin K antagonists, among others. From a clinical point of view, calciphylaxis may progress from painful purpura to extensive areas of skin necrosis that can potentially lead to superinfection and the death of the patient due to sepsis. Treatment is primarily based on managing the wounds, eliminating all the possible precipitating factors of ectopic calcification and administering agents which are capable of inhibiting the process of calcification.

High Dephosphorylated-Uncarboxylated MGP in Hemodialysis patients: risk factors and response to vitamin K2, A pre-post intervention clinical trial

BACKGROUND

Vascular calcifications are highly prevalent in hemodialysis patients. Dephosphorylated-uncarboxylated MGP (dp-ucMGP) was found to increase in vitamin K-deficient patients and may be associated with vascular calcifications. Supplementation of hemodialysis patients with vitamin K2 (menaquinone-7) has been studied in Europe with a maximum 61% drop of dp-ucMGP levels. The aim of this study is to assess first the drop of dp-ucMGP in an Eastern Mediterranean cohort after vitamin K2 treatment and second the correlation between baseline dp-ucMGP and vascular calcification score.

METHODS

This is a prospective, pre-post intervention clinical trial involving 50 hemodialysis patients who received daily 360 μg of menaquinone-7 for 4 weeks. At baseline they were assessed for plasma dp-ucMGP levels and vascular calcification scores (AC-24) as well as for other demographic, clinical and biological variables. Dp-ucMGP levels were measured a second time at 4 weeks.

RESULTS

At baseline, dp-ucMGP levels were extremely elevated with a median of 3179.15 (1825.25; 4339.50) pM and correlated significantly with AC-24 (Spearman's rho = 0.43, P = 0.002). Using a bivariate regression analysis, the association between dp-ucMGP levels and AC-24 was most significant when comparing dp-ucMGP levels less than 1000 to those more than 1000 pM (P = 0.02). Dp-ucMGP levels higher than 5000 pM were significantly associated with females, patients with recent fracture and patients with lower serum albumin (respectively P = 0.02, 0.004 and 0.046). The average drop of dp-ucMGP at 4 weeks of treatment was found to be 86% with diabetics having the lowest drop rate (P = 0.01).

CONCLUSION

Vitamin K deficiency, as assessed by high dp-ucMGP levels, is profound in hemodialysis patients from the Eastern Mediterranean region and it is significantly correlated with vascular calcifications. Daily 360 μg of menaquinone-7, given for 4 weeks, effectively reduces dp-ucMGP in this population. Future studies are needed to assess the changes in vascular calcifications in hemodialysis patients treated with vitamin K2 over a longer follow-up period.

TRIAL REGISTRATION

The clinical trial was registered on clinicaltrials.gov (Identification number NCT02876354 , on August 11, 2016).

Plant phosphates, phytate and pathological calcifications in chronic kidney disease

Phytate, or myo-inositol 1,2,3,4,5,6-hexakis dihydrogen phosphate (InsP6), is a naturally occurring phosphorus compound that is present in many foods, mainly legumes, whole grains and nuts. Patients with chronic kidney disease (CKD) have cardiovascular disease mortality up to 30times higher than the general population. Vascular calcifications (VCs) directly contribute to overall morbidity and mortality, especially in CKD. In part, this high mortality is due to elevated levels of phosphorus in the blood. Therefore, control of dietary phosphorus is essential. Dietary phosphorus can be classified according to its structure in organic phosphorus (plant and animal) and inorganic (preservatives and additives). Plant-phosphorus (legumes and nuts), mainly associated with InsP6, is less absorbable by the human gastrointestinal tract as the bioavailability of phosphorous from plant-derived foods is very low. Recent data indicate that restriction of foods containing plant phosphates may compromise the adequate supply of nutrients that have a beneficial effect in preventing cardiovascular events, such as InsP6 or fibre found in legumes and nuts. Experimental studies in animals and observational studies in humans suggest that InsP6 can prevent lithiasis and VCs and protect from osteoporosis. In conclusion, we need prospective studies to elucidate the potential benefits and risks of phytate (InsP6) through the diet and as an intravenous drug in patients on haemodialysis.

Mineral metabolism disorders, vertebral fractures and aortic calcifications in stable kidney transplant recipients: The role of gender (EMITRAL study)

BACKGROUND AND OBJECTIVES

The relationship between mineral metabolism disorders, bone fractures and vascular calcifications in kidney transplant recipients has not been established.

METHOD

We performed a cross-sectional study in 727 stable recipients from 28 Spanish transplant clinics. Mineral metabolism parameters, the semi-quantification of vertebral fractures and abdominal aortic calcifications were determined centrally.

RESULTS

Vitamin D deficiency (25OHD3<15ng/ml) was more common in female recipients at CKD-T stages I-III (29.6% vs 44.4%; p=0.003). The inverse and significant correlation between 25OHD3 and PTH was gender-specific and women exhibited a steeper slope than men (p=0.01). Vertebral fractures (VFx) with deformity grade ≥2 were observed in 15% of recipients. Factors related to VFx differed by gender; in males, age (OR 1.04; 95% CI 1.01-1.06) and CsA treatment (OR: 3.2; 95% CI: 1.6-6.3); in females, age (OR 1.07; 95% CI: 1.03-1.12) and PTH levels (OR per 100pg/ml increase: 1.27; 95% CI: 1.043-1.542). Abdominal aortic calcifications were common (67.2%) and related to classical risk factors but not to mineral metabolism parameters.

CONCLUSIONS

Vitamin D deficiency is more common among female kidney transplant recipients at earlier CKD-T stages, and it contributes to secondary hyperparathyroidism. Prevalent vertebral fractures are only related to high serum PTH levels in female recipients.

Receptor activator of nuclear factor κB ligand/osteoprotegerin axis and vascular calcifications in patients with chronic kidney disease

Vascular calcifications are commonly observed in patients with chronic kidney disease (CKD) and contribute to the excessive cardiovascular morbidity and mortality rates observed in these patients populations. Although the pathogenetic mechanisms are not yet fully elucidated, recent evidence suggests a link between bone metabolism and the development and progression of vascular calcifications. Moreover, accumulating data indicate that receptor activator of nuclear factor κB ligand/osteoprotegerin axis which plays essential roles in the regulation of bone metabolism is also involved in extra-osseous bone formation. Further studies are required to establish the prognostic significance of the above biomarkers as predictors of the presence and severity of vascular calcifications in CKD patients and of cardiovascular morbidity and mortality. Moreover, randomized clinical trials are needed to clarify whether inhibition of osteoclast activity will protect from vascular calcifications.

Sodium thiosulfate is effective in calcific uremic arteriolopathy complicating chronic hemodialysis

BACKGROUND

Calcific uremic arteriolopathy (CUA) or calciphylaxis is a severe complication of advanced chronic kidney disease (CKD) and dialysis. Few effective treatments are available and the mortality rate is high. We report 4 cases in which sodium thiosulfate therapy was rapidly effective.

CASES

Sodium thiosulfate therapy was given to 4 Caucasian patients (3 females and 1 male aged 49 to 91 years) with CUA. The causes of end-stage CKD were nephroangiosclerosis (n=2) and diabetic nephropathy (n=2). The lesions developed 1 to 6.5 years after the initiation of hemodialysis and involved the lower limbs in 2 patients, the fingers in 1 patient, and a breast in the remaining patient. They were responsible for pain and skin necrosis in all 4 patients. Local superinfection occurred in 3 patients. Intravenous sodium thiosulfate was given in a dosage of 12.5 to 25g after each hemodialysis session, for 12 to 24 weeks. The pain and trophic disorders resolved fully in all 4 patients. The side effects consisted of nausea and vomiting (n=2) and a moderate blood pressure decrease (n=1). No recurrences were noted during the follow-up of 5 to 17 months after treatment discontinuation.

CONCLUSION

The findings from this small case-series suggest that sodium thiosulfate may hold promise for the treatment of CUA.

[The matrix-gla protein awakening may lead to the demise of vascular calcification]

Matrix-gla-protein (MGP) is mainly secreted by chondrocytes and smooth vascular muscle cells. This potent inhibitor of vascular calcification need to undergo 2 post-transcriptional steps to be fully active: one phosphorylation of 3 serine residues (on 5) and a carboxylation of 5 glutamate residues (on 9). Like other "Gla" proteins, this carboxylation is vitamin K dependant. Several forms of MGP thus circulate in the plasma, some of them being totally inactive (the unphosphorylated and uncarboxylated MGP), some others being partially or fully active, according to the number of phosphorylated or carboxylated sites. A theoretical link exists between MGP, vitamin K, vascular calcifications and cardiovascular diseases. This link is even more evident in patients suffering from chronic kidney diseases (CKD), and notably hemodialysis patients. If this link has been demonstrated in different experimental studies, clinical studies are mainly observational and their results must be interpreted accordingly. MGP concentrations are definitely not yet a surrogate to estimate the levels of vascular calcification, but could allow the monitoring of vitamin K treatment. Modulation of MGP concentrations may reduce vascular calcification in hemodialyzed patients, if the large ongoing trials show an efficiency of this treatment. In this review, we will summarize the role of MGP in the vascular calcifications process, describe the problems linked to the analytical determination of MGP in plasma and finally describe the different clinical studies on MGP and vascular calcifications in the general population and in CKD patients.

Medial vascular calcification revisited: review and perspectives

Vascular calcifications (VCs) are actively regulated biological processes associated with crystallization of hydroxyapatite in the extracellular matrix and in cells of the media (VCm) or intima (VCi) of the arterial wall. Both patterns of VC often coincide and occur in patients with type II diabetes, chronic kidney disease, and other less frequent disorders; VCs are also typical in senile degeneration. In this article, we review the current state of knowledge about the pathology, molecular biology, and nosology of VCm, expand on potential mechanisms responsible for poor prognosis, and expose some of the directions for future research in this area.

Vascular calcifications seen on mammography: an independent factor indicating coronary artery disease

PURPOSE

Establish a relationship between vascular calcifications seen via mammography and coronary artery disease, estimate the risk ratios, and investigate the interrelationships between vascular calcification and other risk factors for coronary artery disease.

MATERIALS AND METHODS

This was a case-control study consisting of 40 women with coronary artery disease in the case group and 40 women without any history of coronary artery disease in the control group who were matched according to age. The study was approved by the Institution's Research Ethics Committee (consent statement was obtained). Odds ratios and confidence intervals were calculated using univariate analysis. Interrelationships among other risk factors, such as arterial hypertension, dyslipidemia, smoking and diabetes mellitus, were calculated using multivariate analysis. A p <0.05 was considered to be significant for statistical analysis.

RESULTS

The mean ages for the case and control groups were 64.65 years and 63.88 years, respectively. In multivariate analysis, the only variables related to coronary artery disease were Vascular calcification [OR 4.71 (CI 1.36-16.33) p=0.014], family history [OR 5.76 (CI 1.58-21.03) p=0.008] and arterial hypertension [OR 15.92 (CI 3.12-81.14) p=0.001]. Although smoking and diabetes are important variables in the pathogenesis of coronary artery disease, these factors did not show statistically significant associations in this sample.

CONCLUSION

The presence of vascular calcifications seen via mammography was an independent risk factor for coronary artery disease, as were hypertension and a family history of coronary artery disease.