Calcium Metabolism In Patients Research Articles

The effectiveness of Zafacol 3D on the dynamics of calprotectin and a1-antitrypsin levels and calcium metabolism in patients with non-alcoholic fatty liver disease and intestinal lesions who have had COVID-19

The effectiveness of Zafacol 3D on the dynamics of calprotectin and a1-antitrypsin levels and calcium metabolism in patients with non-alcoholic fatty liver disease and intestinal lesions who have had COVID-19

Changes in serum somatostatin level and its association with calcium metabolism indicators in patients withgastroesophageal reflux disease and spinal injuries of degenerative-dystrophic andinflammatory genesis

Background. The study of clinical features, factors and levels of various biologically active substances that may play an important role in the pathogenetic mechanism of gastroesophageal reflux disease (GERD) in combination with degenerative-dystrophic or inflammatory lesions of the spine, is an extremely important problem of the modern medical community. The purpose of the research is to determine the peculiarities of changes in the level of serum somatostatin (SST) and its relationship with calcium metabolism in patients with GERD and spine lesions of degenerative-dystrophic and inflammatory genesis. Materials and methods. 84 patients with spinal lesions of degenerative-dystrophic or inflammatory genesis in combination with GERD were examined. The examined patients with GERD were divided into two groups depending on the form of spine injury. GroupI included 44 patients with osteochondrosis (OS) of the cervical and thoracic spine (SpA). Group II consisted of 40patients with spinal arthritis. Results. There was a significant increase in the level of serum SST in both groups of the studied patients with GERD and spine injury of degenerative-dystrophic or inflammatory origin. At the same time, a more pronounced deviation from the norm was detected in group II of patients (increase up to (0.756±0.027)pg/ml, p<0.01). Determination of level 25(OH)D in serum indicates vitamin D3 deficiency in patients with GERD and OS (decrease to (23.35±0.71) ng/ml, p<0.05) and its deficiency in patients with SpA (decrease to (18.66±0.52)ng/ml, p<0.01). Serum 25(OH)D levels also decreased more markedly in the atypical clinical course of GERD in the examined patients. Conclusions. In patients with GERD with degenerative-dystrophic and inflammatory lesions of the spine, an increase in the level of serum SST was found with the most pronounced deviation from the norm in atypical manifestation of GERD. A correlation between SST and a decrease in the level of 25(OH)D and Ca++, mainly in patients with atypical clinical course of GERD, was established.

Effect of Fluoride Agents on Calcium Metabolism of Patients Undergoing Orthodontic Treatment: A Randomized Trial

Effect of Fluoride Agents on Calcium Metabolism of Patients Undergoing Orthodontic Treatment: A Randomized Trial

Hypocalcemia in hospitalized patients with COVID-19: roles of hypovitaminosis D and functional hypoparathyroidism.

IntroductionDespite the high prevalence of hypocalcemia in patients with COVID-19, very limited studies have been designed to evaluate etiologies of this disorder. This study was designed to evaluate the status of serum parameters involved in calcium metabolism in patients with COVID-19 and hypocalcemia.Materials and methodsThis cross-sectional study was conducted on 123 hospitalized patients with COVID-19. Serum concentrations of PTH, 25 (OH) D, magnesium, phosphate, and albumin were assessed and compared across three groups of moderate/severe hypocalcemia (serum total calcium < 8 mg/dl), mild hypocalcemia (8 mg/dl ≤ serum total calcium < 8.5 mg/dl) and normocalcemia (serum total calcium ≥ 8.5 mg/dl). Multivariate analyses were performed to evaluate the independent roles of serum parameters in hypocalcemia.ResultsIn total, 65.9% of the patients had hypocalcemia. Vitamin D deficiency was found in 44.4% and 37.7% of moderate/severe and mild hypocalcemia cases, respectively, compared to 7.1% in the normal serum total calcium group (P = 0.003). In multivariate analysis, vitamin D deficiency was independently associated with 6.2 times higher risk of hypocalcemia (P = 0.001). Only a minority of patients with hypocalcemia had appropriately high PTH (15.1% and 14.3% in mild and moderate/severe hypocalcemia, respectively). Serum PTH was low/low-normal in 40.0% of patients with moderate/severe low-corrected calcium group. Magnesium deficiency was not associated with hypocalcemia in univariate and multivariate analysis.ConclusionVitamin D deficiency plays a major role in hypocalcemia among hospitalized patients with COVID-19. Inappropriately low/low-normal serum PTH may be a contributing factor in this disorder.

Effect of empagliflozin on phosphorus and calcium metabolism in patients with type 2 diabetes mellitus with preserved kidney function

Background: Sodium glucose co-transporter type 2 inhibitors (iSGLT2) are antihyperglycemic drugs approved for the treatment of type 2 diabetes mellitus (T2DM). Clinical trials with these drugs have shown evidence of an increased risk of fractures and an effect on phosphorus, vitamin D and parathyroid hormone (PTH) levels.Aim: The aim of this study was to investigate the effect of the most selective iSGLT2 empagliflozin on the calcium and phosphorus metabolism in patients with T2DM and preserved kidney function.Materials and methods: Thirty-nine T2DM patients were received empagliflozin 10 mg in addition to their antihyperglycemic drugs for 12 weeks. Before starting treatment, a dual-energy X-ray absorptiometry (DXA) with an assessment of the trabecular bone score (TBS) was performed. The concentration of phosphorus (P), total (tCa) and ionized calcium (Ca++), fibroblast growth factor 23 (FGF-23), 25(OH)D and PTH were assessed.Results: According to the DXA results, only 2 patients had osteoporosis, 10 (25.6%) patients had bone mineral density (BMD) values below 1.35 g /cm2 on the TCI scale. Treatment with empagliflozin for 12 weeks was lead to significant increase in FGF-23. Compared to the baseline level, there were no statistically significant differences in the concentrations of P, oCa, Ca++, PTH and 25(OH)D after 12 weeks of treatment. The level of FGF-23 did not correlate with the level of glomerular filtration rate either before or after treatment (r = 0.31, p = 0.27 and r = 0.39, p = 0.55, respectively). In addition, baseline BMD adjusted for TBS and baseline 25(OH)D did not correlate with Ca, F, FGF-23, and PTH concentrations (p&gt;0.05).Conclusion: Thus, empagliflozin has increased the level of FGF-23 without significant changes in the concentration of phosphorus, calcium, 25 (OH) D, and PTH after 12 weeks of treatment in patients with T2DM and preserved renal function. The obtained data confirmed the necessity to assess the TBS in patients with T2DM, because it’s provide additional information on the quality of bone tissue.

Clinical Severity and Calcium Metabolism in Patients with Bipolar Disorder.

Parathyroid hormone (PTH), vitamin D and serum calcium play a key role in several physiological and pathological conditions. Vitamin D and PTH receptors are largely expressed in the central nervous system and are involved in the modulation of inflammatory responses. Few studies investigated the association between calcium homeostasis imbalance and psychiatric disorders. This study aims to assess calcium homeostasis imbalance in patients with bipolar disorder (BD) and its impact on clinical outcome. We recruited 199 patients with BD, who were administered with validated assessment instruments to investigate depressive, manic and anxiety symptoms, affective temperaments, childhood trauma and global functioning. Serum calcium, vitamin D and PTH levels were assessed in all patients. Levels of PTH correlated with several clinical characteristics, including the diagnosis of bipolar disorder type I (BD-I), the presence of psychotic symptoms, lithium treatment, suicidality, total number of acute episodes and of hospitalizations (p < 0.0001) and seasonality (p < 0.05). At the regression analyses, higher levels of PTH were predicted by early age at onset, number of hospitalizations, aggressive behaviors (p < 0.05), higher Childhood Trauma Questionnaire total score (CTQ) (p < 0.001) and treatment with lithium (p = 0.01). Our findings suggest that the calcium homeostasis could play a role in BD patients, and that PTH levels are correlated with the clinical severity of the disorder.

Dysregulation of calcium metabolism in type 1 myotonic dystrophy.

Patients with type 1 myotonic dystrophy (DM1) have a higher incidence of hypercalcaemia compared with the general population. The nature and effects of dysregulated calcium metabolism underpinning this phenomenon have not been fully characterised. To determine the characteristics of dysregulated calcium metabolism in patients with DM1 and its association with bone mineral density. A retrospective review of medical records of patients with DM1 attending a DM clinic at Logan Hospital, Brisbane, Queensland, between 2005 and 2018 and who had concurrent serum assays performed of corrected serum calcium, 25 hydroxyvitamin D, parathyroid hormone (PTH) and phosphate and for whom results were available for estimated glomerular filtration rate, bone mineral densitometry tests and urinary calcium clearance to creatinine clearance ratio (UCCR). Forty-four patients with DM1 (22 females, 22 males) were reviewed of whom 14 (32%) had elevated corrected serum calcium and inappropriate PTH. Another 10 patients (23%) had raised PTH with normocalcaemia. Eighteen of 19 (94.7%) patients with hypercalcaemia or high PTH level completed 24-h urinary calcium. All had UCCR ≤0.02. Twelve patients had UCCR <0.01. Seven of 44 (16%) had low 25 hydroxy vitamin D. All patients had normal estimated glomerular filtration rate. None was osteoporotic. One in three patients with DM1 was hypercalcaemic with unsuppressed PTH. Their clinical features and biochemical pictures resemble those of familial hypocalciuric hypercalcaemia (FHH) and raises the possibility that impaired activity of calcium-sensing receptors, due to abnormal splicing of the calcium-sensing receptor messenger RNA in DM1, causes a FHH-like syndrome ('pseudo-FHH of DM1').

Effects of antidiabetic drugs on calcium metabolism in patients with type 2 diabetes mellitus

Objective — to assess the effect of antidiabetic drugs on serum 25-hydroxyvitamin D (25(OH)D) level in patients with type 2 diabetes mellitus (T2DM). Materials and methods. We examined 35 patients with T2DM, at the age of 37—75 years. They were divided into 5 groups according to the blood glucose lowering therapy: metformin alone (n = 9), metformin in combination with insulin (n = 6), metformin in combination with sulphonylurea (n = 4), metformin with DPP-4 inhibitors (n = 7), or metformin with SGLT-2 inhibitors (n = 9). Serum levels of phosphate, ionized calcium, parathyroid hormone (PTH) and 25(OH)D were measured. Results and discussion. The mean age of T2DM patients was 48.32 ± 19.83 years. There were 17 men and 18 women. A study of 25(OH)D level in serum showed that in all patients it was low (14.7 ± 7.28 ng/ml) and was within the limitscorrespon­ding to deficiency or insufficiency of vitamin D. When compared the results in 5 groups according to type of blood glucose lowering therapy, there was no significant difference in the levels of serum phosphate, ionized calcium, PTH and 25(OH)D. However, in the metformin plus da­­pagliflosin group the level of phosphorus (1.65 ± 0.06 mmol/l) was significantly higher than in the met­formin alone group (1.19 mmol/l ± 0.06) (p = 0.002), but the values of serum 25(OH)D levels did not differ sig­nificantly (15.12 ± 7.13 ng/ml and 14.8 ± 7.14 ng/ml respective­­ly) (p > 0.05). Conclusions. Results show that T2DM patients had vitamin D deficiency or insufficiency according to 25(OH)D level in serum. There is no meaningful association between 25(OH)D level and type of blood glucose lowering therapy at T2DM patients. According to the data, there was no significant difference bet­ween 25(OH)D in patients treated with metformin alone and with combination of metformin with other antidiabetic drugs. Results show that patients on met­formin with dapagliflozintherapy have higher serum phosphate levels compared to patients on metformin monotherapy.

Retraction notice to “Abnormal Bone and Calcium Metabolism in Patients After Stroke” [Arch Phys Med Rehabil. 81 (1) 117-121

Retraction notice to “Abnormal Bone and Calcium Metabolism in Patients After Stroke” [Arch Phys Med Rehabil. 81 (1) 117-121

Investigation of calcium metabolism in patients with coronary heart disease complicated by chronic heart failure, stage ii-a

Objective: This study aims to to investigate calcium metabolism indices and bone mineralization in patients with coronary heart disease complicated by stage II-A chronic heart failure.Materials and Methods: The study involved 33 men with coronary heart disease (CHD) complicated by Stage II-A chronic heart failure (according to the classification by N.D. Strazhesko, V.H. Vasilenko and G.F. Lung (1935). Bone mineral density was measured using dual energy x-ray densitometry of lumbar region of spine. The level of 25-hydroxyvitamin D (25(ОН)D) has been detected by ELISA method using commercial Vitamin D3 screening kit (Switzerland). The level of ionized calcium was measuring by ion selective method using analyser of electrolytes AEK-01 (QuertiMed, Ukraine).Results and Discussion: Structural and functional changes of bone tissue of the lumbar spine have been found in 49,2 percent patients with coronary heart disease complicated by Stage II-A chronic heart failure, in particular, I stage of osteopenia – in 44,6 %, II stage of osteopenia – in 27,7 %, III stage of osteopenia – in 10,8 % and osteoporosis – in 16,9 %. It was established the same type of downward trend for BMD decreasing in L1 of patients with different stages of osteopenia, but in case of osteoporosis mineralization decreased equally in all vertebrae. The analysis of calcium metabolism indices indicate that concentration of ionized calcium significantly decreased in patients with CHD complicated by Stage II-A chronic heart failure vs control (1.26±0.02 mmol/l) by 11.1 % (I stage of osteopenia), 18.3 % (II stage of osteopenia) and 31.7 % (III stage of osteopenia). Similar tendency was observed towards concentration of 25(ОН)D.Conclusion: In patients with CHD complicated by Stage II-A chronic heart failure we have established statistically significant decrease in serum level of ionized calcium and 25-hydroxyvitamin D concentration. However, we didn’t find the relationship between serum calcium, 25-hydroxyvitamin D concentration and bone mineral density. Structural and functional changes of bone tissue of the lumbar spine have been found in 49,2 percent patients with coronary heart disease complicated by Stage II-A chronic heart failure. It was established the same type of downward trend for BMD decreasing in L1 of patients with different stages of osteopenia, but in case of osteoporosis mineralization decreased equally in all vertebrae.Bangladesh Journal of Medical Science Vol.17(3) 2018 p.395-401

Особенности экскреции кальция и факторы риска остеопороза у больных мочекаменной болезнью

The prevalence of urolithiasis and osteoporosis (OP) indicates that these diseases may be found concurrently in the same patient. The detection of risk factors for OP and disorders of calcium metabolism in patients with urolithiasis is of interest in the context of primary stone formation and metaphylaxis. To identify risk factors for osteoporosis and disorders of calcium metabolism in patients with urolithiasis. Osteoporosis risk factors were studied in 45 urolithiasis patients undergoing surgical treatment. Patients were asked to fill out the osteoporosis risk factor questionnaire, and urinary calcium excretion was measured in 24-h collections. Risk factors for osteoporosis were detected in 20 (44.4%) urolithiasis patients. Patients with osteoporosis risk factors identified by the questionnaire were statistically significantly older (p=0.032). Osteoporosis risk factors were found in 20% of patients with newly diagnosed urolithiasis and 24.4% of patients with recurrent urolithiasis. The study patients showed increased urinary calcium excretion and decreased diuresis. The negative correlation between urinary calcium excretion and 24-h diuresis was greater in patients who had than in those who did not have osteoporosis. An increase in urinary calcium excretion and a decrease in diuresis can be a predisposing factor for the recurrence of urolithiasis. In patients with risk factors for osteoporosis, it can provide a rationale for administering drugs aimed at preventing stone formation (thiazide diuretics).

The impact of vitamin D status and parameters of calcium metabolism in patients with primary hyperparathyroidism.

There is ample evidence associating vitamin D deficiency in primary hyperparathyroidism (PHP) patients with more severe disease manifestations and increased risk of postoperative hypocalcemia. Yet, there is limited data regarding the safety of vitamin D repletion in these patients. To assess the safety of vitamin D repletion in PHP patients in a real-world setting. We included patients with asymptomatic PHP and few symptomatic patients who declined surgery, followed in our clinic, and treated on a routine basis with 2000 IU/day of vitamin D3. Serum calcium (sCa), PTH, 25-hydroxyvitamin D, and 24 h urinary calcium (uCa) and creatinine collections were compared between the lowest and the highest vitamin D time points. There were 40 patients of a mean age was 63 ± 10 years. 25(OH)D at lowest and highest vitamin D time points was 15.5 ± 6.2 ng/ml and 33.2 ± 8, respectively (P < 0.001). Serum calcium was not affected by the changes in vitamin D levels. In none of the patients did sCa exceed 11.5 mg/dL. uCa was 220 ± 110 mg/24 h at the lowest vitamin D time point and 260 ± 140 at the highest vitamin D time point (P = 0.14). uCa exceeded 400 mg/24 h in two vs. five patients (P = 0.23) at the lowest and highest vitamin D time points, respectively. PTH was not significantly different between the different vitamin D time points. Vitamin D repletion in PHP seems safe. Considering the documented adverse influence of vitamin D deficiency in PHP, particularly on skeletal manifestations and on the postoperative course, vitamin D repletion is warranted.

Association of serum fibroblast growth factor 23 with calcium metabolism in patients with end-stage renal disease undergoing hemodialysis

Background: The association between the function of fibroblast growth factor 23 (FGF23) and different components of calcium metabolism has remained unclear in patients with renal dysfunction undergoing hemodialysis. Objectives: The present study aimed to assess the association of the level of FGF23 and calcium metabolism status in hemodialysis patients. Patients and Methods: This cross-sectional study conducted on 90 consecutive patients suffering end-stage renal disease (ESRD) who underwent hemodialysis. The serum levels of FGF23 and intact parathyroid hormone (iPTH) levels were measured using the ELISA technique. Results: The serum levels of FGF23 were directly associated with iPTH level (r = 0.251, P = 0.020) and slightly with the duration of dialysis (r = 0.203, P = 0.063). However serum FGF23 was not significantly related to other indices including levels of calcium, phosphorus, magnesium, vitamin D, albumin, and even body mass index (BMI). No difference was found in the level of FGF23 between men and women with ESRD under hemodialysis. Conclusions: In ESRD patients undergoing hemodialysis, the association of FGF23 with iPTH was detected, while there was not any relationship of FGF23 with other indices including calcium, phosphorus, and vitamin D.

Calcium Homeostasis During Attack and Remission in Patients With Idiopathic Benign Paroxysmal Positional Vertigo.

To evaluate changes in calcium metabolism in patients with idiopathic benign paroxysmal positional vertigo (BPPV) on initial presentation and at the follow-up visit. The study comprised a total of 31 patients aged greater than 18 years who presented at the otorhinolaryngology outpatient clinic of our hospital, newly diagnosed as idiopathic BPPV based on the history compatible with BPPV and positive provocative maneuver (either Dix-Hallpike or Roll test). The first blood sample was obtained on the day of initial presentation when the patient was found to have active unilateral BPPV. After 6 months, a blood sample was again drawn in accordance with the procedure. Blood samples were analyzed for data on 25-hydroxyvitamin D (25(OH)-D), total calcium, parathormone and ionized calcium on initial presentation, and at the follow-up visit. The patients comprised 20 (64.5%) women and 11 (35.5%) men with a mean age of 49.78 years (range, 23-75 years). During an attack a higher prevalence of decreased serum Vitamin D is less than 20 ng/ml, was determined (93.5% versus 38.7%). There were statistical differences between the Vitamin D values, parathormone, and corrected by pH ionized calcium in both periods (p < 0.05). A statistically significant association was determined between Vitamin D and calcium metabolism in patients with idiopathic BPPV. It can be considered that Vitamin D deficiency and decreased ionized Ca level may be a risk for BPPV, not only in patients with osteoporosis but also in all patients. Very low levels of 25(OH)-D seem to be associated with recurrence of BPPV. The recurrences might possibly be prevented with supplementary Vitamin D especially in those with recurrent idiopathic BPPV but further studies would be necessary to determine this.

Correlation between Left Ventricular Mass Index and Calcium Metabolism in Patients with Essential Hypertension

PP-040 Essential hypertension is a multifactorial condition affecting a large percentage of the adult Turkish population (33.7%). It induces Left ventricular hypertrophy (LVH) and dilatation, which can lead to heart failure. The reasons for the development of LVH in patients with essential

Primary aldosteronism — recent progress and current concepts

Primary aldosteronism is the commonest form of hormone-related hypertension, with an estimated prevalence of 6-13% in the generalpopulation of hypertensive patients. Among patients with resistant hypertension, the proportion of PA is even higher. Through intensiveresearch in the field of basic science and the creation of large registries of patients with PA, it is possible to understand the effect ofexcess aldosterone not only on the cardiovascular system but also on the morphology and function of the other organs. Recent researchhas highlighted the differences in the regulation of calcium metabolism in patients with adrenal adenomas and PA. A lot of attention hasbeen paid to the improvement of diagnostic methods, with particular emphasis on adrenal vein sampling, which is becoming increasinglyimportant. In recent years there have been many publications on the prevalence of mutations in the potassium channel in patients withadrenal tumours and PA. A new form of familial hyperaldosteronism - FIII, has also been distinguished. Treatment of patients with PAstill relies on the use of mineralocorticoid receptor antagonists or adrenalectomy, preferably preceded by a confirmation of aldosteronesecretion lateralisation by adrenal vein sampling.

Correlation between Left Ventricular Mass Index and Calcium Metabolism in Patients with Essential Hypertension.

To determine the correlation between left ventricular mass index and calcium metabolism in patients with essential hypertension. Cross sectional case-control study. Twenty-seven patients with essential hypertension and 20 healthy individuals were compared with respect to calciotropic hormones, left ventricular mass index (LVMI), and urinary and serum biochemical parameters. The correlations between parathormone, vitamin D, and calcitonin levels and LVMI and blood pressure elevation were determined. The parathormone level was significantly higher (p=0.006) and vitamin D level was significantly lower (p=0.01) in the patient group compared with the control group. However, the two groups were similar in terms of albumin-corrected calcium levels, which were within the normal range (p=0.988). The serum sodium (p=0.014) and urinary calcium (p=0.003) levels and LVMI (p<0.01) were also significantly higher in the patient group. No significant correlations were determined between ambulatory blood pressure and parathormone and vitamin D levels, but a significant correlation was found between LVMI and parathormone level (p=0.06) in hypertensive patients. Essential hypertension alters calcium metabolism, causing calciuresis by hypernatremia. Parathormone release increases to compensate for this, and leads to protein synthesis, which in turn provokes the development of myocardial hypertrophy.

EComment. Are mechanical valves better than bioprostheses in patients on dialysis?

We read with great interest the article by Pai et al. regarding the best valve substitute in patients on dialysis [1]. They included in the results of their research, seven retrospective studies and one meta-analysis. However, we found 4 other relevant articles investigating the same problem. In order to be exhaustive, we will summarize the relevant results of these studies and highlight the safety of implanting bioprosthesis in patients on chronic dialysis. The standard of valve selection has changed over time. It has long been believed that tissue valves undergo premature degeneration due to the derangements in calcium metabolism in patients with end-stage renal disease. This is based on largely anecdotal case reports using first generation bioprostheses. In 1998, ACC/AHA guidelines recommended the use of mechanical valves in patients on dialysis. Accumulating data supporting the very low incidence of rapid tissue valve degeneration in dialysis patients had been taken into consideration, and the latest ACC/AHA practice guidelines do not specify the best choice for valve replacement in dialysis patients. Only four cases of structural valve deterioration (SVD) requiring reoperation were identified from the meta-analysis [1], ranging from 10 to 96 months after the initial valve replacement surgery. However, conclusions on the long-term performance of tissue valves in this patient population cannot be drawn. Bleeding was the most common valve-related complication, and represented a major drawback of mechanical valves. Lucke et al. [2] reviewed 19 consecutive patients with end-stage renal disease from a single institution who had undergone aortic, mitral or aorto-mitral valve replacement, 9 had a bioprosthetic valve and 10 a mechanical valve. Mechanical valve patients had a significantly higher rate of postoperative cerebrovascular events or bleeding complications. No subsequent reoperations were required for biological valve failure. The overall estimated Kaplan-Meier survival was 42% ± 14% at 60 months. Kaplon et al. [3] from The Cleveland Clinic Foundation, found comparable results for both types of valves when reviewing 42 patients on preoperative dialysis undergoing valve replacements. Seventeen patients received mechanical valves and 25 received bioprosthesis. Four patients with a bioprosthesis required reoperation, one of whom experienced mitral bioprosthesis degeneration. Prosthetic valve-related complications and survival were similar for both mechanical and bioprosthetic valves. Toole et al. [4] reviewed 50 dialysis patients undergoing left-sided valve replacement. The tissue valve group had significantly higher Kaplan-Meier freedom from valve-related morbidity and mortality at three years. Freedom from reoperation was not significantly different. Umezu et al. [5] analyzed data from 63 consecutive dialysis patients who underwent valvular surgery. The mechanical group had a higher rate of bleeding events. There was no case of SVD up to the 5-year follow-up. However, both mechanical and bioprosthetic valve patients had similar survival and event-free rates. It can be concluded that dialysis patients after cardiac valve replacement suffer poor mid- and long-term survival. Therefore, surgeons should not hesitate to implant bioprosthetic valves because SVD will be uncommon in this patient population. Prosthesis selection should be based on the same criteria used for non-dialysis patients. Conflict of Interest: None declared

Calcium metabolism in patients with castration-resistant prostate cancer: Development of a quantitative urinary assay for extent of bone metastasis.

130 Background: In patients with metastatic castration-resistant prostate cancer (CRPC), the degree of perturbation from normal bone turnover provides a strong indication of risk for disease progression, skeletal complications and death. Biomarkers of bone cell function and bone collagen degradation provide an integrated index of the underlying disease for patients with bony metastases, but available bone markers are not precise or accurate. In this study, patients with CRPC with bony metastases will consume a single oral calcium-41 dose and the pharmacokinetics of this will be measured over an 18 month period. Participants will also be assessed clinically for time to progression, skeletal related events and death. Methods: Patients with metastatic castration-resistant prostate cancer and bony metastatses, as diagnosed via bone scintigraphy, who were on bisphosphonates were enrolled into the study. 12 consenting research subjects consumed a single 1.2 microgram 41Ca tracer dose and provided 30-250mL urine specimens (single voids) after dose on day 1 (6h after dosing), days 7, 14, 28, 42, 60, and monthly thereafter. Isotope ratios were measured via accelerator mass spectrometry. Results: Urinary 41Ca/Ca was significantly and inversely associated with increased skeletal tumor burdens suggesting that development of an isotopic urine test for bone metastasis extent is feasible, providing a non-invasive and quantitative measure of disease extent. A calculation of the area under the curve of the measurements between day zero and 14 were inversely correlated with disease extent at baseline. Clinical deterioration with worsening bony disease was associated with a significant decrease in the urinary 41Ca/Ca value. We are currently assessing correlations between bone turnover and outcomes such as therapy effectiveness, disease progression, skeletal related events and death. Conclusions: This work is the first direct measurement of long-term calcium metabolism in advanced prostate cancer, providing a basic scientific complement to cellular and collagen-based measures of bone formation and resorption rates as well as a correlation to clinically relevant outcomes.

Direct measurement of calcium metabolism in patients with castration-resistant prostate cancer using a novel isotope tracing approach in urine.

e15083 Background: Recent cohort studies have shown that in patients with metastatic castration-resistant prostate cancer, the degree of perturbation from normal bone turnover provides a strong indication of risk for disease progression, skeletal complications and death. Biomarkers of bone cell function and bone collagen degradation provide an integrated index of the underlying disease for patients with bony metastases, but available bone markers are insufficiently precise and accurate. In this study, patients with castration-resistant prostate cancer with bony metastases will consume a single oral calcium-41 dose and the pharmacokinetics of this will be measured over an 18 month period. Participants will also be assessed clinically for time to progression, skeletal related events and death. Methods: Patients with metastatic castration-resistant prostate cancer and bony metastatses, as diagnosed via bone scintigraphy, who were on bisphosphonates were enrolled into the study. As part of this ongoing IRB-approved clinical trial, seven consenting research subjects consumed a single 1.2 microgram 41Ca tracer dose and provided 30-250mL urine specimens (single voids) after dose on day 1 (6h after dosing), days 7, 14, 28, 42, 60, and monthly thereafter. Isotope ratios were measured via accelerator mass spectrometry. Results: Urinary 41Ca/Ca was significantly and inversely associated with increasing skeletal tumor burdens suggesting that development of an isotopic urine test for bone metastasis extent is feasible, providing a non-invasive and quantitative measure of disease extent. Data is currently available to 5 months past 41Ca dosing in four of seven subjects, and we are currently assessing correlations between bone turnover and outcomes such as disease progression, skeletal related events and death. Conclusions: This work is the first direct measurement of long-term calcium metabolism in advanced prostate cancer, providing a basic scientific complement to cellular and collagen-based measures of bone formation and resorption rates as well as a correlation to clinically relevant outcomes. Trial accrual is ongoing and additional analyses are expected.