Large artery calcification on dialysis patients is located in the intima and related to atherosclerosis

BACKGROUND AND OBJECTIVES

Vascular calcification (VC) has a significant effect in cardiovascular diseases on dialysis patients. However, VC is assessed with x-ray-based techniques, which do not inform about calcium localization (intima, media, atherosclerosis-related). The aim of this work is to study VC and its related factors using arterial ultrasound to report the exact location of calcium.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was an observational, cross-sectional, case-control study that included 232 patients in dialysis and 208 age- and sex-matched controls with normal kidney function. Demographic data and laboratory values were collated. Carotid, femoral, and brachial ultrasounds were performed to assess VC and atherosclerosis burden using a standardized protocol.

RESULTS

Cardiovascular risk factors were predominantly found in controls, although the burden of atherosclerosis was higher in the dialysis group. VC was significantly more prevalent in the group of patients on dialysis than control subjects, and in both groups the most prevalent pattern of VC was linear calcification located in the intima of the artery wall. Age and undergoing dialysis (with or without previous cardiovascular diseases) were positively and significantly associated with linear calcification. Conversely, the absence of atherosclerosis and low levels of C-reactive protein and phosphorus significantly impeded the development of linear calcification.

CONCLUSIONS

VC in large, conduit arteries is more prevalent in patients on dialysis than controls and is predominantly located in a linear fashion in the intima of the arteries.

Cardiovascular risk factors underestimate atherosclerotic burden in chronic kidney disease: usefulness of non-invasive tests in cardiovascular assessment

BACKGROUND

Cardiovascular risk scoring (Score) does not specifically address chronic kidney disease (CKD) patients. The aim of our study is to quantify atherosclerosis using carotid ultrasound and ankle-brachial index (ABI) and to assess its additional value in risk scoring.

METHODS

In this cross-sectional, observational study, patients were studied according to a standardized protocol including carotid ultrasound and ABI to determine the atherosclerosis score (AS), ranging from absence of to severe atherosclerosis (AS 0 to AS 3).

RESULTS

We included 409 CKD-affected patients (231 on dialysis, 99 in CKD Stages IV-V and 79 in CKD Stages I-III) and 851 subjects with normal renal function. The presence and severity of atherosclerosis was significantly higher in the CKD group than in the controls at every decade of age studied. Among the CKD-affected subjects, the prevalence of carotid plaques was significantly higher in the dialysis group (78.3%) than in the group in CKD Stages I-III (55.6%, P < 0.001). We identified 174 patients at low-intermediate risk. Among them, 110 (63.2%) presented either moderate (AS 2) or severe (AS 3) atherosclerosis. Variables significantly (P < 0.05) and positively related to atherosclerosis were being on dialysis [OR = 3.40, 95% CI (1.73, 6.78) vs CKD Stages I-III], age [OR = 1.08, 95% CI (1.06-1.11)] and C-reactive protein [OR = 1.04, 95% CI (1.01-1.08)]. Conversely, female sex was negatively related to atherosclerosis [OR = 0.40, 95% CI (0.23-0.71), P = 0.002].

CONCLUSION

The use of carotid ultrasound and ABI identifies atherosclerosis in a population of CKD patients in which risk scoring underestimates atherosclerosis burden.

[A long-term comparative study of calcitriol versus alphacalcidol in patients with secondary hyperparathyroidism on hemodialysis]

Calcitriol has traditionally been the most widely used treatment for secondary hyperparathyroidism (SHPT) in uremic patients. There are currently no crossover equivalence studies of alphacalcidol versus calcitriol establishing which of the two derivatives is more active and better tolerated. The objective of this study was to compare the long term effect on control of PTH of similar doses of alphacalcidol versus calcitriol in the treatment of SHPT in these patients.

METHODS

We conducted a retrospective study on 21 hemodialysis patients with stable SHPT of varying severity treated with intravenous calcitriol. In July 2002, the pharmacy of the reference hospital decided to substitute calcitriol for alphacalcidol based on the similarity of the two drugs. The conversion was made substituting a similar amount of drug. Mean absolute serum levels and percentage change in PTH, calcium and phosphorus were compared between the two periods and at 0, 3, 6, 9, 12 and 15 months after starting treatment with alphacalcidol. Student's t-test for paired means was used to compare the values between the two periods.

RESULTS

In the calcitriol period, mean PTH levels were 275.2 +/- 111.7 pg/ml. The mean dose of drug used was 1.7 +/- 0.8 mcg postdialysis, and serum calcium and phosphorus levels were 10.1 +/- 0,5 mg/dl and 5,2 +/- 0,9 mg/dl, respectively (p < 0.01). Mean dialysate calcium content was 2,9 +/- 0,3 mEq/l. In the alphacalcidol period, PTH increased (441.6 +/- 178.3 pg/ml) (p < 0.001) and the percentage of patients with PTH < 300 pg/ml decreased (24% at the end of the period), in spite of significantly increasing the mean drug dose (2,3 +/- 0,9 mcg postdialysis) (p < 0.05). Serum calcium levels did not show significant differences (10.2 +/- 0.7 mg/dl) (p = NS), but phosphorus control was improved (4,7 +/- 0,5 mg/dl) (p < 0.01). The percentage of patients with PTH < 300 pg/ml decreased progressively from the start of treatment with alphacalcidol from 75% to 24% at the end of follow-up. Our results seem to suggest that the dose of alphacalcidol and calcitriol are not equivalent and we need to increase the dose of alphacalcidol to obtain a similar result to calcitriol on suppression of PTH in uremic patients with SPTH.

[Hypokaliemic nephropathy as a form of presentation of Conn syndrome]

Hypokalemia is generally associated to neuromuscular symtoms, acid-base disorders and even to rhabdomyolysis. However, chronic hypokalemia can induce chronic renal failure through a characteristic tubulointerstitial damage consisting on vacuolization of epithelial tubular cells and interstitial fibrosis. This entity is called hypokalemic nephropathy, quite unusual and probably little know in our speciality. We present a clinical report of a patient admitted to our hospital with a severe hypokalemia secondary to an aldosterone producing adrenal adenoma that was diagnosed during admission. Besides hypokalemia the patient presented renal failure. Renal biopsy proved characteristic tubulointerstitial damage as described in hypokaliemic nephropathy. In summary, we report a Conn syndrome presenting as a hypokalemic nephropathy.

[Evaluation of health-related quality of life (HRQL) based on information from Coop/Wonca sheets in hemodialysis patients]

There has been increasing interest to find instruments to assess the HRQL quickly and easily in daily clinical practice. The main objective of this study is to measure the HRQL inhemodialysis patients using the Coop-Wonca Charts and to analyse whether they can be a useful instrument to assess the patient functional status and the HRQL in this population.

METHODS

A descriptive cross-sectional study was performed between March 2003 and May 2003 in 163 hemodialysis patients (106 males and 57 females). The HRQL has been measured according to the validated Spanish version of the Coop-Wonca Charts. The questionnaire has nine different scales with a single-item. The answers score from 1 to 5 with the higher scores indicating the worst health or functional problems.

RESULTS

The filling middle time of Coop-Wonca charts was less than five minutes. The charts were easily understood for the patients and can be self-administered. The dimensions of "Physical fitness" (3.66 +/- 0.8) and "Overall health" (3.43 +/- 0.8) showed the higher score, and the item aSocial activities) showed the lower scores (better quality of life) (1.98 +/- 1.3). The factors related to the worse health state are the variables: sex (females), the comorbility (diabetes and/or hepatopathy), the labour status (retired) and the way of transport (taxi/ambu lance). The time in hemodialysis was an independent variable and showed the worse score in the "general quality of life" (p < 0.05) and in the "perception of pain" (p < 0.01). The way of transport used (ambulances) was also an independent variable with worse scores for the dimensions "Physical fitness" (p < 0.01), "Daily activities" (p < 0.05) and "Health status" (p < 0.05). The older patients showed a worse score in the dimension "Physical fitness" (p < 0.01) and the patients with more than prescribed medicines scored worse in "Social activities" (p < 0.01). Males (p < 0.05), widows and single (p < 0.05) scored worse in social support.

CONCLUSIONS

The Coop-Wonca Charts could be a good instrument to measure of HRQL in the HD patients. Their application is easy, fast (less than 5 minutes), easily understood, and can be self-administered.

[Impact of a quality program in hemodialysis]

One of the requirements of a health care quality management system is to be able to established clinical performance measures (CPM) for its key organisation processes. We described some of the performance measurement that has been used in our hemodialysis unit, since the implementation in the year 2001, of a Quality Management System (QMS). We analyze and compare the effect that the introduction of a ISO 9002 based QMS had in our CPM during the period 2001-2002 (post QMS) vs. the two previous years -1999-2000- (pre QMS).

METHODS

We defined several CPM for assessment of hemodialysis adequacy and medical management that covered : Anemia, iron status renal osteodystrophy, hemodialysis prescription and nutritional status , follow up of the established guidelines for vascular access care and prevention of nosocomial infections water quality and general performance outcome like annual crude mortality rate and hospitalization (express as hospital days/patient year).

RESULTS

No significant difference was found between both periods regarding annual crude mortality( pre QMS 8.37% vs post QMS 8.95%) or the hospitalization rate ( pre 0.47 patient-days vs. post 0.52 patient-days) . There was a significant difference after implementation of the quality system in the average hemoglobin levels (pre 11.3 +/- 1.5 vs. post 11.9+ +/- .5 p <0,001). Ferritin levels (pre 220 +/- 162 vs. post 313 +/- 373 p<0.01), albumin levels (pre 3.61 +/- 0.46 vs. post 3.82 +/- 0.56 p<0.001) and KTV>1.2 (pre 1.41 +/- 0.26 vs. post 1.50 +/- 0.33 p<0.001). The transferring saturation index (TSI) was unchanged (pre 27.98 +/- 14.39 vs.. post 29.4 +/- 16.66 p=0.11). There was a significant decrease in the average PTH levels (pre 234.9 +/- 285 vs. post 174 +/- 174 p< 0.0001) PTH>300 pg/ml (pre 23.7% vs. post 16.4% p<0.001) calcium levels (pre 10.02 +/- 0.99 vs. 9.83 +/- 0.88 p<0.001), phosphorus (pre 5.50 +/- 1.55 vs. post 5.01 +/- 1.47 p<0.001) as well as serum calcium levels >11 mg/dl (pre 14.6% vs. post 11% p<0.001) and phosphorus >6 g/dl (pre 34% post 21.5% p<0.001). Although the average serum potassium levels decrease (pre 5.51 +/- 0.85 vs. post 5.40 +/- 0.87), the percentage of patients with potassium over 6.5 meq/l was similar in both periods (pre 11.5% vs. post 10. 1%). The number of native A-V vascular access was similar in both periods and above the current DOQI Recommendations. Nevertheless, there was a gradual decrease in native A-V fistula, associated with an increase on the use of permanent catheters. The number of incident patients with a permanent catheter as the only vascular access for hemodialysis increased from 0% in the year 1999, 2000 and 2001 to 6.98% in 2002. There was no hepatitis B and C seroconversión detected in both periods.

CONCLUSION

From our study we concluded that regular follow-up of quality performance measurement associated with an ongoing corrective action, promotes an improvement of the outcome measures results.

[Prognostic significance of programmed dialysis in patients who initiate renal substitutive treatment. Multicenter study in Spain]

BACKGROUND

The aim of our study was to analyse patient characteristics, mortality and costs, all of them in relation to whether starting dialysis was planned or unplanned.

METHODS

A total of 362 patients (227 male and 135 female) from five hospitals of the National Health System, who were started on chronic renal replacement therapy (RRT) during 1996 and 1997 were included. Patients who were started on RRT after acute renal failure were excluded. We carried out a retrospective analysis of the demographic characteristics, patients' conditions at the time of initiating dialysis and outcome and costs at six and thirty-six months of treatment. Patients were classified as planned (PL-D) or unplanned dialysis (UNPL-D), depending on whether or not the patient had a vascular or peritoneal access ready to use for initiating RRT.

RESULTS

One hundred and eighty-six patients (51.4%) started on dialysis in the PL-D group whereas 176 (48.6%) did it as UNPL-D. In this latter group, 135 (37.3% of the total) had previously been monitored by a nephrologist, and 41 (11.3%) initiated dialysis without previous nephrological follow-up. UNPL-D was associated with older age (p < 0.001), non-nephrological follow-up (p < 0.001), diabetes (34.7% vs 22.6%) (p = 0.011), haemodialysis as a first mode of RRT (94.9 vs 81.7%) (p < 0.001), higher comorbidity risk (p < 0.001), dialysis initiation with uraemic symptoms or fluid overload (p < 0.001), increased blood transfusion requirement (p < 0.001) and lower serum albumin (p < 0.001), creatinine clearance (p < 0.001), haemoglobin concentration (p < 0.001), and weight (p = 0.002). In the PL-D group the main primary renal diseases were glomerular and polycystic disease, whereas interstitial and diabetic nephropathy were higher in UNPL-D group (p = 0.005). Multivariate analysis showed that previous non nephrological follow-up, uraemic symptoms, interstitial nephritis as primary renal disease correlated with UNPL-D initiation, and it was followed by choosing haemodialysis as first RRT. UNPL-D was also associated with increased number of days of hospitalization at the initiation of dialysis, and during the first 6 months (p < 0.001), increase of hospitalization days (p = 0.009), and increased 6-month-mortality (10.2% vs 3.2%) (p = 0.015, log rank test), and three-year mortality (24.2 vs 36.9%) (p = 0.006, log rank test). The costs of UNPL-D were fivefold that of the PL-D group.

CONCLUSION

UNPL-D has been associated with worse overall clinical conditions at the initiation of chronic replacement therapy, choosing haemodialysis as first RRT, increased morbi-mortality and subsequent increase of costs.

Rapid decline in renal function reflects reversibility and predicts the outcome after angioplasty in renal artery stenosis

Percutaneous transluminal renal angioplasty (PTRA) has a beneficial effect on renal function in some, but not all, patients with atheromatous renal artery stenosis. Our aim is to identify factors influencing clinical success after PTRA in this group of patients. Seventy-three patients undergoing PTRA were studied; 14 patients were excluded from final analysis because of restenosis. All patients had chronic renal failure secondary to vascular nephropathy and renal artery stenosis. The diagnosis of renal artery stenosis was based on carbon dioxide digital angiography showing greater than 60% luminal narrowing. The rate of renal failure progression was assessed by the slope of the regression line of serum creatinine versus time. At least three consecutive creatinine measurements before and after angioplasty were required for study entry. Response to PTRA was made by comparison of the slope before and after PTRA. The association of age, serum creatinine level, proteinuria, renal size, pre-PTRA slope value, diabetes, ischemic heart disease, peripheral vascular disease, and cerebrovascular disease with response to PTRA was assessed by multiple regression analysis, with changes in slope values as the dependent variable. Renal function improved in 34 of 59 patients (57.6%). Mean follow-up was 627 +/- 284 (SD) days. The slope of the reciprocal serum creatinine plot before PTRA was significantly associated with a favorable change in progression rate after PTRA (beta = -0.012; P = 0.004). A scatter plot showed a statistically significant inverse correlation between pre-PTRA slope values and post-PTRA slope changes (r = -0.46; P = 0.000). Rapidly progressive renal failure is associated with a favorable response on renal failure progression after PTRA in patients with vascular nephropathy and renal artery stenosis.

Vitamin D receptor genotype influences parathyroid hormone and calcitriol levels in predialysis patients

BACKGROUND

BsmI vitamin D receptor (VDR) gene polymorphism has been associated with the severity of hyperparathyroidism in patients on hemodialysis. The aim of this study was to analyze the influence of this polymorphism on parathyroid function and serum calcitriol levels in patients with different degrees of chronic renal failure (CRF) before dialysis.

METHODS

A total of 248 CRF patients, divided into three groups according to creatinine clearance (CCr; mild CRF group> 60 to </=85 ml/min, N = 54; moderate CRF group> 35 to </=60 ml/min, N = 113; severe CRF group> 10 to </=35 ml/min, N = 81), had their serum intact parathyroid hormone (iPTH) and calcitriol levels measured and BsmI genotype frequencies estimated by polymerase chain reaction (PCR) analysis. Diabetics, those on treatment with steroids, vitamin D or derivatives, and phosphorus binding agents were excluded. All those with serum calcium levels of <2.25 mmol/liter or> 2.5 mmol/liter and serum phosphorus levels of> 1.6 mmol/liter or who needed phosphorus binding agents were excluded. The statistical analysis was done with the general factorial analysis of variance entering first PTH and then calcitriol as the dependent variable; the genotype (BB, Bb and bb), sex and CCr group were defined as factors; and covariables included serum calcium, serum phosphorus, 1/creatinine versus time slope, PTH when calcitriol was the dependent variable, and calcitriol when PTH was the dependent variable.

RESULTS

When serum PTH levels were entered as the dependent variable, serum calcium, CCr group, and the interaction of genotype with the CCr group were found to be significant factors (P = 0.025, P <0.001 and P = 0.039, respectively). When serum calcitriol levels were entered as the dependent variable, genotype, the interaction of genotype with CCr, the CCr group, and the 1/creatine versus time slope were found to be significant (P = 0.027, P = 0.028, P <0.001 and P = 0.044, respectively). The marginal means of PTH, adjusted with the general factorial analysis of variance across the three groups were: (a) mild CRF group, BB 5.3 pmol/liter (CI 0 to 13.8), Bb 5.5 pmol/liter (CI 2 to 9), bb 5.4 pmol/liter (CI 0.6 to 10.2); (b) moderate CRF group, BB 6.2 pmol/liter (CI 1.5 to 10.9), Bb 7.8 pmol/liter (CI 5.3 to 10.3), bb 7.5 pmol/liter (CI 4.8 to 10.1); (c) severe CRF group, BB 9.3 pmol/liter (CI 4.2 to 14.3), Bb 17.1 pmol/liter (CI 13.9 to 20.2), bb 21.9 pmol/liter (CI 18.7 to 25.2). The marginal means of calcitriol adjusted with the general factorial analysis of variance across the three groups were: (a) mild CRF group, BB 47 pg/ml (CI 37 to 57), Bb 40.9 pg/ml (CI 37 to 44.8), bb 32.6 pg/ml (CI 26.8 to 38. 4); (b) moderate CRF group, BB 24.1 pg/ml (CI 18.3 to 29.8), Bb 26.6 pg/ml (CI 23.5 to 29.7), bb 25.3 pg/ml (CI 22 to 28.6); (c) severe CRF group, BB 27.4 pg/ml (CI 21.3 to 33.5), Bb 19.4 pg/ml (CI 15.5 to 23.2), bb 20.4 pg/ml (CI 16.1 to 24.7).

CONCLUSION

The progression of hyperparathyroidism is slower in predialysis patients with BB genotypes than in the other genotypes. Also, calcitriol levels are less reduced in the BB genotype, which may act to lessen the severity of secondary hyperparathyroidism.

A 69-year-old woman with intermittent claudication and elevated ESR

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Level-dependent inhibitory effect of hyperaluminaemia on parathyroid hormone secretion in patients with end-stage renal failure

OBJECTIVES

Serum aluminium and parathyroid hormone levels were measured in chronic dialysis patients at discovery of accidental exposure to high dialysate aluminium levels and followed after adequate water purification.

PATIENTS AND METHODS

Twenty-nine patients with chronic renal failure on maintenance haemodialysis were accidently exposed to dialysate aluminium levels of 65 micrograms/L (recommended Food and Drug Administration values less than 10 micrograms/L) for 18 months. At discovery, oral aluminium was withdrawn and dialysate aluminium levels were corrected to less than 5 micrograms/L. Serum aluminium, parathyroid hormone, calcium, phosphorus and alkaline phosphatase levels were determined at discovery and two months and one year after the corrective measures.

RESULTS

Mean serum aluminium level was 167.6 +/- 15 micrograms/L at discovery and simultaneous serum parathyroid levels were 7.9 +/- 2.2 pmol/L (normal values 1.1 to 4.6 pmol/L). Two months after discontinuation of oral aluminium and correction of dialysate aluminium levels to less than 5 micrograms/L, the patients' mean serum aluminium dropped to 49.6 +/- 4.3 micrograms/L and simultaneous serum parathyroid hormone levels rose to 14.6 +/- 3.2-pmol/L (p < 0.001). Similar levels were maintained at one year. Serum calcium did not change significantly. There was a significant correlation between the drop in serum aluminium and the increase in parathyroid hormone.

CONCLUSION

These results confirm animal experiments and show convincingly that aluminium inhibits parathyroid secretion also in humans.