Effect of citric-acid dialysate on the QTC-interval.

Lower dialysate calcium (dCa) concentration and dialysate citric-acidification may positively affect calcification propensity in serum of haemodialysis (HD) patients. However, the accompanying lower ionized blood calcium concentration may lead to a prolonged cardiac action potential, which is possibly pro-arrhythmic. The aim of this study is to investigate the influence of citric-acid dialysate on the QT-interval corrected for heart rate (QTc) compared to conventional dialysate with different dCa concentrations. We conducted a four-week multicentre, randomized cross-over trial. In week one and three patients received acetic-acid dialysate with a dCa of 1.50 mmol/l (A1.5), in week two and four acetic-acid dialysate with a dCa of 1.25 mmol/l (A1.25) or citric-acid dialysate (1.0 mmol/l) with a dCa of 1.50 mmol/l (C1.5) depending on randomization. Patients had continuous ECG monitoring during one session in week one, two and four. The data of 13 patients were available for analysis. Results showed a significant though limited increase of QTc with C1.5 (from 427 to 444 ms (start to end); p = 0.007) and with A1.25 (from 431 to 449 ms; p < 0.001), but not with A1.5 (from 439 to 443 ms; p = 0.13). In conclusion, we found that the use of C1.5 or A1.25 is associated with a significant prolongation of QTc which was however relatively limited.

Citric-acid dialysate improves the calcification propensity of hemodialysis patients: A multicenter prospective randomized cross-over trial.

INTRODUCTION: The concentration of dialysate calcium (dCa) has been suggested to affect vascular calcification, but evidence is scarce. Calcification propensity reflects the intrinsic capacity of serum to prevent calcium and phosphate to precipitate. The use of citric-acid dialysate may have a beneficial effect on the calcification propensity due to the chelating effect on calcium and magnesium. The aim of this study was to compare the intradialytic and short-term effects of haemodialysis with either standard acetic-acid dialysate with dCa1.50 (A1.5) or dCa1.25 (A1.25), as well as citric-acid dialysate with dCa1.50 (C1.5) in bicarbonate dialysis on the calcification propensity of serum. METHODS: Chronic stable hemodialysis patients were included. This multicenter randomized cross-over study consisted out of a baseline week (A1.5), followed by the randomized sequence of A1.25 or C1.5 for one week after which the alternate treatment was provided after a washout week with A1.5. Calcification propensity of serum was assessed by time-resolved nephelometry where the T50 reflects the transition time between formation of primary and secondary calciprotein particles. RESULTS: Eighteen patients (median age 70 years) completed the study. Intradialytic change in T50 was increased with C1.5 (121 [90-152]min) compared to A1.25 (83 [43-108]min, p<0.001) and A1.5 (66 [18-102]min, p<0.001). During the treatment week, predialysis T50 increased significantly from the first to the third session with C1.5 (271 [234-291] to 280 [262-339]min, p = 0.002) and with A1.25 (274 [213-308] to 307 [256-337]min, p<0.001), but not with A1.5 (284 [235-346] to 300 [247-335]min, p = 0.33). CONCLUSION: Calcification propensity, as measured by the change in T50, improved significantly during treatment in C1.5 compared to A1.25 and A1.5. Long-term studies are needed to investigate the effects of different dialysate compositions concentrations on vascular calcification and bone mineral disorders.

Dialysate Calcium Levels: Do They Matter?

BACKGROUND: Calcium (Ca) is an essential element that plays a critical role in many biological processes. In dialysis patients, the regulation of Ca balance is highly complex, given the absence of kidney function, endocrine disturbances and the use of drugs such as phosphate binders, vitamin D analogues, and calcimimetics. Also, the use of different dialysate Ca (DCa) baths has profound effect on Ca balance, which depends both on the difference between the Ca concentration in the bath and the serum of the patients, as on the ultrafiltration volume. SUMMARY: The choice of DCa may have important short- and long-term consequences. While lower DCa (especially < 2.5 mEq/L) concentrations have been associated with an increased risk of sudden cardiac death in observational studies, DCa in the higher ranges (3.0 mEq/L and above) may contribute to vascular pathology. Intra-dialytic hemodynamics may also be affected by the choice of DCa. In general, lower DCa concentrations are associated with an increase, and higher DCa concentrations with a decrease in parathyroid hormone (PTH) levels. Preliminary data has suggested that a DCa of 2.75 mEq/L may help in obtaining a net zero intradialytic Ca balance in individual patients, but clinical experience is still limited. Key Message: The optimal Ca balance depends on multiple parameters including blood Ca levels, PTH and the use of phosphate binders and vitamin D analogues, as well as on the risk of hemodynamic stability and cardiac arrhythmias. Therefore, DCa prescription should be individualised. A DCa of 2.75 mEq/L may be useful adjunct for dialysis providers.

Intraoperative MRI-guided resection of glioblastoma multiforme: a systematic review.

We did a systematic review to address the added value of intraoperative MRI (iMRI)-guided resection of glioblastoma multiforme compared with conventional neuronavigation-guided resection, with respect to extent of tumour resection (EOTR), quality of life, and survival. 12 non-randomised cohort studies matched all selection criteria and were used for qualitative synthesis. Most of the studies included descriptive statistics of patient populations of mixed pathology, and iMRI systems of varying field strengths between 0·15 and 1·5 Tesla. Most studies provided information on EOTR, but did not always mention how iMRI affected the surgical strategy. Only a few studies included information on quality of life or survival for subpopulations with glioblastoma multiforme or high-grade glioma. Several limitations and sources of bias were apparent, which affected the conclusions drawn and might have led to overestimation of the added value of iMRI-guided surgery for resection of glioblastoma multiforme. Based on the available literature, there is, at best, level 2 evidence that iMRI-guided surgery is more effective than conventional neuronavigation-guided surgery in increasing EOTR, enhancing quality of life, or prolonging survival after resection of glioblastoma multiforme.