[Effect of sodium thiosulfate on coronary artery calcification in maintenance hemodialysis patients]

Objective: To investigate the factors correlated to coronary artery calcification (CAC)in maintenance hemodialysis (MHD) patients and observe the effect of sodium thiosulfate (STS) on the progression of vascular calcification and its safety. Methods: Thirty-eight subjects from Fuzhou Genernal Hospital who underwent coronary artery CT scan using Philip's spiral CT were enrolled and the calcification degree was evaluated by CAC scores from December 2013 to December 2014. The hemodialysis patients were divided into CAC group (CAC scores>10, 27 cases) and non-CAC group (CAC scores≤10, 11 cases)according to the CT scan results.The differences of age, duration of dialysis, blood pressure and other hematological indices between the two groups were analyzed to investigate the factors correlated to CAC. Next, those with CAC (CAC scores≥50) received intravenous 0.18 g/kg STS (dissolved in 100 ml saline) in 30 minutes after each dialysis for 3 months (n=17, only 15 patients completed STS treatment) or received conventional treatment (n=10). Baseline data between the two groups before treatment had no significant statistical difference. All examination indices were evaluated before and after the treatment course. The changes of vascular calcification imaging, CAC scores, biochemical indices and bone mineral density were compared between two groups before and after the treatment. Besides, adverse reactions were observed during the treatment of STS. This study was approved by the Ethics Committee of Fuzhou General Hospital(2013No1). Results: Twenty-seven out of 38 patients (71.05%) had CAC, and the patients with CAC had significantly higher age, phosphate, the product of calcium and phosphate, intact parathyroid hormone (hPTH), hypersensitive C-reactive protein (hsCRP), and longer duration of dialysis (P=0.017, 0.038, 0.037, 0.012, 0.002, 0.037) and lower serum albumin (P=0.026) than patients without CAC.There was no significant statistical difference in the baseline characteristics. CAC score did not change significantly before and after treatment in the STS treatment group[1 045(47-12 734) vs 797(50-14 094), P=0.053], but increased significantly in the conventional treatment group[221(59-3 843) vs 174(50-3 369), P=0.021]. Difference of CAC score parameters before and after treatment showed statistically significant difference between the two groups[-67.5(-474-8) vs 52(-248-1 361) , P=0.004]. After STS treatment, level of hsCRP and HCO₃^- decreased (P=0.016 and P=0.020, respectively), and level of serum calcium increased (P=0.005). There was no significant statistical difference observed in iPTH, 25(OH)D, bone alkaline phosphatase (bALP), fibroblast growth factor 23 (FGF23) after STS treatment. Conclusion: STS treatment seems to be feasible, safe and may delay the rate of progression of vascular calcification, reduce inflammation in maintenance hemodialysis patients, but the adverse reactions needs further study.