A nationwide survey for 4,380 dialysis facilities was conducted at the end of 2015, among which 4,321 facilities (98.7％) responded. The response rate of the 2015 survey was comparable with the past, even though it was the first year after the new anonymization method. The number of chronic dialysis patients in Japan continues to increase every year; it has reached 324,986 at the end of 2015. The mean age was 67.86 years. At the end of 2015, the prevalence rate was 2,592 patients per million population. Diabetic nephropathy was the most common primary disease among the prevalent dialysis patients (38.4％), followed by chronic glomerulonephritis (29.8％) and nephrosclerosis (9.5％). The rate of diabetic nephropathy and nephrosclerosis has been increasing year by year, whereas that of chronic glomerulonephritis was declining. The number of incident dialysis patients during 2015 was 39,462; it has remained stable since 2008. The average age was 69.20 years and diabetic nephropathy (43.7％) was the most common cause in the incident dialysis patients. These patients caused by diabetes did not change in number for the last several years. Meanwhile, 31,608 patients died in 2015; the crude mortality rate was 9.6％. The patients treated by hemodiafiltration (HDF) have been increasing rapidly from the revision of medical reimbursement for HDF therapy in 2012. It has attained 53,776 patients at the end of 2015, which were 10,493 greater than that in 2014. In particular, the number of on-line HDF patients increased about ten-times 2012. The number of peritoneal dialysis (PD) patients was 9,322 in 2015, which was slightly more than 2014. 20.0％ of PD patients shared hemodialysis (HD) or HDF therapy. 572 patients underwent home HD patients at the end of 2015; it increased by 43 from 2014.

The stenosis of arteriovenous fistulas (AVF) or arteriovenous grafts (AVG) in chronic hemodialysis patients is often treated with balloon-assisted percutaneous transluminal angioplasty (PTA), but short-term recurrent restenosis remains a problem. We treated recurrent restenosis in 6 vascular access vessel lesions in 5 patients using drug (paclitaxel) -coated balloons (DCB, SeQuent Please balloon). Four of the target lesions were located in AVF, one was located in an AVG, and the remaining lesion involved stent restenosis of the subclavian vein. All lesions were pre-dilated using a 3- or 4-mm-diameter balloon, and paclitaxel was delivered via a 3.5- or 4.0-mm-diameter DCB, which was inflated for 120 sec. Two lesions required re-PTA after 7 and 16 months, but the culprit lesions were not located at the DCB-treated sites; rather, they were new stenotic lesions. No flow disturbance was seen in the other 4 lesions. In comparison with their pre-DCB values, the patency periods of the treated vascular access vessels were significantly longer after the DCB treatment (pre-DCB vs. post-DCB: 3.4±1.9 vs. 10.8±5.9 months, p<0.0001). DCB angioplasty was very effective at maintaining good vascular access flow in recurrent restenotic lesions.

The patient started receiving hemodialysis for renal dysfunction at the age of 59 years. During the same period, he was found to have cardiac dysfunction and type 2 diabetes. Without performing a renal biopsy, a clinical diagnosis of diabetic nephropathy was made. However, mitochondrial disease was suspected based on the presence of a headache, vomiting, sensorineural hearing loss, emaciation, declining intelligence, repeated blood lactic acid measurements of>2 mmol/L, and heart disease in patient’s mother. Genetic tests were conducted when the patient was 65 years old. A tRNA-Leu (UUR) 3243A→G mutation was detected, and mitochondrial myopathy, encephalopathy, lactic acidosis, stroke-like episodes was suspected. Afterward, the patient suffered prolonged hypoglycemia and died. An autopsy was performed, but no morphological lesions that could account for the hypoglycemia were found. The patient’s kidneys were in a severely damaged state, and it was difficult to determine the precise lesion that had caused his renal failure, but it is possible that the renal failure was related to his mitochondrial disease. Many abnormal mitochondria were seen during an examination of the patient’s myocardial and choroid plexus epithelial cells performed with an electron microscope, and pathological findings that were indicative of mitochondrial disease were also detected.

The patient was a 35-year-old-female. She had been treated in the outpatient clinic of our department from 33 years of age due to chronic renal failure caused by giant angiomyolipomas (AML) of the bilateral kidneys associated with tuberous sclerosis (TSC). She consulted the emergency outpatient unit because of severe pain in her right flank. Progressive severe anemia was noted, and an abdominal computed tomography scan revealed an area of high attenuation at the AML site in the right kidney, which was suggestive of intratumoral hemorrhaging related to spontaneous rupturing of the AML. Right-sided nephrectomy was performed. Then, it was pathologically revealed that an oncocytic papillary renal cell carcinoma (OPRCC) at the AML site was the source of the hemorrhaging. After the right-sided nephrectomy, the patient's renal dysfunction progressed, and chronic maintenance hemodialysis was started. This case involved the rare coexistence of AML and renal cell carcinoma of a specific histological type (OPRCC), which might provide useful information for the future management of TSC-related renal lesions.