Kidney Week

Abstract: TH-PO206

Hyperphosphatemia and Acid-Base Equilibrium Disorders Are Newly Recognized Risk Factors for Mönckeberg’s Sclerosis of Vascular Access Artery

Session Information

• Bone and Mineral Metabolism: Clinical - I
  October 25, 2018 | Location: Exhibit Hall, San Diego Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Bone and Mineral Metabolism

• 402 Bone and Mineral Metabolism: Clinical

Authors

• Tani, Takashi, Nippon Medical School, Tokyo, Japan

Takashi Tani,

• Kaneko, Tomohiro, Nippon Medical School, Tokyo, Japan

Tomohiro Kaneko,

• Ikeda, Mariko, Nippon Medical School, Tokyo, Japan

Mariko Ikeda,

• Orimo, Hideo, Nippon Medical School, Tokyo, Japan

Hideo Orimo,

• Shimizu, Akira, Nippion Medical School, Tokyo, Japan

Akira Shimizu,

• Tsuruoka, Shuichi, Nippon Medical School, Tokyo, Japan

Shuichi Tsuruoka,

Background

Medial arterial calcification (MAC), also known as Mönckeberg's sclerosis, in vascular access (VA) artery is reported to be observed with high frequency in end-stage renal disease (ESRD) patients with advanced age and/or diabetic nephropathy. MAC in VA artery is also associated with increased risk of VA failure and cardio-vascular disease (CVD) events. The purpose of this study was to clarify risk factors for MAC formation in VA arteries of patients with ESRD.

Methods

Forty-one patients with ESRD, who underwent VA operation at the initiation of hemodialysis therapy, were enrolled in this study. In addition to clinical information (primary disease, age, gender, blood biochemical and computed tomography (CT) imaging findings etc.), the presence of calcification was examined pathologically by Von Kossa staining of arterial specimens (radical artery).

Results

MAC was observed in 21 patients (51.2%), and their serum phosphorus (Pi) (6.2 vs 4.9), Ca x Pi product (53.3 vs 42.4), blood urea nitrogen (79.7 vs 60.7), urinary osmolality (U-OSM) (333 vs 246) levels were significantly higher, while HCO₃^- (20.1 vs 23.0), base excess (-5.45 vs -2.33) and urinary pH (5.80 vs 6.47) levels were significantly lower than the averages of 20 patients without MAC formation (48.8%). Other biochemical parameters (e.g. i-PTH, FGF-23, α-klotho and pyrophosphate) and patients' age, gender and treatment history did not differ between MAC positive and MAC negative patients. The ROC analysis revealed that the area under curve for serum phosphorus and U-OSM were the highest, 0.771 and 0.874, respectively. By Fisher's test, a serum phosphorus level of 4.8 mg/dl or more significantly increased the probability of MAC (66.7% vs 17.65%, p<0.0037), and its odds ratio was 9.33 times. The U-OSM of 312 mOsm or more significantly increased the incidence of MAC (76.9% vs 9.1%, p<0.0013) with an odds ratio of 33.3.

Conclusion

It was shown that higher serum phosphorus level and severer renal dysfunction and acid-base equilibrium disorders at the start of hemodialysis were risk factors for MAC in VA artery. Particularly, patients with hyperphosphatemia over 4.8 mg/dl were highly likely to display MAC in VA artery, so that attention should be paid to potential VA failure and CVD events.