Kaoru Tabei

Cardiac Arrhythmias in Hemodialysis Patients

Cardiac arrhythmias were evaluated in 100 patients undergoing regular maintenance hemodialysis for chronic renal failure by Holier ECG monitoring a 72-hour period beginning on the day of hemodialysis.

Japanese Society for Dialysis Therapy Guidelines for Management of Cardiovascular Diseases in Patients on Chronic Hemodialysis

Hideki Hirakata, Kosaku Nitta, Masaaki Inaba, Tetsuo Shoji, Hideki Fujii, Shuzo Kobayashi, Kaoru Tabei, Nobuhiko Joki, Hiroki Hase, Masato Nishimura, Shigeyuki Ozaki, Yuji Ikari, Yoshitaka Kumada, Kazuhiko Tsuruya, Shouichi Fujimoto, Tohru Inoue, Hiroyoshi Yokoi, Sumio Hirata, Kazuaki Shimamoto, Kiyotaka Kugiyama, Takashi Akiba, Kunitoshi Iseki, Yoshiharu Tsubakihara, Tadashi Tomo, and Tadao Akizawa

An Overview of Regular Dialysis Treatment in Japan (as of 31 December 2004)

Abstract:  A statistical survey of 3932 nationwide hemodialysis (hereafter, dialysis) facilities was carried out at the end of 2004, and 3882 facilities (98.73%) responded. The population undergoing dialysis at the end of 2004 was 248 166, an increase of 10 456 patients (4.4%) from that at the end of 2003. The number of dialysis patients per million people was 1943.5. The crude death rate of dialysis patients from the end of 2003 to the end of 2004 was 9.4%. The mean age of patients who underwent dialysis in 2004 was 65.8 years, and that of the total dialysis population was 63.3 years. The percentage distribution of patients who underwent dialysis according to a newly underlying disease showed that 41.3% of patients had diabetic nephropathy and 28.1% had chronic glomerulonephritis. The frequency of calcium carbonate use for dialysis patients was 75.1% and that of sevelamer hydrochloride use was 26.2%. The frequency of sevelamer hydrochloride use does not necessarily have a strong correlation with the dose of calcium carbonate. Patients who received high doses of sevelamer hydrochloride tended to have a low concentration of arterial blood HCO3–. Approximately 15% of dialysis patients used an intravenous vitamin D preparation, generally maxacalcitol. The longer the patients had been on dialysis, the higher the frequency of use of an intravenous vitamin D preparation. When the concentration of serum intact parathyroid hormone (PTH) was more than 200 pg/mL, the frequency of use of an orally administered vitamin D preparation decreased; but that of intravenous vitamin D preparation increased. The percentage of dialysis patients who received percutaneous ethanol injection therapy (PEIT) was 1.4%. The percentage was more than 50% in the patients who had been on dialysis for more than 10 years. The percentage of patients who received PEIT again was 35.0%. The percentage of patients who had been on hemodialysis for more than 10 years and received PEIT again was more than 50%. 

Dopaminergic inhibition of the action of vasopressin on the cortical collecting tubule.

The dopaminergic inhibition of the hydrosmotic effect of vasopressin was studied by in vitro perfusion of the cortical collecting tubule isolated from the rabbit kidney. Arginine vasopressin (AVP) 100 microU/ml increased hydrosmotic water permeability (Pf, 10(-3) cm/s) by 11.4 +/- 1.59. Although dopamine 10(-5) M added alone to the bath did not affect Pf, the combined administration of 10(-5) M dopamine and 100 microU/ml AVP reduced the hydrosmotic effect of AVP to to 2.37 +/- 0.34. This inhibitory effect of dopamine was reversed by the simultaneous addition of 10(-5) M metoclopramide, a D2-antagonist. These observations suggest that dopaminergic receptors also exist in the cortical collecting tubule. The dopaminergic inhibition of the hydrosmotic action of AVP may be at least in part responsible for the diuretic action of dopamine.

Ventricular Arrhythmias in Hemodialysis Patients: A Study of Incidence and Contributory Factors

One hundred patients undergoing maintenance hemodialysis for chronic renal failure were evaluated by Holter ECG monitoring for a 72-hour period from the day of hemodialysis therapy. Eighteen patients (the frequent group) who had more than 700 premature ventricular contractions (PVCs) per day were found among these 100 patients. In those eighteen, the PVCs were recorded frequently during and for 4 hours after hemodialysis. The values of the serum calcium concentration times those of phosphorus, which are thought to be an index of parathyroid function, were significantly higher in the frequent group than in patients without PVCs (the no arrhythmia group) or in those with fewer PVCs (less than 700 beats per day; sporadic group). Also, in the frequent group, the percent fractional shortening of the left ventricle, as measured by 2-dimensional echocardiography, was significantly lower than those in the no arrhythmia and sporadic groups. From these results, we conclude that the pathogenesis of the PVCs in chronic renal failure resulted partially from impaired cardiac performance and accelerated parathyroid function.

Luminal vasopressin modulates transport in the rabbit cortical collecting duct.

We explored the action of luminal AVP in rabbit CCD perfused in vitro at 37 degrees C. Nanomolar concentrations of luminal AVP induced a sustained hyperpolarization of transepithelial voltage (Vt) in contrast to a transient hyperpolarization caused by basolateral AVP. 10 microM basolateral ouabain abolished the latter but not the former change in Vt. Despite a sustained hyperpolarization (from -20.7 +/- 2.9 to -34.1 +/- 4.7 mV; P less than 0.01), 10 nM luminal AVP only slightly altered net Na+ and K+ fluxes (7.6% stimulation and no significant change, respectively). Instead, luminal AVP appeared to modulate an acetazolamide-sensitive electrogenic ion transport because 200 microM basolateral acetazolamide suppressed the luminal AVP-induced hyperpolarization (percentage of Vt from -50.4 +/- 10.8 to -5.1 +/- 1.4; P less than 0.005). In terms of water transport, 10 nM luminal AVP did not change hydraulic conductivity (Lp, x 10(-7) cm/atm per s) (from 3.9 +/- 0.8 to 5.0 +/- 1.2), but suppressed the increase in Lp induced by 20 pM basolateral AVP (134.9 +/- 19.2 vs. 204.3 +/- 21.1 in control; P less than 0.05). These findings demonstrate distinct luminal action of AVP, suggesting amphilateral regulation of epithelial transport by AVP in the CCD.

Monocyte chemoattractant protein-1 A-2518G gene polymorphism and renal survival of Japanese patients with immunoglobulin A nephropathy.

BackgroundMonocyte chemoattractant protein (MCP)-1 is closely related to the pathogenesis of the progression of various chronic renal diseases, including IgA nephropathy (IgAN), through its chemoattractant effect on macrophages. However, the correlation of MCP-1 gene polymorphism with the long-term prognosis of Japanese patients with IgAN has not been clearly determined yet.MethodsWe investigated 277 Japanese patients diagnosed with IgAN based on renal biopsy to clarify the association between the progression of IgAN and MCP-1 gene polymorphism at position A-2518G, which regulates the transcription of the MCP-1 gene.ResultsThe incidence of endstage renal disease was significantly higher in patients with the AA genotype (47.1%) compared to those with the AG (24.1%) or GG (27.4%) genotype (P = 0.024). Moreover, Kaplan-Meier analysis revealed that the AA genotype significantly facilitated the progression of renal disease (log rank; P = 0.0029), and Cox proportional hazards regression model analysis showed that the AA genotype represented a 2.058-fold risk for the progression of renal disease (P = 0.026) compared to the AG/GG genotype. However, when the patients were treated with angiotensin-converting enzyme inhibitor and/or angiotensin receptor blocker, or corticosteroid, homozygosity for the -2518A allele was not associated with a higher rate of incidence of endstage renal disease. Serum MCP-1 levels were higher although not significantly so, in the patients with IgAN possessing the AA genotype.ConclusionsThe AA genotype at MCP-1 -2518 was an independent risk factor for the progression of renal disease in Japanese patients with IgAN, and was closely associated with renal survival.

A study on regulating factors of plasma refilling during hemodialysis.

Hypotension is frequently encountered during hemodialysis (HD). One of the main factors of the HD-induced hypotension is acute reduction of circulating plasma volume by water removal, which is induced by the poor plasma refilling from the extravascular space into vessels. The determinants of plasma refilling, however, have not been clearly identified. Recently, we devised a mathematical model of water transport in HD patients, which can estimate the plasma-refilling coefficient (Kr) during HD. In the present study, we evaluated the factors determining plasma refilling by using this model. In 13 patients undergoing regular HD, the changes of Kr during HD were calculated from the model. Levels of ANP, cGMP, cAMP, endothelin, angiotensin II and vasopressin were measured before and after HD. Kr fell from 750.4 +/- 558.0 to 112.8 +/- 81.9 ml/mm Hg/h during HD. The rate of water removal during HD showed no significant correlation with the changes of Kr. Among the hormones and nucleotides measured here, plasma ANP level and cGMP were significantly correlated with Kr (r = 0.78, p < 001 and r = 0.62, p < 0.01, respectively). Our findings suggest that severe reduction in the level of serum ANP during HD, which is induced by water removal, plays some role in HD-induced hypotension through the attenuation of plasma refilling in HD patients.

An Index of Plasma Refilling in Hemodialysis Patients

During hemodialysis therapy, a large amount of water is removed from the patients blood in a short time; however, blood pressure remains stable in most patients. As water is removed, the circulating serum proteins become more concentrated, resulting in a marked increase in the driving force which pulls water from the extravascular space into the blood vessels, by a process called plasma refilling. However, since a method for studying plasma refilling has not previously been proposed, it is not known what determines the plasma refilling capacity of hemodialysis patients. To evaluate the plasma refilling capacity of patients, we propose here a method for calculating an index of plasma refilling capacity, which we have called the plasma-refilling coefficient (Kr). In 14 patients receiving maintenance hemodialysis therapy, total serum protein was measured before hemodialysis, and hematocrits were measured hourly during hemodialysis. From the changes in the hematocrits, we estimated the changes in the circulating plasma volume and in the intracapillary oncotic pressure at each time point. The water removal rate was also measured hourly. From these values, we calculated Kr. An averaged volume of 2,692 +/- 219 ml of water was removed from each patient resulting in a decrease in the estimated circulating blood volume, while the hematocrit and the estimated intracapillary oncotic pressure increased gradually. Kr calculated after 1 h of hemodialysis varied widely between patients, 140.3-1,744.2 ml/mm Hg/h, and decreased gradually as water removal continued. The average Kr of 14 patients was 698.9 +/- 15.2 ml/mm Hg/h at the beginning of water removal, and it decreased to 405.3 +/- 75.4, 203.9 +/- 39.5, 130.2 +/- 20.5 and 93.9 +/- 14.3 each hour thereafter. The index of plasma refilling proposed in this paper is useful for examining capillary water permeability and the degree of plasma refilling in hemodialysis patients.

Japanese Society for Dialysis Therapy Clinical Guideline for “Maintenance Hemodialysis: Hemodialysis Prescriptions”

Yuzo Watanabe, Hideki Kawanishi, Kazuyuki Suzuki, Shigeru Nakai, Kenji Tsuchida, Kaoru Tabei, Takashi Akiba, Ikuto Masakane, Yoshiaki Takemoto, Tadashi Tomo, Noritomo Itami, Yasuhiro Komatsu, Motoshi Hattori, Michio Mineshima, Akihiro Yamashita, Akira Saito, Hidemune Naito, Hideki Hirakata, and Jun Minakuchi, for “Maintenance Hemodialysis: Hemodialysis Prescriptions” Guideline Working Group, Japanese Society for Dialysis Therapy