Dialysis,cardiovascular disease,and the future

Atherosclerosis, particularly coronary atherosclerosis, is accelerated in renal failure, as originally postulated by Belding Scribner. But in contrast to previous opinion, myocardial infarction from coronary heart disease is not the single major cause of cardiac death in dialyzed patients, the most common causes being sudden death and cardiac failure. Apart from coronary heart disease, the following cardiomyopathic features are prevalent and explain a large part of the excess cardiac risk: cardiomyocyte dropout, left ventricular hypertrophy, cardiac interstitial fibrosis, microangiopathy with arteriolar thickening, and capillary deficit as well as reduced ischemia tolerance. Recently, cardiovascular risk factors related to abnormal mineral metabolism, particularly phosphate and vitamin D, have gained unanticipated importance. Controlled evidence has become available concerning intervention with ACE inhibitors, angiotensin receptor blockers, β‐blockers, and statins in dialyzed patients. It is imperative that apart from the “classical” cardiovascular risk factors that do not exhaustively explain the excessive cardiovascular risk in dialyzed patients, novel pathomechanisms are considered and investigated; potential examples include depression, sleep abnormalities, etc. The above arguments do not negate the fact that today's modalities of renal replacement therapy are poor substitutes for the normal kidney's function so that as a result alternative strategies, e.g., daily dialysis, may also dramatically improve cardiovascular risk.     

Bioreactance: A new tool for cardiac output and thoracic fluid content monitoring during hemodialysis

Outpatient hemodialysis therapy (HD) can be associated with hemodynamic compromise. Bioreactance^® has recently been shown to provide accurate, noninvasive, continuous, measurements of cardiac output (CO) and thoracic impedance (Zo) from which thoracic fluid content (TFC) can be derived assuming TFC=1000/Zo. This study was designed to evaluate the changes in TFC in comparison with the traditional indices of fluid removal (FR) and to understand the trends in CO changes in HD patients. Minute-by-minute changes in TFC and CO were prospectively collected using the bioreactance system (NICOM^®) in HD patients of a single unit. Changes in body weight (ΔW), hematocrit (ΔHct), and amount of FR were also measured. Twenty-five patients (age 77 ± 11 years) were included. The TFC decreased in all patients by an average of 5.4 ± 7.9 kΩ⁻¹, weight decreased by 1.48 ± 0.98 kg, and FR averaged 2.07 ± 1.93 L over a 3- to 4-hour HD session. There were good correlations between ΔTFC and ΔW (R=0.80, P<0.0001) and FR (R=0.85, P<0.0001). ΔHct (4.13 ± 3.42%) was poorly correlated with ΔTFC (R=0.35, P=0.12) and FR (R=0.40, P=0.07). The regression line between FR and TFC yielded FR=1.0024−0.1985TFC; thus, a 1 kΩ⁻¹ change of Zo correlates with an ∼200 mL change in total body water. The change in CO (−0.52 ± 0.49 L/min m²) during HD did not correlate with FR (R=0.15, P=NS). Changes in TFC represented the monitored variable most closely related to FR. CO remained fairly constant in this stable patient cohort. Further studies in high-risk patients are warranted to understand whether TFC and CO monitoring can improve HD session management.     

Beyond ultrapure hemodialysis: A necessary and achievable goal

Survival of chronic hemodialysis patients is worse than that of many patients with cancers or severe infections. An important cause of chronic inflammation is impurities infused into patients during dialysis. Definitions of dialysis purity have been narrow and focused on metals in dialysate water and on bacterial contaminants. There is no standard for priming fluids or toxins released directly into blood from inside the extracorporeal circuit. We propose a much broader standard of dialysis purity that also includes phthalate metabolites, bisphenols, spalled particles, and other contaminants from dialysis machines, filters, and bloodlines. Standards must include new methods for measuring bacteriological contaminants in addition to colony‐forming units and endotoxin determinations. These include the sensitive silkworm larva plasma test that detects peptidoglycan that is missed by endotoxin tests and standards for newly detected small molecular bacterial detritus. Current levels for “standard” bacteriological contaminants are woefully inadequate and should be increased. New standards for contamination with plasticizers and spallation are also necessary. Studies with ultrapure dialysis have shown almost immediate patient benefits with increased well‐being and stabilization of the cardiovascular system during and between dialyses. Intermediate effects include lower C‐reactive protein levels, better response to erythropoietin, increased appetite, and improved nutrition. Over the years, amyloidosis and carpal tunnel syndrome have become less common and cardiovascular deaths have decreased. Standards for dialysis purity must be sharpened and expanded and this becomes even more urgent with daily and long nightly hemodialysis. All contaminants received by patients, whether biological, chemical, or physical, must be considered.     

Psychological Symptoms Are Greater in Caregivers of Patients on Hemodialysis Than Those of Peritoneal Dialysis

Background: The purpose of this study was to evaluate and compare psychosocial characteristics in caregiving relatives (caregivers) of hemodialysis (HD) and peritoneal dialysis (PD) patients. Methods: Thirty‐three caregivers (17 women, 16 men) of HD patients, 27 caregivers (11 women, 16 men) of PD patients, and a control group of 49 subjects who do not care for family members with chronic illness (23 women, 26 men) are included in this study. The brief symptom inventory (BSI), social disability schedule (SDS), and brief disability questionnaire (BDQ) were used for the psychosocial evaluation. Results: The mean age, men‐to‐women ratios, duration of education, and distribution of marital status did not differ significantly among the three groups. In addition, dialysis duration and distribution of caregiver type were not different between the HD and PD groups. Although the mean global severity index scores of the three groups were similar, somatization and depression scores from BSI subitems were greater in the HD group than the scores of the PD and control groups. Although the mean SDS and BDQ scores were higher in the HD group, the differences did not achieve statistical significance. BSI subitems such as somatization, obsession–compulsion, interpersonal sensitivity, depression, and anxiety were positively correlated among themselves. Hostility and somatization were negatively correlated with age and education, respectively. Nevertheless, somatization was positively correlated with age. Social disability was negatively correlated with duration of education. Conclusion: Somatization and depression are greater in the caregivers of center HD patients compared to PD and control groups. According to the findings of this study, we suggest that caregiving family members of dialysis patients especially on HD also should be evaluated for psychosocial problems and supported as needed. Further studies are needed to explore whether psychosocial parameters of caregivers predict outcomes for caregivers and patients.     

Persistent left superior vena cava: Two case reports and a review from nephrologists’ perspective

Thoracic venous anomalies without congenital heart anomalies are present in minority of the population, but they are frequent enough to be encountered while placing hemodialysis catheters through the jugular or subclavian veins. Persistent left superior vena cava is the most commonly seen anomaly and it is rarely noticed before the observation of an unusual course of hemodialysis catheter or guidewire on chest X‐ray. We present two patients with previously unspotted persistent left superior vena cava and uncomplicated hemodialysis catheter insertions through the internal jugular veins with good catheter functions. Review of the relevant literature from a nephrologists’ perspective with technical aspects is provided.     

Personal viewpoint: Limiting maximum ultrafiltration rate as a potential new measure of dialysis adequacy

While the solute clearance marker (Kt/V_urea) is widely used, no effective marker for volume management exists. Two principles apply to acute volume change in hemodialysis: (1) the plasma refill rate, the maximum rate the extracellular fluid can replace a contracting intravascular volume (±5 mL/kg/hour) and (2) the rate of intravascular volume contraction where coronary hypoperfusion, myocardial stun, and vascular risk escalates (observed at ≥10 mL/kg/hour). In extended hour and higher frequency hemodialysis, intravascular contraction rates are usually equilibrated by the plasma refill rate, but in “conventional” in‐center hemodialysis, volume contraction rates commonly exceed the capabilities of the plasma refill rate, resulting in inevitable hypovolemia. To minimize cardiovascular risk, fluid removal rates should ideally be ≤10 mL/kg/hour, acknowledging that this may be challenging in the in‐center setting. Two options exist to limit volume removal to >10 mL/kg/hour: restricting interdialytic weight gain (always conflict‐fraught, often unachievable) or extending sessional duration to allow additional removal time. Just as Kt/V_urea quantifies solute removal, a simple‐to‐apply rate variable should also apply for volume removal. As predialysis and target postdialysis weights are both known, a simple measure—a maximum rate for ultrafiltration (UFR_max)—would advise the sessional duration (T) required to minimize organ stun by removing the required fluid load (V) from any patient of predialysis weight (W). This would ensure a removal rate no greater than 10 mL/kg/hour—T (hours) = V (mL)/10 × W (kg). Used together, Kt/V_urea and UFR_max would form a solute and volume composite, each dialysis treatment continuing until both solute and volume requirements are fulfilled.     

Safety analysis of intermittent hemodialysis in patients with continuous flow left ventricular assist devices

Dialysis centers adopt a cautious approach when it comes to performing intermittent hemodialysis (HD) on patients with continuous flow (CF) left ventricular assist devices (LVADs) because of the potential for volume flux‐related complications and absence of pulsatile blood pressure for monitoring. Many patients have to remain hospitalized because of the inability of the dialysis centers to accept them for outpatient dialysis. In this study, the effect of HD was observed in such patients. Between June 2009 and October 2012, 139 patients received LVADs, of which 10 patients (7%) required intermittent HD postoperatively. The mean age of the patients was 53 ± 14 years and 90% were men. A total of 281 dialysis sessions were administered amounting to 1025 hours of dialysis. The mean systolic blood pressure monitored with Doppler device was 97 ± 18 mmHg. Dialysis durations averaged 218 ± 18 minutes. Mean blood flow rate was 334 ± 38 cc/min, and 2.6 ± 1.1 L was ultrafiltrated during each session. Only 15 (5.3%) sessions were interrupted or terminated in six patients. The reasons for termination were symptomatic hypotension—6 (2.1%), asymptomatic hypotension—3 (1%), ventricular tachycardia—1 (0.36%), dialysis machine malfunction—2 (0.7%), low phosphorus—2 (0.7%), and abdominal cramps—1 (0.36%). Volume expansion was necessary on three occasions. Low‐flow device alarms were registered during two (0.71%) sessions. The results showed no serious adverse effects or deaths.     

Inflammation,high ferritin,and erythropoietin resistance in indigenous maintenance hemodialysis patients from the Top End of Northern Australia

Use of erythropoiesis‐stimulating agents (ESAs) has improved the management of anemia in patients on maintenance hemodialysis (MHD). Iron deficiency and inflammation cause ESAs resistance and are both common among indigenous people of Northern Australia. As part of quality assurance in our Renal Anaemia Management program, we observed that there was use of higher doses of ESAs and adjuvant iron therapy in our MHD patients. This study aimed to explore the relationship among iron studies, inflammation, ESA responsiveness, and ESAs and iron requirements in indigenous patients on MHD from the Top End of Northern Australia. We performed a retrospective cohort analysis of anemia management in a cohort of our patients on MHD. We extracted data for 178 indigenous and 19 non‐indigenous patients from 1 March 2009 to 28 February 2010 from the Renal Anaemia Management database, which collects data prospectively in MHD patients. Ninety‐nine percent of the whole sample had a ferritin level above the international guidelines threshold of >500 µg/L. Indigenous patients had higher ferritin (1534 ± 245.5 µg/L vs. 1013 ± 323.3 µg/L, P = 0.002). C‐reactive protein (CRP) was high in 56.9% of the total cohort. One hundred percent of those with normal CRP had high ferritin (>500 µg/L). C‐reactive protein was higher in indigenous than in non‐indigenous patients. Erythropoiesis‐stimulating agents hyporesponsiveness was higher in indigenous patients (P < 0.0001). There was no significant difference in ESAs hyporesponsiveness among different levels of CRP (P = 0.116), ferritin (P = 0.408), and transferrin saturation (P = 0.503). Indigenous patients required higher total iron dose (2820.30 [2000–4350] vs. 2336.12 [1912–2900], P = 0.02). There was no significant relationship between the high ferritin and CRP. In indigenous dialysis patients, iron therapy and ESAs use are higher. The high iron use is due to a lack of published evidence to guide the administration of iron in patients with high ferritin. The high ferritin and ESAs resistance could not be fully explained by inflammation and need further evaluation. Further studies are required to determine the safe use of iron and management of ESAs resistance in our hemodialysis population.     

护理干预对血液透析患者生活质量的影响

目的探讨护理干预对血液透析患者生活质量的影响。方法回顾性分析我院近年来收治的150例血液透析患者的临床资料,比较分析护理干预前后患者生活质量评分。结果实施护理干预后,150例血液透析患者的物质生活状况、躯体功能、心理功能、社会功能4个维度评分明显升高,与干预前比较,(P<0.05),有显著性差异。由此可见,良好的护理干预可以明显提高血液透析患者的生活质量。结论实施护理干预可以明显提高血液透析患者的生活质量,值得临床推广。     

Right intra-atrial catheter placement for hemodialysis in patients with multiple venous failure

The purpose of this study is to evaluate the efficacy and safety of direct right atrial catheter insertion for hemodialysis in patients with multiple venous access failure. We retrospectively evaluated the charts of 27 patients with multiple venous access failure who had intra-atrial dialysis catheter placement between October 2005 and October 2010 in our clinic. Permanent right atrial dialysis catheters were placed through a right anterior mini-thoracotomy under intratracheal general anesthesia in all patients. Demographics of the cases, the patency rates of hemodialysis via atrial catheterization, existence of any catheter thrombosis, and catheter-related infections were documented and used in statistical analysis. Seventeen women (63%) and 10 men (37%) with the mean age of 59.0 ± 7.1 years (47-71) were enrolled in this study. Chronic renal failure was diagnosed for the mean of 78.9 ± 24.3 months (33-130). Five patients (18.5%) died. Ventricular fibrillation and myocardial infarction were the causes of death in the early postoperative period in two patients. Two of the remaining three patients died because of cerebrovascular events, and one patient died because of an unknown cause. Ten patients (37%) had been using anticoagulate agents (warfarin) because of concomitant disorders such as deep vein thrombosis, operated valve disease, and arrhythmias. Catheter thrombosis and malfunction was determined in three cases (11.1%). Intra-atrial hemodialysis catheterization is a safe and effective life-saving measure for the patients with multiple venous failure and without any possibility of peritoneal dialysis or renal transplantation.