A review of evolving dialysis catheter technologies

Dialysis catheters continue to play a vital role in the delivery of hemodialysis to patients for both temporary vascular access, serving as a bridge to permanent access, and for long-term access for patients with end-stage renal disease (ESRD). During the past decade, there has been an emergence of technological advancements in the design of dialysis catheters in an attempt to reduce catheter malfunction, decrease infection rates, and improve their long-term efficiency. New improvements in catheter design are aimed at translating into improved catheter performance. This review article summarizes some of the novel catheter designs developed within the last decade.

Pleural effusion in a peritoneal dialysis patient

A 34-year-old female presented with end-stage renal disease (ESRD) treated by peritoneal dialysis (CAPD) complained of a dry cough. Chest X-ray and chest computed tomography (CT) scan revealed massive right hydrothorax. Because the glucose concentration of pleural fluid was markedly high compared with that of serum, we performed isotope and contrast peritoneography. We used CT for localizing it. MRI was also trying to show transdiaphragmatic leakage in peritoneoflural fistula. Temporary discontinuation of CAPD, tetracycline instillation into the pleural space and surgical patch grafting of the diaphragmatic leak have all been described. A novel method may be video-assisted talc pleurodesis.

Prevalence of occult hepatitis B virus infection

Occult hepatitis B virus (HBV) infection (OBI) is characterized by the persistence of HBV DNA in the liver tissue in individuals negative for the HBV surface antigen. The prevalence of OBI is quite variable depending on the level of endemic disease in different parts of the world, the different assays utilized in the studies, and the different populations studied. Many studies have been carried out on OBI prevalence in different areas of the world and categories of individuals. The studies show that OBI prevalence seems to be higher among subjects at high risk for HBV infection and with liver disease than among individuals at low risk of infection and without liver disease.

Importance of early electrocardiographic recognition and timely management of hyperkalemia in geriatric patients

Hyperkalemia is a potentially life-threatening electrolyte imbalance that can be difficult to diagnose due to the paucity of specific signs and symptoms. Because hyperkalemia can lead to sudden death from cardiac arrhythmias and asystole, any patient whose history, physical examination or laboratory studies raise clinical suspicion of hyperkalemia requires an immediate 12-lead electrocardiogram to ascertain whether electrocardiographic manifestations of electrolyte imbalance are present. The current report describes a case involving an elderly man who developed hyperkalemia secondary to acute-on-chronic kidney injury. Factors affecting the vulnerability of geriatric patients to hyperkalemia, the electrocardiographic manifestations of elevated serum potassium levels, and the importance of timely recognition and management are discussed. Understanding the factors that contribute to hyperkalemia, timely recognition of electrocardiogram changes and timely initiation of appropriate therapy are all critical in the approach to hyperkalemia in the geriatric patient.

Crush Injuries and the Crush Syndrome

Combat related injuries bring untold misery to the victims and their loved ones. While injuries to vital organs cause immediate death, delayed mortality after reaching a hospital may occur due to several reasons, rhabdomyolysis or the crush syndrome being the most important. Crush syndrome predominantly affects the kidneys leading to renal failure, but the clinical picture may include acute respiratory distress syndrome, dyselectrolytaemia, disseminated intravascular coagulation, hypovolemic shock, arrhythmias and psychological trauma. Rescue, resuscitation and rehabilitation are onerous tasks and so a coordinated strategy with well trained team of professionals through various chains of evacuation is advocated. This article addresses these issues drawing upon the experience of the writer in combat casualty care in active operations.

Percutaneous intervention in axillary loop-configured arteriovenous grafts for chronic hemodialysis patients

Objective

The purpose of this study was to evaluate the fistulographic features of malfunctioning axillary loop-configured arteriovenous grafts and the efficacy of percutaneous interventions in failed axillary loop-configured arteriovenous grafts.

Materials and Methods

Ten patients with axillary loop-configured arteriovenous grafts were referred for evaluation of graft patency or upper arm swelling. Fistulography and percutaneous intervention, including thrombolysis, percutaneous transluminal angioplasty and stent placement, were performed. Statistical analysis of the procedure success rate and the primary and secondary patency rates was done.

Results

Four patients had graft related and subclavian venous stenosis, two patients had graft related stenosis and another four patients had subclavian venous stenosis only. Sixteen sessions of interventional procedures were performed in eight patients (average: 2 sessions / patient) until the end of follow-up. An interventional procedure was not done in two patients with central venous stenosis. The overall procedure success rate was 69% (11 of 16 sessions). The post-intervention primary and secondary patency rates were 50% and 63% at three months, 38% and 63% at six months and 25% and 63% at one year, respectively.

Conclusion

Dysfunctional axillary loop-configured arteriovenous grafts almost always had subclavian venous and graft-related stenosis. Interventional treatments are helpful to overcome this and these treatments are expected to play a major role in restoring and maintaining the axillary loop-configured arteriovenous loop grafts.

Application of cystatin C reduction ratio to high-flux hemodialysis as an alternative indicator of the clearance of middle molecules

BACKGROUND/AIMS

Although high-flux (HF) dialyzers with enhanced membrane permeability are widely used in current hemodialysis (HD) practice, urea kinetic modeling is still being applied to indicate the adequacy of both low-flux (LF) and HF HD. In comparison with urea (molecular weight, 60 Da) and beta(2)-microglobulin (beta(2)MG, 12 kDa), cystatin C (CyC, 13 kDa) is a larger molecule that has attractive features as a marker for assessing solute clearance. We postulated that CyC might be an alternative for indicating the clearance of middle molecules (MMs), especially with HF HD.

METHODS

Eighty-nine patients were divided into LF and HF groups. Using single pool urea kinetic modeling, the urea reduction ratio (URR) and equilibrated Kt/V(urea) (eKt/V(urea)) were calculated. The serum CyC concentrations were measured using particle-enhanced immunonephelometry. As indices of the middle molecular clearance, the reduction ratios of beta(2)MG and CyC were calculated.

RESULTS

The beta(2)MG reduction ratio (beta(2)MGRR) and CyC reduction ratio (CyCRR) were higher in the HF group compared to the LF group. However, the URR and eKt/Vurea did not differ between the two groups. The CyCRR was significantly correlated with the eKt/V(urea) and beta(2)MGRR (r = 0.47 and 0.69, respectively, both p < 0.0001).

CONCLUSIONS

Compared to the LF dialyzer, the HF dialyzer removed CyC and beta(2)MG more efficiently. Unlike the beta(2)MGRR, the CyCRR was correlated with the eKt/V(urea) and beta(2)MGRR. This study suggests a role for the CyCRR as an alternative indicator of the removal of MMs.

The effect of simvastatin on lowering panel reactive antibody titer in sensitized dialysis patients: a randomized placebo controlled clinical trial

BACKGROUND

Patients with panel reactive antibodies (PRA) have many difficulties to find a crossmatch-negative kidney for transplantation and are at a higher risk of post-transplantation rejection.

OBJECTIVE

To evaluate the effect of simvastatin on PRA and post-transplant outcome of these sensitized patients.

METHODS

82 patients with end-stage renal disease (ESRD) with a PRA ≥25% were evaluated. In a one-year follow-up, the patients were treated with simvastatin. These patients were compared with 82 matched controls receiving placebo tablets. At the end of the second and 12(th) month, PRA was rechecked in all patients. Those patients who underwent transplantation continued to take simvastatin six months after transplantation. Serum creatinine levels were checked at monthly intervals post-operation.

RESULTS

The mean±SD PRA level at the end of the second month was 36.63%±31.14% and 45.34%±24.36% in cases and controls, respectively (P=0.012). Seven patients in the case group and 10 in the control group were lost to follow-up. The remaining patients continued to take simvastatin for 12 month. The mean±SD PRA level at the end of the 12(th) month was 24.02%±31.04% in cases and 43.15%±26.56% in controls (P=0.001). 25 patients underwent renal transplantation and continued to receive simvastatin 6 months after transplantation. These patients were matched with 25 controls treating with placebo. The mean±SD creatinine level 6 months after kidney transplantation was 2.05±1.14 mg/dL and 3.15±1.09 mg/dL in cases and controls consecutively (P=0.02).

CONCLUSION

Simvastatin can be safely used to lower PRA and improve post-transplantation outcomes.

Transition metal ion capture using functional mesoporous carbon made with 1,10-phenanthroline

Functional mesoporous carbon has been built using 1,10-phenanthroline as the fundamental building block, resulting in a nanoporous, high surface area sorbent capable of selectively binding transition metal ions. This material had a specific surface area of 870 m2/g, an average pore size of about 30 Å, and contained as much as 8.2 wt% N. Under acidic conditions, where the 1,10-phenanthroline ligand is protonated, this material was found to be an effective anion exchange material for transition metal anions like [Formula: see text] and [Formula: see text]. 1,10-Phenanthroline functionalized mesoporous carbon ("Phen-FMC") was found to have a high affinity for Cu(II), even down to a pH of 1. At pHs above 5, Phen-FMC was found to bind a variety of transition metal cations (e.g. Co(II), Ni(II), Zn(II), etc.) from filtered ground water, river water and seawater. Phen-FMC displayed rapid sorption kinetics with Co(II) in filtered river water, reaching equilibrium in less than an hour, and easily lowering the [Co(II)] to sub-ppb levels. Phen-FMC was found to be more effective for transition metal ion capture than ion-exchange resin or activated carbon.

Psychiatric issues in renal failure and dialysis

This article aims to bring to the fore, issues regarding the interface of psychiatry and renal failure. Depression, anxiety, suicide and delirium are common complications observed in patients with renal failure. Pharmacological management of these problems need stringent monitoring on part of the psychiatrist. This article examines the various complications that may be observed in patients with renal failure while discussing treatment approaches and also emphasizing the need for interdisciplinary team work in improving the quality of life of patients with renal failure and those on dialysis.

Indirect Complication of AV Graft Thrombectomy-Thrombolysis Secondary to Previously Attempted Placement of a Temporary Hemodialysis Catheter

Common interventional procedures on frequently encountered patients may wrongly place one on a track that deals with the task at hand while not assessing the global patient. Nowhere is this more problematic than in the dialysis population where in the course of achieving and maintaining vascular access, the interventionist becomes exceedingly familiar with each patient and his or her particular clinical history. Unfortunately, events that may have occurred in the past few hours may rarely be overlooked. We present a case of patient mortality as an indirect result of an upper extremity polytetrafluoroethylene graft thrombectomy-thrombolysis procedure that followed attempted nontunneled catheter placement via the groin.

Hepatorenal syndrome

Hepatorenal syndrome (HRS) is a “functional” and reversible form of renal failure that occurs in patients with advanced chronic liver disease. The distinctive hallmark feature of HRS is the intense renal vasoconstriction caused by interactions between systemic and portal hemodynamics. This results in activation of vasoconstrictors and suppression of vasodilators in the renal circulation. Epidemiology, pathophysiology, as well as current and emerging therapies of HRS are discussed in this review.

Pharmacomechanical Thrombolysis of Dialysis Access Grafts Using the MTI Castañeda Over-the-Wire Brush Catheter and Reteplase

Pharmacomechanical thrombolysis (PMT) has emerged as an alternate treatment used in most patients presenting with a thrombosed hemodialysis graft. Although the gold standard, surgical revision of thrombosed hemodialysis grafts is reserved for those cases of recurrent thrombosis despite the use of percutaneous techniques and for complicated cases after PMT. Nevertheless, as for every other procedure, PMT has its own set of limitations and cost issues. New mechanical devices have begun to emerge on the market to help accelerate clot dissolution with or without thrombolytic medications. These devices have decreased the time required to lyse clot and decrease the overall cost of percutaneous treatment. This article describes the use of the Microtherapeutics, Inc. (MTI) Castañeda over-the-wire brush and our experience with this device in the treatment of the clotted hemodialysis graft.

The Role of Interventional Radiology in a Comprehensive Hemodialysis Program: The Access Surgeon's View

The successful hemodialysis program addressing the complex needs of the dialysis patient population employs a collaborative effort among the medical nephrologist, access surgeon, and interventional radiologist. It is imperative that all team members understand the basic tenets of hemodialysis access and afford open and continuous communication to achieve the best results. This monograph will serve to highlight the access surgeon's view of the optimal integration of the interventional radiologist in the development and maintenance of a successful hemodialysis program.