Subcutaneous implantable cardioverter defibrillator for dialysis patients: a strategy to reduce central vein stenoses and infections.

Central venous stenosis is a common complication of the transvenous leads associated with an implantable cardioverter defibrillator (ICD). Although epicardial leads have been reported to bypass this complication, their placement is much more invasive than the subcutaneous ICDs (SICDs) and requires the services of a cardiothoracic surgeon. Recent data have demonstrated successful defibrillation using an SICD. In this report, we present 4 long-term hemodialysis patients treated successfully with an SICD. 3 patients received the device for primary prevention of sudden cardiac death (cardiomyopathy with low ejection fraction). The patient in the fourth case had a prolonged QT interval and received the device for secondary prevention. 3 patients had an arteriovenous fistula, whereas 1 patient was dialyzing with a tunneled dialysis catheter. Insertion of an SICD is a minimally invasive procedure. By virtue of leaving the venous system untouched, this approach might offer the advantage of reduced risk of central venous stenosis and infection over an endocardial ICD with transvenous leads. SICD is not experimental; it has been approved by the US Food and Drug Administration and is currently being used in the United States and Europe.

Renal artery stenosis: to intervene, or not to intervene, "that is the question".

Renal artery stenosis (RAS) due to atherosclerosis continues to be a major cause of secondary hypertension. It can also lead to renal dysfunction due to ischemic nephropathy. While major clinical trials have emphasized that medical management should be preferred over angioplasty and stenting for the treatment of renal artery stenosis, clinical scenarios continue to raise doubts about the optimal management strategy. Herein, we present two cases that were admitted with hypertensive emergency and renal function deterioration. Medical therapy failed to control the blood pressure and in one patient, renal failure progressed to a point where renal replacement therapy was required. Both patients underwent angioplasty (for >90% stenosis) and stent insertion with successful resolution of stenosis by interventional radiology. Postoperatively, blood pressure gradually decreased with improvement in serum creatinine. Dialysis therapy was discontinued. At 4- and 8-month follow-up, both patients continue to do well with blood pressure readings in the 132-145/70-90 mmHg range. This article highlights the importance of percutaneous interventions in the management of atherosclerotic RAS and calls for heightened awareness and careful identification of candidates who would benefit from angioplasty and stent insertion.

A Case of Nephrotic Syndrome With Minimal-Change Disease and Waldenstrom's Macroglobulinemia.

Kidney disease is a rare complication of Waldenstrom's macroglobulinemia. We report a case of nephrotic syndrome and minimal change disease in a patient with biopsy proven Waldenstrom's macroglobulinemia. The patient presented with over 12 grams of proteinuria and was successfully treated with oral prednisone over the course of 4 weeks. Repeat serum protein electrophoresis as well as serum immunoelectrophoresis revealed no paraproteins, urine analysis was negative for protein or blood by dipstick and spot urine protein was 9 mg/dL with creatinine of 101 mg/dL at time of last office visit. This case illustrates the successful treatment with corticosteroids alone with prolonged complete remission.

Blood pressure recordings during hemodialysis access interventions: implications for acute management.

A retrospective study evaluating the pattern of blood pressure and its related complications before, during, and after percutaneous hemodialysis interventions was performed in patients presenting with asymptomatic hypertension. Hemodialysis patients undergoing percutaneous interventions including tunneled hemodialysis catheter insertion, percutaneous balloon angioplasty and thrombectomy procedure, and stage II hypertension (systolic blood pressure ≥160 mmHg) were included in this analysis. Blood pressure medications were not used while midazolam and fentanyl were routinely administered. Patients were followed for up to 4 weeks to monitor any complications. The mean blood pressure before, during, and after the procedures were 185 ± 18/96 ± 14, 172 ± 22/92 ± 15, and 153 ± 25/87 ± 14, respectively. There was a statistically significant difference between the blood pressure readings before and after the procedure (before = 185 ± 18/96 ± 14, after = 153 ± 25/87 ± 14; p = 0.001). None of the patients had a stroke, myocardial infarction, or acute pulmonary edema before, during, or after the procedure or during the 4-week follow-up period. A significant reduction in blood pressure was observed after the procedure without the administration of any antihypertensive medication. These results suggest that the reduction in blood pressure observed after percutaneous dialysis access interventions (particularly in the presence of midazolam and fentanyl) may make it unnecessary to treat asymptomatic hypertension prior to these procedures.

Radial artery harvest: a potential cause of arteriovenous access-associated hand ischemia.

Hand ischemia has multiple causes. In this article, we report an additional factor that can induce hand ischemia in hemodialysis patients. A 64-year-old white man with coronary artery disease underwent a coronary artery bypass graft procedure using the left radial artery as the bypass graft. Several months later, a left extremity Gracz fistula was created for arteriovenous access. Ever since dialysis was performed via the fistula the patient has experienced a cold hand and pain during dialysis that was somewhat relieved by wearing a woolen glove while on dialysis. Absence of the radial artery in the context of an ipsilateral arteriovenous access was highlighted as a possible etiology. A complete arteriography to determine the presence of stenoses, distal arteriopathy, and true steal was recommended, but the patient refused to undergo any investigation or procedure and instead decided to continue wearing the glove during the treatment. A plan for close follow-up and possible interventions in the event of worsening pain/ulceration was agreed upon. Radial artery harvest can result in hand ischemia if an ipsilateral arteriovenous access is created. We suggest that the contralateral extremity should be considered if an arteriovenous access is required to minimize this risk of this phenomenon.

Transvenous cardiac implantable electronic devices and hemodialysis catheters: recommendations to curtail a potentially lethal combination.

Abnormal renal function is an independent risk factor for cardiac implantable electronic device (CIED) infection. The risk of CIED infection increases as the degree of renal dysfunction worsens with the highest risk observed in patients with stage V chronic kidney disease. A significant portion of these patients use a tunneled hemodialysis catheter (TDC) for dialysis therapy. These devices are associated with very high rates of catheter-related bacteremia (1.6-5.5 episodes of bacteremia per 1000 catheter days), and have been known to cause infection of CIED indwelling in the bloodstream. In this context, the cardiac device is exposed to the risk of infection due to the presence of renal failure and episodes of bacteremia related to TDCs. Both increase the risk of CIED infection. Once infected, a cardiac rhythm device carries a marked increase in morbidity and mortality. In this context, the combination of a TDC and a CIED indwelling in the bloodstream becomes a potentially deadly combination. Recent data have emphasized that epicardial CIED implantation reduces cardiac device infection in TDC patients. This report highlights the risk of CIED infection in renal patients, presents TDC's contribution to the cardiac device infection, and suggests recommendations to minimize the risk of CIED infection in chronic hemodialysis patients dialyzing with a TDC.

Acute hemolysis with acute renal failure in a patient with valproic acid poisoning treated with charcoal hemoperfusion.

Hemoperfusion consists of the passage of anticoagulated blood through a column containing adsorbent particles. It was introduced in 1940 and refined from 1950 to 1970, and then introduced clinically for the treatment of acute intoxications between 1970 and 1980. Life-threatening valproic acid toxicity is an indication for coated charcoal hemoperfusion usually accomplished without complications, but we report a case of acute severe intravascular hemolysis during the time of hemoperfusion with coated charcoal column.

Metabolic and skeletal effects of low and high doses of calcium acetate in patients with preterminal chronic renal failure.

BACKGROUND: Secondary hyperparathyroidism commonly evolves, as the glomerular filtration rate falls. The metabolic and skeletal effects of a possible remedy, calcium acetate, have not been studied in patients with preterminal chronic renal failure. METHODS: Men with a mean creatinine clearance of approximately 30 ml/min took calcium acetate for 24 weeks at doses which provided 507 or 1,521 mg calcium/day with meals. Metabolic determinations were made at intervals of 4-8 weeks, and the bone mineral density (BMD) was measured at the beginning and at the end of the trial. RESULTS: The low-dose regimen produced no metabolic or skeletal effect. In subjects prescribed the high-dose regimen, the 24-hour urine phosphorus excretion fell from 0.53 mg/mg creatinine to values ranging from 0.34 to 0.41 mg/mg creatinine. The theoretical phosphorus threshold concentration rose by a maximum of 38.6%, and the serum phosphorus concentration did not change. The mean serum calcium concentration rose by a maximum of 7.2%. The mean fractional changes in parathyroid hormone and 1,25-dihydroxyvitamin D concentrations ranged from -27.0 to -39.6% and from -5.0 to -20.3%, respectively. The BMD increased at L1, L3, and L4. CONCLUSION: Calcium acetate prescribed to deliver 1,521 mg calcium/day with meals reduced parathyroid hormone and 1,25-dihydroxyvitamin D concentrations and increased lumbar BMD in men with preterminal chronic renal failure.