Sidney Kobrin

Single-center Experience with the Arrow-Trerotola Percutaneous Thrombectomy Device in the Management of Thrombosed Native Dialysis Fistulas

PURPOSE The present study sought to evaluate the performance of the Arrow-Trerotola Percutaneous Thrombolytic Device (PTD) in the treatment of native fistula thrombosis in a U. S. hemodialysis population. Specifically, the technical success, clinical success, complication rate and type, primary and secondary patency rates, effect of adjunctive thrombolytic therapy, and any variables that affected outcomes of procedures in which this device was used were analyzed. MATERIALS AND METHODS Forty-two patients with 44 thrombosed native fistulas (17 radiocephalic, 10 brachiocephalic, 10 transposed or superficialized, five graft/fistula hybrids, and two leg fistulas) were treated with 62 mechanical thrombolysis procedures with use of the PTD. All patients had large clot burden. The device type was recorded in 43 procedures: standard (n = 21), over-the-wire (OTW; n = 19), or both (n = 3). No device was used in two cases because of inability to cross the anastomosis. Adjunctive therapies (n = 18) included the use of tissue plasminogen activator (tPA; n = 16) and deployment of the AngioJet device with (n = 1) or without tPA (n = 1). Stents were inserted in four procedures. Outcome variables included technical and clinical success, complications, and primary and secondary patency. Cox proportional-hazards regression and Kaplan-Meier analyses were performed. RESULTS The technical success rate was 87% (54 of 62) and the clinical success rate was 79% (49 of 62). Percutaneous transluminal angioplasty was performed in all but two procedures. Complications occurred in 13% of procedures (n = 8); three resulted in technical failure. The primary patency rates were 38% at 6 months and 18% at 12 months; secondary patency rates were 74% and 69%, respectively. Outcomes were not affected by adjunctive techniques, fistula type, age of fistula, device type (ie, OTW vs standard), or patient sex. Secondary patency was superior when no residual clot or stenosis was present (P = .003). CONCLUSIONS The PTD is effective for percutaneous treatment of thrombosed hemodialysis fistulas, with good short- and long-term outcomes in a U.S. population. Within the limitations of a retrospective study with a small sample size, use of an adjunctive thrombolytic agent did not appear to improve results compared with the use of the device alone.

Transcatheter and Surgical Aortic Valve Replacement in Dialysis Patients: A Propensity-Matched Comparison.

BACKGROUND Transcatheter aortic valve replacement (TAVR) clinical trials in North America excluded patients on dialysis and, consequently, the outcomes of TAVR in dialysis-dependent patients remain unknown. METHODS All Medicare fee-for-service patients undergoing TAVR (n = 5,005) or surgical aortic valve replacement (SAVR) (n = 32,634) between January 1, 2011, and November 30, 2012, were identified using procedural codes collected by the Centers for Medicare & Medicaid Services. Dialysis status and comorbidities were identified using diagnosis codes present on arrival for TAVR hospitalization. Patients supported on dialysis who underwent TAVR (n = 224) were compared with non-dialysis patients who underwent TAVR as well as a propensity-matched group of contemporaneous dialysis patients who underwent SAVR (n = 194 pairs). RESULTS The TAVR patients on dialysis were younger than non-dialysis TAVR patients (79.2 years vs 84.1 years; p < 0.01) but had higher prevalence of comorbidities. Dialysis TAVR patients had increased mortality at 30 days (13% vs 6%, p < 0.01) and significantly worse survival by Kaplan-Meier analysis. Multivariable regression found dialysis to be independently associated with worse survival (hazard ratio, 1.73; 95% confidence interval, 1.33% to 2.25%, p < 0.01) in TAVR patients. Propensity-matched dialysis SAVR and dialysis TAVR patients had no significant differences in demographic or risk factors. Matched dialysis TAVR patients had shorter length of stay (6 interquartile range, 4 to 10] vs 10 [IQR 7 to 18] days; p < 0.01) and comparable survival. CONCLUSIONS TAVR in dialysis patients is associated with decreased survival compared with non-dialysis patients; however, it is comparable with SAVR in high risk dialysis patients based on a propensity-matched comparison.

Incidence and management of percutaneous transluminal angioplasty-induced venous rupture in the "fistula first" era.

PURPOSE Percutaneous transluminal angioplasty (PTA)-induced venous rupture is a common complication of hemodialysis access interventions. The authors sought to determine if venous rupture rates and management differed between grafts and fistulas, and in the fistula subset, between transposed and nontransposed fistulas. MATERIALS AND METHODS Patients experiencing venous rupture during hemodialysis PTA over a 5-year period were identified. Of 1,985 hemodialysis interventions, 75 ruptures occurred in 69 patients (46 women) with a mean age of 63 years (range, 31-88 y). Rupture rates, proportion of successful treatments, and treatment type and number (ie, balloon tamponade, stent, covered stent) were determined. RESULTS Rupture was more common in fistulas overall (5.6%, 39 of 693) compared with grafts (2.8%, 36 of 1,292; P = .002), in transposed (10.7%, 20 of 187) compared with nontransposed fistulas (3.8%, 19 of 506; P = .001), and in transposed fistulas compared with grafts (P = .0001). There was no significant difference between nontransposed fistulas and grafts. Treatment success (ie, resolution of extravasation) was the same among groups: 69% (27 of 39) in fistulas overall, 70% (14 of 20) in transposed fistulas, 68% (13 of 19) in nontransposed fistulas, and 72% (26 of 36) in grafts. There was a greater need for stents in grafts (38.9%, 14 of 36) compared with fistulas (12.8%, five of 39; P = .003). CONCLUSIONS PTA-induced rupture is more common in fistulas than grafts, and this effect seems nearly entirely driven by transposed fistulas. Although rupture treatment in fistulas of all types yielded similar success to grafts, and graft ruptures were more difficult to treat than fistula ruptures, the high rupture rates in transposed fistulas attest to the increased difficulty of treating this subset of fistulas.

Quinine--a tonic too bitter for hemodialysis-associated muscle cramps?

Hemodialysis patients are susceptible to muscle cramps, both during dialysis sessions as well as in the interdialytic interval. These cramps are often very painful, disruptive to the dialysis treatment, and adversely affect quality of life. There is no well‐defined means of preventing or treating these cramps. Quinine sulfate has been used with apparent success in some patients, but the Food and Drug Administration recently ordered the cessation of marketing of unapproved quinine formulations and advised consumers to avoid “off‐label” use of quinine for cramps. We review the causes and consequences of hemodialysis‐associated cramps, and discuss possible preventive measures and treatments.

Staff security and work pressure: Contrasting patterns of stability and change across five dialysis units

Differences among clinical care units in social dynamics and social organization are associated with differences in the clinical course of patients with a range of chronic illness. These differences are also associated with well-being of staff members. Recent attention has focused on understanding these differences among units with an eye towards correcting deficiencies and enhancing strengths of clinical care units. The current study sought to delineate the effect of social and organizational dynamics unique to each unit on staff perceptions of the security of their relationships with other staff and their perceived work pressure. The unit as a major source of differences among staff subjects was compared with the impact of ethnic identity, of work in the morning shift vs other shifts, and of professional role. Results confirmed that unit membership was, by far, the most important correlate of staff perceptions of the unit, particularly those concerning security of relationships with others and perceived work pressure. Moreover, the results suggested that unit differences in perceived security were due to differences among units in long standing turmoil within the unit or long standing problematic ties between the unit and the larger institution which controls it. However, perceived work pressure seems more transient and may reflect the challenge of shorter-term fluctuations in the demands of patient care.

Dramatic Recovery of Renal Function After 6 Months of Dialysis Dependence Following Surgical Correction of Total Renal Artery Occlusion in a Solitary Functioning Kidney

Revascularization of renal artery stenosis for the treatment of hypertension is an established procedure. In selected clinical scenarios, successful revascularization procedures may preserve or restore renal function. We present a 31-year-old man who underwent successful renal revascularization of a solitary functioning kidney after being dialysis dependent for approximately 190 days. He had dramatic improvement of renal function and has remained off dialysis since his surgery 18 months ago. He continues to have severe but controllable hypertension.

Extracorporeal Treatment of Cast Nephropathy

Acute kidney injury (AKI) is common in patients with multiple myeloma (MM), most commonly caused by cast nephropathy resulting from precipitation of free light chains (FLC) in renal tubules. AKI may be irreversible and require dialysis and predicts a poor prognosis. Reduction in serum FLC concentration is thought to be associated with improved likelihood of kidney function recovery in MM patients with AKI. Plasma exchange (PE), by removing circulating FLC, has been used as a treatment modality to improve kidney function in MM, although its efficacy remains uncertain. Extracorporeal treatment with extended high cutoff hemodialysis (HCO‐HD) has also recently been studied as a potentially more effective means of FLC removal. Both PE and HCO‐HD may be beneficial in some patients, but only when used as adjuncts to successful chemotherapy. Further research is necessary to establish the specific efficacy of each of these extracorporeal methods in the treatment of cast nephropathy.

Endocarditis Is a Common Stroke Mechanism in Hemodialysis Patients

Background and Purpose— Hemodialysis patients are at high risk for ischemic stroke, and previous studies have noted a high rate of cardioembolism in this population. The aim of this study was to determine ischemic stroke causes among hemodialysis patients and elucidate specific cardioembolic stroke mechanisms. Methods— This study is a retrospective cross-sectional study of hemodialysis patients admitted with acute stroke to the University of Pennsylvania Health System between 2003 and 2010. Strokes were classified using modified Trial of Org 10 172 in Acute Stroke Treatment (TOAST) criteria as large vessel, cardioembolism, small vessel, atypical, multiple causes, or cryptogenic. Cardioembolic strokes were further characterized for specific mechanism. Results— We identified 52 patients hospitalized with acute stroke while receiving hemodialysis. Mean age was 64±13 years, 56% were female, and 67% were black. Stroke subtypes included 3 (6%) large vessel, 20 (38%) cardioembolism, 6 (11%) small vessel, 3 (6%) other, 4 (8%) with multiple causes, and 16 (31%) were unknown. Among patients who had an echocardiogram performed, 5 of 52 (10%; 95% confidence interval, 1%–18%) had a patent foramen ovale. Cardioembolic stroke mechanisms included 6 with infective endocarditis (accounting for 12% of all strokes). Conclusions— Cardioembolism and cryptogenic stroke are the predominant stroke mechanisms among hemodialysis patients. Infective endocarditis was identified frequently relative to other stroke cohorts, and a raised index of suspicion is warranted in the hemodialysis population.

A clone-directed approach may improve diagnosis and treatment of proliferative glomerulonephritis with monoclonal immunoglobulin deposits

The optimal treatment for the monoclonal gammopathies of renal significance is not known, but there is consensus among experts that treatment should be specific for the underlying clone. The majority of patients with proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMID) do not have an identifiable clone, and prior studies have found poor renal outcomes for patients with PGNMID treated with a variety of regimens. Here we present a retrospective case series of 19 patients with PGNMID with a more uniform, clone-directed approach. A circulating paraprotein was detected in 37% of patients, and the overall clone detection rate was 32%. Treatment was directed at the underlying clone or, for patients without a detectable clone, empirically prescribed to target the hypothesized underlying clone. Of the 16 patients who underwent treatment, the overall renal response rate was 88%, and 38% of patients experienced complete renal response (proteinuria reduction to under 0.5 gm/24 hours) with initial treatment. All patients were End Stage Renal Disease-free at last follow-up (median 693 days after diagnosis), and treatment was well tolerated. Thus, a clone-directed approach may lead to novel, targeted treatment strategies that could significantly improve outcomes for patients with PGNMID.

Heme-pigment nephropathy after transurethral resection of prostate cancer

Introduction: Transurethral resection of the prostate is one of the most common surgical procedures performed in men to relieve bladder outlet obstruction, most often due to benign prostatic hyperplasia. However, transurethral resection of the prostate may also be used in patients with metastatic prostate cancer who have bladder outlet obstruction. Acute kidney injury after transurethral resection of the prostate has been described and attributed to a variety of mechanisms, including acute tubular necrosis, rhabdomyolysis, and hemolysis with heme-pigment nephropathy. However, to our knowledge, no case of kidney biopsy-proven heme-pigment nephropathy due to hemolysis from a transurethral resection of the prostate procedure has been published to date. Case description: We describe a case of an 82-year-old man with metastatic prostate cancer who presented with severe oliguric renal failure 2 weeks after transurethral resection of the prostate for bladder outlet obstruction. Laboratory studies showed evidence of hemolysis, and a kidney biopsy showed heme-pigment cast nephropathy. Conclusions: We hypothesize that the patient’s kidney injury was induced by hemolysis resulting from rapid absorption of hypotonic fluid administered during the transurethral resection of the prostate procedure. Patients with prostate cancer undergoing transurethral resection of the prostate for bladder outlet obstruction may experience severe complications related to rapid absorption of hypotonic fluid. Our case illustrates the importance of nephrology evaluation and kidney biopsy in patients with benign and malignant prostate conditions who experience post-transurethral resection of the prostate syndrome and acute kidney injury in order to better characterize these complications, and to develop preventative strategies for future cases.