Paul G. Schmitz

Percutaneous renal biopsy in the 1990s: Safety, value, and implications for early hospital discharge

To determine the parameters associated with significant bleeding and to examine the value of performing a renal biopsy, we studied 83 consecutive patients, including 24 renal allograft recipients, who had undergone percutaneous renal biopsy. The patients were stratified into four groups according to the percentage of decline in their hematocrit (Hct) at 24 hours postbiopsy, as follows: 10% or greater (n = 21; 25%) and less than 10% decline (n = 62; 75%). The latter group was further subgrouped into 5% to 10% (n = 22) and less than 5% decline (n = 40). There was a significant decline in Hct postbiopsy, with a linear correlation between the decrease in Hct at 6 and 24 hours (R2 = 0.47; P < 0.0001), suggesting that the former was a predictor of the latter. There was a linear correlation between the number of passes and number of cores obtained for the first four passes, but an inverse correlation when five passes or greater were required. Interestingly, there was no correlation between bleeding (>10% decline in Hct) and the number of passes or cores obtained. Gross hematuria and blood transfusion requirement were each encountered in three patients (3.6%). Importantly, the prebiopsy clinical diagnosis was altered in 18 of 59 native kidney biopsies (33%) and 10 of 24 transplant biopsies (41%). We conclude that percutaneous renal biopsy using an automated spring-loaded gun device coupled with ultrasound guidance is a safe technique and provides essential clinical information. Importantly, patients with a stable Hct at 6 hours were at low risk for bleeding at 24 hours while hospitalized. It remains to be determined if these findings could be extrapolated to early discharge from hospital.

Serum Bicarbonate Is an Independent Determinant of Protein Catabolic Rate in Chronic Hemodialysis

Serum bicarbonate is an independent determinant of protein catabolic rate in chronic hemodialysis. Recent biochemical studies suggest that metabolic acidosis induces an increase in protein catabolic rate. Therefore, we retrospectively examined the relationship between serum total CO2, normalized protein catabolic rate (NPCR), midweek BUN, KT/V, and serum albumin in 70 chronic hemodialysis patients over a period of 4-6 months (total of 270 determinations). Multiple regression analysis indicated an independent and inverse association of tCO2 with NPCR (p < 0.0001). Subsequent analysis of the data indicated a nonlinear relationship between serum CO2 and NPCR. Indeed, the slope of the regression abruptly increased from -0.015 +/- 0.005 to -0.108 +/- 0.032 when analyzed for serum CO2 < or = 15 mEq/l. We conclude that metabolic acidosis may modulate protein kinetics in patients receiving maintenance hemodialysis. Moreover, this relationship appears to be exaggerated at moderate to severe reductions in tCO2. Thus, this analysis suggests that decreases in tCO2 have a detrimental effect on protein catabolism in stable patients maintained on chronic hemodialysis.

Aliskiren as an Alternative in a Patient With Life-Threatening ACE Inhibitor–induced Angioedema

kinases has yet to be identified. Finally, we are aware that the insulin receptor is not expressed in resting T cells. However, we cannot completely exclude the possibility that circulating T cells in allograft recipients may express some degree of functional activation despite long-term exposure to immunosuppressive drugs, bearing in mind the T cell response to insulin resistance and transient hyperglycemia, which occur commonly in immunosuppressed transplant recipients. Regardless, we wish to reinforce the point that our study aimed to explore in vivo the activation of the PI3K [phosphoinositide-3kinase]/Akt/mTOR/S6K pathway and its inhibition by rapamycin in peripheral blood mononuclear cells (ie, predominantly, if not exclusively, in monocytes), in an attempt to simulate alloantigenactivation of the mTOR pathway in T cells and its modulation by rapamycin. A direct measurement of the modulation of mTOR activity by rapamycin in T cells would require in vivo stimulation of the mTOR pathway by alloantigens or anti-CD3 antibodies, for example, which is obviously not feasible in humans. In conclusion, we are aware of the inherent limitations of our approach, but we were unable to devise any alternative strategy which might directly explore immune cell response in vivo. On the other hand, we would like to stress that our study is the first investigation which attempts to explore the pharmacodynamics of rapamycin and its correlation with blood concentrations of rapamycin in humans. We join Weichhart and colleagues in awaiting further and more specific strategies which will help determine the immunosuppressive consequences of rapamycin in the individual patient.

Progressive renal insufficiency. Office strategies to prevent or slow progression of kidney disease.

PREVIEW Although renal replacement therapies have revolutionized the management of renal failure, the morbidity and mortality associated with this condition remain unacceptably high. In this article, Dr Schmitz summarizes recent advances in our understanding of progressive renal insufficiency and discusses practical strategies that may prevent or significantly slow down the progression of kidney damage.

Safety and Efficacy of Transjugular Renal Biopsy Performed by Interventional Nephrologists

Obtaining renal tissue is often critical in the diagnosis and management of patients with renal disease of unknown etiology. Bleeding diathesis, liver disease, and obesity are common contraindications for percutaneous renal biopsy. In high‐risk patients, transjugular renal biopsy is believed to be a safe and effective procedure. This study reports the experience of an academic interventional nephrology program with performing transjugular renal biopsy. We performed a retrospective observational study of 23 patients with either acute or chronic kidney disease with contraindications for percutaneous renal biopsy. All transjugular renal biopsies were performed by interventional nephrologists at our university. We studied the efficacy and safety of transjugular renal biopsy in these patients. Twenty out of 23 (87%) of the procedures yielded adequate tissue for pathologic diagnosis. Three (13%) patients required blood transfusions, none required coil embolization or nephrectomy, and there were no deaths. Even though performing transjugular renal biopsy requires considerable technical expertise and must be performed in an interventional radiology suite, it can be safely and effectively performed by well‐trained interventional nephrologists to achieve pathological diagnosis.

Adrenocorticotropic hormone analog use for podocytopathies

Background Adrenocorticotropic hormone is being increasingly studied for treatment of various glomerulopathies, most notably membranous nephropathy. Less data are available regarding its use in idiopathic nephrotic syndrome (INS) secondary to minimal change disease (MCD) or focal segmental glomerulosclerosis (FSGS). We report here our experience with H.P. Acthar® Gel (repository corticotropin injection) as first-line or subsequent therapy in patients with INS. Methods Data were taken from three patients with MCD and ten patients with FSGS from around the US, who were treated with Acthar Gel as initial or subsequent therapy. Treatment was solely at the discretion of the primary nephrologist without a specific protocol. A complete response (CR) was defined as final urine protein-to-creatinine ratio <500 mg/g and a partial response (PR) as 50% decrease without rise of serum creatinine. Side effects and tolerability were noted. Results All three patients with MCD received Acthar Gel as second-line or later immunosuppressive (IS) therapy and all responded (one CR and two PRs). Two of the ten patients with FSGS received Acthar Gel as first-line IS therapy, while the other eight had failed multiple agents. Four of the ten patients with FSGS had responses, including two CRs and two PRs. The three patients with MCD tolerated therapy well without side effects. Five patients with FSGS tolerated therapy well, while five had various steroid-like side effects, resulting in therapy discontinuation in two patients. Conclusion Acthar Gel is a viable alternative IS agent for treatment of INS in patients intolerant or resistant to conventional therapy. More data are needed to better define its appropriate place.