Echocardiographic changes after arteriovenous fistula creation in hemodialysis patients.

BACKGROUND: Pulmonary hypertension (PH) is common in end-stage renal disease (ESRD) patients and is associated with increased all-cause and cardiovascular mortality in this group. There is scarce data on the long-term effect of arteriovenous fistula (AVF) creation on pulmonary hypertension (PH) and the reflected changes in echocardiographic measurements. MATERIALS AND METHODS: This is a retrospective study of 54 patients who underwent AVF creation between 2009 and 2014 and with echocardiographic evaluations before and after surgery. We analyzed pairwise changes in right ventricular systolic pressure (RVSP), right atrial pressure (RAP) during systole, left ventricular mass (LVM), tricuspid regurgitation (TR), mitral E/E' ratio, and ejection fraction (EF), as well as the factors that predicted change in RVSP after surgery. RESULTS: The median time for the preoperative echocardiogram was 0.3 years (interquartile range (IQR) 0.2 - 0.7 years) prior to AVF creation, while the follow-up echo was done 1.3 (0.6 - 2.1) years after surgery. 67% of the patients had RVSP > 37 mmHg at baseline. There was a significant reduction in RVSP after AVF creation compared to baseline (median 33 (IQR 26 - 43) vs. 46 mmHg, p = 0.0015), with 59% of the patients experiencing a decrease and 19% remaining stable. There were also significant decreases in LVM (201 (143 - 256) vs. 215 (163 - 276), p = 0.045) and RAP systole (10 (10 - 15) vs. 3 (3 - 8); p < 0.001) after surgery. Higher preoperative weight (p = 0.038) and RVSP (p = 0.006), and use of loop diuretics (p = 0.015) were significantly associated with improvement in RVSP after AVF creation. CONCLUSION: Our results suggest that AVF creation is associated with a significant reduction or stable measurements of RVSP in the ESRD population, likely due to an improvement in volume status.

An atypical case of hemodialysis access stent migration.

Endovascular stent fractures are commonly seen in arteries but are rare events in the venous system. Stents deployed in hemodialysis vascular accesses can fracture and migrate to proximal locations. Complications associated with stent fracture include in-stent stenosis and central vein stenosis. In this report, we present a unique case of a hemodialysis access stent fracture that migrated to the left ventricle and manifested with chest pain.

Acute interstitial nephritis following treatment with direct-acting antiviral agents in hepatitis C virus-infected patients: A case series.

Hepatitis C virus (HCV) infection has been associated with several extrahepatic adverse clinical outcomes, including an accelerated rate of loss of kidney function in patients with chronic kidney disease (CKD) and an increased mortality in patients with CKD and kidney failure on hemodialysis. Clinical trials using direct-acting antiviral (DAA) agents have uniformly achieved sustained viral response at 12 weeks (SVR12) rates of > 90% in the general population as well as in patients with CKD/kidney failure on hemodialysis. Sofosbuvir is a DAA prodrug that is phosphorylated into the active metabolite GS-461203, with subsequent dephosphorylation into the inactive metabolite GS-331007. The kidneys clear both sofosbuvir and GS-331007, and its use has been associated with worsening kidney function in some studies. In the HCV-TARGET study, patients with an estimated glomerular filtration rate (eGFR) < 30 mL/min at the initiation of sofosbuvir-based therapy had higher rates of deterioration of kidney function compared to patients with higher eGFR [1]. However, based on recent data demonstrating safety in patients with advanced CKD, the US Food and Drug Administration (FDA) approved the use of sofosbuvir-containing regimens in patients with CKD 4/5 (eGFR of less than 30 mL/min/1.73m2) and end-stage renal disease (ESRD) in late 2019. The current report describes 8 HCV-infected patients who developed acute kidney injury (AKI) with biopsy-proven acute interstitial nephritis (AIN) temporally associated with the use of DAAs. The mean age of the group was 61.3 (± 6 years). The most common HCV genotype (GT) was 1a (n = 7). The DAA formulations were sofosbuvir/ledipasvir (n = 5), elbasvir/grazoprevir (n = 2), and sofosbuvir/simeprevir (n = 1). All patients achieved an SVR12. The mean serum creatinine at the initiation of DAA treatment was 1.5 mg/dL (± 0.6) and increased to 2.03 mg/dL (± 0.7) by the last day of DAA administration. The kidney biopsies were performed at a mean of 320 days (± 247) after achieving an SVR12, at which point the mean creatinine had increased to 2.3 mg/dL (± 1.4). All patients received a course of high-dose corticosteroids after the diagnosis of AIN was confirmed by biopsy. Serum creatinine levels at 3 and 6 months following the completion of steroid therapy were 2.8 (± 1.2) and 3.1 mg/dL (± 1.5), respectively. Three patients had worsening CKD and progressed to kidney failure requiring hemodialysis. These results are consistent with earlier studies demonstrating the efficacy of the DAAs in HCV-infected CKD patients. Of note, the demonstration of AIN in these patients may explain some of the AKI events reported with the use of DAAs in patients with CKD.

Assessment of left ventricular mass changes after arteriovenous fistula surgical banding in end-stage renal disease.

Left ventricular hypertrophy (LVH) is a multifactorial complication frequently seen in patients with advanced chronic kidney disease. An arteriovenous fistula (AVF) is the preferred method for hemodialysis access. Once functional, AVFs demonstrate better patency rates and fewer complications when compared to other forms of vascular access. AVFs have been implicated in cardiac remodeling, but it is controversial whether those changes can be reversed by surgical ligation or blood flow reduction. In this study, we describe a cohort of asymptomatic patients with LVH who underwent AVF banding with a two-dimensional-echocardiogram done before and after the intervention to evaluate the association between AVF surgical banding and left ventricular mass (LVM) changes. Our results show that AVF surgical banding did not alter the left ventricular mass index (LVMI) with a mean prebanding LVMI of 70.3 ± 57.5 g/m2 and mean postbanding LVMI of 81.9 ± 55.9 g/m2, (P = 0.4). Our study shows that AVF flow reduction by surgical banding did not alter LVMI, and therefore LVH, in end-stage renal disease patients who have not yet shown clinical manifestations of cardiac disease.

Arteriovenous fistula outcomes in human immunodeficiency virus-positive patients.

Arteriovenous fistula (AVF) remodeling is an active area of research in vascular biology given the high rates of primary failure, complications, and cost burden for the health-care system. Comorbidities such as diabetes and different types of vascular disease are known to influence AVFs outcomes. However, little is known about the effects of immunosuppression, particularly human immunodeficiency virus (HIV) infection, on AVF primary failure and patency. This retrospective study assessed the impact of HIV infection and T-cell counts on AVF outcomes. Using a retrospective cohort of 495 patients, we compared the risk of AVF primary failure and primary unassisted patency on HIV-positive and nonimmunocompromised individuals using logistic regressions and Cox proportional hazard models. Within the HIV-infected subset (n = 43), we analyzed the association between immunological parameters such as T-cell counts and primary failure. Positive predictors of primary failure were HIV infection [odds ratio (OR) = 3.09, P = 0.002] and history of a previous AVF (OR = 2.18, P = 0.003). However, there was no difference in primary unassisted patency between HIV-positive and negative individuals after excluding primary failure cases. There was no association between T-cell subset counts and AVF outcomes. Our results indicate that HIV-positive individuals have a higher risk of AVF primary failure than nonimmunocompromised patients. However, this increased susceptibility is not explained by the degree of immunosuppression.

Vitamin B1 for type B metabolic acidosis: An underrecognized approach.

Lactic acidosis is a life-threatening and rather common complication and reason for consultation to the nephrologist. The cause for this condition is usually thought to be secondary to hypoperfusion and ischemia collectively. However, many other rare causes have been described, yet there is little awareness of these, consequently delaying optimal care. We present a multifactorial case of lactic acidosis due to thiamine deficiency, liver disease, and lymphoma; all underrecognized causes of Type B lactic acidosis.

Treatment and management options for the hepatitis C virus infected kidney transplant candidate.

A substantial body of literature has unequivocally established that prevalent hepatitis C virus infection in chronic kidney disease (CKD), end stage renal disease (ESRD) and kidney transplant recipients is associated with a negative impact on patient survival. As a consequence of remarkable work that explained the details of the hepatitis C virus (HCV) genome, a class of drugs referred to as the direct-acting antiviral (DAA) agents were developed that targeted specific key sites in viral replication. Large clinical trials in the HCV-infected general population followed soon after that demonstrated cure rates exceeding 95%. Treatment paradigms have been further refined and expanded to populations of patients that were initially excluded from the large pivotal trials. This includes the CKD and ESRD patients for whom there are now safe and effective DAAs available as well. In this context, the focus of decision making has shifted from initially demonstrating safety and efficacy to now identifying which patient should receive therapy and at what point in their CKD/ESRD journey. The specific issue of timing of treatment is particularly relevant to the HCV-infected ESRD patient who is being considered for kidney transplantation. The option of treating with DAAs prior to the transplant or alternatively delaying therapy and treating in the posttransplant period will be influenced by several factors, including patient preference, the extent of liver injury, the availability of a living or deceased donor, and more recently the option of transplanting a kidney from HCV-positive donor. The latter has been associated with the advantage of shortened waiting times and expansion of the organ donor pool. The optimal timing and choice of therapy will be the result of a decision that has been individualized for each patient as a consequence of a process of clear communication involving the patient, primary care physician, nephrologist, gastroenterologist (GI)/hepatologist, and local transplant center.

The potential role of complements in cocaine-induced thrombotic microangiopathy.

Thrombotic microangiopathy (TMA) is a rare disorder characterized by microvascular injury and occlusion resulting in tissue ischemia and dysfunction. TMA occurs in a variety of settings including cocaine use. Although cocaine is widely used in the United States, cocaine-associated TMA is only rarely reported. Therefore, other factors may predispose cocaine users to the development of TMA. Emerging evidence indicates that cocaine activates complements. Therefore, complement activation may contribute to the development of cocaine-induced TMA. Here, we report a cocaine user who presented with renal failure. Renal biopsy demonstrated TMA. Laboratory tests revealed reduced serum complement C3 and normal complement C4 levels indicative of alternative complement activation. We postulate that complement activation is involved in the pathogenesis of cocaine-induced TMA.

Phaeohyphomycosis due to Exophiala infections in solid organ transplant recipients: Case report and literature review.

This case report and literature review underscores the cutaneous presentations of phaeohyphomycosis in the solid organ transplant population. Increased cognizance with prompt identification is critical. The therapy and clinical outcomes of phaeohyphomycosis, caused by the Exophiala genus, in the solid organ transplant population, is analyzed to examine optimal care. This review highlights the inherent difficulties in providing the appropriate duration of antifungal therapy to avoid relapsing infections in immunosuppressed patients.