Nephrology considerations in the management of durable and temporary mechanical circulatory support

Durable and temporary mechanical circulatory support (MCS) use is growing for a range of cardiovascular indications. Kidney dysfunction is common in persons evaluated for or receiving durable or temporary MCS, and portends worse outcomes. This kidney dysfunction can be due to pre-existing kidney chronic kidney disease (CKD), acute kidney injury (AKI) related to acute cardiovascular disease necessitating MCS, AKI due to cardiac procedures, and due to acute and chronic MCS effects and complications. Durable MCS, with implantable continuous flow pumps, is used for long-term support in advanced HF refractory to guideline directed medical and device therapy, either permanently or as a bridge to heart transplantation. Temporary MCS-encompassing in this review intra-aortic balloon pumps (IABPs), axial flow pumps, centrifugal flow pumps, and venoarterial ECMO-is used for diverse situations: high risk percutaneous coronary interventions (PCI), acute decompensated heart failure (HF), cardiogenic shock, and resuscitation following cardiac arrest. The wide adoption of MCS makes it imperative to improve understanding of the effects of MCS on kidney health/function, and of kidney health/function on MCS outcomes. The complex structure and functions of the kidney, and the complex health states of individuals receiving MCS, makes investigations in this area challenging, and current knowledge is limited. Fortunately, the increasing nephrology toolbox of non-invasive kidney health/function assessments may enable development and testing of individualized management strategies and therapeutics in the future. We review technology, epidemiology, pathophysiology, clinical considerations, and future directions in MCS and nephrology.

Extrarenal Effects of Aldosterone on Potassium Homeostasis

The role of aldosterone in regulating K+ excretion in the distal nephron is well established in kidney physiology. In addition to effects on the kidney, aldosterone modulates K+ and Na+ transport in salivary fluid, sweat, airway epithelia, and colonic fluid. More controversial and less well defined is the role of aldosterone in determining the internal distribution of K+ across cell membranes in non-transporting epithelia. In vivo studies have been limited by the difficulty in accurately measuring overall K+ balance and factoring in both variability and secondary changes in acid-base balance, systemic hemodynamics, and other K+-regulatory factors such as hormones and adrenergic activity. Despite these limitations, the aggregate data support a contributory role of aldosterone along with insulin and catecholamines in the normal physiologic regulation of internal K+ distribution. The authors speculate differences in tissue sensitivity to aldosterone may also contribute to differential tissue response of cardiac and skeletal muscle to conditions of total body K+ depletion.

Systemic Profile of Cytokines in Arteriovenous Fistula Patients and Their Associations with Maturation Failure

Background: Systemic cytokines are elevated in chronic kidney disease (CKD) and hemodialysis patients compared to the general population. However, whether cytokine levels interfere with vascular remodeling increasing the risk of arteriovenous fistula (AVF) failure remains unknown. Methods: This is a case-control study of 64 patients who underwent surgery for AVF creation (32 with AVF maturation failure and 32 matching controls with successful maturation). A total of 74 cytokines, including chemokines, interferons, interleukins, and growth factors, were measured in preoperative plasma samples using multiplex assays. Sixty-two patients were included in the statistical analyses. Associations with AVF failure were assessed using paired comparisons and conditional logistic regressions accounting for paired strata. Results: Seven cytokines were significantly higher in patients with AVF maturation failure than in matching controls (G-CSF, IL-6, MDC, RANTES, SDF-1α/β, TGFα, and TPO). Of these, G-CSF (odds ratio 1.71 [1.05-2.79] per 10 pg/mL), MDC (1.60 [1.08-2.38] per 100 pg/mL), RANTES (1.55 [1.10-2.17] per 100 pg/mL), SDF-1α/β (1.18 [1.04-1.33] per 1000 pg/mL), and TGFα (OR 1.39 [1.003-1.92] per 1 pg/mL) showed an incremental association by logistic regression. Conclusions: This study identified a profile of plasma cytokines associated with adverse maturation outcomes in AVFs. These findings may open the doors for future therapeutics and markers for risk stratification.

The role of kidney biopsy in Immune Checkpoint Inhibitor-associated AKI

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Do PPIs cause CKD and progression of CKD? Commentary

This is an Early Access article. Please select the PDF button, above, to view it. Be sure to also read the PRO: 10.34067/KID.0007622021 and the CON: 10.34067/KID.0005852021

Do PPIs cause CKD and progression of CKD? PRO

This is an Early Access article. Please select the PDF button, above, to view it. Be sure to also read the CON: 10.34067/KID.0005852021 and the COMMENTARY: 10.34067/KID.0008302021

Initial home dialysis is increased for rural patients by accessing urban facilities

Background: The 240,000 rural patients with end stage kidney disease in the United States have less access to nephrology care and higher mortality than those in urban settings. The Advancing American Kidney Health initiative aims to increase the use of home renal replacement therapy. Little is known about how rural patients access home dialysis and the availability and quality of rural dialysis facilities. Methods: Incident dialysis patients in 2017 and their facilities were identified in the United States Renal Data System. Facility quality and service availability was analyzed with descriptive statistics. We assessed the availability of home dialysis methods depending on rural versus urban counties, and then we used multivariate logistic regression to identify the likelihood of rural patients with home dialysis as their initial modality and the likelihood of rural patients changing to home dialysis within 90 days. Finally, we assessed mortality after dialysis initiation based on patient home location. Results: Of the 97,930 dialysis initiates, 15,310 (15.6%) were rural. Rural dialysis facilities were less likely to offer home dialysis (51.4% vs 54.1%, P<0.001). While a greater proportion of rural patients (9.2 vs 8.2%, P<0.001) were on home dialysis, this was achieved by traveling to urban facilities to obtain home dialysis (OR 2.74, P<0.001). After adjusting for patient and facility factors, rural patients had a higher risk of mortality (HR 1.06, P=0.004). Conclusions: Despite having fewer facilities that offer home dialysis, rural patients were more often on home dialysis methods because they traveled to urban facilities, representing an access gap. Even if rural patients accessed home dialysis at urban facilities, rural patients still suffered worse mortality. Future dialysis policy should address this access gap to improve care and overall mortality for rural patients.

Do PPIs cause CKD and progression of CKD? CON

This is an Early Access article. Please select the PDF button, above, to view it. Be sure to also read the PRO: 10.34067/KID.0007622021 and the COMMENTARY: 10.34067/KID.0008302021