Increased Hepato-Splanchnic Vasoconstriction in Diabetics during Regular Hemodialysis

BACKGROUND AND OBJECTIVES:Ultrafiltration (UF) of excess fluid activates numerous compensatory mechanisms during hemodialysis (HD). The increase of both total peripheral and splanchnic vascular resistance is considered essential in maintaining hemodynamic stability. The aim of this study was to evaluate the extent of UF-induced changes in hepato-splanchnic blood flow and resistance in a group of maintenance HD patients during regular dialysis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS:Hepato-splanchnic flow resistance index (RI) and hepato-splanchnic perfusion index (QI) were measured in 12 chronic HD patients using a modified, non-invasive Indocyaningreen (ICG) dilution method. During a midweek dialysis session we determined RI, QI, ICG disappearance rate (kICG), plasma volume (Vp), hematocrit (Hct), mean arterial blood pressure (MAP) and heart rate (HR) at four times in hourly intervals (t1 to t4). Dialysis settings were standardized and all patient studies were done in duplicate. RESULTS:In the whole study group mean UF volume was 1.86 ± 0.46 L, Vp dropped from 3.65 ± 0.77L at t1 to 3.40 ± 0.78L at t4, and all patients remained hemodynamically stable. In all patients RI significantly increased from 12.40 ± 4.21 mmHg∙s∙m2/mL at t1 to 14.94 ± 6.36 mmHg∙s∙m2/mL at t4 while QI significantly decreased from 0.61 ± 0.22 at t1 to 0.52 ± 0.20 L/min/m2 at t4, indicating active vasoconstriction. In diabetic subjects, however, RI was significantly larger than in non-diabetics at all time points. QI was lower in diabetic subjects. CONCLUSIONS:In chronic HD-patients hepato-splanchnic blood flow substantially decreases during moderate UF as a result of an active splanchnic vasoconstriction. Our data indicate that diabetic HD-patients are particularly prone to splanchnic ischemia and might therefore have an increased risk for bacterial translocation, endotoxemia and systemic inflammation

Early detection and intervention using neutrophil gelatinase-associated lipocalin (NGAL) may improve renal outcome of acute contrast media induced nephropathy: A randomized controlled trial in patients undergoing intra-arterial angiography (ANTI-CIN Study)

<p>Abstract</p> <p>Background</p> <p>Patients with pre-existing impaired renal function are prone to develop acute contrast media induced nephropathy (CIN). Neutrophil gelatinase-associated lipocalin (NGAL), a new biomarker predictive for acute kidney injury (AKI), has been shown to be useful for earlier diagnosis of CIN; however, urinary NGAL values may be markedly increased in chronic renal failure at baseline. Results from those studies suggested that urinary NGAL values may not be helpful for the clinician. An intravenous volume load is a widely accepted prophylactic measure and possibly a reasonable intervention to prevent deterioration of renal function. The aim of our study is to evaluate NGAL as an early predictor of CIN and to investigate the clinical benefit of early post-procedural i.v. hydration.</p> <p>Methods/Design</p> <p>The study will follow a prospective, open-label, randomized controlled design. Patients requiring intra-arterial contrast media (CM) application will be included and receive standardized, weight-based, intravenous hydration before investigation. Subjects with markedly increased urinary NGAL values after CM application will be randomized into one of two study groups. Group A will receive 3-4 ml/kg BW/h 0.9% saline intravenously for 6 hours. Group B will undergo only standard treatment consisting of unrestricted oral fluid intake. The primary outcome measure will be CIN defined by an increase greater than 25% of baseline serum creatinine. Secondary outcomes will include urinary NGAL values, cystatin C values, contrast media associated changes in cardiac parameters such as NT-pro-BNP/troponin T, changes in urinary cytology, need for renal replacement treatment, length of stay in hospital and death.</p> <p>We assume that 20% of the included patients will show a definite rise in urinary NGAL. Prospective statistical power calculations indicate that the study will have 80% statistical power to detect a clinically significant decrease of CIN of 40% in the treatment arm if 1200 patients are recruited into the study.</p> <p>Discussion</p> <p>A volume expansion strategy showing a benefit from earlier intervention for patients with markedly elevated urinary NGAL values, indicating a CIN, might arise from data from this study.</p> <p>Trial registration</p> <p>ClinicalTrials.gov <a href="http://www.clinicaltrials.gov/ct2/show/NCT01292317">NCT01292317</a></p

Protein analysis of precipitates.

<p>Representative silver-stained SDS-PAGE gel of protein precipitates. Lanes correspond to serum precipitated with 70% ethanol (S1) or 35% ethanol (S2), lithium-heparin plasma precipitated with 70% ethanol (H1) or 35% ethanol (H2), and citrate plasma precipitated with 70% ethanol (C1) or 35% ethanol (C2).</p

Dilution studies.

<p>The arrow indicates the precipitated protein within the tube (V0) after centrifugation of the test solution consisting of 1 mL plasma and 4 mL ethanol 70%. Concentrations decrease from left to right. Tubes with test solutions containing ethanol locks of ≤28% in the dilution series (V6 toV9) revealed no signs of precipitation. The test series was performed at room temperature (24°C).</p

Results of in-vitro protein precipitation tests (dilution studies).

<p>^a Test solutions consisted of 1 ml plasma (or serum) and 4 ml ethanol lock solution (V0– V9, concentrations ranged from 70 to 7%).</p><p>^b mimicking the conditions inside the catheter. Tests were conducted at room and body temperature.</p><p>^c Precipitation was assessed with a visual score, ranging from +++ (much) to – (none).</p><p>^d Blood sample characteristics: hematocrit 0,42; albumin 4.5 g/dl; total protein 6.5 g/dl.</p

Relative catheter positions and plasma influx.

<p>a) If the venous insertion point (y) is higher relative to the tip (x), there is no plasma or in-vivo whole blood influx b) If the venous insertion point is lower (y) relative to the tip (x) plasma or in-vivo whole blood enters the lumens of the catheter (as indicated by green colour). The same relative catheter position can be assumed for patients in upright position with femoral catheters.</p