Niina Koivuviita

Association of oliguria with the development of acute kidney injury in the critically ill

Urine output (UO) criterion may increase the sensitivity of the definition of acute kidney injury (AKI). We determined whether the empirically derived definition for oliguria (<0.5 ml/kg/h) is independently associated with adverse outcome. Data analysis included hourly recorded UO from the prospective, multicenter FINNAKI study conducted in 16 Finnish intensive care units. Confounder-adjusted association of oliguria of different severity and duration primarily with the development of AKI defined by creatinine criterion (Cr-AKI) or renal replacement therapy (RRT) was assessed. Secondarily, we determined the association of oliguria with 90-day mortality. Of the 1966 patients analyzed for the development of AKI, 454 (23.1%) reached this endpoint. Within this AKI cohort, 312 (68.7%) developed Cr-AKI, 21 (4.6%) commenced RRT without Cr-AKI, and 121 (26.7%) commenced RRT with Cr-AKI. Episodes of severe oliguria (<0.1 ml/kg/h) for more than 3 h were independently associated with the development of Cr-AKI or RRT. The shortest periods of consecutive oliguria independently associated with an increased risk for 90-day mortality were 6-12 h of oliguria from 0.3 to <0.5 ml/kg/h, over 6 h of oliguria from 0.1 to <0.3 ml/kg/h, and severe oliguria lasting over 3 h. Thus, our findings underlie the importance of hourly UO measurements.Kidney International advance online publication, 9 September 2015; doi:10.1038/ki.2015.269.

Increased basal myocardial perfusion in patients with chronic kidney disease without symptomatic coronary artery disease

BACKGROUND Even minor renal dysfunction is a powerful cardiovascular risk factor. The abnormalities in coronary and peripheral artery function in different stages of chronic kidney disease (CKD) remain poorly understood. Our aim was to test by a positron emission tomography (PET)-based method whether microvascular dysfunction, an early marker of coronary dysfunction, exists already in early stages of CKD. METHODS Myocardial blood flow was measured at baseline and during dipyridamole-induced hyperaemia by PET. Peripheral artery endothelial function was examined by measuring flow-mediated dilatation (FMD) of the brachial artery at rest and during reactive hyperaemia. Twenty-two patients with moderate to severe kidney failure and 10 healthy controls were investigated. Diabetic patients were excluded. Baseline characteristics were similar between the groups with the exception of antihypertensive medication in all CKD patients. RESULTS The basal myocardial perfusion was statistically significantly higher in CKD patients than observed values in similarly aged controls. There was a statistically significant negative correlation between the baseline myocardial perfusion and the estimated glomerular filtration rate. Coronary flow reserve was comparable to healthy controls in all patients. FMD was significantly reduced in all patients with CKD regardless of the stage of kidney failure. CONCLUSIONS Coronary flow reserve was normal although baseline myocardial blood flow was increased in all CKD patients as compared to healthy controls. Peripheral endothelial dysfunction was detected in all patients. Our findings suggest that coronary perfusion and peripheral vascular function are disturbed by different mechanisms in patients with CKD.

The effect of revascularization of renal artery stenosis on renal perfusion in patients with atherosclerotic renovascular disease

BACKGROUND Only a small fraction of patients with atherosclerotic renovascular disease (ARVD) treated with revascularization have improved renal function after the procedure. It has been suggested that this may be due to effects of renal microvascular disease. Our aim was to measure the effect of renal artery stenosis (RAS) revascularization on renal perfusion in patients with renovascular disease. METHODS Seventeen renovascular disease patients were treated by dilatation of unilateral (N = 8) or bilateral (N = 9) RAS (N = 23 kidneys), mainly because of uncontrolled or refractory hypertension. The patients were studied before and after (103 ± 29 days) the procedure. Renal perfusion was measured using quantitative positron emission tomography (PET) perfusion imaging. RESULTS Although renal perfusion correlated inversely with the degree of RAS in patients with renovascular disease, it did not change after revascularization. CONCLUSIONS Our data support the notion of former clinical trials that angiographic severity of RAS does not determine the response to revascularization. Quantitative PET perfusion imaging is a promising tool to noninvasively measure renal perfusion for the assessment of physiological impact of RAS.

The Effect of Revascularization of Atherosclerotic Renal Artery Stenosis on Coronary Flow Reserve and Peripheral Endothelial Function

Background: Patients with atherosclerotic renovascular disease (ARVD) are at increased risk of heart disease because of associated hypertension, coronary artery disease, cardiac failure and chronic kidney disease. Although suggested to be beneficial, the cardiac effects of renal artery revascularization have not been well characterized. Our aim was to analyze the effects of percutaneous dilatation of renal artery stenosis (RAS) in ARVD patients on coronary and peripheral vascular function. Methods: Nineteen ARVD patients [11 females and 8 males, age at study entry (mean ± SD) 69 ± 10 years] were treated by dilatation of unilateral (n = 9) or bilateral (n = 10) RAS, mainly because of uncontrolled or refractory hypertension. The patients were studied before and after the procedure (103 ± 29 days). They underwent echocardiography and peripheral artery endothelial function testing using flow-mediated dilatation (FMD) of brachial artery at rest and during reactive hyperemia. Myocardial blood flow was measured using quantitative PET perfusion imaging at baseline and during dipyridamole-induced hyperemia. Results: Peripheral endothelial function, tested by FMD, as well as systolic blood pressure and left ventricular mass were improved in patients with bilateral RAS. However, myocardial perfusion and coronary flow reserve (CFR) did not change after the RAS dilatation. Conclusion: This is the first study to analyze the stage of myocardial perfusion and CFR in ARVD patients. Although peripheral endothelial function, systolic blood pressure and left ventricular hypertrophy were improved in patients with bilateral RAS by revascularization of RAS, it did not have any effect on coronary perfusion.

Thromboembolism as a Cause of Renal Artery Occlusion and Acute Kidney Injury: The Recovery of Kidney Function after Two Weeks

Thromboembolic occlusion is a rare cause of acute kidney injury (AKI). It may lead to permanent loss of renal function. Our patient, who had dilated cardiomyopathy and prosthetic aortic valve, presented with AKI due to thromboembolic arterial occlusion of a solitary functioning kidney. After 2 weeks delay, local intra-arterial thrombolytic treatment with recombinant tissue plasminogen activator was performed without sufficient effect. However, a subsequent percutaneous transluminal angioplasty with stenting was successful. Diuresis began immediately, and renal function was fully recovered after 2 weeks. Although there had been no evident arterial circulation in the kidney, we think that minor flow through subtotal occlusion of the main renal artery made the hibernation of kidney tissue possible and contributed to the recovery. Thus, even after prolonged ischemia, revascularization can be useful.

A case report: a patient with IgA nephropathy and coeliac disease. Complete clinical remission following gluten-free diet

IgA nephropathy (IgAN) presents usually as a primary disease. However, secondary forms of IgAN have been described, most commonly associated with liver disease [1]. The presence of high levels of IgA against food antigens including gliadin and IgG and IgA antiendomysial antibodies in some patients with IgAN has raised the possibility of a pathophysiological link between IgAN and coeliac disease (CD) [2]. Experimental IgAN can be induced by dietary gluten or gliadin [3]. Furthermore, a favourable outcome of gluten-free diet on IgAN has been described [4].

Widespread vascular inflammation in a patient with antineutrophil cytoplasmic antibody-associated vasculitis as detected by positron emission tomography

A 47-year-old man had fever, fatigue, abdominal pain, and claudication due to antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Whole-body [18 F] FDG PET/CT scan was performed as a diagnostic procedure, and it revealed abnormal [18 F] FDG accumulation in smalland medium-sized vessels of the upper extremities and in the lower extremities appearing as a tree-root-like [18 F] FDG uptake pattern (Panel A). Increased [18 F] FDG uptake in vertebral bone marrow and the spleen was observed due to hematopoietic stimulation. For comparison, two different [18 F] FDG PET/CT scans are presented. A 76-year-old woman had an atypical [18 F] FDG uptake pattern in the larger arteries, which indicated giant cell vasculitis (Panel B). A 39-year-old man had Staphylococcus aureus septicaemia. He had no [18 F] FDG metabolic activity in vessel walls, but the activation of axillary lymph nodes and metastatic infectious foci in the left leg and spleen was observed (Panel C). [F] FDG PET/CT is a useful tool for evaluating the distribution of inflammation and infection, as in our case. It can detect the affected organs and also show unexpected localizations of ANCA-associated vasculitis [1].

One‐ and three‐year outcomes in patients treated with intermittent hemodialysis for acute kidney injury: prospective observational multicenter post‐hoc FINNAKI study

Studies reporting renal and overall survival after acute kidney injury (AKI) treated exclusively with intermittent modalities of renal replacement therapy (IRRT) are rare. This study focused on outcomes of AKI patients treated with IRRT both in intensive care units (ICUs) and non‐ICU dialysis units.

A Nanoparticle-Lectin Immunoassay Improves Discrimination of Serum CA125 from Malignant and Benign Sources.

BACKGROUND Measurement of serum cancer antigen 125 (CA125) is the standard approach for epithelial ovarian cancer (EOC) diagnostics and follow-up. However, the clinical specificity is not optimal because increased values are also detected in healthy controls and in benign diseases. CA125 is known to be differentially glycosylated in EOC, potentially offering a way to construct CA125 assays with improved cancer specificity. Our goal was to identify carbohydrate-reactive lectins for discriminating between CA125 originating from EOC and noncancerous sources. METHODS CA125 from the OVCAR-3 cancer cell line, placental homogenate, and ascites fluid from patients with cirrhosis were captured on anti-CA125 antibody immobilized on microtitration wells. A panel of lectins, each coated onto fluorescent europium-chelate-doped 97-nm nanoparticles (Eu(+3)-NPs), was tested for detection of the immobilized CA125. Serum samples from high-grade serous EOC or patients with endometriosis and healthy controls were analyzed. RESULTS By using macrophage galactose-type lectin (MGL)-coated Eu(+3)-NPs, an analytically sensitive CA125 assay (CA125(MGL)) was achieved that specifically recognized the CA125 isoform produced by EOC, whereas the recognition of CA125 from nonmalignant conditions was reduced. Serum CA125(MGL) measurement better discriminated patients with EOC from endometriosis compared to conventional immunoassay. The discrimination was particularly improved for marginally increased CA125 values and for earlier detection of EOC progression. CONCLUSIONS The new CA125(MGL) assay concept could help reduce the false-positive rates of conventional CA125 immunoassays. The improved analytical specificity of this test approach is dependent on a discriminating lectin immobilized in large numbers on Eu(+3)-NPs, providing both an avidity effect and signal amplification.