Nikolaos Pagonas

Impact of Atrial Fibrillation on the Accuracy of Oscillometric Blood Pressure Monitoring

The introduction of automated oscillometric blood pressure monitors was the basis for today’s widespread use of blood pressure self-measurement. However, in atrial fibrillation, there is a controversial debate on the use of oscillometry because there is a high variability of heart rate and stroke volume. To date, the accuracy of oscillometric blood pressure monitoring in atrial fibrillation has only been investigated using auscultatory sphygmomanometry as reference method, which may be biased by arrhythmia as well. We performed a cross-sectional study in 102 patients (52 sinus rhythm, 50 atrial fibrillation) assessing the accuracy of an automated and validated oscillometric upper arm (M5 Professional, Omron) and wrist device (R5 Professional, Omron) to invasively assessed arterial pressure. Blood pressure values were calculated as the mean of 3 consecutive measurements. Systolic and diastolic blood pressure did not significantly differ in patients with sinus rhythm and atrial fibrillation, independent of the method of measurement (P>0.05 each). The within-subject variability of the oscillometric measurements was higher in patients with atrial fibrillation compared with sinus rhythm (P<0.01 each). The biases of systolic and diastolic blood pressure, however, did not significantly differ in presence or absence of atrial fibrillation in Bland-Altmann analysis (P>0.05 each). In conclusion, atrial fibrillation did not significantly affect the accuracy of oscillometric measurements, if 3 repeated measurements were performed.

Urinary calprotectin and posttransplant renal allograft injury

Objective Current methods do not predict the acute renal allograft injury immediately after kidney transplantation. We evaluated the diagnostic performance of urinary calprotectin for predicting immediate posttransplant allograft injury. Methods In a multicenter, prospective-cohort study of 144 incipient renal transplant recipients, we postoperatively measured urinary calprotectin using an enzyme-linked immunosorbent assay and estimated glomerular filtration rate (eGFR) after 4 weeks, 6 months, and 12 months. Results We observed a significant inverse association of urinary calprotectin concentrations and eGFR 4 weeks after transplantation (Spearman r = −0.33; P<0.001). Compared to the lowest quartile, patients in the highest quartile of urinary calprotectin had an increased risk for an eGFR less than 30 mL/min/1.73 m2 four weeks after transplantation (relative risk, 4.3; P<0.001; sensitivity, 0.92; 95% CI, 0.77 to 0.98; specificity, 0.48; 95% CI, 0.31 to 0.66). Higher urinary calprotectin concentrations predicted impaired kidney function 4 weeks after transplantation, as well as 6 months and 12 months after transplantation. When data were analyzed using the urinary calprotectin/creatinine-ratio similar results were obtained. Urinary calprotectin was superior to current use of absolute change of plasma creatinine to predict allograft function 12 months after transplantation. Urinary calprotectin predicted an increased risk both in transplants from living and deceased donors. Multivariate linear regression showed that higher urinary calprotectin concentrations and older donor age predicted lower eGFR four weeks, 6 months, and 12 months after transplantation. Conclusions Urinary calprotectin is an early, noninvasive predictor of immediate renal allograft injury after kidney transplantation.

Dynamics of Urinary Calprotectin after Renal Ischaemia.

Background: Urinary calprotectin has been identified as a promising biomarker for acute kidney injury. To date, however, the time-dependent changes of this parameter during acute kidney injury remain elusive. The aim of the present work was to define the time-course of urinary calprotectin secretion after ischaemia/reperfusion-induced kidney injury in comparison to neutrophil gelatinase—associated lipocalin, thereby monitoring the extent of tubular damage in nephron sparing surgery for kidney tumours. Methods: The study population consisted of 42 patients. Thirty-two patients underwent either open or endoscopic nephron sparing surgery for kidney tumours. During the surgery, the renal arterial pedicle was clamped with a median ischaemic time of 13 minutes (interquartile range, 4.5–20.3 minutes) in 26 patients. Ten retro-peritoneoscopic living donor nephrectomy patients and 6 nephron sparing surgery patients in whom the renal artery was not clamped served as controls. Urinary calprotectin and neutrophil gelatinase—associated lipocalin concentrations were repeatedly measured by enzyme-linked immunosorbent assay and assessed according to renal function parameters. Results: Urinary concentrations of calprotectin and neutrophil gelatinase—associated lipocalin increased significantly after ischaemia/reperfusion injury, whereas concentrations remained unchanged after nephron sparing surgery without ischaemia/reperfusion injury and after kidney donation. Calprotectin and neutrophil gelatinase—associated lipocalin levels were significantly increased 2 and 8 hours, respectively, post-ischaemia. Both proteins reached maximal concentrations after 48 hours, followed by a subsequent persistent decrease. Maximal neutrophil gelatinase—associated lipocalin and calprotectin concentrations were 9-fold and 69-fold higher than their respective baseline values. The glomerular filtration rate was only transiently impaired at the first post-operative day after ischaemia/reperfusion injury (p = 0.049). Conclusion: Calprotectin and neutrophil gelatinase—associated lipocalin can be used to monitor clinical and sub-clinical tubular damage after nephron sparing surgery for kidney tumours. Urinary calprotectin concentrations start rising within 2 hours after ischaemia/reperfusion-induced kidney injury.

Effects of Treatment of Asymptomatic Hyperuricemia on Graft Survival and Mortality in Kidney Transplant Recipients.

BACKGROUND Hyperuricemia is very common after renal transplantation. It is associated with an increased risk of cardiovascular events and graft loss. To date, however, treatment is only recommended in symptomatic disease. MATERIAL AND METHODS We included 503 adult patients who underwent kidney transplantation at the Charité-Universitätsmedizin Berlin in this retrospective study. Patients were followed up for up to 120 months. All-cause mortality, graft survival, changes in level of serum uric acid (SUA), and estimated glomerular filtration rate (eGFR) were analyzed. RESULTS At 12 months post-transplantation, 225 patients had a serum uric acid (SUA) level >7 mg/dl: 52 patients were treated with allopurinol, 37 with benzbromarone, and 136 patients received no medication for hyperuricemia (control). At 12 months, eGFR did not differ between groups (p=0.15) but treated patients had higher SUA levels (p<0.001) compared to the control group. SUA-lowering treatment was associated with a lower risk of all-cause mortality (p=0.013) and graft loss (p=0.014) compared to controls. At 120 months, patients in the treatment group had lower SUA levels (p=0.001) and higher eGFR (p<0.001) compared to the control group. CONCLUSIONS Treatment of asymptomatic hyperuricemia was associated with a substantial benefit in patient and graft survival.

Urinary Calprotectin Differentiates Between Prerenal and Intrinsic Acute Renal Allograft Failure.

BackgroundUrinary calprotectin has recently been identified as a promising biomarker for the differentiation between prerenal and intrinsic acute kidney injury (AKI) in the nontransplant population. The present study investigates whether calprotectin is able to differentiate between these 2 entities in transplant recipients as well. MethodsUrinary calprotectin was assessed by enzyme-linked immunosorbent assay in 328 subjects including 125 cases of intrinsic acute allograft failure, 27 prerenal graft failures, 118 patients with stable graft function, and 58 healthy controls. Acute graft failure was defined as AKI stages 1 to 3 (Acute Kidney Injury Network criteria), exclusion criteria were obstructive uropathy, urothelial carcinoma, and metastatic cancer. The clinical differentiation of prerenal and intrinsic graft failure was performed either by biopsy or by a clinical algorithm including response to fluid repletion, history, physical examination, and urine dipstick examination. ResultsReasons for intrinsic graft failure comprised rejection, acute tubular necrosis, urinary tract infection/pyelonephritis, viral nephritis, and interstitial nephritis. Calprotectin concentrations of patients with stable graft function (50.4 ng/mL) were comparable to healthy controls (54.8 ng/mL, P = 0.70) and prerenal graft failure (53.8 ng/mL, P = 0.62). Median urinary calprotectin was 36 times higher in intrinsic AKI (1955 ng/mL) than in prerenal AKI (P < 0.001). Receiver-operating characteristic curve analysis revealed a high accuracy of calprotectin (area under the curve, 0.94) in the differentiation of intrinsic versus prerenal AKI. A cutoff level of 134.5 ng/mL provided a sensitivity of 90.4% and a specificity of 74.1%. Immunohistochemical stainings for calprotectin in renal allograft biopsy specimens confirmed the serological results. ConclusionsUrinary calprotectin is a promising biomarker for the differentiation of prerenal and intrinsic acute renal allograft failure.

Aortic Valve Replacement as a Trigger of Atypical Hemolytic Uremic Syndrome

Mechanical hemolysis is a frequent but usually harmless complication of aortic valve replacement. The most common reason is valvular leakage. This report presents atypical hemolytic uremic syndrome (aHUS) as an alternative cause of mechanical hemolysis after this procedure. aHUS is a complement-mediated disease characterized by microangiopathic hemolytic anemia, thrombocytopenia, and renal failure. It necessitates immediate specific treatment including plasma exchange or complement inhibition to avoid an adverse outcome. The present case identifies aortic valve replacement as a trigger of aHUS and shows that this disease must be taken into account in the differential diagnosis of hemolysis after valve surgery.

[OP.4A.07] THE IMPACT OF BLOOD PRESSURE VARIABILITY ON ADVERSE OUTCOMES AFTER KIDNEY TRANSPLANTATION.

Objective: Elevated long-term blood pressure variability has been shown to be predictive of adverse outcomes in patients with chronic kidney disease. In kidney transplant recipients a negative correlation between endothelial function and short-term variability has been found. No data exist, however, for associations of visit-to-visit variability (long-term variability) and outcomes after kidney transplantation. Design and method: 877 patients who underwent kidney transplantation at the Charité-Universitätsmedizin Berlin and at the Universitätsklinikum Knappschaftskrankenhaus Bochum, Germany were included in this retrospective study. Patients were followed up for at least 12 months (up to 266 months) after transplantation. Visit-to-visit blood pressure variability over the first 12 months after transplantation (3 visits) and during the first 120 months after transplantation (7 visits) was calculated as the coefficient of variation (CV) = standard deviation (SD)/ mean blood pressure. Results: Patients were categorized to those with low vs. high level of systolic CV at 12 months, defined by the median value (CV < 5.6 and CV> = 5.6%). After adjustment for gender, age and mean creatinine over the first 12 months the combined endpoint of death or graft loss did not differ between the two groups (HR (95% CI) = 1.1 (0.82 – 1.56), p = 0.44). No association was also found between patients with low and high systolic CV over 120 months (p = 0.15). Only primary graft function was associated with better outcomes after transplantation (p < 0.001). Conclusions: Visit-to-visit blood pressure variability is not associated with mortality or graft loss after kidney transplantation in this retrospective analysis. The presence of primary graft function was predictive of better long-term outcomes after transplantation. Figure. No caption available.

Sonographic assessment of spleen size in Turkish migrants with Familial Mediterranean fever in Germany.

Familial Mediterranean fever (FMF) can be associated with splenomegaly. Prospective quantitative data are lacking. We performed a sonographic assessment of spleen size in patients with FMF and healthy control participants to assess its diagnostic value.

Diagnostic Use of Sonography in the Evaluation of Hypertension

Hypertension is the most frequently treated disease in internal medicine. More than 1 billion people worldwide suffer from hypertension. Hypertension leads to cardiovascular end-organ damage increasing morbidity and mortality and is related with high costs to society, making this disease an important public health challenge. Sonography is a crucial diagnostic tool in the evaluation of a hypertensive patient. It is used both for the search of secondary forms of hypertension and for the identification of hypertensive end organ damage. There are several ultrasound examinations that may be warranted in hypertension. Abdominal ultrasound is recommended by several guidelines for the basic diagnostic workup in every newly diagnosed hypertensive patient. Doppler sonography of the renal arteries is reasonable only in a subset of hypertensives that are at increased risk of renal artery stenosis. Echocardiography is able to reveal cardiac end organ damage in terms of hypertensive heart disease. Ultrasound of the carotid arteries is frequently used to detect and evaluate in the case of hypertension-induced vascular end organ damage. The assessment of the intima-media thickness allows the detection of early stages of atherosclerotic wall changes. Prior to any structural vascular damage that may be visualized by ultrasound techniques, hypertension leads to functional changes of the endo‐ thelium, called endothelial dysfunction. Endothelial dysfunction encompasses a variety of changes in vascular function including a reduced endothelium-dependent vasodilation. This can be diagnosed by sonography measuring the diameter changes of the brachial artery in response to predefined endothelial stimuli. Flow-mediated dilation in response to hyperemia is regarded as the gold-standard in the non-invasive assessment of endothelial dysfunction. To date, it is rather used scientifically than in daily clinical practice. The present chapter provides

Response to Does Atrial Fibrillation Affect the Automated Oscillometric Blood Pressure Measurement

We thank Stergiou and coworkers for their interest in our study.1 The authors criticize that we did not use a validation protocol. The present study examines the impact of one single parameter (atrial fibrillation, AF) on the accuracy of oscillometry. It is not a validation study. The performance of a device in a validation procedure is determined by a broad variety of parameters. Bland–Altman analysis—as used in our study—is the statistical gold standard to assess the accuracy of a measurement technique and allows to analyze the impact of a single parameter like AF by statistical comparison of the resulting biases.2 Furthermore, the …