Higher Body Mass Index is associated with increased arterial stiffness prior to target organ damage: a cross-sectional cohort study.

BACKGROUND: Obesity is associated with several neurohumoral changes that play an essential role in organ damage. Increased arterial stiffness causes functional vessel wall changes and can therefore lead to accelerated target organ damage as well. Whether obesity causes an independent increase in central arterial stiffness is, however, not yet fully known. METHODS: One hundred thirty-three patients (63.2% male) were included. Body Mass Index (BMI) was defined as body weight in kilograms, divided by the square of body height in meters. Chronic Kidney Disease Epidemiology Collaboration creatinine 2009 equation was used to estimate the glomerular filtration rate (eGFR). Non-invasive applanation tonometry was used for arterial stiffness measurements (Sphygmocor Atcor Medical, Sydney, Australia). All patients underwent coronarography. RESULTS: The mean age of our patients was 65.0 ± 9.2 years. Their mean BMI was 28.5 ± 4.4 kg/m2, eGFR 75.5 ± 17.2 ml/min/1.73 m2 and ankle-brachial index (ABI) 1.0 ± 0.1. Their arterial stiffness measurements showed mean carotid-femoral pulse wave velocity (cfPWV) 10.3 ± 2.7 m/s, subendocardial viability ratio (SEVR) 164.4 ± 35.0%, and pulse pressure (PP) 47.8 ± 14.5 mmHg. Spearman's correlation test revealed a statistically significant correlation between BMI and SEVR (r = -0.193; p = 0.026), BMI and cfPWV (r = 0.417; p < 0.001) and between BMI and PP (r = 0.227; p = 0.009). Multiple regression analysis confirmed an independent connection between BMI and cfPWV (B = 0.303; p < 0.001) and between BMI and SEVR (B = -0.186; p = 0.040). There was no association between BMI and kidney function, ABI, or coronary artery disease. CONCLUSION: Increased BMI is independently associated with augmented central arterial stiffness and reduced subendocardial perfusion but not with coronary artery disease, kidney function, or ABI.

Early Detection of Arteriovenous Fistula Stenosis in Hemodialysis Patients through Routine Measurements of Dialysis Dose (Kt/V).

BACKGROUND: Monitoring of arteriovenous (AV) fistula to detect hemodynamically important stenosis is crucial for the prevention of AV fistula thrombosis. The aim of our study was to analyze the importance of dialysis dose (Kt/V) during online postdilution hemodiafiltration (HDF) for early detection of AV fistula stenosis. METHODS: Hemodialysis patients with AV fistula were included in this study. We compared a group of 44 patients who have undergone fistulography and subsequently percutaneous transluminal angioplasty (PTA) of significant AV fistula stenosis (active group) with a group of 44 age- and sex-matched patients without PTA (control group). Observational time in both groups was the same. RESULTS: All patients had postdilution online HDF using a F5008 dialysis machine, which can measure online single-pool Kt/V. All data were analyzed during the performance of 2056 HDF procedures. In the active group, we found statistically significantly lower values of Kt/V, all 8 weeks before PTA. In the active group, there was a significant improvement in Kt/V in the first (p < 0.001) and second week (p = 0.049) after PTA. Three and 8 weeks after PTA, we did not find any statistically significant difference in Kt/V between both groups (p = 0.114; p = 0.058). Patients in the active group had statistically significantly lower substitution volumes and blood pump flow rates during HDF over the whole observation period before and after PTA. In contrast, there were no differences in venous pressure in the dialysis circuit between both groups throughout the observation period. CONCLUSION: In hemodialysis patients with AV fistula, treated with online HDF, routine measurements of Kt/V during each HDF are a beneficial, quick, and straightforward method for early detection of hemodynamically significant AV fistula stenosis.

Serum zinc values, ankle brachial index and mortality in hemodialysis patients.

INTRODUCTION: The atherosclerotic state of haemodialysis (HD) patients may be influenced by heavy metals. The purpose of our study was to assess the relationship between serum zinc (Zn) ankle brachial index (ABI) as a non-invasive diagnostic tool for atherosclerosis, and mortality in chronic haemodialysis (HD) patients. METHODS: Sixty one HD patients were included (mean age 61.2 ± 13.8 years). The ABI was measured with an automated measuring device (ABPI MD, MESI®, Slovenia). Two groups of patients were formed based on the median value of Zn (14.1 mcmol/l). The average observation time was 2.8 years. Comorbidities (arterial hypertension (AH), diabetes mellitus (DM), dyslipidaemia), smoking and oral nutritional supplements (ONS) consumption were noted. Survival rates were analysed by Kaplan-Meier and Cox regression was used to determine the influence of Zn, ABI, AH, DM, dyslipidaemia, smoking and ONS. RESULTS: Zn values were between 9.2 and 23.5 mcmol/l (14.4 ± 2.34), ABI values ranged from 0.8 to 1.4 (1.14 ± 0.12). Patients with lower Zn values had lower ABI (p = 0.036). Mean survival time of patients with higher Zn values was 985 days ± 277 days and with lower Zn values 1055 ± 143 days. Six (19.4%) patients with lower Zn and five (16.7%) patients with higher Zn died. We found statistically insignificant lower survival in patients with higher Zn. We failed to find any predictor of all-cause mortality, except for ONS consumption (95% CI 1.6-33.3; p = 0.012). CONCLUSIONS: Lower Zn is associated with lower ABI in HD patients, but we found no impact of Zn on patient survival.

A randomized multicenter trial on a lung ultrasound-guided treatment strategy in patients on chronic hemodialysis with high cardiovascular risk.

Lung congestion is a risk factor for all-cause and cardiovascular mortality in patients on chronic hemodialysis, and its estimation by ultrasound may be useful to guide ultrafiltration and drug therapy in this population. In an international, multi-center randomized controlled trial (NCT02310061) we investigated whether a lung ultrasound-guided treatment strategy improved a composite end point (all-cause death, non-fatal myocardial infarction, decompensated heart failure) vs usual care in patients receiving chronic hemodialysis with high cardiovascular risk. Patient-Reported Outcomes (Depression and the Standard Form 36 Quality of Life Questionnaire, SF36) were assessed as secondary outcomes. A total of 367 patients were enrolled: 183 in the active arm and 180 in the control arm. In the active arm, the pre-dialysis lung scan was used to titrate ultrafiltration during dialysis and drug treatment. Three hundred and seven patients completed the study: 152 in the active arm and 155 in the control arm. During a mean follow-up of 1.49 years, lung congestion was significantly more frequently relieved in the active (78%) than in the control (56%) arm and the intervention was safe. The primary composite end point did not significantly differ between the two study arms (Hazard Ratio 0.88; 95% Confidence Interval: 0.63-1.24). The risk for all-cause and cardiovascular hospitalization and the changes of left ventricular mass and function did not differ among the two groups. A post hoc analysis for recurrent episodes of decompensated heart failure (0.37; 0.15-0.93) and cardiovascular events (0.63; 0.41-0.97) showed a risk reduction for these outcomes in the active arm. There were no differences in patient-reported outcomes between groups. Thus, in patients on chronic hemodialysis with high cardiovascular risk, a treatment strategy guided by lung ultrasound effectively relieved lung congestion but was not more effective than usual care in improving the primary or secondary end points of the trial.

CHA2DS2-VASc Score as a Predictor of Cardiovascular and All-Cause Mortality in Chronic Kidney Disease Patients.

INTRODUCTION: Chronic kidney disease (CKD) is a risk factor for cardiovascular and all-cause mortality. Recognition of high-risk patients is important and could lead to a different approach and better treatment. The CHA2DS2-VASc score was originally used to predict cerebral infarction in patients with atrial fibrillation (AF), but it is also a useful predictor of outcome in other cardiovascular conditions, independent of AF. Therefore, the aim of our research was to assess the role of CHA2DS2-VASc score in predicting cardiovascular and all-cause mortality in CKD patients. METHODS: Stable nondialysis CKD patients were included. At the time of inclusion, medical history data and standard blood results were collected and CHA2DS2-VASc score was calculated. Patients were followed till the same end date, until kidney transplantation or until their death. RESULTS: Eighty-seven CKD patients were included (60.3 ± 12.8 years, 66% male). Mean follow-up time was 1,696.5 ± 564.6 days. During the follow-up, 21 patients died and 11 because of cardiovascular reasons. Univariate Cox regression analysis showed that CHA2DS2-VASc score is a significant predictor of cardiovascular and all-cause mortality. In multivariate Cox regression analysis, in which CHA2DS2-VASc score, serum creatinine, urinary albumin/creatinine, hemoglobin, high-sensitivity C-reactive protein, and intact parathyroid hormone were included, CHA2DS2-VASc score was an independent predictor of cardiovascular (HR: 2.04, CI: 1.20-3.45, p = 0.008) and all-cause mortality (HR: 2.06, CI: 1.43-2.97, p = 0.001). The same was true after adding total cholesterol, triglycerides, and smoking status to both the analyses. CONCLUSION: The CHA2DS2-VASc score is a simple, practical, and quick way to identify the risk for cardiovascular and all-cause mortality in CKD patients.

The association between pulse wave analysis, carotid-femoral pulse wave velocity and peripheral arterial disease in patients with ischemic heart disease.

INTRODUCTION: Functional changes in peripheral arterial disease (PAD) could play a role in higher cardiovascular risk in these patients. METHODS: 123 patients who underwent elective coronary angiography were included. Ankle-brachial index (ABI) was measured and arterial stiffness parameters were derived with applanation tonometry. RESULTS: 6 patients (4.9%) had a previously known PAD (Rutherford grade I). Mean ABI was 1.04 ± 0.12, mean subendocardial viability ratio (SEVR) 166.6 ± 32.7% and mean carotid-femoral pulse wave velocity (cfPWV) 10.3 ± 2.4 m/s. Most of the patients (n = 81, 65.9%) had coronary artery disease (CAD). There was no difference in ABI among different degrees of CAD. Patients with zero- and three-vessel CAD had significantly lower values of SEVR, compared to patients with one- and two-vessel CAD (159.5 ± 32.9%/158.1 ± 31.5% vs 181.0 ± 35.2%/166.8 ± 27.8%; p = 0.048). No significant difference was observed in cfPWV values. Spearman's correlation test showed an important correlation between ABI and SEVR (r = 0.196; p = 0.037) and between ABI and cfPWV (r = - 0.320; p ≤ 0.001). Multiple regression analysis confirmed an association between cfPWV and ABI (ß = - 0.210; p = 0.003), cfPWV and mean arterial pressure (ß = 0.064; p < 0.001), cfPWV and age (ß = 0.113; p < 0.001) and between cfPWV and body mass index (BMI (ß = - 0.195; p = 0.028), but not with arterial hypertension, dyslipidemia, diabetes mellitus or smoking status. SEVR was not statistically significantly associated with ABI using the same multiple regression model. CONCLUSION: Reduced ABI was associated with increased cfPWV, but not with advanced CAD or decreased SEVR.

Cystatin C and arterial stiffness in patients without chronic kidney disease.

BACKGROUND: Cystatin C (cysC) is freely filtered in the glomeruli, and its serum concentration is independent of muscle mass, diet, gender, or age. In patients with chronic kidney disease (CKD), cysC is associated with advanced atherosclerosis and increased arterial stiffness. The purpose of this study was to define possible associations between arterial stiffness parameters and cysC in patients without CKD. MATERIALS AND METHODS: The study included 111 non-CKD patients. Basic demographic and laboratory data were recorded. Arterial stiffness was measured by applanation tonometry (sphygmocor, Australia). RESULTS: Mean age of the patients was 64.3 ± 9.4 years, 65.8% were men. Most common co-morbidities were arterial hypertension (AH) (n = 86, 77.5%), hyperlipidemia (n = 64, 57.7%), and diabetes mellitus (DM) (n = 22; 19.8%). Mean creatinine was 77.7 ± 13.8 µmol/L (range 49 - 108), estimated GFR 81.3 ± 9.4 mL/min/1.73m2 (range 62 - 90), and cysC 0.94 ± 0.18 mg/L (range 0.67 - 1.63). Mean carotid-femoral pulse wave velocity (cfPWV) was 10.1 ± 2.4 m/s (range 6.2 - 16.8), subendocardial viability ratio (SEVR) 165.7 ± 36.1% (range 92 - 299), ejection duration (ED) 33.8 ± 4.4 ms (range 22 - 46), and pulse pressure (PP) 46.6 ± 14.8 mmHg (range 17 - 94). A statistically significant association was found between cysC and cfPWV (r = 0.472, p < 0.001), SEVR (r = -0.316, p < 0.001), ED (r = 0.217, p = 0.025), and pulse pressure (PP) (r = 0.241, p = 0.012). Multiple regression analysis between arterial stiffness parameters and cysC, age, male gender, AH, DM, hyperlipidemia, and eGFR confirmed a statistically significant and independent association between cysC and cfPWV (ß = 0.220, p = 0.038), between cysC and SEVR (ß = -0.278, p = 0.017), and between cysC and ED (ß = 0.241, p = 0.045). CONCLUSION: Elevated cysC is associated with increased cfPWV, increased ED, and decreased SEVR.

Assessment of volume status with bioimpendance prior to hemodialysis and its importance for predicting survival in hemodialysis patients.

BACKGROUND: Optimal fluid management is a physician's everyday challenge in patients on maintenance hemodialysis (HD). Bioimpedance spectroscopy (BIS) is a non-invasive method to estimate body composition, including estimates of fluid overload (FO). Our study aimed to analyze the association between FO and the mortality rate in HD patients. MATERIALS AND METHODS: We performed a retrospective single-center cohort study in 92 HD patients. The body composition was measured before HD using the portable whole-body BIS device Body Composition Monitor (BCM). We have analyzed the mortality rates of HD patients in two FO groups, a standard definition FO group (> 1.1 L), and a severe FO group (> 2.5 L) and compared them to mortality rates of patients without FO or without severe FO, respectively. RESULTS: The mean age of patients was 64.3 ± 13.0 years, mean dialysis vintage 64 months, 60.9% were men. 68 (73.9%) patients had FO of > 1.1 L and 30 (32.6%) had FO of > 2.5 L. During the follow-up period of 1,020 ± 417 days, 29 (31.5%) patients died. Kaplan-Meier survival analysis showed that patients with FO > 2.5 L had worse survival (p = 0.039). In a Cox regression model, which included FO > 2.5 L, age, dialysis vintage, hemoglobin, C-reactive protein, and albumin, only FO > 2.5 L and advanced age turned out to be predictors of death (p = 0.044 and p = 0.001, respectively). CONCLUSION: HD patients with FO > 2.5 L before HD have poorer survival than patients with normohydration or lower overhydration.

Lung ultrasound, hemoglobin, and NT-proBNP in peritoneal dialysis patients.

BACKGROUND: Lung ultrasound (LUS) is a non-invasive technique for estimating extravascular lung water in patients with end-stage renal disease and heart diseases. In this study, we examined an association between the severity of lung congestion as detected by LUS B-lines (LUS comets), anemia, and serum biomarker N-terminal pro-brain natriuretic peptide (NT-proBNP) in peritoneal dialysis (PD) patients. MATERIALS AND METHODS: 19 patients, who were treated with PD in our dialysis center were enrolled. On the day of their routine check-up, we performed a lung auscultation, LUS on 28 typical locations and determined blood levels of hemoglobin and NT-proBNP. RESULTS: The average age of patients was 54 (range 30 - 71) years, the average duration of PD treatment was 53 (range 10 - 194) months, 63% (12) of the patients were male. Nine (47.4%) patients had peripheral edema, and only 1 (5.3%) patient had inspiratory crackles. Using LUS, we found mean 17 (range 1 - 87) lung comets. Mean hemoglobin level was 108.6 g/L (SD ± 10.4), mean NT-proBNP level 1,151 pmol/L (SD ± 1,077). We found a statistically significant correlation between the number of lung comets and hemoglobin level (r = -0.655; p = 0.002) and NT-proBNP (r = 0.759; p < 0.0001). Multiple regression analysis with the number of lung comets as dependent variable and hemoglobin and NT-proBNP levels as independent variables confirmed a statistically significant association between the number of lung comets and NT-proBNP (ß = 0.572; p = 0.009). CONCLUSION: In PD patients, the number of LUS comets is associated with hemoglobin and NT-proBNP.

Association between lung comets and subendocardial viability ratio in peritoneal dialysis patients.

AIMS: Pulmonary congestion is a direct result of either general overhydration or cardiac dysfunction. Lung ultrasonography (LUS) with lung B-lines (LUS comets) can be used to assess extravascular lung water in patients with end-stage renal disease on hemodialysis or peritoneal dialysis (PD). Subendocardial viability ratio (SEVR) is a pulse wave analysis parameter that is a non-invasive measure of coronary perfusion and is related to cardiac work and oxygen consumption. Our aim was to investigate the association between LUS comets and SEVR in PD patients. MATERIALS AND METHODS: We performed an observational study in 25 PD patients in a single dialysis center. Extravascular lung water was quantified by the number of LUS comets, using a portable ultrasound (US) device. LUS comets were recorded in each intercostal space and defined as hyperechoic US bundles at a narrow base extending from the transducer to the edge of the screen. The sum of LUS comets yields a score reflecting the extent of water accumulation in the lungs. SEVR was determined non-invasively by radial applanation tonometry. RESULTS: Mean age of patients was 54.7 ± 10.7 years, mean PD vintage 27 ± 33 (1 - 167) months, 60% were men. The mean number of LUS comets was 13 ± 19 (0 - 71), and the mean SEVR was 153 ± 40%. We found a statistically significant negative correlation between the number of LUS comets and SEVR (r = -0.467; p = 0.019). Multiple regression analysis with LUS comets as dependent variable, and SEVR and age as independent variables showed a statistically significant relationship between SEVR and the number of LUS comets (ß = -0.467, p = 0.021). CONCLUSION: Higher number of LUS comets is associated with lower SEVR in PD patients.

Hyperuricemia, the heart, and the kidneys - to treat or not to treat?

BACKGROUND: Hyperuricemia is a state in which the serum levels of uric acid are elevated. As such it has a pronounced effect on vascular and renal function with their consequences, while also showing some antioxidant effects that show to be beneficial. SUMMARY: Hyperuricemia has shown to have a J-shaped relationship with mortality, is frequently associated with development and progression of heart and kidney disease, and is correlated with malnutrition-inflammation-atherosclerosis syndrome, although several Mendelian studies have failed to show an association with morbidity and mortality. Hyperuricemia is usually associated with gout flares and tophi development but can also present as asymptomatic hyperuricemia. It is still uncertain whether asymptomatic hyperuricemia is an independent risk factor for cardiovascular or renal disease and as such its treatment is questionable. KEY MESSAGES: Some possible tools for future decision making are the use of noninvasive techniques such as pulse wave analysis, urinary sediment analysis, and joint ultrasound, which could help identify individuals with asymptomatic hyperuricemia that could benefit from urate lowering therapy most.

SGLT-2 inhibitors and GLP-1 receptor agonists for nephroprotection and cardioprotection in patients with diabetes mellitus and chronic kidney disease. A consensus statement by the EURECA-m and the DIABESITY working groups of the ERA-EDTA.

Chronic kidney disease (CKD) in patients with diabetes mellitus (DM) is a major problem of public health. Currently, many of these patients experience progression of cardiovascular and renal disease, even when receiving optimal treatment. In previous years, several new drug classes for the treatment of type 2 DM have emerged, including inhibitors of renal sodium-glucose co-transporter-2 (SGLT-2) and glucagon-like peptide-1 (GLP-1) receptor agonists. Apart from reducing glycaemia, these classes were reported to have other beneficial effects for the cardiovascular and renal systems, such as weight loss and blood pressure reduction. Most importantly, in contrast to all previous studies with anti-diabetic agents, a series of recent randomized, placebo-controlled outcome trials showed that SGLT-2 inhibitors and GLP-1 receptor agonists are able to reduce cardiovascular events and all-cause mortality, as well as progression of renal disease, in patients with type 2 DM. This document presents in detail the available evidence on the cardioprotective and nephroprotective effects of SGLT-2 inhibitors and GLP-1 analogues, analyses the potential mechanisms involved in these actions and discusses their place in the treatment of patients with CKD and DM.

Cystatin C as a predictor of mortality in elderly patients with chronic kidney disease.

BACKGROUND: The prevalence of chronic kidney disease (CKD) in the elderly is high. Serum cystatin C is an accurate marker of kidney function and it also has prognostic utility in CKD patients. The aim of our study was to determine the prediction of serum cystatin C and other markers of kidney function on long-term survival in elderly CKD patients. METHODS: Fifty eight adult Caucasian patients, older than 65 years, without known malignancy, thyroid disease and/or not on steroid therapy were enrolled in the study. In each patient, 51CrEDTA clearance, serum creatinine, serum cystatin C, and estimated glomerular filtration rate using different equations were determined on the same day and patients were then followed for 11 years or until their death. RESULTS: The means are as follows: 51CrEDTA clearance 53.3 ± 17.4 ml/min/1.73 m2, serum creatinine 1.62 ± 0.5 mg/dl, serum cystatin C 1.79 ± 0.5 mg/l, Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine equation 40.1 ± 14 ml/min/1.73 m2, Berlin Initiative Study 2 (BIS2) equation 38.9 ± 10.7 ml/min/1.73 m2, full age spectrum (FAS) creatinine equation 43.8 ± 13.8 ml/min/1.73 m2, FAS cystatin C equation 40.1 ± 11.7 ml/min/1.73 m2. In the follow up period, 47 (81%) patients died. Cox regression analysis showed different hazard ratios (HRs) for death: for 51CrEDTA clearance HR 1.022 (95% CI 1.004-1.042; p = .015), serum creatinine HR 1.013 (95% CI 1.006-1.019; p = .001), serum cystatin C HR 2.028 (95% CI 1.267-3.241; p = .003), CKD-EPI creatinine equation HR 1.048 (95% CI 1.019-1.076; p = .001), BIS2 equation HR 1.055 (95% CI 1.021-1.088; p = .001), FAS creatinine equation HR 1.046 (95% CI 1.017-1.074; p = .001), FAS cystatin C equation HR 1.039 (95% CI 1.010-1.071; p = .009). CONCLUSIONS: Our results showed the highest HR for serum cystatin C among kidney function markers for prediction of outcome in elderly CKD patients.

Students as partners: Our experience of setting up and working in a student engagement friendly framework.

BACKGROUND: Student engagement (SE) in the curriculum is a positive indicator in the development of students deeply involved in their learning. It also has several benefits for the schools' level of educational innovation and quality assurance. METHOD: In order to identify the most important pearls from the last decade of educational developments within the field of SE at the Faculty of Medicine University of Maribor, we searched through our school's archives, publications and research in the field of medical education. RESULTS: Three areas were identified as the most important SE complements: (i) peer teaching, (ii) school governance, and (iii) extracurricular activities. The paper highlights how many student-driven initiatives move from informal frameworks toward a formal structure, elective courses, and, in the end, compulsory components of the curriculum. DISCUSSION: As demonstrated by the three educational achievements at our school, fostering a high level of SE can lead to innovative curricular changes, benefit the whole school and enable students to deliver highly impactful extracurricular projects.

Hyperuricemia and long-term survival in patients with chronic kidney disease undergoing hemodialysis.

INTRODUCTION: Uric acid (UA), a breakdown product of purines, has been associated with mortality in different populations. Less is known about associations between hyperuricemia and mortality in chronic kidney disease (CKD) patients, later undergoing hemodialysis (HD), during a long observation period. The aim of this study was to determine the impact of elevated UA levels on long-term (19.5 years) survival of CKD patients. METHODS: 120 CKD patients (49 female, 71 male) enrolled in our study were observed from their first visit at the patients' nephrology outpatient clinic (NOC). All patients later started HD and were followed until their death or January 1, 2016. UA was measured regularly from venous sampling during NOC visits and HD sessions. Patients with mean UA below 420 µmol/L were defined as normouricemic, patients with mean UA above 420 µmol/L as hyperuricemic. No patients were treated for hyperuricemia. Survival rates were analyzed using Kaplan-Meier survival curves. Cox regression model was used to assess the influence of UA, age, arterial hypertension, diabetes mellitus, total cholesterol, triglycerides, smoking, and body mass index on the survival of our patients. RESULTS: Mean UA was 383.6 ± 83, range 220 to 710 µmol/L. 86 (71.7%) patients were normouricemic, and 34 (28.3%) hyperuricemic. 43 (50.0%) normouricemic and 28 (82.4%) hyperuricemic patients died. Kaplan-Meier survival analysis showed the risk of death to be higher for hyperuricemic patients (log-rank test; p < 0.0001). With Cox multivariable regression model, the mean UA still remained a predictor of mortality in our patients (p < 0.0001). CONCLUSIONS: The results indicate an association between UA and long-term survival of CKD patients and show that hyperuricemia was directly associated with higher mortality among our patients.
.

Measurement of breath ammonia for detection of patients with chronic kidney disease.

BACKGROUND: In a healthy individual, ammonia is converted to urea in the liver. Urea is then transported through the bloodstream and then excreted into the urine by the kidneys. In patients with chronic kidney disease (CKD), the accumulated urea is degraded by salivary urease into ammonia, which is then excreted by breathing. Breath ammonia can therefore be used for detecting the increased nitrogen-bearing wastes. In our pilot study, an electrochemical sensor was used to measure and analyze breath ammonia in healthy volunteers and patients with CKD. PATIENTS AND METHODS: In our study, 8 patients with CKD (stages 4 and 5) and 6 healthy volunteers were enrolled. All participants were nonsmokers and without pulmonary or liver disease. One controlled breath sample was collected from each participant. Immediately after the sample was collected, a gas analyzer was used for measuring breath ammonia in our participants. RESULTS: Mean creatinine value of CKD patients was 455.2 ± 294.1 µmol/L and 62.1 ± 7.5 µmol/L for healthy volunteers. Breath ammonia levels (3.32 ± 2.19 ppm vs. 0.49 ± 0.08 ppm; p = 0.003) and measured electric current (4.33 ± 0.25 mA vs. 4.01 ± 0.01 mA; p = 0.003) were significantly higher in the CKD group. CONCLUSIONS: The results of our pilot study show that breath monitoring of ammonia can be a simple, useful, fast, and noninvasive tool for detection of advanced kidney impairment.
.

Relationship between subendocardial viability ratio and hemoglobin in patients with chronic kidney disease.

AIMS: Pulse wave analysis (PWA) uses the technique of applanation tonometry to obtain a peripheral pulse pressure waveform from which central hemodynamic information is derived. Using PWA, subendocardial viability ratio (SEVR) can be measured. SEVR represents a noninvasive measure of myocardial perfusion. It is related to the work of the heart, the oxygen consumption, and the energy supply of the heart. Anemia is a common complication of chronic kidney disease (CKD). A complex relationship exists between CKD, cardiovascular disease (CVD), and anemia. The aim of our study was to assess the relationship between SEVR and hemoglobin in non-dialysis CKD patients. MATERIAL AND METHODS: We examined the associations between PWA hemodynamic parameters, 24-hour ambulatory blood pressure (BP) measurements, and laboratory variables including hemoglobin, cardiac biomarkers troponin I, NT-proBNP, and hs-CRP in a cohort of 91 nondialysis CKD patients. PWA was assessed by radial applanation tonometry (SphygmoCor, Atcor, Sydney, Australia). The patients were divided into two groups according to the median value of hemoglobin. RESULTS: Mean age of included patients was 60.2 years, 67% were men, 44% were smokers, 25.3% had diabetes. A significant correlation between hemoglobin and SEVR was found (r = 0.26; p = 0.012). With multivariate regression analysis, SEVR as dependent variable turned out to be statistically significantly associated with hemoglobin (ß = 0.344, p = 0.013) and with troponin I (ß = -0.217, p = 0.037). Patients in the group with lower hemoglobin had statistically-significantly higher serum creatinine, cystatin C, NT-proBNP, and 24-hour ambulatory systolic BP and lower e-GFR, SEVR, and office diastolic BP. CONCLUSIONS: Results of our study show that SEVR is independently associated with hemoglobin in nondialysis CKD patients. CKD patients with lower hemoglobin have lower SEVR.
.

Problem-based learning in internal medicine: virtual patients or paper-based problems?

BACKGROUND: Teaching using paper problem-based learning (p-PBL) sessions has left some students fatigued with the learning process. Therefore, attempts have been made to replace p-PBL with digitally enhanced, decision-making PBL in the form of virtual patients (VP). Student enthusiasm for substituting p-PBL with VP has not been quantitatively evaluated on the intended educational effects. AIM: To determine the educational effects of substituting p-PBL sessions with VP on undergraduate medical students in their internal medicine course. METHODS: We conducted a randomised controlled study on 34 third-year undergraduate medical students in the academic year 2015-2016. Student performance after an intervention substituting p-PBL sessions with VP was analysed. The educational outcomes were measured with knowledge exams and the Diagnostic Thinking Inventory. RESULTS: There was no difference in exam performance between groups (P > 0.833) immediately after the intervention, or in long term. Nor was there a significant difference in improvement of diagnostic thinking between groups (P > 0.935 and P > 0.320). CONCLUSIONS: Our study showed no significant improvement in diagnostic thinking abilities or knowledge exam results with the use of VP. Educators can add VP to sessions to motivate students, but a significant improvement to educational outcome should not be expected.