Dysfunction In Group Of Patients Research Articles

Diagnostic value of N-terminal pro-B-type natriuretic peptide in hemodialysis patients

Aim. To assess the diagnostic value of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in hemodialysis (HD) patients.Material and methods. A total of 80 patients over the age of 18 with an end-stage renal disease (ESRD) on HD were included in this study. NT-proBNP serum levels were measured for all patients in addition to traditional clinical and biochemical studies. Transthoracic echocardiography and bioimpedance spectroscopy using the Body Composition Monitor (BCM) device (Fresenius, Germany) were performed for all patients on HD. Patients were divided into two groups depending on the hydration status determined by BCM. Patients were also divided into three groups depending on the ejection fraction (EF) of the left ventricle: HF with reduced EF (less than 40%) (HFrEF), mid-range EF (from 40% to 49%) (HFmrEF), and HF with preserved EF (50% or more) (HFpEF). Three groups of patients were identified according to quartile level of NT-proBNP (<1095 pg/ml (n=20); 1095-4016 pg/ml (n=40); >4016 pg/ml (n=20).Results. The median of the NT-proBNP serum level was 2114,6 [1095; 4016] pg/ml. A significant increase in the NT-proBNP levels was found in HD patients with hyperhydration (p<0,05). Statistically significant differences were generally found between the concentration of NT-proBNP depending on the LVEF (n=80). However, in pairwise comparisons, significant differences were found only between the groups of patients with HFpEF and HFmrEF (p=0,02); a tendency to differences was revealed when comparing the groups of HFpEF and HFrEF (p=0,07). A proportional increase in the concentration of prohormone to the increase in systolic dysfunction was found while analyzing the median NT-proBNP, both among all patients and after separation into groups depending on the hydration status. A tendency to increase the frequency of new cardiovascular events, systolic and diastolic myocardial dysfunction in group of patients with prohormone increase was revealed.Conclusion. NT-proBNP serum levels in HD patients are significantly higher than the average population levels. A significant increase in the NT-proBNP levels was found in hemodialysis patients with hyperhydration. NT-proBNP should be used as an additional method for the diagnosis of heart failure on HD, including clarifying of the phenotype of heart failure depending on left ventricle EF. NT-proBNP high levels in patients on HD may be associated with a risk of developing cardiovascular events, systolic and diastolic myocardial dysfunction. It is necessary to use an examination algorithm for the differential diagnosis of heart failure and hyperhydration syndrome during dialysis: clinical examination, bioimpedansometry, transthoracic echocardiography, determination of serum NT-proBNP level.

Reliability of pulse waveform separation analysis responses to an orthostatic challenge.

Cardiovascular autonomic nervous system function can be assessed using an orthostatic challenge to induce arterial wave reflection. While arterial reflection is typically estimated using a central augmentation index, a superior estimation can be obtained using pulse wave separation analysis to estimate the aortic backward pressure wave (Pb). However, to be of value in a clinical or research setting, an assessment tool must be precise (reliable). Therefore, this study sought to determine the measurement precision of Pb responses to a modified tilt-table test. Twenty healthy adults (26.4 year (SD 5.2), 24.7 kg/m2 (SD 3.8), 55% female) were tested in a fasted state on three different mornings separated by a maximum of seven days. Pressure waveforms were recorded on the left arm, and aortic waveforms were generated using a generalized transfer function. Subsequently, a physiologic flow waveform was assumed to separate the aortic pressure wave into its forward and timing-independent backward (Pb) components. The criterion intra-class correlation coefficient of ≥0.75 was exceeded at baseline (0.79), following a 5-min tilt (0.75), and following a 5-min recovery from tilt (0.75). The standard error of measurement was 7%. These findings indicate that in a healthy cohort, the Pb response to an orthostatic challenge can be assessed with acceptable precision. The next step is to determine the sensitivity (validity) of this technique in identifying cardiovascular autonomic dysfunction in patient groups.

The value of near-infrared spectroscopy for the assessment of calf muscle function in venous patients.

Near-infrared spectroscopy (NIRS) is a noninvasive technique with the potential to determine the degree of tissueoxygenation. The aim of the current study was to investigate the use of NIRS as a reliable method of detecting calf muscle pump dysfunction in groups of patients with venous disease. Patients with superficial venous insufficiency (SVI) orhistory of deep venous thrombosis (DVT) were classified according to the comprehensive classification system for chronic venous disorders (clinical class, etiology, anatomy, andpathophysiology) and compared with controls (GROUP variable). A 10-stage evaluation of ambulatory venous function was performed, and corresponding values of calf regional oxygen saturation (crSaO2, %) at each phase were recorded (TIME variable). Thereafter, the percentage changes of crSaO2 values (Δ scores, %) between a given phase and the reference phase were estimated. Differences among groups and phases were evaluated using analysis of variance. Subgroup analysis between C0-C2 and C3-C6 patients was performed. The receiver operating characteristic curve analysis was used todetect the best predictive capability for SVI and DVT. A total of 30 patients with SVI, 31 patients with DVT, and 34 controls were included in the study. A statistically significant effect of TIME (F= 382.4; P< .001) andTIME×GROUP interaction (F= 6.3; P< .001) was recorded. Concerning prediction, we found a statistically significant area under the curve (AUC) for SVI (AUC= 0.72; 95% confidence interval, 0.58-0.83; P= .003) and forDVT (AUC= 0.83; 95% confidence interval, 0.71-0.92; P< .0001) patients. The measurement of crSaO2 using NIRS detected alterations in calf muscle pump oxygenation during exercise and differences in tissue oxygenation among SVI patients, DVT patients, and controls. NIRS may represent a reliable noninvasive tool for the study of calf muscle dysfunction in venous disease and a useful vehicle for generating testable hypotheses in the laboratory setting.

Progressive Changes in Right Ventricular Geometric Shortening and Long-term Survival in Pulmonary Arterial Hypertension

Until now, many investigators have focused on describing right ventricular (RV) dysfunction in groups of patients with pulmonary arterial hypertension (PAH), but very few have addressed the deterioration of RV function over time. The aim of this study was to investigate time courses of RV geometric changes during the progression of RV failure. Forty-two patients with PAH were selected who underwent right-sided heart catheterization and cardiac MRI at baseline and after 1-year follow-up. Based on the survival after this 1-year run-in period, patients were classified into two groups: survivors (26 patients; subsequent survival of > 4 years) and nonsurvivors (16 patients; subsequent survival of < 4 years). Four-chamber cine imaging was used to quantify RV longitudinal shortening (apex-base distance change), RV transverse shortening (septum-free wall distance change), and RV fractional area change (RVFAC) between end diastole and end systole. Longitudinal shortening, transverse shortening, and RVFAC measured at the beginning of the run-in period and 1 year later were significantly higher in subsequent survivors than in nonsurvivors (P < .05). Longitudinal shortening did not change during the run-in period in either patient group. Transverse shortening and RVFAC did not change during the run-in period in subsequent survivors but did decrease in subsequent nonsurvivors (P < .05). This decrease was caused by increased leftward septal bowing. Progressive RV failure in PAH is associated with a parallel decline in longitudinal and transverse shortening until a floor effect is reached for longitudinal shortening. A further reduction of RV function is due to progressive leftward septal displacement. Because transverse shortening incorporates both free wall and septum movements, this parameter can be used to monitor the decline in RV function in end-stage PAH.

Nystagmus: a parameter of mental function.

Nystagmographic records from an unusual case of spontaneous nystagmus probably of the central vestibular type were presented, demonstrating that nystagmus under selected conditions reflects with exquisite sensitivity certain aspects of mental functioning. Something of the process or processes monitored seems to be communicated by what is popularly indicated by such terms as “concentration,” “mental activity,” and “mental effort” and are not adequately explained by such concepts as changes in “alertness” or “attention” and “release from a central inhibition.” The importance of these mental factors lies in the additional hazard they impose on the use of quantitative changes in nystagmus for neurological diagnosis. Studies using nystagmus to demonstrate vestibular dysfunction in patient groups characterized by less than optimal cooperation must be reassessed. The usefulness of this parameter in the future study of mental function is emphasized.