Lung Ultrasound in PD Patients

Study Overview
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Brief Summary
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Although many alternative methods are present, maintaining ideal volume status in peritoneal dialysis (PD) patients still rely on clinical evaluation due to lack of an evidence based method. Lung ultrasound (LUS) is a new method for evaluation of hidden congestion in this group. LUS findings and its relationship with other volumetric methods are investigated in this study. LUS was performed to all peritoneal dialysis patients and compared with symptoms of hypervolemia, physical examination, vascular endothelial growth factor-C (VEGF-C) and N-terminal pro-brain natriuretic peptide levels, chest radiography, echocardiography, bioelectrical impedance analysis.

Detailed Description
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Maintaining volume control is crucial in all renal replacement therapy modalities. Fluid overload is associated with increased mortality both in hemodialysis patients and peritoneal dialysis (PD) patients although peritoneal dialysis has the advantage of better preservation of residual renal function compared to hemodialysis. Many methods have been used to fine tune the volume status of patients including physical examination, chest radiography, blood pressure, laboratory parameters, echocardiography, bioelectrical impedance analysis (BIA), ultrasound for lung. Symptoms of hypervolemia are mainly paroxysmal nocturnal dyspnea, orthopnea, edema, dyspnea on exertion. On physical examination, hypertension or hypotension, third heart sound, jugular venous distension, rales, edema can be seen. Pulmonary venous congestion, cardiomegaly, interstitial edema, alveolar edema, pleural effusion can be seen on chest radiographies. Level of N-terminal pro-brain natriuretic peptide (NT-proBNP) increases upon stretching of cardiac myocytes. This is accepted as a reflection of volume status. There are a few studies in which NT-proBNP was found as a useful marker for hypervolemia both in hemodialysis and peritoneal dialysis population. Vascular endothelial growth factor-C (VEGF-C) is an osmosensitive gene product secreted by macrophages through activation of tonicity-responsive enhancer binding protein found in mononuclear phagocyte system cells infiltrating the interstitium. The result is hypertonic sodium accumulation in the skin which is accepted as a buffer mechanism maintaining blood pressure homeostasis. Serum VEGF-C levels had been found as a promising marker of hypervolemia in a hemodialysis patient cohort by a recent study. Echocardiography has been used extensively in dialysis patients in which a number of parameters have been measured. Bioelectrical impedance analysis (BIA) is another non-invasive bedside method for the evaluation of volume status. Lung ultrasound (LUS) is a technique that has become popular in nephrology recently. B lines or lung comets are the reverberation artifacts arising from the pleural line. They are produced due to thickened subpleural interlobular septa by edema. The gold standard for volume assessment is isotope dilution and neutron activation analysis methods which are only limited to research activities. The best widely accepted, non-invasive, practical, easy to access method has not been decided yet. Moreover evidence is quite scarce for the peritoneal dialysis than hemodialysis or normal renal functioning group. Lung ultrasound is the most recent promising method for volume control. The investigators aimed to define lung ultrasound findings in our peritoneal dialysis cohort and its relation with other volumetric parameters.

Official Title
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Comparison of Lung Ultrasound and Other Volumetric Methods in Peritoneal Dialysis Patients

Conditions
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Peritoneal Dialysis, Hypervolemia, VEGF Overexpression

Intervention / Treatment
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* Diagnostic Test: NT-BNP, VEGF
* Diagnostic Test: Echocardiography
* Radiation: Chest Radiography
* Diagnostic Test: Lung Ultrasound
* Diagnostic Test: Bioelectrical Impedence Analysis


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients older than 18 years old, History of PD more than 3 months, Providing written informed consent Exclusion Criteria: Patients younger than 18 years old, Unwilling to participate to the study, Immobile patients unable to perform test in the same day, History of PD less than 3 months, Presence of active infection, History of lung cancer and/or operations.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| PD patients<br>All PD patients treated in out unit were enrolled. | Diagnostic Test: NT-BNP, VEGF<br>* VEGF-C levels were measured in the serum samples. R&D Systems kit (Minneapolis, MN) (Catalog Number DVEC00) was used for the assays according to the user instructions. NT-proBNP was measured on the Elecsys 2010 analyzer (Elecsys proBNP Immunoassay; Roche Diagnostics).<br>Diagnostic Test: Echocardiography<br>* Transthoracic echocardiography was performed by the same cardiologist blinded to all other parameters. It was done while abdomen was empty. LV end diastolic diameter (mm), interventricular septum thickness (mm), posterior wall thickness (mm), ejection fraction (%), left ventricle end diastolic volume (ml), left atrial volume (ml), left ventricle mass index (LVMI) (g/m2), left ventricle filling velocity(cm/sec), E/E' ratio, pulmonary artery systolic pressure (mm Hg) were the parameters taken by echocardiography<br>Radiation: Chest Radiography<br>* All radiographies were taken when the patient was standing erect position during deep inhalation. They were reported by an expert radiologist blinded to clinical data. Films taken at supine position or during exhalation were excluded. Chest radiographies were classified into 3 stages to reflect degree of hypervolemia. Stage 1 was redistribution defined as increased artery-to-bronchus ratio in the upper and middle lobes. Stage 2 was interstitial edema evident by Kerley B lines and peribronchial cuffing. Stage 3 was alveolar edema phase perihilar consolidation and air bronchograms, pleural fluid, increased width of the vascular pedicle, enlarged cardiac silhouette.<br>Diagnostic Test: Lung Ultrasound<br>* It was performed by 28 area method which contains ultrasound examination from second to fifth intercostals spaces at parasternal region, midclavicular line, anterior and mid axillary lines. Lung ultrasound had been done by same radiologist who was an expertise in ultrasonography blinded to all other parameters. It was performed by 1,6 megaHertz convex probe when patient lying at the supine position.<br>Diagnostic Test: Bioelectrical Impedence Analysis<br>* The Body Composition Monitor (BCM) (type 0BJA1394, Fresenius Medical Care AG & Co. KGaA, D-61343 Bad Homburg) was used for assessment of hydration status in patients. Peritoneal cavities were free of intraperitoneal fluid during measurement. Patients were accepted as normovolemic if their result were between -1.1lt and 1.1 lt.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Association Between Number of Kerley B Lines by Ultrasound and Serum VEGF-C Level (pg/ml) by Enzyme-linked Immunosorbent Assay | Assessing the relationship between number of Kerley B lines by ultrasound and serum VEGF-C level (pg/ml) by enzyme-linked immunosorbent assay | 4 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Association Between Number of Kerley B Lines by Ultrasound and Dyspnea by Questionnaire | Assessing the relationship between number of Kerley B lines by ultrasound and dyspnea by questionnaire | 4 months | 
| Association Between Number of Kerley B Lines by Ultrasound and Class of New York Heart Association Classification | Assessing the relationship between number of Kerley B lines by ultrasound and class of New York Heart Association Classification | 4 months | 
| Association Between Number of Kerley B Lines by Ultrasound and Presence of Third Sound/Pretibial Edema by Auscultation/Edema by Physical Examination | Assessing the relationship between number of Kerley B lines by ultrasound and presence of third sound (S3) by auscultation/edema by physical examination | 4 months | 
| Association Between Number of Kerley B Lines by Ultrasound Left Ventricle End Diastolic Diameter (mm) Obtained by the Cardiologist With Echocardiography | Assessing the relationship between number of Kerley B lines by ultrasound and left ventricle end diastolic diameter (mm) obtained by the cardiologist with echocardiography | 4 months | 
| Association Between Number of Kerley B Lines by Ultrasound Interventricular Septum Thickness (mm) Obtained by the Cardiologist With Echocardiography | Assessing the relationship between number of Kerley B by ultrasound and interventricular septum thickness (mm) (mm) obtained by the cardiologist with echocardiography | 4 months | 
| Association Between Number of Kerley B by Ultrasound and Posterior Wall Thickness (mm) Obtained by the Cardiologist With Echocardiography | Assessing the relationship between number of Kerley B by ultrasound and posterior wall thickness (mm) obtained by the cardiologist with echocardiography | 4 months | 
| Association Between Number of Kerley B Lines by Ultrasound and Ejection Fraction (%) Obtained by the Cardiologist With Echocardiography | Assessing the relationship between number of Kerley B lines by ultrasound and ejection fraction (%) obtained by the cardiologist with echocardiography | 4 months | 
| Association Between Number of Kerley B Lines by Ultrasound and Left Ventricle End Diastolic Volume (ml) Obtained by the Cardiologist With Echocardiography | Assessing the relationship between number of Kerley B lines by ultrasound and left ventricle end diastolic volume (ml) obtained by the cardiologist with echocardiography | 4 months | 
| Association Between Number of Kerley B Lines by Ultrasound and Left Atrial Volume (ml) Obtained by the Cardiologist With Echocardiography | Assessing the relationship between number of Kerley B lines by ultrasound and left atrial volume (ml) obtained by the cardiologist with echocardiography | 4 months | 
| Association Between Number of Kerley B Lines by Ultrasound and Left Ventricle Mass Index (g/m2) Obtained by the Cardiologist With Echocardiography | Assessing the relationship between number of Kerley B lines by ultrasound and left ventricle mass index (g/m2) obtained by the cardiologist with echocardiography | 4 months | 
| Association Between Number of Kerley B Lines by Ultrasound and Left Ventricle Filling Velocity (cm/Sec) Obtained by the Cardiologist With Echocardiography | Assessing the relationship between number of Kerley B lines by ultrasound and left ventricle filling velocity (cm/sec) obtained by the cardiologist with echocardiography | 4 months | 
| Association Between Number of Kerley B Lines by Ultrasound and Early Mitral Inflow Velocity and Mitral Annular Early Diastolic Velocity (E/E') Obtained by the Cardiologist With Echocardiography | Assessing the relationship between number of Kerley B lines by ultrasound and early mitral inflow velocity and mitral annular early diastolic velocity (E/E') obtained by the cardiologist with echocardiography | 4 months | 
| Association Between Number of Kerley B Lines by Ultrasound and Pulmonary Artery Systolic Pressure (mmHg) Obtained by the Cardiologist With Echocardiography | Assessing the relationship between number of Kerley B lines by ultrasound and pulmonary artery systolic pressure (mmHg) obtained by the cardiologist with echocardiography | 4 months | 
| Association Between Number of Kerley B Lines by Ultrasound and Bioimpedance Analysis [Assessed With the Body Composition Monitor; Normovolemic if Their Result Between -1,1 lt and 1,1 lt) | Assessing the relationship between number of Kerley B lines by ultrasound and bioimpedance analysis [assessed with the body composition monitor; normovolemic if their result between -1,1 lt and 1,1 lt) | 4 months | 
| Association Between Number of Kerley B Lines by Ultrasound and NT-proBNP Level (pg/ml) by Elecsys proBNP Immunoassay | Assessing the relationship between number of Kerley B lines by ultrasound and NT-proBNP level (pg/ml) by Elecsys proBNP Immunoassay | 4 months |