Cardiopulmonary Exercise Testing Parameters' Variability in Hemodialysis Patients.

Study Overview
=================
Brief Summary
-----------------
Chronic kidney disease (CKD), especially end-stage kidney disease (ESKD), is associated with increased risk for cardiovascular events and all-cause mortality. Exercise intolerance as well as reduced cardiovascular reserve are extremely common in patients with CKD. Cardiopulmonary exercise testing (CPET) is a non-invasive, dynamic technique that provides an integrative evaluation of cardiovascular, pulmonary, neuropsychological and metabolic function during maximal or submaximal exercise, allowing the evaluation of functional reserves of these systems. CPET is currently considered to be the gold-standard for identifying exercise limitation and differentiating its causes. It has been widely used in several medical fields for risk stratification, clinical evaluation and other applications. However, the use of CPET in assessment of exercise intolerance in everyday nephrology practice is limited. Hence, this is the first study possible differences in CPET's parameters during long and short interdialytic intervals in hemodialysis patients.

Detailed Description
-----------------
This is an observational study with a cross-over design performed in the Department of Nephrology and the Third Department of Cardiology in Hippokration Hospital of Thessaloniki in Greece. For the purposes of this study, hemodialysis patients fulfilling the inclusion/exclusion criteria, as well as controls without CKD, were invited to participate. All included patients signed a written informed consent form. The study protocol was approved by the Ethics Committee of the School of Medicine, Aristotle University of Thessaloniki. All procedures and evaluations are performed according to the Declaration of Helsinki 2013 Amendment. Baseline evaluation includes the recording of demographics and anthropometric characteristics, medical history, concomitant medications and dialysis-related parameters, as well as physical examination and venous blood sampling for routine laboratory tests. Hemodialysis patients will be evaluated at two time points (at the end of the long and at the end of the short interdialytic interval), while controls at one time point. All the participants will undergo spirometry, CPET, cardiac ultrasound, lung ultrasound and bioelectrical impedance analysis.

Official Title
-----------------
Cardiopulmonary Exercise Testing Parameters' Variability During Long and Short Interdialytic Intervals in Hemodialysis Patients.

Conditions
-----------------
Chronic Kidney Disease Requiring Chronic Dialysis, Chronic Kidney Diseases

Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Hemodialysis patients aged >18 years. Patients with a total duration of hemodialysis >3 months. Patients enrolled in a dialysis program that includes three sessions per week. Hemodialysis patients who are capable of exercising on a cycle ergometer. Hemodialysis patients who are capable of understanding and providing written, signed consent to participate in the study Exclusion Criteria: Absolute and relative contraindications for performing CPET according to the American Thoracic Society (ATS) and the American College of Chest Physicians (ACCP), such as Acute myocardial infarction (3-5 days) Unstable angina Uncontrolled arrhythmias causing symptoms or haemodynamic compromise Syncope Active endocarditis Acute myocarditis or pericarditis Symptomatic severe aortic stenosis Uncontrolled heart failure Acute pulmonary embolus or pulmonary infarction Thrombosis of lower extremities Suspected dissecting aneurysm Uncontrolled asthma Pulmonary oedema Acute non-cardiopulmonary disorder that may affect exercise performance or be aggravated by exercise (ie, infection, renal failure, thyrotoxicosis) Mental impairment leading to inability to cooperate Orthopaedic impairment that compromises exercise performance Electrolyte abnormalities Advanced or complicated pregnancy...

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Hemodialysis patients<br>The present study will comparatively evaluate a series of parameters (measured with cardiopulmonary exercise testing, spirometry, heart ultrasound, lung ultrasound and bioelectrical impedance analysis) in end-stage kidney disease patients undergoing hemodialysis between the end of the long and the end of the short interdialytic interval. The primary aim of the study is the evaluation of cardiorespiratory fitness - cardiovascular reserve assessed with cardiopulmonary exercise testing at these time points. | |
| Controls without CKD<br>Controls without CKD will be evaluated with cardiopulmonary exercise testing, spirometry, heart ultrasound, lung ultrasound and bioelectrical impedance analysis at one time point (baseline visit) | |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Difference in VO2peak (ml/min/kg) | Difference in VO2peak (ml/min/kg) assessed with CPET between long and short Interdialytic Interval in Hemodialysis Patients. | Two-week time frame between the study evaluation time points (before dialysis session after the long interdialytic interval versus before dialysis session after the short interdialytic interval) | 
| Difference in VO2peak ((ml/min) | Difference in VO2peak (ml/min) assessed with CPET between long and short Interdialytic Interval in Hemodialysis Patients. | Two-week time frame between the study evaluation time points (before dialysis session after the long interdialytic interval versus before dialysis session after the short interdialytic interval) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Difference in Maximum workload (Watt) | Difference in Maximum workload (Watt) assessed with CPET between long and short Interdialytic Interval in Hemodialysis Patients. | Two-week time frame between the study evaluation time points (before dialysis session after the long interdialytic interval versus before dialysis session after the short interdialytic interval) | 
| Difference in VCO2 (ml/min) | Difference in VCO2 (ml/min) assessed with CPET between long and short Interdialytic Interval in Hemodialysis Patients. | Two-week time frame between the study evaluation time points (before dialysis session after the long interdialytic interval versus before dialysis session after the short interdialytic interval) | 
| Difference in Heart Rate (bpm) | Difference in Heart Rate (bpm) assessed with CPET between long and short Interdialytic Interval in Hemodialysis Patients. | Two-week time frame between the study evaluation time points (before dialysis session after the long interdialytic interval versus before dialysis session after the short interdialytic interval) | 
| Difference in O2 pulse | Difference in O2 pulse assessed with CPET between long and short Interdialytic Interval in Hemodialysis Patients. | Two-week time frame between the study evaluation time points (before dialysis session after the long interdialytic interval versus before dialysis session after the short interdialytic interval) | 
| Difference in VE (L/min) | Difference in VE (L/min) assessed with CPET between long and short Interdialytic Interval in Hemodialysis Patients. | Two-week time frame between the study evaluation time points (before dialysis session after the long interdialytic interval versus before dialysis session after the short interdialytic interval) | 
| Difference in Tidal Volume, VT (ml) | Difference in Tidal Volume, VT (ml) assessed with CPET between long and short Interdialytic Interval in Hemodialysis Patients. | Two-week time frame between the study evaluation time points (before dialysis session after the long interdialytic interval versus before dialysis session after the short interdialytic interval) | 
| Difference in Respiratory Rate, RR | Difference in Respiratory Rate, RR assessed with CPET between long and short Interdialytic Interval in Hemodialysis Patients. | Two-week time frame between the study evaluation time points (before dialysis session after the long interdialytic interval versus before dialysis session after the short interdialytic interval) | 
| Difference in PETCO2 (mmHg) | Difference in PETCO2 (mmHg) assessed with CPET between long and short Interdialytic Interval in Hemodialysis Patients. | Two-week time frame between the study evaluation time points (before dialysis session after the long interdialytic interval versus before dialysis session after the short interdialytic interval) | 
| Difference in PETO2 (mmHg) | Difference in PETO2 (mmHg) assessed with CPET between long and short Interdialytic Interval in Hemodialysis Patients. | Two-week time frame between the study evaluation time points (before dialysis session after the long interdialytic interval versus before dialysis session after the short interdialytic interval) | 
| Difference in VE/VCO2 | Difference in VE/VCO2 assessed with CPET between long and short Interdialytic Interval in Hemodialysis Patients. | Two-week time frame between the study evaluation time points (before dialysis session after the long interdialytic interval versus before dialysis session after the short interdialytic interval) |