Identifying an Ideal Cardiopulmonary Exercise Test Parameter (PVA)
Cardiopulmonary exercise testing (CPET) is a safe, noninvasive investigation where a patient walks on a treadmill or cycles whilst attached to an ECG and with a mask that measures the air breathed in and out. It has numerous clinical uses, such as diagnosing the main cause in patients with breathlessness, deciding on timing for heart transplantation and assessing whether patients are safe for a general anaesthetic.
A patient's peak oxygen consumption, the maximum amount of oxygen taken up by the blood from the lungs when breathing increases during exercise, is the main measurement taken from CPET. It is low in heart disease and has been used to predict the risk of death and therefore plan treatments for patients. However this is also low in numerous other diseases including lung disease; reduced oxygen consumption in patients with two conditions may be wrongly thought to be because of the heart leading to inappropriate action and distress to the patient.
Newer measurements of exercise capacity from the same exercise test are better at predicting death in heart failure.
We propose that they are more specific for heart failure over other diseases, for example lung disease, when compared with peak oxygen consumption, and are superior when a single best test for heart failure is required.
This research aims to identify which measurement of exercise capacity is most specific for heart failure. We will perform the test on many patients with different diseases, and before and after procedures such as the implantation of special pacemakers, and heart valve operations. This should lead to a more accepted use of this investigation and the more appropriate identification of which patient should have which procedure.
Left Ventricular Systolic Dysfunction
|Study Design:||Observational Model: Cohort
Time Perspective: Prospective
|Official Title:||Identifying the Ideal Parameter of the Cardiopulmonary Exercise Test to Distinguish Between the Cardiovascular and Respiratory Components of Functional Limitation and to Detect Relevant Physiological Changes in Function|
- The relation or change between Cardiopulmonary exercise test variables [ Time Frame: Up to 6 months ]
In the Observational Cohort Study the primary outcome measure is the relation between variables (peak VO2, VE/VCO2, OUES, Tau, AT) when compared between the groups with different disease states.
In the Interventional Cohort Study the primary outcome is the change in a variable (peak VO2, VE/VCO2, OUES, Tau, AT) from before to after an intervention which is required on clinical grounds.
- Using Cardiopulmonary Exercise Test Variables to help Assess for Functional Improvement [ Time Frame: 6 months ]In patients undergoing heart valve replacements or an ablation for atrial fibrillation the improvement in symptomatic benefit will be compared to the change in cardiopulmonary exercise test variables.
|Study Start Date:||October 2010|
|Study Completion Date:||May 2013|
|Primary Completion Date:||May 2013 (Final data collection date for primary outcome measure)|
Mitral Valve disease
Patients with mitral valve disease, deemed suitable and ready for elective valve repair or replacement. No significant arrhythmias, other valvular disease or LV dysfunction present. We shall also be recruiting patients undergoing a Mitraclip procedure.
Patients with isolated chronic obstructive pulmonary disease and no cardiac disease.
Patients with proven limitation from both cardiac and respiratory disease.
Patients with symptomatic heart failure who have responded to cardiac resynchronisation therapy (biventricular pacemaker).
Heart Failure of primarily myopathic origin, without rhythm disturbance, ongoing ischaemia or significant valvular disease.
Heart failure, where the heart muscle is damaged and is unable to pump blood efficiently, affects 9% of those aged 55 or more and is responsible for about 2% of the hospital admissions in the UK. The first symptom many patients complain of is breathlessness on exercise and an inability to perform their normal daily activities. Unfortunately these symptoms are similar to those experienced in numerous diseases of the heart and lungs. Cardiopulmonary exercise testing, through measuring numerous values taken from breathing during exercise can tell us which disease is causing the symptoms.
The leading parameter from a CPET, peak VO2, has for many years been the single value used to guide management of patients following a diagnosis of many diseases from the heart and lungs. Newer measures predict outcome from heart failure (our principal area of interest) better. We believe this may be because they are less affected by lung disease than peak VO2 and we know that many patients have both heart and lung diseases.
By showing the best CPET variable for each individual disease state, we will be able to ensure patients are correctly put into a level of risk for their condition and that they will be followed-up with the most accurate marker from exercise testing, rather than a "one size fits all" approach of peak VO2.
With regards to heart valve disease, standard exercise testing just using ECG leads, rather than cardiopulmonary exercise testing, is starting to be used more in identifying patients without symptoms for possible surgery. The inaccuracy of this test will inevitably lead to patients being wrongly categorised. Cardiopulmonary exercise testing is a much more accurate way of establishing the impact of any disease on the heart or lung over traditional exercise testing and therefore we believe that evidence of its role around the time of surgery could be used as further support for its role in improving decision making for patient.
Ultimately the greater knowledge of this test and when we should use it will help patients with very common heart conditions to be treated appropriately, potentially helping many patients.
Please refer to this study by its ClinicalTrials.gov identifier: NCT01162083
|Imperial College Healthcare NHS Trust|
|London, United Kingdom, W2 1LA|
|Principal Investigator:||Roland Wensel, MD PhD||Imperial College London|