Exercise Tolerance in Patients With Implanted Left Ventricular Assist Device

Study Overview
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Brief Summary
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To evaluate the concept of dynamic pump speed optimization based on the echocardiographic assessment of aortic valve opening during cardiopulmonary exercise test.

Detailed Description
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Left ventricular assist devices (LVAD) are becoming a destination therapy in patients with end-stage left ventricular dysfunction. Current generation pumps operate with a fixed rotation speed without the capability of automated speed adjustment. It was shown that acceleration of the pump speed during stress test increases the maximum exercise tolerance. Periodic aortic valve opening (AVO) is used to set up an optimal resting pump speed. The study aimed to evaluate the concept of dynamic pump speed optimization based on the echocardiographic assessment of AVO during the cardiopulmonary exercise test (CPET). Patients with implanted third-generation LVADs with hydrodynamic bearing (HVAD, Medtronic, MN, USA) are prospectively enrolled. Two CPETs are performed after resting speed optimization. The first one with maintained baseline pump speed settings, and the second one with gradually increased speed depending on live echocardiographic imaging. The sequence of tests is random.

Official Title
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Exercise Tolerance in Patients With Implanted Left Ventricular Assist Device

Conditions
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Left Ventricular Assist Device

Intervention / Treatment
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* Other: Cardiopulmonary exercise tests with maintained baseline optimal pump speed settings.
* Other: Cardiopulmonary exercise test with gradually increased pump speed depending on live echocardiographic imaging.


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with implanted cardioverter-defibrillator and third-generation centrifugal CF-LVAD with hydrodynamic bearing (HVAD, Medtronic, Minnesota, United States), at least three months after surgery. Exclusion Criteria: Hemodynamic instability. Non-therapeutic anticoagulation. Device or intracardiac thrombus. Inflammation. Active bleeding.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Non-Randomized
Intervention Model: Sequential Assignment
Interventional Model Description: prospective crossover AB/BA study
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: LVAD pump speed dynamically adjusted<br> | Other: Cardiopulmonary exercise test with gradually increased pump speed depending on live echocardiographic imaging.<br>* During the modified speed exercise, when the aortic valve opening ratio rises above 50%, the pump speed is increased by 100 revolutions per minute (RPM). As the aortic valve remains closed the RPM is lowered by 100. Speed increment is not greater than 100 RPM per 45 seconds to enable an echocardiographic analysis of resulting changes and prevent suction events. There is no determined target speed, neither per time period nor maximal.<br>|
| Active Comparator: LVAD pump at optimal resting speed<br> | Other: Cardiopulmonary exercise tests with maintained baseline optimal pump speed settings.<br>* Optimal resting LVAD speed settings is defined as periodic aortic valve opening while maintaining the central position of the intraventricular septum, minimizing mitral regurgitation, and preserving the mean systemic blood pressure above 65 mmHg. The aim is to achieve an aortic valve opening ratio of around 25-33% by changing the pump speed at resting conditions.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Echocardiographic appraisal of aortic valve opening during cycle ergometer exercise. | Assessment of aortic valve opening during cycle ergometer exercise in LVAD patients. | Immediately, during cycle ergometer exercise | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in oxygen consumption | By using the cardiopulmonary exercise test | Immediately, during cycle ergometer exercise | 
| Change in perceived exertion | By using the Borg rating of perceived exertion scale. Score 6-20 (6 - no exertion, 20 - maximal exertion) | Immediately, during cycle ergometer exercise | 
| Change in pump speed | By assessing pump speed (RPM) | Immediately, during cycle ergometer exercise. | 
| Change in pump flow | By assessing pump flow (l/min) | Immediately, during cycle ergometer exercise | 
| Change in pump power | By assessing pump power (W) | Immediately, during cycle ergometer exercise | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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peak VO2, left ventricular assist device, cardiopulmonary exercise test, stress echocardiography, heart failure, mechanical circulatory support