Volume Challenge Added to DSE in the Diagnosis of Severe LFLGAS

Study Overview
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Brief Summary
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The aim of this study is to test the diagnostic added value of Volume Challenge (VC) to low-dose dobutamine stress echocardiography (LDDSE) in patients with a low-flow, low-gradient aortic stenosis (LFLGAS). This study will assess if LDDSE plus VC allows to increase the proportion of patients in whom a true severe AS can be differentiated from a pseudo severe AS.

Detailed Description
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The design of the study is a monocentric prospective non-randomized pilot clinical trial. A standard LDDSE will be performed. The stroke volume (SV) will be recorded. The addition of VC with the passive leg raise method at peak dobutamine dose will be performed. A transesophageal echocardiography (TEE) with low dose dobutamine and a bolus of normal saline will be performed as a validation method to measure AVA with the planimetry method. The SV will be recorded. Proportion of patient receiving the diagnosis of true severe AS defined as a combination of AVA <1.0 cm2 and ∆SV ≥ 20% will be compared between standard LDDSE and LDDSE with addition of VC. Calculating sensitivity, specificity, performing ROC curve analysis and calculating the Youden-index, the accuracy of the test method (LDDSE plus passive leg raising) for the detection of truly severe AS in comparison with the reference method (TEE) will be determined.

Official Title
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Volume Challenge Added to Dobutamine Stress Echocardiography in the Diagnosis of Severe Low-Flow, Low-Gradient Aortic Stenosis

Conditions
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Aortic Valve Stenosis

Intervention / Treatment
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* Diagnostic Test: Volume Challenge


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age > 18 years Written informed consent Patients with LFLGAS (mean Gradient: < 40 mmHg, AVA ≤ 1.0 cm2 (by continuity equation using LVOT diameter) SVI ≤ 35 ml/m2), by rest TTE Exclusion Criteria: Hypersensitivity to dobutamine or midazolam Lack of safe contraception defined as: Female participants of childbearing potential not using and not willing to continue contraception for study duration, such as oral, injectable, or implantable contraceptives, or intrauterine contraceptive devices. Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia, etc., Enrolment of the investigator, his/her family members, employees and other dependent persons Previous enrolment into the current study, ADDITIONAL SPECIFIC EXCLUSION CRITERIA REGARDING STRESS ECHOCARDIOGRAPHY: Systolic left ventricular ejection fraction (LVEF) < 20% More than mild aortic regurgitation Mitral valve disease, defined by mitral valve area < 2.0 cm2 or more than mild mitral regurgitation Unstable angina Acute pulmonary oedema Signs of relevant left ventricular heart failure defined as crackles more than one fourth of lung field on auscultation Signs of relevant right ventricular heart failure defined as central venous pressure (CVP) > 15 mmHg estimated with dilatation and collapsibility of vena cava inferior (VCI) Severe pulmonary, renal or hepatic disease ADDITIONAL SPECIFIC EXCLUSION CRITERIA REGARDING TRANSESOPHAGEAL ECHOCARDIOGRAPHY: Oesophageal varices History of bariatric surgery

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
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Arm Volume Challenge<br>A standard LDDSE will be performed. The stroke volume (SV) will be recorded. The addition of VC with the passive leg raise method at peak dobutamine dose will be performed. A TEE with low dose dobutamine and a bolus of normal saline will be performed as a validation method. | Diagnostic Test: Volume Challenge<br>* Addition volume challenge with passive leg raising method in LDDSE as well as administration of normal saline and dobutamine during TEE<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Diagnosis of true severe AS | Proportion of patients receiving the diagnosis of true severe AS defined as a combination of AVA <1.0 cm2 and ∆SV ≥ 20% will be compared between standard LDDSE and LDDSE with addition of VC | Measures taken during echocardiograph a few minutes after administration of VC | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Low - flow, Low - gradient, Low - dose dobutamine, Volume challenge, Echocardiography