Intrathoracic Bloodvolume Measurement by Contrast Enhanced Ultrasound: Validation of the Technique and Evaluation as a Measurement of Response to Cardiac Resynchronization Therapy: a Pilot Study

Study Overview
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Brief Summary
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Summary Rationale: Cardiac resynchronisation therapy (CRT) with biventricular pacemakers and implantable cardiac defibrillators (ICD) has proven to be a valuable therapy in selected patients with systolic heart failure, ameliorating both morbidity and mortality. However, with current selection criteria and implant technique, about 20 to 30 % of patients remain non-responders. Non-responders might be due to failing selection criteria or methodology in casu echocardiography. Moreover, the definition of response to CRT is unequivocal and there is a need for a simple and reproducible measure of response with low inter- and intra-observer variability. Primary objectives: This study evaluates the correlation between intrathoracic blood volume (ITBV) measured by contrast enhanced ultrasound (CEUS) and magnetic resonance imaging (MRI), as well as the feasibility to use intrathoracic blood volume as a predictor for response to CRT. Study design: a prospective nonrandomized pilot study Study population: patients with heart failure New York Heart Association (NYHA) class III or IV, a left ventricular ejection fraction equal to or less than 35% and a QRS-duration equal to or more than 0.12 seconds who are referred to our centre for implantation of a CRT-P or CRT-D device. Intervention: No specific intervention will be performed. Main study parameters: correlation between intrathoracic bloodvolume measured by CEUS and MRI, correlation between LVEF measured by CEUS and by standard 2D ultrasound (biplane methods of discs), change in intrathoracic blood volume as a response to CRT. Nature and extent of the burden and risks associated with participation, benefit and group relatedness: at baseline a clinical examination, laboratory analysis, cardiopulmonary exercise testing, echocardiography and cardiac magnetic resonance imaging will be performed. All of these examinations will be repeated at 3-months follow-up except for the cardiac magnetic resonance imaging. All examinations, except for the MRI, are part of the standard workup in our hospital for patients undergoing implantation of a CRT device. Data needed for the purpose of this study, will be acquired by offline image analysis with dedicated software.

Official Title
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Intrathoracic Bloodvolume Measurement by Contrast Enhanced Ultrasound: Validation of the Technique and Evaluation as a Measurement of Response to Cardiac Resynchronization Therapy: a Pilot Study

Conditions
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Intrathoracic Blood Volume in Heart Failure Patients

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥18y LVEF ≤35% QRS-duration ≥0.12 seconds NYHA functional class III or IV despite optimal medical therapy defined as use of angiotensin-converting enzyme inhibitors or angiotensin-II receptor blocker and beta-blockers unless they are not tolerated or contra-indicated sinus rhythm or atrial fibrillation Exclusion Criteria: episode of acute heart failure ≤3 months change in dosage of beta-blockers, angiotensin-converting enzyme inhibitors or angiotensin-II receptor blockers ≤3 months unstable angina pectoris, acute myocardial infarction, percutaneous intervention or coronary bypass surgery ≤3 months chronic atrial arrhythmias other than atrial fibrillation any mechanical or biological valve prosthesis atrial septal defect right-to-left shunt severe pulmonary hypertension (systolic pulmonary artery pressure >90 mmHg) uncontrolled arterial hypertension known allergy to sulphur hexafluoride end-stage renal or hepatic disease inability to provide written informed consent pregnancy or childbearing potential without use of birth-control measurements general contra-indications to magnetic resonance imaging

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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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| a. change in ITBV measured by CEUS before and after CRT |  | two years anticipated | 
| b. correlation of ITBV measured by CEUS and MRI before CRT |  | two years anticipated | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| a. correlation between LVEF estimated with CEUS and standard contrast 2D ultrasound |  | two years anticipated | 
| b. correlation between LVEF estimated with CEUS and MRI |  | two years anticipated |