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Quantitative Assessment of Hypertrophic Obstructive Cardiomyopathy With Intraoperative Three-dimensional Transesophageal Echocardiography Under Provocative Dobutamine Stress Test

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ClinicalTrials.gov Identifier: NCT05025644
Recruitment Status : Not yet recruiting
First Posted : August 27, 2021
Last Update Posted : November 8, 2022
Sponsor:
Information provided by (Responsible Party):
University Health Network, Toronto

Brief Summary:

The objectives of this study are to determine if the left ventricle outflow tract (LVOT) gradients may be reproduced with dobutamine (DBT) provocation test in obstructive HCM patients under general anesthesia and to analyze the change in anatomic LVOT area and pressure gradients (PG) before and after septal myectomy.

If the DBT stress test can reproduce preoperative gradients in HCM patients during septal myectomy surgery, surgeons will have the opportunity to assess the quality of the surgical procedure depending on the obtained gradients with DBT stress test after surgery when gradients can't be reproduced during general anesthesia after myectomy, and decide if further myectomy is required, saving a re-operation on the patient in the future.


Condition or disease Intervention/treatment Phase
Hypertrophic Obstructive Cardiomyopathy Drug: Pre and post-CPB Drug: Dobutamine Hydrochloride Drug: Post-CPB Drug: Dobutamine Hydrochloride Phase 4

Detailed Description:

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiomyopathy. Echocardiography is the noninvasive method of choice for the evaluation of morphologic and functional abnormalities in HCM. It is of paramount importance to distinguish between obstructive or non-obstructive HCM, based on the presence or absence of left ventricle outflow tract (LVOT) gradient using continuous wave Doppler (CWD), under resting and/or provocable conditions. HCM can then be divided into three different subgroups. When the gradient at rest is ≥ 30 mmHg the HCM is considered obstructive (HOCM); when the gradient is <30 mmHg at rest but ≥ 30 mmHg with provocation, the HCM is considered latent obstructive, and finally, non-obstructive occurs when the gradient is < 30mmHg at rest or with provocation.

The gold standard technique to treat symptomatic HOCM is the surgical transaortic septal myectomy, when the resting gradient or the provocable gradient is ≥50 mmHg. Hemodynamic conditions may change and lead to worsening or improvement in LVOT obstruction during general anesthesia. LVOT gradients during surgery should be measured under reproducible conditions possibly mimicking preoperative hemodynamics.

Dobutamine is a well-known inotropic agent, capable to induce sub-aortic gradients in HOCM. The development of a dynamic LVOT gradient during this test is a pharmacological phenomenon with no clinical significance, not been associated with increased frequency of chest pain, shortness of breath or ischemic wall motion abnormalities, because obstruction resolves after termination of dobutamine (DBT) infusion.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 60 participants
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Intervention Model Description:

This is a monocentric Phase IV prospective study that will be conducted on patients undergoing surgical myectomy treatment for HOCM, at Toronto General Hospital, to assess if LVOT gradients may be reproduced with dobutamine provocation test in HOCM patients under general anesthesia.

The participants in the study will require a standard 2D echocardiography within 6 months pre and post-surgery. Intraoperatively, the patients will be divided into two groups, one with preoperative PG under anesthesia <50mmHg (Group A), and one with preoperative PG under anesthesia ≥ 50mmHg (Group B).

Masking: None (Open Label)
Primary Purpose: Diagnostic
Official Title: Quantitative Assessment of Hypertrophic Obstructive Cardiomyopathy With Intraoperative Three-dimensional Transesophageal Echocardiography Under Provocative Dobutamine Stress Test
Estimated Study Start Date : March 2023
Estimated Primary Completion Date : August 2024
Estimated Study Completion Date : November 2024


Arm Intervention/treatment
Experimental: Preoperative Transesophageal Echocardiogram (TEE) PG under anesthesia <50mmHg (Group A)
  • Pre-cardiopulmonary bypass (CPB) (pre-myectomy) echocardiographic parameters: PG under DBT stress test at 5, 10, 15 and 20 mcg/kg/min or until a PG ≥ 50mmHg is achieved, will be recorded.
  • Post-CPB (post-myectomy) echocardiographic parameters: PG at DBT peak dose (DBT-pd) will be recorded.

If LVOT PG post myectomy are >16 mmHg, the surgeon will be advised, for surgical management considerations.

Drug: Pre and post-CPB Drug: Dobutamine Hydrochloride
  • Pre-CPB provocation test with DBT stress test will be started (starting at 5 mcg/kg/min, increasing every 3 min, to 10, 15 and 20 mcg/kg/min) until a PG ≥ 50mmHg is achieved (DBT peak dose). The DBT peak dose (DBT-pd) will be recorded.
  • Post-CPB provocation test at the DBT-pd achieved preoperatively.
Other Names:
  • Transthoracic or 2D Echocardiogram
  • Transesophageal Echocardiogram (TEE)

Experimental: Preoperative PG under anesthesia ≥ 50mmHg (Group B)
  • Pre-cardiopulmonary bypass (CPB) (pre-myectomy) echocardiographic parameters: PG without DBT stress test will be recorded.
  • Post-CPB (post-myectomy) echocardiographic parameters: PG at 5, 10, 15, 20 mcg/kg/min DBT stress test or until the postoperative provocable PG is >16 mmHg will be recorded.
Drug: Post-CPB Drug: Dobutamine Hydrochloride
  • Pre-CPB no intervention will be required.
  • Post-CPB provocation test with DBT stress test will be started (starting at 5 mcg/kg/min, increasing every 3 min, to 10, 15 and 20 mcg/kg/min) or until postoperative provocable PG is >16 mmHg.
Other Names:
  • Transthoracic or 2D Echocardiogram
  • Transesophageal Echocardiogram (TEE)




Primary Outcome Measures :
  1. Analyze if TEE immediate post-myectomy LVOT gradients, may be reproduced with provocation dobutamine test in HOCM patients, when compared to TTE LVOT gradients performed within 6 months post-myectomy, to prove septal myectomy efficacy. [ Time Frame: Pre-operative up to 6 months, Immediate Intra-operative Pre-myectomy, Immediate Intra-operative Post-myectomy and Post-operative up to 6 months ]

    The preoperative gradients obtained by TTE, with and without stress test, within 6 months pre-myectomy, will be compared with the intraoperative TEE pre-myectomy gradients at baseline (before and after DBT stress test).

    The post-myectomy TEE gradients (before and after DBT stress test), will be compared with the follow up TTE gradients with and without stress test, performed within 6 months post-myectomy, to assess short term outcomes.




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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  1. HOCM refractory to medical treatment with symptoms like syncope, angina or NYHA functional classes III and IV, with a resting gradient or provocable gradient equal or greater than 50 mmHg, requiring surgical intervention.
  2. Absence of other cardiac or systemic diseases capable of producing hypertrophy.
  3. Sinus rhythm.

Exclusion Criteria:

  1. Patient refusal.
  2. Patient unable to give consent.
  3. TEE contraindication.
  4. Different rhythm than sinus.
  5. Other systemic diseases capable of producing hypertrophy.
  6. Severe Aortic or coronary artery pathology.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT05025644


Contacts
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Contact: Azad Mashari, MD (416) 340-4800 ext 5164 azad.mashari@uhn.ca
Contact: Jo Carroll 416 340-4800 ext 3243 jo.carroll@uhn.ca

Sponsors and Collaborators
University Health Network, Toronto
Investigators
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Principal Investigator: Jacobo Moreno Garijo, MD Sunnybrook Health Science Centre
Principal Investigator: Azad Mashari, MD University Health Network, Toronto
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Responsible Party: University Health Network, Toronto
ClinicalTrials.gov Identifier: NCT05025644    
Other Study ID Numbers: 16-5412
First Posted: August 27, 2021    Key Record Dates
Last Update Posted: November 8, 2022
Last Verified: November 2022

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by University Health Network, Toronto:
Transesophageal Echocardiography
Dobutamine Stress test
Additional relevant MeSH terms:
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Cardiomyopathies
Cardiomyopathy, Hypertrophic
Hypertrophy
Heart Diseases
Cardiovascular Diseases
Pathological Conditions, Anatomical
Aortic Stenosis, Subvalvular
Aortic Valve Stenosis
Aortic Valve Disease
Heart Valve Diseases
Dobutamine
Cardiotonic Agents
Sympathomimetics
Autonomic Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Adrenergic beta-1 Receptor Agonists
Adrenergic beta-Agonists
Adrenergic Agonists
Adrenergic Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Protective Agents