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

NCT ID: NCT05025644

Last Updated: 2022-11-08

Basic Information

• Recruitment Status: UNKNOWN
• Clinical Phase: PHASE4
• Total Enrollment: 60 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2023-03-31
• Study Completion Date: 2024-11-30

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.

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.

Conditions

Hypertrophic Obstructive Cardiomyopathy

Study Design

• Allocation Method: NON_RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: DIAGNOSTIC
• Blinding Strategy: NONE

Study Groups

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.

Group Type: EXPERIMENTAL

Pre and post-CPB Drug: Dobutamine Hydrochloride

Intervention Type: DRUG

• 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.

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.

Group Type: EXPERIMENTAL

Post-CPB Drug: Dobutamine Hydrochloride

Intervention Type: DRUG

• 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.

Interventions

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.

Intervention Type: 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.

Intervention Type: DRUG

Other Intervention Names

Transthoracic or 2D Echocardiogram; Transesophageal Echocardiogram (TEE); Transthoracic or 2D Echocardiogram; Transesophageal Echocardiogram (TEE)

Eligibility 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.

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

University Health Network, Toronto

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Jacobo Moreno Garijo, MD

Role: PRINCIPAL_INVESTIGATOR

Sunnybrook Health Science Centre

Azad Mashari, MD

Role: PRINCIPAL_INVESTIGATOR

University Health Network, Toronto

Central Contacts

Azad Mashari, MD

Role: CONTACT

azad.mashari@uhn.ca

(416) 340-4800 ext. 5164

Jo Carroll

Role: CONTACT

jo.carroll@uhn.ca

416 340-4800 ext. 3243

Other Identifiers

16-5412

Identifier Type: -

Identifier Source: org_study_id