Comparison of Squat-to-Stand Maneuver With Amyl Nitrite, Valsalva, and Exercise Stress Echocardiography in Inducing Latent Left Ventricular Outflow Obstruction in Hypertrophic Cardiomyopathy

Hypertrophic Cardiomyopathy Clinical Trial

Official title:

Comparison of Squat-to-Stand Maneuver With Amyl Nitrite, Valsalva, and Exercise Stress Echocardiography in Inducing Latent Left Ventricular Outflow Obstruction in Hypertrophic Cardiomyopathy

Clinical Trial Details — Status: Withdrawn

Administrative data

• NCT number: NCT04905173
• Other study ID #: 21-003194
• Status: Withdrawn
• Phase: N/A
• Start date: November 2021
• Est. completion date: May 2022

Study information

• Verified date: December 2021
• Source: Mayo Clinic
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

The purpose of this study is to assess the effectiveness of squat-to-stand maneuver in eliciting left ventricular outflow gradients in patients with Hypertrophic Cardiomyopathy (HCM) compared to Valsalva, amyl nitrite inhalation, and exercise stress echocardiogram (ESE).

Description:

Left ventricular hypertrophy and abnormal ventricular configuration result in dynamic left ventricular outflow obstruction in ~75% of HCM patients, which is associated with increased cardiac morbidity and mortality. However, the dynamic nature of the gradient can make obstruction difficult to identify. Provocative maneuvers such as Valsalva maneuver, administration of amyl nitrite, and ESE are currently used to assess for obstruction.

A shortage of amyl nitrite beginning in December 2018 spurred a search for alternative provocative maneuvers. Beginning in February 2019, the Mayo Clinic echocardiography laboratory began utilizing a squat-to-stand maneuver as an alternative to amyl nitrite inhalation. Anecdotally, the squat-to-stand maneuver, which decreases both preload and afterload, has been successful in provoking latent left ventricular outflow obstruction. A retrospective study (Peng et al, in progress) studying 119 patients who performed the squat-to-stand maneuver between February and September 2019 demonstrated squat-to-stand to be a more robust provocative maneuver than the Valsalva maneuver for identifying severe dynamic left ventricular obstruction with Doppler echocardiography. Squat-to-stand elicited latent obstruction in a greater proportion of the study participants and higher average gradients. It also demonstrated the potential to alter clinical management - six patients had severe obstruction only with squat-to-stand (otherwise would not have been diagnosed) and subsequently underwent septal reduction surgery.

The recent return of amyl nitrite to the echocardiography laboratory creates an opportunity for direct comparison with squat-to-stand, particularly regarding cost savings and diagnostic performance. The primary purpose of this study is to evaluate the efficacy and degree of provocation of left ventricular outflow gradients by the squat-to-stand maneuver compared to amyl nitrite inhalation in patients with HCM undergoing echocardiography. Squat-to-stand will also be compared with other provocation methods, including Valsalva maneuver, which should be performed on every patient going on to squat-to-stand, and ESE when available. Validating this novel provocative maneuver can broaden the toolbox of techniques used to elicit left ventricular outflow gradients and improve clinical evaluation and management of symptomatic HCM patients.

Recruitment information / eligibility

• Status: Withdrawn
• Enrollment: 0
• Est. completion date: May 2022
• Est. primary completion date: May 2022
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years and older

Eligibility

Inclusion Criteria:

• Adults = 18 y/o referred for an outpatient echocardiogram.

• Clinical diagnosis of Hypertrophic Cardiomyopathy (HCM).

• Both amyl nitrite inhalation and squat-to-stand maneuver performed during echocardiogram.

Exclusion Criteria:

• Patients < 18 at the time of echocardiogram.

• Studies without documented provocative maneuvers.

• Patients with resting obstruction (MIG > 50 mmHg).

• Patients unable to undergo the squat-to-stand as protocolled based because of physical limitations.

• Patient with contraindications to amyl nitrite administration.

Related Conditions & MeSH terms

• Cardiomyopathies
• Cardiomyopathy, Hypertrophic
• Hypertrophic Cardiomyopathy
• Hypertrophic Obstructive Cardiomyopathy
• Hypertrophy
• Ventricular Outflow Obstruction

Intervention

Other:
• Squat-to-stand maneuver
Subjects will squat for 5 seconds and then stand. The squat-to-stand exercise will be done up to 10 times, and then immediately undergo echocardiographic imaging.

Drug:
• Amyl nitrite inhalation
Subjects will inhale amyl nitrite prior to undergoing echocardiographic imaging. This is administered according to current laboratory protocol and is part of standard of care. This is an FDA-regulated drug that will be used as a control and will not be studied experimentally.

Other:
• Valsalva
Subjects will undergo echocardiographic imaging while performing the Valsalva maneuver. This is according to current laboratory protocol and is part of standard of care.

Locations

Country	Name	City	State
n/a

Sponsors (1)

Lead Sponsor	Collaborator
Mayo Clinic

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Severe provokable obstruction	Percentage of patients with provokable obstruction (rest gradient < 30 mmHg AND gradient w/ maneuver = 30 mmHg) by provocation technique	Baseline
Secondary	Maximal instantaneous gradient	Maximal instantaneous gradient (MIG) by provocation technique measured in mm Hg	Baseline
Secondary	Completion of squat-to-stand maneuver	Percentage of patients unable to complete a squat-to-stand maneuver	Baseline

External Links

•   Mayo Clinic Clinical Trials