Evaluation of the Hemodynamic Significance of Myocardial Bridge by Coronary Blood Fractional Flow Reserve

Study Overview
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Brief Summary
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This study clarified the influence of myocardial bridge on coronary hemodynamics by clarifying FFR and d-FFR to guide clinical intervention and treatment.

Detailed Description
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Myocardial bridge is a congenital anatomical abnormality, which is generally considered to be a benign change, but individual can cause angina, myocardial infarction and even sudden death. Previously, it was believed that the degree of myocardial ischemia induced by myocardial bridge was related to factors such as the location, length, and systolic stenosis of the myocardial bridge shown by coronary angiography.However, in recent years, more and more evidence has suggested that there is a high degree of mismatch between anatomical stenosis and its function.Studies have shown that FFR and d-FFR can accurately evaluate the functional significance of stenotic lesions.This study intends to enroll patients who underwent coronary angiography due to chest pain and confirmed the left anterior descending artery (LAD) simple myocardial bridge systolic stenosis ≥30%, and the pressure guide wire was used to measure the FFR and d-FFR of the myocardial bridge lesion under static and dobutamine stress.Analyze the relationship between these functional parameters and the anatomical morphological characteristics of the myocardial bridge and other possible clinical influencing factors, and explore the influence of the morphological characteristics of the myocardial bridge on myocardial hemodynamics，so as to clarify the degree of myocardial bridge shown by angiography may induce obvious myocardial ischemia, which requires clinical intensive intervention.

Official Title
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Evaluation of the Hemodynamic Significance of Myocardial Bridge by Coronary Blood Fractional Flow Reserve

Conditions
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Myocardial Bridge

Intervention / Treatment
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* Diagnostic Test: FFR and d-FFR


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with chest pain aged ≥18 years old, regardless of gender; Coronary angiography shows a solitary myocardial bridge with systolic diameter stenosis ≥30% in LAD; Have the ability to complete an ECG exercise test; Sign informed consent and are willing to participate in the intended study. Exclusion Criteria: Patients with acute coronary syndrome; Coronary angiography shows that the diameter of atherosclerosis in the non-myocardial bridge area of LAD is ≥30%; RCA or LCX has severe fixed stenosis, diameter stenosis ≥70% or FFR<0.75, and no interventional therapy is accepted; Hypertrophic obstructive cardiomyopathy or more than moderate heart valve disease; Atrial fibrillation or severe slow or rapid arrhythmia; Heart failure with NYHA ≥ Grade III; Uncontrolled hypertension or systolic blood pressure <100mmHg; Asthma or severe chronic obstructive pulmonary disease; Severe liver and kidney dysfunction; Allergic to contrast agents.

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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Myocardial bridge<br>Measure FFR and d-FFR | Diagnostic Test: FFR and d-FFR<br>* Measure FFR and d-FFR<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Morphological index of myocardial bridge | The minimum lumen diameter of the target vessel | All indicators were completed within 1 week of coronary angiography. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Exercise electrocardiogram | ST segment depression time | 72 hours after coronary angiography |