Association Between Microvascular Resistance and Outcomes in Patients With Obstructive Hypertrophic Cardiomyopathy

Study Overview
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Brief Summary
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About 60% of patients with hypertrophic cardiomyopathy have microvascular dysfunction. Microvascular dysfunction is directly related to prognosis in hypertrophic cardiomyopathy. This new measurement method is microcirculation resistance (MR) based on quantitative flow ratio (QFR), which does not need a pressure guide wire on the basis of angiography. The QFR system is used to evaluate the blood vessels distal pressure and blood flow, and their ratio is microcirculation resistance (MR). The quantitative blood flow fraction measurement system was analyzed by interventional laboratory platform image analysis software (AngioPlus 2.0). This study is a single-center retrospective cohort study. Participants were selected from patients who were diagnosed with hypertrophic obstructive cardiomyopathy in Fuwai Hospital from January 2020 to November 2021. The risk factor is whether there is microcirculation resistance disorder. The outcome was the major adverse cardiovascular events related to HCM (including all-cause death, heart transplantation, left ventricular pacemaker, and heart failure readmission) that were followed up one year after angiography. Aim To further clarify whether there is a certain correlation between microvascular resistance and adverse cardiovascular prognosis.

Official Title
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Evaluation of the Correlation Between Coronary Microvascular Resistance Based on Quantitative Flow Ratio and Major Adverse Cardiovascular Events in Patients With Obstructive Hypertrophic Cardiomyopathy: A Retrospective Cohort Study

Conditions
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Microvascular Dysfunction, Hypertrophic Obstructive Cardiomyopathy, Microcirculation Resistance

Participation Criteria
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Eligibility Criteria
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Inclusion criteria: Aged 18-80 years old; Patients with hypertrophic obstructive cardiomyopathy undergoing coronary angiography. Diagnosis criteria that meet the diagnostic guidelines for hypertrophic obstructive cardiomyopathy: It usually refers to the thickness of the ventricular septum or left ventricular wall measured by two-dimensional echocardiography > 15 mm, or the thickness of > 13mm in patients with a clear family history, usually without enlargement of the left ventricular cavity, and the thickening of the left ventricular wall caused by increased loads, such as hypertension, aortic stenosis, and congenital subvalvular septum should be excluded; LVOTG>30 mmHg under quiet or exercise conditions. The informed consent form for the use of sample data of patients admitted to the hospital has been signed; Exclusion criteria: No contrast examination is performed for various reasons; Missing baseline important information indicators; Loss of follow-up;

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 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 |
| --- | --- |
| Artery without microcirculation resistance<br>The angiographic microvascular resistance (AMR) index was analyzed by interventional laboratory platform image analysis software (AngioPlus 2.0). AMR<2.5 mmHg*s/cm is defined as no microvascular resistance. | |
| Single artery with microcirculation resistance<br>The angiographic microvascular resistance (AMR) index was analyzed by interventional laboratory platform image analysis software (AngioPlus 2.0). AMR≥2.5 mmHg*s/cm is defined as microvascular resistance. There is only one of three major coronary arteries in 3 that meets this condition. | |
| Multiple arteries with microcirculation resistance<br>The angiographic microvascular resistance (AMR) index was analyzed by interventional laboratory platform image analysis software (AngioPlus 2.0). AMR≥2.5 mmHg*s/cm is defined as microvascular resistance. Two of the three major coronary arteries meet this condition. | |
| Three arteries with microcirculation resistance<br>The angiographic microvascular resistance (AMR) index was analyzed by interventional laboratory platform image analysis software (AngioPlus 2.0). AMR≥2.5 mmHg*s/cm is defined as microvascular resistance. All three major coronary arteries meet this condition. | |
| Significant microcirculation resistance<br>The angiographic microvascular resistance (AMR) index was analyzed by interventional laboratory platform image analysis software (AngioPlus 2.0). AMR≥2.5 mmHg*s/cm is defined as microvascular resistance. The sum of AMR of the three main arteries is greater than 7.5mmHg*s/cm | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The Major Adverse Cardiovascular Events related to HoCM | including all-cause death, heart transplantation, left ventricular pacemaker, heart failure readmission | One-year followed up after angiography | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Scale of KCCQ-12 | KCCQ-12, a questionnaire of cardiomyopathy in Kansas City, which comes from the telephone follow-up or reexamination of cardiac rehabilitation records of departments, consists of 8 questions and 12 items, which are simplified from KCCQ-23. The score ranged from 0 to 100 points, with a higher score and better health. | One-year followed up after angiography | 
| Borg Index after 6MWT | Borg index reflects the dyspnea and fatigue level after 6MWT, with a standard score of 0-10. The score ranged from 0 to 10 points, and a higher score indicated a better prognosis. | One-year followed up after angiography |