Coronary microvascular angina (MVA) significantly reduces quality of life and increases the risk of heart problems in patients with angina. Unfortunately, there are no effective treatments available yet. The endothelin-1 (ET-1) - endothelin receptor (ETRs) system plays a critical role in MVA. Preclinical studies demonstrate that ETRs antagonists or pericyte-specific knockdown of ETRs can improve coronary microvascular function in myocardial ischemia/reperfusion mice and diabetic mice. Foreign clinical drug trials have shown that ETRs antagonists may alleviate patients' symptoms. However, these studies predominantly rely on conventional coronary angiography rather than direct assessment of coronary microvascular function. Early experimental trials using ETRs antagonists reported a high incidence of side effects, such as sodium retention and headaches, which negatively impacted treatment satisfaction. To address these limitations, a pilot study is proposed to evaluate the efficacy of macitentan in MVA treatment. This investigation will implement thermodilution-based coronary microcirculation function testing to precisely characterize the severity and subtype of coronary microvascular lesions in MVA patients. By administering macitentan - a safer ETRs antagonist - the study aims to systematically assess improvements in coronary microvascular function, angina symptom relief, and adverse event incidence. The findings are expected to provide critical evidence regarding the therapeutic potential and safety profile of macitentan, while establishing foundational data for subsequent large-scale clinical trials.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
30
After the patient signed an informed consent form, Macitentan was given as an oral medication (10 mg once daily) for a period of 4 weeks
China-Japan Friendship Hospital
Beijing, Beijing Municipality, China
RECRUITINGChange From Baseline to Week 4 in the Coronary Microcirculatory Function Indices Assessed by CFR and IMR
Coronary microcirculatory function indices include Coronary Flow Reserve (CFR) and Index of Microcirculatory Resistance (IMR) 1. Coronary Flow Reserve (CFR): A unitless ratio quantifying maximal coronary blood flow augmentation capacity, measured via thermodilution as the ratio of hyperemic to resting coronary flow. The commonly used cut-off value is 2.0 or 2.5. Increased ratio indicates improved microvascular dilation capacity 2. Index of Microcirculatory Resistance (IMR): A pressure-derived metric (units: mmHg·s) assessing microvascular resistance using thermodilution, calculated as distal coronary pressure multiplied by mean transit time during maximal hyperemia. The commonly used cut-off value is 25. Decreased value indicates reduced microvascular resistance
Time frame: the duration of hospital stay, an expected average of 2 weeks; 4-week follow-up
Change in Score of the Seattle Angina Questionnaire (SAQ)
The Seattle Angina Questionnaire (SAQ) is a 19-item instrument designed to assess the impact of angina on patients' daily lives across five domains: physical limitation, angina stability, angina frequency, treatment satisfaction, and disease perception. Each item is scored on a 0-100 scale, where higher scores indicate fewer symptoms and better quality of life.
Time frame: the duration of hospital stay, an expected average of 2 weeks; 4-week follow-up; 8-week follow-up
Change in Angina Symptoms Assessed by Angina Diary
The angina diary is a structured log where patients record angina episodes, including their frequency, severity, duration, and possible triggers. Symptom severity is classified using a 4-level grading system similar to the Canadian Cardiovascular Society (CCS) angina.
Time frame: the duration of hospital stay, an expected average of 2 weeks; 4-week follow-up; 8-week follow-up
Change in the Score of 6-minute Walking Distance (6MWD)
The 6MWD test evaluates functional exercise capacity by measuring the total distance a patient can walk on a flat surface in 6 minutes. The test reflects cardiovascular fitness and symptom severity.
Time frame: the duration of hospital stay, an expected average of 2 weeks; 4-week follow-up; 8-week follow-up
Incidence of rehospitalisation for angina or heart failure.
Time frame: 4-week follow-up; 8-week follow-up
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