A Plant-Based Diet in the Treatment of Coronary Microvascular Dysfunction

N/ANot Yet RecruitingNCT07821372

Emory University20 enrolled

Overview

This study will evaluate whether a fully provided, unrefined, polyphenol-rich plant-based diet can improve blood vessel function in adults with coronary microvascular dysfunction (CMD), a condition that causes reduced blood flow in the small vessels of the heart despite the absence of major coronary artery blockages. Participants will follow the diet for 12 weeks while continuing their usual medical care. Researchers will assess changes in vascular function, symptoms, blood pressure, blood lipids, and other health measures throughout the study. Participants have up to 60 days after consent to complete screening and pre-intervention baseline assessments, potentially over two visits. Day 0 is counseling/education, and diet initiation. Weeks 4, 8, and 12 are measured from Day 0.

Coronary microvascular dysfunction (CMD) is characterized by impaired coronary microvascular vasodilation and reduced coronary flow reserve in the absence of obstructive epicardial coronary artery disease. CMD is a common cause of ischemic symptoms and is associated with persistent angina, reduced quality of life, and increased cardiovascular risk. Existing therapies are largely directed toward symptom management, and additional strategies that address underlying disease mechanisms are needed. Oxidative stress, impaired nitric oxide bioavailability, and abnormalities in vascular function are believed to contribute to CMD pathophysiology. Diets rich in unrefined plant foods contain polyphenols and other bioactive compounds that may favorably affect vascular biology, endothelial function, and redox balance. However, the effects of a polyphenol-rich plant-based dietary intervention in individuals with CMD have not been well characterized. The purpose of this study is to evaluate the effects of an unrefined, polyphenol-rich plant-based dietary pattern on vascular function in adults with CMD and to explore potential biological pathways associated with response to the intervention. The study will also assess the impact of the dietary intervention on symptoms, cardiometabolic health, and measures related to vascular and redox biology. Findings from this study may improve understanding of the role of dietary modification as a potential adjunctive approach for CMD and help inform future dietary and lifestyle interventions targeting coronary microvascular disease.

Study Type

INTERVENTIONAL

Allocation

Interventions

Polyphenol-Rich Plant-Based DietOTHER

A fully provided, weight-maintaining, unrefined, polyphenol-rich plant-based dietary intervention administered for 12 weeks. The diet is designed around whole plant foods, including fruits, vegetables, legumes, whole grains, nuts, and seeds, and excludes animal products, refined grains, added sugars, sugar-sweetened beverages, and commercially processed plant-based meat or cheese substitutes. Participants receive nutrition education, ongoing dietary counseling, meal provision, and vitamin B12 supplementation throughout the intervention period

Eligibility

Sex: ALLMin age: 45 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Women must be postmenopausal. * History of angina, ischemic symptoms, or symptoms consistent with ischemia in the absence of obstructive coronary artery disease. * No obstructive coronary artery disease (\<50% stenosis in any epicardial coronary artery or fractional flow reserve \>0.80). * Clinically documented coronary microvascular dysfunction (CMD), including coronary flow reserve \<2.5 and/or index of microcirculatory resistance ≥25, or equivalent documentation in the medical record. * Stable cardiometabolic medication regimen for at least 2 months before enrollment. * Willingness to consume the study-provided plant-based diet and complete all study procedures. * Ability to provide informed consent Exclusion: * Obstructive coronary artery disease or prior coronary revascularization (PCI or CABG). * Recent acute coronary syndrome, unstable angina, decompensated heart failure, or other clinically unstable cardiovascular disease. * Significant structural heart disease, uncontrolled arrhythmia, severe uncontrolled hypertension, or symptomatic hypotension. * Severe renal disease (eGFR \<30 mL/min/1.73 m²) or significant liver disease. * Current vegetarian or vegan diet, or habitual consumption of ≤4 servings of animal products per week. * Severe food allergies, dietary restrictions, or gastrointestinal conditions that would prevent adherence to the study diet. * Current use of weight-loss medications, including GLP-1 receptor agonists. * Active eating disorder. * Recent (\>5%) intentional or unintentional weight change within the previous 3 months. * Participation in another interventional study that could affect study outcomes. * Any medical, psychiatric, or social condition that, in the investigator's judgment, would make participation unsafe or interfere with study completion.

Outcomes

Primary Outcomes

Change in Brachial Artery Flow-Mediated Dilation (FMD)

Brachial artery flow-mediated dilation (FMD) will be assessed by ultrasound and reported as the percentage increase in brachial artery diameter from the resting pre-occlusion diameter to the peak post-occlusion diameter. FMD is a continuous physiological measurement. Higher FMD percentages indicate greater endothelium-dependent vasodilation and better peripheral endothelial function. Change from baseline will be calculated as the FMD percentage at each post-baseline visit minus the baseline FMD percentage and reported in percentage points.

Time frame: Baseline (pre-intervention), Week 4, Week 8, and Week 12

Secondary Outcomes

Change in Cutaneous Microvascular Function

Cutaneous microvascular function will be assessed using laser Doppler flowmetry during standardized local heating. Mean cutaneous vascular conductance during the stable local-heating plateau will be calculated by dividing laser Doppler flux by concurrently measured mean arterial pressure and reported in perfusion units per millimeter of mercury (PU/mmHg). Cutaneous vascular conductance is a continuous physiological measurement. Higher values during local heating indicate greater cutaneous microvascular vasodilatory responsiveness. Change from baseline will be calculated as the value at each post-baseline visit minus the baseline value.

Time frame: Baseline, Week 4, Week 8, and Week 12

Change in Digital Endothelial Function

Digital endothelial function will be assessed using peripheral arterial tonometry and reported as the Reactive Hyperemia Index (RHI). RHI is a continuous, dimensionless physiological index derived from the post-occlusion digital pulse-amplitude response and normalized to the control finger. RHI has no fixed minimum or maximum. Higher RHI values indicate better digital endothelial function. Change from baseline will be calculated as the value at each post-baseline visit minus the baseline value.

Time frame: Baseline, Week 4, Week 8, and Week 12

Change in Central Arterial Stiffness

Central arterial stiffness assessed by carotid-femoral pulse wave velocity (PWV) using the SphygmoCor system. Pulse wave velocity will be analyzed in meters per second, with lower values reflecting lower arterial stiffness.

Time frame: Baseline, Week 4, Week 8, and Week 12.

Change in Systemic Redox Status

Plasma aminothiol redox status measured by concentrations of reduced and oxidized aminothiol species, including cysteine, cystine, glutathione, and glutathione disulfide.

Time frame: Baseline, Week 4, Week 8, and Week 12.

Change in Total cholesterol concentration

Fasting blood total cholesterol concentration will be measured at baseline and each post-baseline assessment. Change from baseline will be calculated as the post-baseline concentration minus the baseline concentration and reported in milligrams per deciliter (mg/dL).

Time frame: Baseline, Week 4, Week 8, and Week 12

Change in Low-Density Lipoprotein Cholesterol Concentration

Fasting blood low-density lipoprotein (LDL) cholesterol concentration will be measured at baseline and each post-baseline assessment. Change from baseline will be calculated as the post-baseline concentration minus the baseline concentration and reported in milligrams per deciliter (mg/dL).

Time frame: Baseline, Week 4, Week 8, and Week 12

Change in High-Density Lipoprotein Cholesterol Concentration

Fasting blood high-density lipoprotein (HDL) cholesterol concentration will be measured at baseline and each post-baseline assessment. Change from baseline will be calculated as the post-baseline concentration minus the baseline concentration and reported in milligrams per deciliter (mg/dL).

Time frame: Baseline, Week 4, Week 8, and Week 12

Change in Triglyceride Concentration

Fasting blood triglyceride concentration will be measured at baseline and each post-baseline assessment. Change from baseline will be calculated as the post-baseline concentration minus the baseline concentration and reported in milligrams per deciliter (mg/dL).

Time frame: Baseline, Week 4, Week 8, and Week 12

Change in Apolipoprotein B Concentration

Fasting blood apolipoprotein B (ApoB) concentration will be measured at baseline and each post-baseline assessment. Change from baseline will be calculated as the post-baseline concentration minus the baseline concentration and reported in milligrams per deciliter (mg/dL).

Time frame: Baseline, Week 4, Week 8, and Week 12

Change in Apolipoprotein A-I Concentration

Fasting blood apolipoprotein A-I (ApoA-I) concentration will be measured at baseline and each post-baseline assessment. Change from baseline will be calculated as the post-baseline concentration minus the baseline concentration and reported in milligrams per deciliter (mg/dL).

Time frame: Baseline, Week 4, Week 8, and Week 12

Change in Lipoprotein(a) Concentration

Fasting blood lipoprotein(a) concentration will be measured at baseline and each post-baseline assessment. Change from baseline will be calculated as the post-baseline concentration minus the baseline concentration and reported in nanomoles per liter (nmol/L).

Time frame: Baseline, Week 4, Week 8, and Week 12

Change in Blood Glucose Concentration

Fasting blood glucose concentration will be measured at baseline and each post-baseline assessment. Change from baseline will be calculated as the post-baseline concentration minus the baseline concentration and reported in milligrams per deciliter (mg/dL).

Time frame: Baseline, Week 4, Week 8, and Week 12.

Change in Blood Urea Nitrogen

Blood urea nitrogen (BUN) will be measured at baseline and each post-baseline assessment. Change from baseline will be calculated as the post-baseline value minus the baseline value and reported in milligrams per deciliter (mg/dL).

Time frame: Baseline, Week 4, Week 8, and Week 12.

Change in Blood Creatinine Concentration

Blood creatinine concentration will be measured at baseline and each post-baseline assessment. Change from baseline will be calculated as the post-baseline concentration minus the baseline concentration and reported in milligrams per deciliter (mg/dL).

Time frame: Baseline, Week 4, Week 8, and Week 12.

Change in Blood Sodium Concentration

Blood sodium concentration will be measured at baseline and each post-baseline assessment. Change from baseline will be calculated as the post-baseline concentration minus the baseline concentration and reported in millimoles per liter (mmol/L).

Time frame: Baseline, Week 4, Week 8, and Week 12.

Change in Blood Potassium Concentration

Blood potassium concentration will be measured at baseline and each post-baseline assessment. Change from baseline will be calculated as the post-baseline concentration minus the baseline concentration and reported in millimoles per liter (mmol/L).

Time frame: Baseline, Week 4, Week 8, and Week 12.

Change in Blood Chloride Concentration

Blood chloride concentration will be measured at baseline and each post-baseline assessment. Change from baseline will be calculated as the post-baseline concentration minus the baseline concentration and reported in millimoles per liter (mmol/L).

Time frame: Baseline, Week 4, Week 8, and Week 12.

Change in Blood Carbon Dioxide Concentration

Blood total carbon dioxide, reflecting serum bicarbonate, will be measured at baseline and each post-baseline assessment. Change from baseline will be calculated as the post-baseline concentration minus the baseline concentration and reported in millimoles per liter (mmol/L).

Time frame: Baseline, Week 4, Week 8, and Week 12.

Change in Blood Calcium Concentration

Blood calcium concentration will be measured at baseline and at each post-baseline assessment. Change from baseline will be calculated as the post-baseline concentration minus the baseline concentration and reported in milligrams per deciliter (mg/dL).

Time frame: Baseline, Week 4, Week 8, and Week 12.

Change in Blood Total Protein Concentration

Blood total protein concentration will be measured at baseline and each post-baseline assessment. Change from baseline will be calculated as the post-baseline concentration minus the baseline concentration and reported in grams per deciliter (g/dL).

Time frame: Baseline, Week 4, Week 8, and Week 12.

Change in Total Blood Albumin Concentration

Blood albumin concentration will be measured at baseline and at each post-baseline assessment. Change from baseline will be calculated as the post-baseline concentration minus the baseline concentration and reported in grams per deciliter (g/dL).

Time frame: Baseline, Week 4, Week 8, and Week 12.

Change in Total Bilirubin Concentration

Blood total bilirubin concentration will be measured at baseline and each post-baseline assessment. Change from baseline will be calculated as the post-baseline concentration minus the baseline concentration and reported in milligrams per deciliter (mg/dL).

Time frame: Baseline, Week 4, Week 8, and Week 12.

Change in Alkaline Phosphatase Activity

Blood alkaline phosphatase activity will be measured at baseline and each post-baseline assessment. Change from baseline will be calculated as the post-baseline value minus the baseline value and reported in units per liter (U/L).

Time frame: Baseline, Week 4, Week 8, and Week 12.

Change in Alanine Aminotransferase Activity

Blood alanine aminotransferase (ALT) activity will be measured at baseline and each post-baseline assessment. Change from baseline will be calculated as the post-baseline value minus the baseline value and reported in units per liter (U/L).

Time frame: Baseline, Week 4, Week 8, and Week 12.

Change in Aspartate Aminotransferase Activity

Blood aspartate aminotransferase (AST) activity will be measured at baseline and each post-baseline assessment. Change from baseline will be calculated as the post-baseline value minus the baseline value and reported in units per liter (U/L).

Time frame: Baseline, Week 4, Week 8, and Week 12.

Change in Complete Blood Count With Differential

Changes in hematologic measures obtained from complete blood count with differential testing.

Time frame: Baseline, Week 4, Week 8, and Week 12.

Change in Angina Burden and Disease-Specific Quality of Life

The Seattle Angina Questionnaire (SAQ) is a validated disease-specific patient-reported outcome measure for patients with angina and ischemic heart disease. The SAQ will be used to assess changes in angina burden and disease-specific quality of life during the 12-week plant-based dietary intervention. Higher scores indicate better health status and fewer angina-related limitations.

Time frame: Baseline, Week 4, Week 8, and Week 12.

Change in Body Weight

Body weight measured during study visits and home monitoring to evaluate weight stability during the intervention.

Time frame: Baseline, Week 4, Week 8, and Week 12.

Change in Blood Pressure

Blood pressure measured during study visits and through home monitoring to assess hemodynamic response to the dietary intervention

Time frame: Baseline, Week 4, Week 8, and Week 12.

A Plant-Based Diet in the Treatment of Coronary Microvascular Dysfunction

Overview

Conditions

Interventions

Eligibility

Locations (1)

Outcomes

Primary Outcomes

Secondary Outcomes

Central Contacts