Case-Based Learning on Coronary Vasomotor Dysfunction With Preserved Cardiac Structure

Abstract

Coronary vasomotor dysfunction (CVDys) with preserved cardiac structure represents a complex clinical entity that is increasingly recognized as a cause of angina and myocardial ischemia in the absence of obstructive coronary artery disease. This review explores CVDys through a case-based learning lens, integrating contemporary research, epidemiological data, mechanistic insights, diagnostic strategies, and evidence-based management. The goal is to equip clinicians with a nuanced understanding of this condition, its risk profiles, and the evolving therapeutic landscape, emphasizing the importance of individualized patient-centered care.

Introduction

Coronary vasomotor dysfunction refers to abnormal regulation of coronary vascular tone, manifesting as either epicardial or microvascular dysfunction, despite structurally normal coronary arteries. Patients frequently present with angina-like symptoms and demonstrate myocardial ischemia on testing, yet lack significant atherosclerotic obstruction. This paradox challenges traditional paradigms of ischemic heart disease and necessitates a refined clinical approach. Recent guideline updates and research underscore the importance of recognizing CVDys to optimize outcomes, reduce unnecessary interventions, and improve quality of life in affected individuals.

Epidemiology / Disease Burden

CVDys is estimated to account for up to 50% of patients undergoing coronary angiography for angina with non-obstructive coronary arteries (ANOCA). The prevalence is particularly high among women, with studies such as the WISE (Women\'s Ischemia Syndrome Evaluation) reporting microvascular angina in over half of female patients with chest pain and preserved cardiac structure. Epidemiologic data reveal that CVDys is underdiagnosed, leading to recurrent symptoms, repeated hospitalizations, and increased healthcare utilization. The disease burden is compounded by the psychosocial impact of persistent, unexplained symptoms and the risk of future adverse cardiovascular events.

Pathophysiology

The underlying mechanisms of CVDys are multifactorial, involving impaired endothelial-dependent and endothelial-independent vasodilation, heightened vasoconstrictor response, and microvascular spasm. Endothelial dysfunction, often secondary to inflammation, oxidative stress, or neurohormonal activation, reduces nitric oxide bioavailability, thereby compromising vascular homeostasis. Smooth muscle cell hyper-reactivity and autonomic dysregulation further promote inappropriate vasoconstriction. Importantly, these abnormalities occur in the absence of significant structural coronary lesions, distinguishing CVDys from classical atherosclerotic disease. Myocardial perfusion defects may result, leading to ischemia and angina despite preserved ejection fraction and cardiac morphology.

Risk Factors

Risk factors for CVDys overlap with traditional cardiovascular risk profiles but also include unique contributors. Female sex, particularly in postmenopausal women, is a strong predictor, likely related to hormonal influences on endothelial function. Other risk factors include hypertension, dyslipidemia, diabetes mellitus, obesity, smoking, systemic inflammatory disorders, and psychosocial stress. Genetic predisposition and certain medications (e.g., vasoconstrictive agents) may also play a role. Notably, the absence of overt coronary atherosclerosis in these patients can delay recognition and risk stratification.

Clinical Features

Patients with CVDys typically present with exertional or rest angina, chest discomfort, or dyspnea. Symptoms may mimic those of obstructive coronary artery disease but often exhibit atypical features such as prolonged episodes, poor response to nitrates, and occurrence at rest or nocturnally. Recurrent emergency department visits and negative angiograms are common. Objective evidence of ischemia, such as transient ECG changes or perfusion defects on non-invasive imaging, is frequently observed. Importantly, these patients are at increased risk for major adverse cardiovascular events, including myocardial infarction and heart failure with preserved ejection fraction.

Diagnosis

Diagnosis of CVDys requires a high index of suspicion and a systematic approach. Initial assessment includes detailed clinical history, risk factor evaluation, and exclusion of obstructive coronary disease via coronary angiography or computed tomography angiography. Functional testing, such as stress echocardiography, cardiac magnetic resonance imaging, or myocardial perfusion scintigraphy, may reveal ischemia. Definitive diagnosis involves invasive coronary function testing: acetylcholine or adenosine provocation assesses endothelial and microvascular reactivity, and measurement of coronary flow reserve (CFR) or index of microcirculatory resistance (IMR) quantifies dysfunction. Recent guidelines recommend tailored diagnostic algorithms to improve detection rates and guide therapy.

Treatment & Management

Management of CVDys is multifaceted, focusing on symptom relief, risk modification, and prevention of adverse events. First-line therapy includes lifestyle modification and pharmacological agents such as beta-blockers, calcium channel blockers, and long-acting nitrates to modulate coronary tone. Statins and ACE inhibitors address endothelial dysfunction, while antiplatelet therapy may be considered in select patients. Non-pharmacologic interventions, including exercise training and stress reduction, have demonstrated benefit. Comprehensive risk factor control—hypertension, dyslipidemia, diabetes, and smoking cessation—remains foundational. Patient education and psychological support are essential to address the chronic nature of the condition and enhance adherence.

Recent Advances / Emerging Therapies

Emerging therapies for CVDys target the underlying pathophysiology, with ongoing research into endothelin receptor antagonists, novel nitric oxide donors, and phosphodiesterase inhibitors. Precision medicine approaches, including genotype-guided therapy and biomarker-driven strategies, hold promise for individualized care. Advances in non-invasive imaging and invasive function testing are improving diagnostic accuracy. Randomized controlled trials, such as the CorMicA study, have demonstrated the efficacy of stratified medical therapy based on invasive diagnostics, leading to symptom improvement and enhanced quality of life. Ongoing clinical trials continue to refine therapeutic algorithms and identify new treatment targets.

Guideline Recommendations

Recent consensus documents from the European Society of Cardiology (ESC), American Heart Association (AHA), and other major societies emphasize the need for structured diagnostic pathways and patient-centered management in CVDys. Guidelines advocate for coronary function testing in patients with ANOCA and persistent symptoms, as well as aggressive risk modification and use of antianginal agents. Multidisciplinary care, including cardiology, psychology, and rehabilitation services, is recommended to optimize outcomes. The importance of ongoing patient follow-up and reassessment is highlighted to address symptom progression and treatment response.

Conclusion

Coronary vasomotor dysfunction with preserved cardiac structure represents a distinct and clinically significant cause of angina and ischemia. Recognition of this syndrome requires an integrated, evidence-based approach encompassing detailed clinical assessment, targeted diagnostic testing, and personalized management. Ongoing research and guideline updates continue to expand the therapeutic armamentarium, offering new hope for improved outcomes. Increasing awareness among clinicians is crucial to reduce diagnostic delays, minimize unnecessary procedures, and enhance the quality of care for this challenging patient population.