UNMASKING ISCHEMIA: PREVALENCE AND CLINICAL IMPLICATIONS OF CORONARY MICROVASCULAR DYSFUNCTION AND VASOSPASM IN NON-OBSTRUCTIVE CORONARY ARTERY DISEASE

Background: Ischemic heart disease remains a leading global cause of morbidity and mortality. A significant proportion of patients presenting with chest pain undergo coronary angiography that reveals no obstructive coronary artery disease (CAD). Despite the absence of obstructive lesions, these patients often experience myocardial ischemia, which can be attributed to coronary microvascular dysfunction (CMD) or coronary vasospasm. However, the true prevalence of CMD and coronary vasospasm among this population remains unclear. Methods: A systematic review was conducted to assess the prevalence of CMD and coronary vasospasm in patients with non-obstructive CAD. PubMed and Scopus were systematically searched from inception until August 2024. Studies were included if they assessed patients with suspected CAD who had undergone diagnostic testing for CMD or coronary vasospasm and reported the proportion of positive cases. Data were extracted on patient demographics, clinical characteristics, diagnostic methods, and prevalence rates. A random-effects model was used to estimate pooled prevalence rates with 95% confidence intervals (CIs), and heterogeneity was assessed using the I² statistic. Results: Nearly half of the patients with non-obstructive CAD exhibited CMD or coronary vasospasm. CMD was more frequently observed in women, though men were also significantly affected. Findings underscore the need for increased awareness, standardized diagnostic approaches, and improved management strategies to optimize care for patients with myocardial ischemia without obstructive CAD. Conclusion: The high prevalence of CMD and coronary vasospasm in patients with non-obstructive CAD highlights the need for better diagnostic tools and clinical guidelines. Increased physician awareness and targeted management strategies can improve patient outcomes and reduce unnecessary invasive procedures. Future research should focus on refining diagnostic criteria and developing effective therapeutic interventions for this patient population.