From the Guidelines
Coronary microvascular dysfunction should be treated with a baseline therapy that includes aspirin, statin, and ACEi, along with lifestyle changes and sublingual nitroglycerin as needed, and antianginal therapy should be initiated with beta blockers, such as carvedilol 6.25 mg BID uptitrated, as the first line of treatment. This approach is based on the most recent guidelines for the management of patients with chronic coronary disease, which emphasize the importance of addressing the underlying mechanisms of microcirculatory dysfunction 1. The treatment strategy should be tailored to the individual patient's needs, taking into account the results of invasive coronary function testing, such as coronary flow reserve measurement and index of microvascular resistance.
The diagnosis of coronary microvascular dysfunction typically requires specialized tests, as standard coronary angiography may appear normal. The condition is more common in women and can cause chest pain, shortness of breath, and fatigue. The underlying mechanisms of coronary microvascular dysfunction include endothelial dysfunction, smooth muscle cell abnormalities, and microvascular remodeling, which impair the ability of small vessels to dilate appropriately in response to increased oxygen demand.
In patients with microvascular angina, the treatment should address the dominant mechanism of microcirculatory dysfunction. For example, patients with abnormal coronary flow reserve <2.0 or index of microvascular resistance ≥25 units may benefit from beta blockers, ACE inhibitors, and statins, along with lifestyle changes and weight loss 1. Additionally, patients who develop ECG changes and angina in response to acetylcholine testing but without severe epicardial vasoconstriction may be treated with a strategy similar to that used for vasospastic angina patients.
Some key points to consider in the treatment of coronary microvascular dysfunction include:
- The importance of lifestyle modifications, such as regular exercise, Mediterranean diet, smoking cessation, and stress management
- The use of beta blockers, such as carvedilol, as the first line of antianginal therapy
- The potential benefits of ACE inhibitors and statins in improving endothelial function and reducing symptoms
- The need for tailored treatment strategies based on the individual patient's needs and the results of invasive coronary function testing.
From the Research
Definition and Prevalence of Coronary Microvascular Dysfunction
- Coronary microvascular dysfunction (CMD) is a condition associated with impaired cardiovascular prognosis, often underdiagnosed and undertreated 2.
- The prevalence of obstructive coronary artery disease (CAD) in unselected patient populations referred for evaluation of angina is less than 10%, and a significant proportion of patients with angina and no obstructive CAD have CMD 2.
- CMD is a prevalent and often underdiagnosed condition with significant implications for adverse cardiovascular outcomes 3.
Pathophysiology of Coronary Microvascular Dysfunction
- The pathophysiology of CMD includes structural and functional abnormalities in the coronary microvasculature, and epicardial atherosclerosis contributes to downstream reduction in myocardial perfusion and symptoms 3.
- The term "coronary microvascular dysfunction" encompasses several pathogenic mechanisms resulting in functional and/or structural changes in the coronary microcirculation, determining angina and myocardial ischemia in patients with angina without obstructive CAD 4.
- The pathogenesis of CMD is complex and involves the combination of functional and structural alterations leading to impaired coronary blood flow and resulting in myocardial ischemia 4.
Diagnosis and Management of Coronary Microvascular Dysfunction
- Non-invasive and invasive evaluation of coronary microvascular function is feasible and widely available, and coronary microvascular testing should be considered in angina patients with no obstructive CAD 2.
- Diagnosis relies on advanced invasive or noninvasive imaging techniques, such as PET and cardiac magnetic resonance, capable of quantifying myocardial perfusion and myocardial blood flow reserve 3.
- Effective management includes optimizing cardiovascular risk factors and symptom control, and novel therapeutic strategies recently approved for management of diabetes, obesity, and heart failure with preserved ejection fraction offer potentially powerful options for management of CMD 3.
- A patient-tailored treatment approach guided by coronary microvascular testing shows promising results for patient-reported outcomes of symptom burden and quality of life 2.