Coronary small vessel disease (CSVD), also known as microvascular angina or microvascular coronary disease, is a condition that affects the heart’s tiniest arteries. Unlike traditional coronary artery disease), which involves blockages in the larger arteries of the heart, CSVD involves dysfunction in the small vessels that supply blood to the heart muscle. This condition can lead to chest pain (angina), shortness of breath, and other symptoms that resemble those of traditional coronary artery disease. Women are most often affected by this disease.
Pathophysiology
Coronary small vessel disease CSVD occurs when the small coronary arteries do not function properly. These arteries, which are less than 500 micrometers in diameter, can become constricted or spasm, leading to reduced blood flow to the heart muscle. This reduction in blood flow can result in ischemia, which is a lack of sufficient oxygen to the heart muscle.
The dysfunction in these small vessels is often due to endothelial dysfunction, which is the inability of the blood vessels’ inner lining to function normally. This can be caused by various factors, including high blood pressure, diabetes, smoking, and high cholesterol levels. Inflammation and increased oxidative stress are also believed to play significant roles in the development of CSVD.
Cardiovascular disease in men is very different than women often leading to diagnostic confusion since the male model is routinely used as the paradigm of cardiovascular disease (CVD). Men are more likely to have obstructive CVD specifically, large plaques causing blockage of the large coronary arteries. Women on the other hand are more likely to have microvascular disease and plaque erosion. There is over-representation of women with MI (heart attack) with Non-Obstructed Coronary Arteries (MINOCA) relative to those with elevated troponin (a protein marker of cardiac damage) resulting from obstructive Coronary-Artery-Disease (CAD) Only 24–30% are women present with obstructive CVD. Mechanisms of MINOCA that are more commonly observed in women include coronary microvascular dysfunction and coronary artery plaque erosions.
Symptoms
The symptoms of CSVD can be similar to those of traditional coronary artery disease and may include:
- Chest pain or discomfort (angina) that may occur during physical activity or emotional stress
- Shortness of breath
- Fatigue
- Discomfort in other areas of the upper body, including the arms, neck, jaw, or stomach
- Nausea and dizziness
It’s important to note that CSVD can occur in individuals with or without significant blockages in the larger coronary arteries. This can make diagnosis challenging, as traditional tests for coronary artery disease may not detect small vessel dysfunction. However, several methods can help in diagnosing the condition:
While coronary angiography is commonly used to visualize blockage in the larger coronary arteries, it may not detect abnormalities in the small vessels. However, it may still be useful in ruling out significant blockages in the larger arteries.
Coronary Flow Reserve (CFR) Measurement:
Measures the ability of the coronary arteries to dilate and increase blood flow when needed. Reduced CFR can indicate small vessel dysfunction.
Intravascular Ultrasound (IVUS) and Optical Coherence Tomography (OCT):
These imaging techniques can provide detailed images of the coronary arteries’ inner walls, helping to identify abnormalities in the small vessels.
Magnetic Resonance Imaging (MRI):
Cardiac MRI can assess the heart muscle’s perfusion and identify areas of reduced blood flow.
Positron Emission Tomography (PET):
PET scans can measure blood flow to the heart and detect areas with reduced perfusion.
The treatment of CSVD aims to relieve symptoms, improve heart function, and reduce the risk of future cardiovascular events. Treatment options may include:
Medications:
- Nitrates: These medications help to relax and widen the blood vessels, improving blood flow to the heart.
- Beta-Blockers: These drugs reduce the heart’s workload and improve blood flow by slowing the heart rate.
- Calcium Channel Blockers: These medications help to relax and dilate the small blood vessels, improving blood flow.
- Statins: These drugs lower cholesterol levels and have anti-inflammatory effects that can improve endothelial function.
- ACE Inhibitors or ARBs: These medications help to lower blood pressure and improve heart function.
Controlling conditions that contribute to CSVD, such as high blood pressure, diabetes, and high cholesterol, is essential. Regular monitoring and medication adjustments may be necessary to keep these conditions in check.
Coronary small vessel disease is a challenging condition that requires a comprehensive approach to diagnosis and treatment. By understanding the pathophysiology, recognizing the symptoms, and utilizing advanced diagnostic techniques, healthcare providers can effectively manage CSVD and improve the quality of life for those affected by this condition. Adopting a heart-healthy lifestyle and managing underlying conditions are also crucial in preventing the progression of the disease. With proper care and attention, individuals with CSVD can lead healthy, fulfilling lives.