SVD in cardiology typically refers to Small Vessel Disease, also known as coronary microvascular disease or small artery disease. It's a condition affecting the tiny arteries in the heart.
Understanding Small Vessel Disease (SVD)
Small Vessel Disease (SVD) occurs when the walls of the small arteries within the heart are damaged. This damage prevents these arteries from dilating properly. This impaired dilation restricts blood flow to the heart muscle, potentially leading to symptoms of angina (chest pain), shortness of breath, and fatigue, even in the absence of significant blockages in the larger coronary arteries.
Key Characteristics of SVD:
- Affects Small Arteries: SVD primarily impacts the small coronary arteries and microvessels of the heart, not the major epicardial arteries.
- Impaired Dilation: The small vessels fail to dilate appropriately in response to increased demand, limiting blood supply.
- Angina-like Symptoms: Patients often experience angina-like chest pain, despite having "normal" coronary arteries on angiography (a common test to visualize the larger heart vessels).
- Diagnosis Challenges: SVD can be challenging to diagnose because standard angiograms primarily visualize the larger coronary arteries and may not reveal problems in the smaller vessels. Specialized tests like coronary flow reserve (CFR) or microvascular resistance (IMR) assessment are often required.
Causes of SVD:
While the exact causes of SVD are not fully understood, several factors are associated with an increased risk:
- Diabetes: High blood sugar levels can damage blood vessels, including the small arteries in the heart.
- High Blood Pressure (Hypertension): Chronic hypertension can lead to thickening and stiffening of the small artery walls.
- High Cholesterol: Elevated cholesterol levels can contribute to the buildup of plaque in the small arteries.
- Smoking: Smoking damages blood vessels and increases the risk of SVD.
- Insulin Resistance: This condition can impair the function of the small blood vessels.
- Hormonal Changes: Women, particularly after menopause, are at increased risk, possibly due to hormonal changes affecting blood vessel function.
Diagnosis of SVD:
Diagnosis often involves:
- Exclusion of epicardial coronary artery disease: Ruling out blockages in the major coronary arteries using angiography.
- Assessment of coronary microvascular function: Using tests like coronary flow reserve (CFR) measurement, which assesses the ability of the small vessels to dilate.
- Cardiac MRI: Can help assess myocardial perfusion and identify areas of ischemia related to microvascular dysfunction.
Treatment of SVD:
Treatment strategies focus on managing risk factors and relieving symptoms:
- Lifestyle Modifications: Diet, exercise, smoking cessation.
- Medications:
- Nitrates: To dilate blood vessels.
- Beta-blockers: To reduce heart rate and blood pressure.
- Calcium channel blockers: To dilate blood vessels and reduce blood pressure.
- ACE inhibitors or ARBs: To manage blood pressure and protect blood vessels.
- Statins: To lower cholesterol levels.
- Aspirin: For antiplatelet effects (use is controversial and should be discussed with a doctor).
- Management of underlying conditions: Such as diabetes, hypertension, and high cholesterol.
In summary, SVD in cardiology refers to a condition affecting the small arteries of the heart, leading to impaired blood flow and angina-like symptoms. Diagnosis can be challenging, requiring specialized tests, and treatment focuses on risk factor management and symptom relief.
