Cardiovascular Disease Overview

Cardiovascular Disease

• Endothelium: The inner lining of blood vessels, single-cell layer thick. It's mechanosensitive, responding to blood flow and pressure. It regulates vascular tone (dilation/constriction) and homeostasis. It reacts to various body signals.

• Pulse Wave Velocity (PWV): Measures speed of arterial pressure waves along arteries; calculated by distance/transit time. Used to assess arterial stiffness.

• Atherosclerosis: Buildup of lipoproteins in artery walls, forming plaque. This narrows vessels, increasing risk of thrombi and plaque rupture. Affects blood flow to organs (heart, brain, etc.). A carotid artery plaque scan (ultrasound) can reveal normal flow (red), high velocities (yellow), and very high velocities (blue).

• Shear Stress: Frictional force from blood flow affecting vessel health. Disturbed flow (irregular) is different from laminar flow (smooth), impacting endothelial cell behavior.

• Vascular Calcification: Calcium deposits in arterial walls (intima and/or media), increasing over time. Causing vessel stiffness and elevated blood pressure.

Consequences of Atherosclerosis

• Ischemic Heart Disease (Angina): Coronary artery obstruction reduces oxygen to the heart muscle, causing angina (chest pain). Exercise, stress, and cold can trigger symptoms. Unstable angina can lead to myocardial infarction. Treatment includes nitrates, calcium channel blockers, or beta-blockers.

• Acute Myocardial Infarction (Heart Attack): Coronary artery blockage by an embolus (blood clot). Leading to heart muscle ischemia (lack of oxygen). Severity depends on blockage size and location. Symptoms like chest pain, shortness of breath, weakness, anxiety, plus elevated serum troponin (indicating cardiac muscle death).

• In-Stent Restenosis: Re-narrowing of an artery after a stent (a small tube placed to keep the artery open) insertion. Caused by neointimal hyperplasia (tissue growth inside the stent triggered by artery injury from stent placement). Drug-eluting stents are used to prevent this but re-endothelialization takes months.

• Coronary Artery Bypass Graft (CABG): Surgeons graft a blood vessel (e.g., saphenous vein or internal mammary artery) to bypass coronary artery blockage. Increases blood flow to the heart, reducing myocardial infarction risk. Procedures range from single to quadruple bypass.

• Ischemic Stroke: Reduced blood supply to a brain region. Causes include thrombus formation in the brain or plaque rupture elsewhere (often the internal carotid artery). Symptoms vary based on affected brain area. a thrombolytic agent (tissue plasminogen activator, tPA) helps reduce stroke effects, and anticoagulants and carotid endarterectomy might be needed. Identifying vulnerable carotid plaques prevents complications. Patients displaying symptoms such as dizziness, visual disturbances, or memory loss are scanned.

• Peripheral Vascular Disease (PVD): Obstruction of large arteries outside the heart, aorta, and brain, often due to atherosclerosis in lower extremities. Symptoms include claudication (leg pain during activity), color changes, slow-healing wounds/ulcers. Serious PVD can lead to limb loss. High mortality rate after foot ulcer development.

• Aortic Aneurysms: Pro-atherogenic stimuli (high blood pressure, high cholesterol, smoking, inflammation) cause aortic stiffening, weakening and bulging. Often asymptomatic, but rupture is life-threatening. All men over 65 in the UK are screened through ultrasound for aortic aneurysms. Grafts can increase aortic stability.

Explore key concepts related to cardiovascular disease, including the role of the endothelium, pulse wave velocity, atherosclerosis, shear stress, and vascular calcification. This quiz will test your understanding of how these factors influence heart health and blood circulation.