Chapter 32: Alterations of Cardiovascular Function Study Notes

Chapter 32: Alterations of Cardiovascular Function

Chapter Objectives

  • Distinguish between arteriosclerosis and atherosclerosis.

    • Arteriosclerosis: General term for the thickening and hardening of arterial walls.
    • Atherosclerosis: Specific type of arteriosclerosis characterized by the buildup of lipids, cholesterol, and plaque in the arterial wall.

  • State and describe the pathophysiologic events for the development of atheromatous plaque.

    1. Endothelial Injury: Damage to the endothelium of blood vessels.
    2. Inflammation: Inflammatory response to the injury.
    3. Cytokine Release: Recruitment and activation of immune cells.
    4. Cellular Proliferation: Smooth muscle cells proliferate in response to signaling molecules.
    5. Macrophage Migration: Immune cells migrate to the site of injury and engulf oxidized LDLs.
    6. Foam Cell Formation: Accumulation of lipid-laden macrophages forms a fatty streak.
    7. Plaque Development: Transition of fatty streak to fibrous plaque with a fibrous cap eventually leading to complicated lesions.

  • Diagram the progression of atherosclerotic heart disease from risk factor identification through the complications of acute myocardial infarction.

    • Risk Factors: Include dyslipidemia, hypertension, smoking, obesity, and diabetes.
    • Complications: Progression can lead to stable angina, unstable angina, myocardial infarction (MI), and sudden cardiac death.

  • Define and describe the incidence of hypertension.

    • Hypertension Incidence: The consistent elevation of systemic arterial blood pressure over 140 mmHg systolic or 90 mmHg diastolic.

  • Characterize primary, secondary, complicated, and malignant hypertension.

    • Primary (Essential) Hypertension: Has no identifiable cause; multifactorial.
    • Secondary Hypertension: Results from identifiable causes (e.g., renal disease, medications).
    • Complicated Hypertension: Involves target organ damage (e.g., hypertrophy, heart failure).
    • Malignant Hypertension: Severe, rapidly progressive form of hypertension that can lead to encephalopathy.

Diseases of the Veins

Varicose Veins
  • Definition: Engorged veins resulting from blood pooling.
  • Causes: Valvular incompetence, venous obstruction, muscular dysfunction.
  • Mechanism: Increased intravascular hydrostatic pressure leads to vein inflammation and distortion.
  • Pathophysiology: Altered balance between prostacyclin (anti-clotting) and thromboxane A2 (promotes clotting).
Chronic Venous Insufficiency
  • Definition: Persistent lower extremity venous hypertension.
  • Treatment:
    • Weight loss.
    • Reduced standing/sitting time.
    • Leg elevation & compression stockings.
    • Physical exercise.
    • Interventional therapies (e.g., endovenous ablation).
Deep Venous Thrombosis (DVT)
  • Definitions: Presence of a thrombus in a large vein; can lead to pulmonary embolism if the thrombus detaches.
  • Virchow's Triad:
    1. Venous stasis.
    2. Venous intimal damage.
    3. Hypercoagulable states.
  • Clinical Importance: Obstruction increases venous pressure and can lead to post-thrombotic syndrome.
  • Prevention: Early mobilization, prophylactic anticoagulation.
  • Tests: d-dimer and Doppler ultrasound.
Superior Vena Cava Syndrome
  • Definition: Progressive occlusion of the superior vena cava.
  • Causes: Primarily caused by malignancies (e.g., lung cancer, lymphoma).
  • Clinical Symptoms: include facial/upper extremity edema, cyanosis, dyspnea,
    dysphagia.
  • Treatment: Typically involves chemotherapy and radiation therapy.

Diseases of the Arteries

  • Conditions: Include hypertension, aneurysms, thrombus and embolism formation, peripheral arterial disease, atherosclerosis, coronary artery disease, and myocardial ischemia.
Hypertension Definition
  • Isolated Systolic Hypertension: Elevated systolic BP with normal diastolic BP.
  • Clinical Definition: Sustained BP of 140 mmHg (systolic) or higher, 90 mmHg (diastolic) or higher.
Primary Hypertension
  • Causes: Multifactorial influences including genetics andenvironmental factors.
Secondary Hypertension
  • Description: Imbalance due to systemic disease affecting hemodynamics.
Complicated Hypertension
  • Characteristics: Hypertrophy, hyperplasia, and fibrosis of blood vessel layers.
Malignant Hypertension
  • Definition: Rapidly progressing hypertension; diastolic BP > 140 mmHg.
  • Consequences: Risk for encephalopathy and associated complications.
Hypertension Risk Factors
  • Contributing Factors: Family history, age, gender, race (e.g., Black), sodium intake, glucose intolerance, alcohol use, obesity, smoking.
Pathophysiology of Hypertension
  • Mechanisms:
    1. Increased cardiac output due to higher heart rate/stroke volume.
    2. Elevated peripheral resistance due to increased blood viscosity or vessel narrowing.
Treatments for Hypertension
  • Lifestyle Modifications:
    • Low-sodium diet.
    • Increase physical activity.
    • Smoking cessation.
  • Pharmacological Options:
    • ACE inhibitors, ARBs, beta-blockers, calcium channel blockers, and thiazide diuretics.

Orthostatic (Postural) Hypotension

  • Definition: A decrease in BP upon standing—20 mmHg systolic & 10 mmHg diastolic.
  • Pathophysiology: Impaired compensatory mechanisms in response to gravitational changes.
  • Clinical Manifestation: Fainting upon standing.
  • Treatment:
    • Increased salt intake, elevate bed, thigh-high stockings, hydration, vasoconstrictors (e.g., midodrine).

Aneurysm

  • Definition: Localized dilation or outpouching of a vessel wall or cardiac chamber.
  • Types:
    • True Aneurysms: Involve all three layers of arterial wall (e.g., fusiform, circumferential).
    • False Aneurysms: A rupture between a vascular graft and a artery (e.g., saccular).
  • Clinical Manifestations: Can cause dysrhythmias, heart failure, and embolic events.
  • Aorta Symptoms: Often asymptomatic until ruptured; pain occurs with rupture.
  • Treatment: Low blood volume to reduce mechanical stress, smoking cessation, β-blockers may assist.
  • Complication: Aortic dissection, surgical emergency due to risk of vascular rupture.
Thrombus Formation in Arteries
  • Pathophysiology: Lead by damage to endothelium caused by atherosclerosis, leading to coagulation cascade activation.
  • Treatment: Heparin, thrombolytics, endovascular interventions (e.g., catheter therapies).
Embolism
  • Definition: A bolus of matter obstructing blood flow; can include thrombi, air, amniotic fluid, fat aggregates, or foreign substances.
  • Causes: Often arise from venous thrombi, especially following MI, valve disease or dysrhythmias.
  • Consequences: Ischemia or infarction in distal tissues; neurological manifestations from cerebral blockage.
Peripheral Vascular Diseases
  • Thromboangiitis Obliterans (Buerger Disease): Inflammatory disease of small- and medium-sized arteries, primarily in smokers.
  • Raynaud Phenomenon and Disease: Episodic vasospasm of peripheral arteries, leading to color changes and ischemic symptoms.

Atherosclerosis

  • Definition: A form of arteriosclerosis involving lipid accumulation and plaque formation within arterial walls.
  • Progression: Involves endothelial injury, inflammation, LDL oxidation, formation of foam cells, fatty streak, fibrous plaque, complicated plaques.
  • Clinical Manifestations: Dependent upon the organ affected, leading to signs of ischemia.
  • Management: Focused on modifying risk factors, lifestyle changes, and medications to control cholesterol.

Coronary Artery Disease (CAD)

  • Definition: Narrowing or obstruction of coronary arteries resulting in myocardial ischemia or infarction.
  • Risk Factor Categories:
    • Nonmodifiable: Age, gender, family history.
    • Modifiable: Dyslipidemia, hypertension, smoking, diabetes, obesity.
  • Dyslipidemia as a Risk Factor: Elevated LDL and low HDL correlate with higher risk of CAD.

Myocardial Infarction**

  • Primary Mechanism: Results from prolonged ischemia leading to irreversible myocardial damage (necrosis).
  • Classification:
    • Types of Infarction: Subendocardial vs. transmural based on severity and extent.

Heart Failure

  • Definition: Condition where the heart fails to maintain adequate circulation and perfusion of tissues, contributes to stronger filling pressures.
  • Types:
    • Left-sided (congestive): Includes HFrEF (heart failure reduced ejection fraction) and HFpEF (heart failure preserved ejection fraction).
    • Right-sided: Inability of the right heart to effectively pump blood.
  • Complications: Include pulmonary congestion, systemic congestion, poor exercise tolerance.
  • Risk Factors: Include coronary artery disease, hypertension, and history of myocardial infarction.

Dysrhythmias

  • Definition: Disturbances in heart rhythm, can impact heart function and include a range from minor to severe.