Cardiovascular Pathophysiology

Diseases of the Veins

• Varicose veins are veins where blood has pooled, becoming distended, tortuous, and palpable
• Trauma or gradual venous distension can cause varicose veins
• Risk factors include age, being female, family history, obesity, pregnancy, deep vein thrombosis, and prior leg injury
• Chronic venous insufficiency is inadequate venous return over a long period, often due to varicose veins or valvular incompetence, which can lead to venous stasis ulcers
• Thrombus formation in veins obstructs venous flow, leading to increased venous pressure
• The Triad of Virchow leads to thrombus formation, components of this triad include:
  • Venous stasis
  • Venous endothelial damage
  • Hypercoagulable states
• Other factors that contribute to thrombus formation include cancer, orthopedic surgery/trauma, heart failure, and immobility
• Superior vena cava syndrome is the progressive occlusion which leads to venous distension of upper extremities and the head
• Bronchogenic cancer (75%), lymphoma, and metastases of other cancers are leading causes of superior vena cava syndrome
• Superior vena cava syndrome is an oncological emergency

Diseases of the Arteries

• Hypertension is a consistent elevation of systemic arterial blood pressure
• Sustained systolic blood pressure of 140 mm Hg or greater or a diastolic pressure of 90 mm Hg or greater indicates hypertension
• Primary hypertension is essential or idiopathic and is influenced by genetic and environmental factors
• Primary hypertension affects 92 to 95% of individuals with hypertension
• Indigenous populations are more likely to have hypertension, other risk factors, and comorbidities
• Risk factors for primary hypertension include high sodium intake, natriuretic peptide abnormalities, inflammation, obesity, and insulin resistance
• Secondary hypertension is caused by a systemic disease process that raises peripheral vascular resistance or cardiac output
• Renal vascular or parenchymal disease, adrenocortical and adrenomedullary tumors, and medications induce secondary hypertension
• Complicated hypertension causes chronic hypertensive damage to blood vessels and tissues
• Heart, kidney, brain, and eyes are the main organs impacted by complicated hypertension
• Myocardial hypertrophy can arise due to complicated hypertension

Diseases of the Arteries and Veins

• Malignant hypertension is rapidly progressive hypertension with a diastolic pressure usually >140 mm Hg, leading to life-threatening organ damage
• Orthostatic (postural) hypotension involves a decrease in both systolic and diastolic blood pressure upon standing and a lack of normal blood pressure compensation in response to gravitational changes
• Acute and chronic orthostatic hypertension are possible

Aneurysms

• Aneurysms are local dilations or outpouchings of a vessel wall or cardiac chamber
• True aneurysms can be fusiform, circumferential, or saccular
• False aneurysms are extravascular hematomas that communicate with the intravascular space
• The aorta is the most susceptible, especially abdominal, to aneurysms
• Causes for aortic aneurysms can be atherosclerosis and hypertension
• Aortic aneurysms can lead to aortic dissection or rupture

Thrombus and Embolism

• Thrombus formation is a blood clot that remains attached to the vessel wall
• Risk factors for thrombus formation include intimal injury/inflammation, obstruction of flow, and pooling (stasis)
• Thromboembolus and arterial thrombi can arise from thrombus formation
• Embolism is a bolus of matter circulating in the bloodstream
• Embolisms consist of dislodged thrombi, air bubbles, amniotic fluid, aggregates of fat, bacteria, cancer cells, or foreign substances

Peripheral Artery Disease

• Thromboangiitis obliterans (Buerger's disease) is an inflammatory disease of the peripheral arteries strongly associated with smoking and autoimmune factors
• Thrombi are filled with inflammatory and immune cells, becoming organized and fibrotic for permanent occlusion and obliteration of small/medium arteries in extremities
• Buerger's disease causes pain, tenderness in the affected area, and symptoms from sluggish blood flow
• Gangrenous lesions and amputations can result from Thromboangiitis obliterans
• Raynaud's phenomenon causes episodic vasospasm in arteries and arterioles of the fingers, less commonly the toes
• Primary Raynaud's is a vasospastic disorder of unknown origin
• Secondary Raynaud's is secondary to other systemic diseases or conditions like collagen vascular disease, smoking pulmonary hypertension, myxedema and cold environments
• Manifestations of Raynaud's include pallor, cyanosis, cold, and pain

Atherosclerosis and Arteriosclerosis

• Arteriosclerosis is a chronic disease of the arterial system with abnormal thickening and hardening of the vessel walls
• Atherosclerosis is a form of arteriosclerosis
• It causes thickening and hardening caused by accumulation of lipid-laden macrophages in the arterial wall
• This process causes plaque development
• Atherosclerosis progression:
  • Inflammation of endothelium
  • Cellular proliferation
  • Macrophage migration and adherence
  • LDL oxidation (foam cell formation)
  • Fatty streak
  • Fibrous plaque
  • Complicated plaque
• Risk factors include diabetes, smoking, dyslipidemia, hypertension, genetics
• Inadequate perfusion, ischemia, and necrosis result from atherosclerosis

Coronary Artery Disease

• Coronary artery disease (CAD) causes any vascular disorder that narrows or occludes the coronary arteries, leading to myocardial ischemia.
• Atherosclerosis is the most common cause of CAD
• Nonmodifiable risk factors include increased age, family history, and male gender/female postmenopause
• Modifiable risk factors include dyslipidemia, hypertension, cigarette smoking, diabetes mellitus, obesity/sedentary lifestyle, and atherogenic diet
• Nontraditional risk factors for CAD include markers of inflammation and thrombosis
• High-density C-reactive protein, erythrocyte sedimentation rate, von Willebrand factor concentration, interleukin-6, interleukin-18, tumour necrosis factor, fibrinogen, and CD 40 ligand are markers of inflammation and trombosis
• Some nontraditional factors are Troponin I, adipokines, infection, and air pollution
• Myocardial ischemia is a local/temporary deprivation of the coronary blood supply, resulting in stable angina, Prinzmetal's angina, or silent ischemia
• Acute coronary syndromes include transient ischemia, unstable angina, sustained ischemia, and myocardial infarction (STEMI or non-STEMI)
• Myocardial inflammation and necrosis are additional acute coronary syndromes
• Unstable angina involves reversible ischemia
• Sudden/extended obstruction of the myocardial blood supply can lead to myocardial infarction.
• The types of myocardial infarction include subendocardial infarction and transmural infarction

Myocardial Infarction

• Myocardial infarction causes cellular injury and death
• Leading to structural and functional changes:
  • Myocardial stunning
  • Hibernating myocardium
  • Myocardial remodelling
• Repair processes within the myocardium can occur after myocardial infarction
• Manifestations include sudden severe chest pain, nausea, vomiting, diaphoresis, and dyspnea
• Ischemia, left ventricular dysfunction, and electrical instability are main complications of myocardial infarction

Disorders of the Heart Wall

• Disorders of the pericardium include acute pericarditis, pericardial effusion, tamponade, and constrictive pericarditis

Disorders of the Myocardium

• Cardiomyopathies include dilated (congestive) cardiomyopathy, hypertrophic cardiomyopathy and restrictive cardiomyopathy.
• Hypertensive hypertrophic, and valvular hypertrophic cardiomyopathy are subtypes of Hypertrophic cardiomyopathy

Disorders of the Endocardium

• Valvular dysfunctions include valvular stenosis, valvular regurgitation, and mitral valve prolapse syndrome (MVPS)
• Aortic and mitral valves are often impacted by valvular stenosis
• Aortic, mitral, and tricuspid valves are associated with valvular regurgitation

Acute Rheumatic Fever

• Rheumatic fever is a systemic, inflammatory disease caused by a delayed immune response to pharyngeal infection by group A beta-hemolytic streptococci causing a febrile illness.
• The inflammation of joints, skin, the nervous system, and heart arise in the fever response
• Untreated rheumatic fever may cause rheumatic heart disease
• Common clinical manifestations for rheumatic fever:
  • Fever
  • Lymphadenopathy
  • Arthralgia
  • Nausea/vomiting
  • Tachycardia
  • Abdominal pain
  • Epistaxis
• Major clinical manifestations for rheumatic fever:
  • Carditis
  • Polyarthritis
  • Chorea
  • Erythema marginatum
  • Subcutaneous nodules

Infective Endocarditis

• Infective endocarditis is inflammation of the endocardium
• Bacterial, viral, fungal, rickettsiae and parasitic agents are related to endocarditis
• Pathogeneis of infective endocarditis include:
  • Damaged (prepared) endocardium
  • Blood-borne microorganism adherence
  • Proliferation of the microorganism (vegetations)
• Classic findings include fever, new/changed cardiac murmur, and petechial lesions of the skin/conjunctiva/oral mucosa
• The characteristic findings, Osler nodes (painful erythematous nodules on the pads of fingers and toes), and Janeway lesions (nonpainful hemorrhagic lesions on the palms/soles) are other manifestations
• Weight loss, back pain, night sweats, and heart failure are other symptoms

Cardiac issues with AIDS

• AIDS can result in conditions such as dilated cardiomyopathy, myocarditis, pericardial effusion, endocarditis, pulmonary hypertension and nonantiretroviral medication related cardiotoxicity.

Heart Failure

• Heart failure is a general term describing several types of cardiac dysfunction that result in inadequate tissue perfusion with blood-borne nutrients
• Left ventricular failure can arise as heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF)
• HFrEF includes systolic heat failure, which involves the inability of the heat to generate adequate cardiac output to perfuse tissues
  • Ventricular remodelling is linked to HFrEF
  • Main causes for HFrEF are myocardial infarction, myocarditis, and cardiomyopathy
• HFpEF is diastolic heart failure characterized by pulmonary congestion despite normal stroke volume and cardiac output
  • Causes for HFpEF include myocardial hypertrophy/ischemia, diabetes, valvular, and pericardial disease
• Left heart failure manifests as pulmonary vascular congestion and inadequate perfusion of the systemic circulation
• Symptoms include dyspnea, orthopnea, cough of frothy sputum, fatigue, decreased urine output, and edema Pulmonary edema (cyanosis, inspiratory crackles, pleural effusions), hypotension/hypertension, an S3 gallop, and underlying CAD/hypertension are common signs
• Right heart failure is commonly caused by diffuse hypoxic pulmonary disease
• Increased left ventricular filling pressure reflected back into the pulmonary circulation can trigger right heart failure
• High-output failure causes the heart to be unable to supply the body with blood-borne nutrients despite adequate blood volume and normal/elevated myocardial contractility
• Anemia, hyperthyroidism, septicemia, and beriberi, can initiate high-output failure

Shock

• In shock, the cardiovascular system fails to perfuse tissues adequately, which leads to impaired cellular metabolism, oxygen use, and glucose use
• Manifestations vary based on stage but often include hypotension, tachycardia, and increased respiratory rate
• Types of shock:
  • Cardiogenic
  • Hypovolemic
  • Neurogenic
  • Anaphylactic
  • Septic

Multiple Organ Dysfunction Syndrome

• Multiple Organ Dysfunction Syndrome (MODS) is the progressive dysfunction of two or more organ systems resulting from an uncontrolled inflammatory response to severe illness or injury
• Sepsis/septic shock are most common in patients with MODS
• Causes also include any severe injury (trauma, burns, major surgery)
• Manifestations vary but are mainly:
  • Respiratory
  • Hepatic
  • Renal
  • GI
  • Myocardial failure

Explore myocardial infarction, cardiac arrest, and atherosclerosis. This quiz covers risk factors and symptoms. Test your knowledge of cardiology concepts.