Pulmonary Vascular Disease

Overview

• Important chapters referenced: Egans Chapter 28, Linz Chapter 17.

Circulatory System

Basic Concepts

• Illustrated with the Amoeba Sisters, providing a simplified overview of circulatory functions.

Pulmonary Vascular Diseases

Venous Thromboembolism (VTE)

1. Deep Vein Thrombosis (DVT)

   • Formation of a thrombus in the venous system, often occurring in the deep veins.

   • Symptoms may include swelling, pain, and redness in the affected limb.

2. Pulmonary Embolism (PE)

   • Occurs when a thrombus from the venous system travels to pulmonary circulation.

   • Often originates in the deep veins and leads to obstruction of pulmonary arteries.

   • Sudden obstruction of a pulmonary arterial branch results in decreased or total cessation of blood flow to distal areas of the lung, leading to significant clinical implications.

   • Can cause an increase in alveolar dead space, leading to ventilation without perfusion and potentially bronchoconstriction.

   • Not all patients exhibit significant desaturation of oxygen levels, but a widened alveolar-arterial oxygen tension gradient is typically observed.

   • Results in reduced partial pressure of oxygen ( PaO2).

Pulmonary Hypertension (PH)

1. Definition

   • An increase in pressure in the pulmonary arteries, indicating potentially serious underlying conditions affecting lung vessels, parenchyma, or heart.

2. Pulmonary Artery Hypertension (PAH)

   • A specific subgroup of patients with PH characterized by a progressive narrowing of the pulmonary arteries that can lead to right heart failure (cor pulmonale) and death if untreated.

3. Classification of PH

   • Group 1: Pulmonary arterial hypertension (PAH)

   • Group 2: Pulmonary hypertension associated with left heart disease

   • Group 3: Pulmonary hypertension associated with lung diseases and/or hypoxia

   • Group 4: Pulmonary hypertension associated with pulmonary artery obstructions

   • Group 5: Pulmonary hypertension with unclear and/or multifactorial mechanisms

4. Common Causes of PH

   • Typically linked to existing heart or lung diseases.

Key Statistics and Insights

• Approximately 30%-50% of elderly patients with COPD present with significant pulmonary hypertension, emphasizing the need for early diagnosis and management.

Venous Thromboembolic Disease

Conditions Associated with Thrombus Formation

• Includes factors like:

  1. Recent major surgery

  2. Trauma

  3. Prolonged immobilization (such as bed rest)

  4. Congestive heart failure (CHF)

  5. Varicose veins

  6. Other: Fat/air emboli, obesity, atrial fibrillation, antiphospholipid antibodies, malignancy, pregnancy, and childbirth, and the use of oral contraceptives.

Clinical Features of Pulmonary Embolism (PE)

Symptoms and Signs

1. General Appearance

   • Patients may present as anxious, diaphoretic (sweating), cyanotic (blueish skin), and have cool or clammy skin.

2. Respiratory Pattern

   • Symptoms typically include shortness of breath and tachypnea (rapid breathing).

3. Auscultation Findings

   • May reveal wheezing, crackles, and a pleural friction rub.

4. Cough

   • Patients may experience hemoptysis (coughing up blood).

5. History

   • Symptoms commonly have a sudden onset.

Diagnosis of Pulmonary Embolism

Diagnostic Modalities

1. Chest X-Ray (CXR)

   • May show increased density in the infarcted area, dilation of pulmonary arteries, and wedge-shaped infiltrates.

2. Arterial Blood Gas (ABG)

   • Typically indicates respiratory alkalosis paired with hypoxemia.

   • Measurement of partial arterial pressure (PAP) shows increased levels (normal being 13-14 mmHg or 25/8 mmHg).

3. D-Dimer Test

   • Useful for ruling out PE; a positive result requires further investigation.

4. Imaging Techniques

   • Computed Tomography Pulmonary Angiography (CTPA): Considered the primary diagnostic modality for PE, involving contrast injection to visualize pulmonary arteries.

   • V/Q Scanning: Selected when CTPA is contraindicated or inconclusive.

   • Pulmonary Angiography, when necessary, and Echocardiography to assess right ventricular dysfunction.

Management and Treatment of Pulmonary Embolism

1. Prevention Measures

   • Anticoagulation therapy and anti-embolism (compression) stockings.

   • Use of pneumatic compression devices and early ambulation tactics.

   • Administration of oxygen at 100% to maintain partial arterial oxygen pressure ( PaO2) over 80 mmHg.

2. Specific Therapies

   • Anticoagulants, particularly Heparin, analgesics to relieve chest pain, and digitalis agents like digoxin to aid circulation.

   • Thrombolytic agents for actively dissolving blood clots.

Heart Failure

Introduction and Definitions

• Important chapters referenced: Egans Chapter 31, Linz Chapters 15 and 16.

Acute Heart Failure

1. Definition

   • A complex clinical syndrome marked by symptoms and signs stemming from structural or functional impairments in ventricular filling or blood ejection.

2. Common Causes

   • Ischemic heart disease and myocardial infarction are prominent contributors alongside valvular heart disease and other factors like cardiomyopathy, congenital heart defects, pericardial diseases, and cardiac tamponade.

   • Can affect the left, right, or both ventricles, resulting in multi-organ failure due to hypoperfusion or venous congestion.

Ischemic Heart Disease (IHD)

1. Definition and Terminology

   • Also known as coronary heart disease or coronary artery disease, leading to heart attacks and ischemic cardiomyopathy.

   • Initiated when the intima of arteries is damaged, primarily due to atherosclerosis – plaque buildup in coronary arteries decreasing blood supply.

2. Causes and Risk Factors

   • High blood pressure, smoking, elevated levels of fats/cholesterol, diabetes contribute to artery damage and ischemia.

3. Atherosclerotic Process
   a. Stages

   • Damage to the intimal layer

   • Migration of smooth muscle from the medial layer to the intima

   • Formation of plaque.

Clinical Manifestations of Ischemic Heart Disease

1. Symptoms

   • Angina pectoris: characterized by chest pain, often described as constricting or knifelike, which arises due to increased myocardial oxygen demand and reduced perfusion.

   • Angina can last up to 15 minutes, often presenting under the sternum or near the precordial chest area.

   • Three main types: stable, Prinzmetal, and unstable angina.

2. Diagnostic Methods

   • Non-invasive tests like 12-lead electrocardiograms, exercise stress tests, pharmacological stress tests, and echocardiograms.

   • Radiologic imaging such as CT scans for in-depth analysis and the coronary angiogram as the gold standard for invasive diagnosis.

3. Management Strategies

   • Combination of medications and lifestyle changes, angioplasty techniques including plain old balloon angioplasty and rotational atherectomy, alongside stent placements for revascularization.

4. Coronary Artery Bypass Grafting (CABG)

   • A surgical bypass technique for patients with significant coronary artery disease.

   • Indicated for patients with diabetes, severe lesions, and for those with left main coronary artery involvement.

   • General anesthesia is required; the procedure may necessitate the use of a heart-lung bypass machine.

   • Patients typically require 3-7 days in the hospital, with full recovery taking up to 3 months and possible complications including inflammation, infection, and strokes.

Myocardial Infarction (Heart Attack)

1. Definition

   • Prolonged interruption of coronary blood flow causing irreversible damage to heart muscle, potentially leading to sudden cardiac arrest.

2. Patient Assessment Findings

   • Presentation as diaphoretic, anxious, reporting chest pain, possible cyanosis, tachypneic patterns during respiration.

   • Diagnostic testing may show electrolyte imbalances, changes in EKG with inverted T waves and elevated S-T segments, and elevated cardiac enzymes (e.g., troponin).

3. Management Protocol

   • Administration of the MONA protocol: Morphine, Oxygen, Nitrates, and Aspirin to alleviate pain and maintain blood pressure using fluids or vasopressors.

Valvular Heart Disease

Types of Conditions

• Aortic insufficiency (regurgitation), aortic stenosis, mitral regurgitation, mitral stenosis, pulmonic regurgitation, pulmonary stenosis, tricuspid regurgitation, and tricuspid stenosis.

Acute Heart Failure Pathophysiology

Key Definitions

1. Preload

   • Refers to the amount of vascular stretch at the end of diastole before contraction begins; measured as left ventricular end-diastolic pressure (LVEDP).

2. Afterload

   • The resistance that the heart must overcome to eject blood, also known as vascular resistance opposing ventricle ejection.

3. Contractility

   • The inherent strength of ventricular contraction during systole.

Consequences of Congestion

• Elevated pressure within the cardiac chambers due to systolic or diastolic dysfunction.

• Hypoperfusion due to decreased cardiac output can lead to symptoms such as altered level of consciousness (ALOC) and delayed capillary refill.

Cardiogenic Shock

• Represents inadequate organ perfusion due to heart failure, marked by systolic blood pressure typically falling below 90 mmHg or necessitating vasopressive medications to maintain blood pressure.

Impacts of Right-Sided Heart Failure

Function and Symptoms

1. Physiology

   • Pumps blood into the pulmonary system; any failure may arise from diastolic dysfunction.

   • Seen in patients with chronic lung diseases like COPD or pulmonary hypertension.

2. Clinical Manifestations

   • Symptoms include jugular vein distention, liver enlargement, swelling in the legs due to venous congestion.

Left-Sided Heart Failure

Function and Symptoms

1. Physiology

   • Inability to properly pump blood to the peripheral circulatory system can lead to pulmonary edema and is more common than right-sided dysfunction.

2. Clinical Manifestations

   • Symptoms are characterized by fluid accumulation leading to pulmonary congestion and may experience a sudden sensation of suffocation, cough, and expectoration of pink foamy liquid.

3. Diagnostic Findings

   • Patients often display signs of increased work of breathing (WOB), increased respiratory rates, and hypoxemia with characteristic lung sounds like wheezes and crackles.

Diagnostic Techniques for Acute Heart Failure

1. Chest Radiography

   • Detects pulmonary venous congestion, interstitial edema, and other related conditions such as cardiomegaly.

2. Electrocardiography

   • While not a reliable predictor of heart failure, it assists in the identification of the underlying etiology.

3. Echocardiography

   • Alongside ECG, is vital for assessing heart failure, analyzing chamber volumes, ventricular function, wall thickness, and valve integrity.

   • Differentiates conditions like heart failure with preserved ejection fraction (HFpEF) from heart failure with reduced ejection fraction (HFrEF).

Treatment and Management of Acute Heart Failure

1. Immediate Interventions

   • Oxygen therapy and non-invasive ventilation (NIV), with intubation as a last resort if NIV fails.

   • Positive end-expiratory pressure (PEEP) can facilitate fluid removal from alveoli.

2. Other Therapeutics

   • Use of diuretics to manage fluid overload, vasodilators, and inotropes to support cardiac function.