PANCE Blueprint Pulmonary (9%)

Right ventricular enlargement and eventually failure secondary to lung disorder that causes pulmonary artery HTN

• Etiology: COPD (most common), pulmonary embolism, vasculitis, asthma, ILD, acute respiratory distress syndrome
• Physical Exam: Lower extremity edema, neck vein distention, hepatomegaly, parasternal lift, tricuspid/pulmonic insufficiency, loud S2

DX: The diagnosis of cor pulmonale is usually made with an echocardiogram → increased pressure in the pulmonary arteries and right ventricle

• Spirometry can be done to look for chronic lung disease
• The gold standard diagnostic test to directly measure pulmonary pressures and assess for response to vasodilating medications is a right heart catheterization

TX: Diagnose and treat the underlying condition before cardiac structure change becomes irreversible

• • Long-term O2 for chronic hypoxemia (improves survival in COPD); diuretics only cautiously for edema — over-diuresis drops RV preload

Pathophysiology of cor pulmonale (Image by Lecturio)

ReelDx Virtual Rounds (pulmonary embolism)

pulmonary embolism

You are called to see a 51 y/o male with an acute onset of shortness of breath x 24 hours

Patient

• Gender: Male
• Age: 51 years
• Weight: 253.5 lb/115 kg
• Height: 73 in/185.4 cm

Vitals

• Temperature: 97.7 F/36.5 C
• Blood Pressure: 139/98
• Heart Rate: 113
• Respiratory Rate: 20
• Pulse Oximetry: 96% RA

Signs and Symptoms

• Acute onset of shortness of breath the previous night

Click here to work through this patient case simulation.

A pulmonary embolism is a blockage in one of the pulmonary arteries in the lungs

• More than 90% originate from clots in the deep veins of the lower extremities
• Presents with dyspnea (most common) and pleuritic chest pain
• R/F: Virchow’s triad = hypercoagulable state, trauma, venostasis (surgery, cancer, oral contraceptives, pregnancy, smoking, long bone fracture/fat emboli)
• Homans sign: (Dorsiflexion of the foot causes pain in the calf), indicative of deep vein thrombosis
• EKG: TACHYCARDIA (most common), S1Q3T3 (rare), non-specific ST wave changes

Diagnosis: Well’s Score is used to assess the probability of pulmonary embolism

• CT pulmonary angiography (CTPA) = first-line imaging (most accurate test)
• Pulmonary angiography = historic gold standard (catheter-based; rarely needed now)
• CXR: Westermark sign or Hampton hump (triangular or rounded pleural base infiltrate adjacent to hilum)
• V/Q scan = use when CTPA is contraindicated (renal failure, contrast allergy, pregnancy): perfusion defects with normal ventilation (normal VQ rules out PE; abnormal – non-specific)
• Venous duplex ultrasound of lower extremities (normal test does not exclude PE)
• ABG = respiratory alkalosis secondary to hyperventilation
• D-dimer

Tx: Anticoagulation — DOACs are preferred for most patients: apixaban or rivaroxaban can be started alone, while edoxaban and dabigatran follow at least 5 days of heparin; unfractionated heparin is used for unstable patients, possible thrombolysis, or severe renal failure

Blood pressure in the lungs is usually extremely low 15/5. In pulmonary hypertension, the pressure increases > 20 mmHg at rest

• Usually caused by an underlying disorder (constrictive pericarditis, left heart disease/LV failure = MC, mitral stenosis (classic valvular cause), mediastinal disease, compression of pulmonary veins)
  • Mitral stenosis: mitral valve = tight, so blood can’t pass into the left ventricle ⇒ pressure backs up to lungs
• When the right heart can’t pump against vascular resistance ⇒ right heart failure = Cor pulmonale
• Presentation: Dyspnea on exertion, fatigue, chest pain, edema
• Physical Exam: Loud pulmonic component of second heart sound (P2); Jugular venous distension; Ascites; Hepatojugular reflux; Lower limb edema

Diagnose with a right heart catheterization (gold standard) → most accurate measure of pressures

• CXR
  • Enlarged pulmonary arteries
  • Lung fields may or may not be clear, dependent on the underlying cause
• Echocardiogram
  • Increased pressure in pulmonary arteries, right ventricles → dilated pulmonary artery
  • Dilatation/hypertrophy of right atrium, right ventricle
  • Large right ventricle → bulging septum
• ECG → Right heart strain pattern: T wave inversion in right precordial (V1–V4) and inferior leads (II, III, aVF)

TX: identify and treat the underlying cause

• Pulmonary hypertension secondary to left ventricular failure → optimize left ventricular function
  • Diuretics (cautiously—individuals may be preload dependent)
  • Digoxin
  • Anticoagulants
• Pulmonary arterial hypertension (WHO group 1) — confirmed by right heart catheterization
  • Relax smooth muscle (promote vasodilation), reduce vascular remodeling, improve exercise capacity with prostanoids, phosphodiesterase inhibitors, endothelin antagonists
  • Not used for pulmonary HTN due to left heart disease or lung disease (can worsen pulmonary edema or hypoxemia)
• PAH drug classes to know
  • Endothelin receptor antagonists
  • Prostanoids

The classic findings on chest radiography in a patient with pulmonary arterial hypertension include enlarged central pulmonary arteries that taper distally (peripheral pruning), attenuated peripheral vessels, and oligemic lung fields. Image: Hellerhoff, CC BY-SA 4.0, via Wikimedia Commons.