Pulmonary Hypertension

Definition/Etiology:

Normal mean pulmonary artery pressure is 12-16 mmHg.
Pulmonary hypertension is >20 mmHg.

Five groups of Pulmonary Hypertension:

• Group 1: pulmonary arterial (PA) hypertension (PAH), which has several causes (eg, inheritable causes, drugs, connective tissue disease)
• Group 2: due to left-sided heart failure (most common PH)
• Group 3: due to chronic lung disorders and hypoxemia
• Group 4: due to acute or chronic PE
• Group 5: due to unidentified mechanisms

Pathophysiology:

• Pulmonary arterial hypertension (group 1): small pulmonary muscular arterioles develop vasoconstriction, hyperplasia, hypertrophy, fibrosis, and thrombosis that involves all three layers of the vascular wall.
• Pulmonary hypertension:
  Group 2–elevated left-sided pressure backs up into the pulmonary system.
• Group 3–restrictive (kyphosis), obstructive (COPD), hypoxia (sleep apnea, obesity hypoventilation)
• Group 4–rare (1%) complication of PE. Poorly understood. Not related to genetic hypercoagulable states.

Clinical Presentation:

• Exertional dyspnea / chest pain / syncope
• Lethargy / fatigue

Right-sided heart failure signs and symptoms:

• Ascites / hepatomegaly
• Leg edema
• Early satiety
• RUQ pain

Collaborative Management:

• EKG: right axis deviation due to RV/RA enlargement
• CXR: pleural effusions
• Labs: elevated BNP
• Echocardiogram: RV strain, tricuspid regurg
• Accurate history: travel, cocaine, diet pills, cigarettes, HIV, connective tissue disease, sleep apnea, prior DVT/PE
• Possible left and right heart catheterization
• Pulmonary function test
• Sleep study
• VQ scan or CT angio chest (PE protocol)
• Treat underlying process (anticoagulation if from PEs, CPAP if from apnea, diuretics if from CHF, oxygen if from hypoxia)
• Smoking cessation
• Pulmonary rehab / exercise
• Lung transplantation for Group 3
• Heart transplantation for Group 2 (or LVAD)
• Cardiology consult

Evaluation | Patient Monitoring | Education:

• Oxygen saturation monitoring
• Home infusion of IV medications for Group 1
• Transplant center referral PRN
• Importance of follow-up on sleep study / apnea treatment
• Drug / smoking cessation / counseling / support
• Home oxygen use and teaching re: safety
• Importance of exercise / pulmonary rehab

Linchpins: (Key Points)

• Treat underlying disease.
• Thin right ventricular wall can’t push against high pressures.
• Pressure in pulmonary system should be quite low.
• Group 1 (PAH) is really bad.
• LOTS of things can cause PH/PAH. You don’t have to memorize all of the groups and causes.