Pulmonary Hypertension Diagnosis

See Also

Diagnosis
Step 1

Basic Tests (indicated in all cases)
1. Complete Blood Count (CBC)
  1. Evaluate for Anemia (high output Heart Failure)
2. Comprehensive Metabolic Panel (Electrolytes, Renal Function tests, Liver Function Tests)
3. B-Type Natriuretic Peptide (BNP)
4. Serum Troponin
5. HIV Test
6. Consider D-Dimer
7. Thyroid Stimulating Hormone (TSH)
  1. Evaluate for Hyperthyroidism (high output Heart Failure)
8. Arterial Blood Gas (ABG) or Venous Blood Gas
  1. Supplemental Oxygen for all hypoxic patients
9. Oximetry (6 Minute Walk Test)
10. Pulmonary Function Tests
11. Coagulation studies (PTT, INR)
  1. Preparation for Anticoagulation
Diagnostic Findings suggestive of Pulmonary Hypertension (All cases)
1. Electrocardiogram (EKG)
  1. See Right Ventricular Strain EKG Pattern
  2. Right Axis Deviation
  3. Right Ventricular Hypertrophy
  4. Right atrial enlargement
  5. Right strain pattern (S1Q3T3)
  6. Sinus Tachycardia
  7. Atrial Fibrillation
  8. Anterior T Wave Inversion (leads V1-4)
2. Chest XRay (abnormal in 90% of Pulmonary Arterial Hypertension)
  1. Primary pulmonary artery dilation
  2. Increased distal pulmonary vasculature markings
  3. Right atrial and ventricular enlargement
  4. Right Interlobar pulmonary diameter >16 mm
  5. Hilar to thoracic ratio >0.44
Additional Tests as indicated
1. Sleep Study
2. Sickle Cell Anemia screening
3. Imaging
  1. CT Chest PE protocol
  2. Liver Ultrasound
4. Autoimmune panel
  1. Anticentromere Antibody level
  2. Antinuclear Antibody level
  3. Anti-Scl-70 Antibody level
  4. Ribonucleoprotein Antibody level
Interpretation of Pulmonary Function Tests (PFT)
1. Nearly normal PFT
  1. Go to Step 2 below
2. Severe Chronic Obstructive Lung Disease (COPD)
  1. See COPD Management
3. Severe Restrictive Lung Disease
  1. High resolution CT Chest
    1. Exclude Interstitial Lung Disease
    2. Exclude mediastinal fibrosis
  2. Interpretation
    1. Interstitial Lung Disease
      1. Lung biopsy for tissue diagnosis
    2. Normal or mediastinal fibrosis
      1. Go to Step 2 below

Diagnosis
Step 2

Tests: Transthoracic Echocardiogram (most useful)
1. Early findings
  1. Tricuspid regurgitation
  2. Peak pulmonary pressure estimated (Bernoulli equation)
    1. Peak tricuspid regurgitation velocity >2.8 m/s
    2. Mean Right Atrial Pressure added to Peak tricuspid jet velocity
    3. Systolic pulmonary artery pressure >35 to 40 mmHg consistent with Pulmonary Hypertension
2. Late findings
  1. Right ventricular dilation
  2. Right Ventricular Hypertrophy
  3. Displaced interventricular septum
  4. Dilated main pulmonary artery
Interpretation
1. Precautions
  1. Peak pulmonary pressure has poor accuracy and is operator dependent
  2. Interpretation is best based on a general gestalt that there is high right sided heart pressure
2. Findings not consistent with Pulmonary Hypertension
  1. No further evaluation needed
3. Classification based on Echocardiogram findings
  1. Left ventricular disease
  2. Right Ventricular Failure with elevated pulmonary artery pressure
  3. Right Ventricular Failure without elevated pulmonary artery pressure
  4. Pericardial disease (Cardiac Tamponade)
4. Findings consistent with Pulmonary Hypertension
  1. Structural heart disease suspected
    1. Follow Step 3 below (Cardiac Catheterization, Gold standard)
  2. No structural heart disease suspected
    1. Evaluate for chronic or recurrent Pulmonary Embolism
    2. Obtain CT Pulmonary Embolism (CT PE) or Ventilation Perfusion Scan (V-Q Scan)
      1. V-Q Scan may have higher sensitivity for chronic, smaller multiple distal emboli
    3. Management
      1. Anticoagulation
      2. Consider for pulmonary endarterectomy (or balloon Angioplasty) for proximal thrombus

Diagnosis
Step 3

Right Heart Catheterization
1. Indicated Pulmonary Hypertension classification
2. Further evaluation of Pulmonary Arterial Hypertension and chronic thromboembolic Pulmonary Hypertension
3. Optional when Pulmonary Hypertension has a clear cardiopulmonary cause (e.g. lung disease, left sided heart disease)
4. Measures pulmonary artery wedge pressure (left atrial pressure)
  1. Normal in precapillary pulmonary vascular bed causes (e.g. Pulmonary Arterial Hypertension)
  2. Wedge pressure is increased in postcapillary causes (e.g. left-sided Heart Failure)
5. Measures pulmonary vascular resistance (PVR)
  1. Calculate PVR as the difference between mean pulmonary artery pressure and left atrial pressure
  2. PVR is increased in Pulmonary Arterial Hypertension (normal in Heart Failure)
Interpretation
1. Pulmonary Arterial Hypertension (and other precapillary causes)
  1. Normal pulmonary artery wedge pressure (left atrial pressure)
  2. Increased pulmonary vascular resistance (PVR)
2. Left-sided Heart Failure (and other postcapillary causes)
  1. Increased pulmonary artery wedge pressure (left atrial pressure)
  2. Normal pulmonary vascular resistance (PVR)

References