The Diagnosis of Pulmonary Hypertension with Dr. Chad Miller and Dr. Craig Patterson
“It took me 8 years to get a diagnosis. I was getting increasingly breathless and I kept on going to the doctor, and kept being told it was anxiety, or I was getting unfit.”
Craig Patterson, MD completed his fellowship at the Louisiana State University Health Sciences Center and the Ochsner Clinic Foundation in New Orleans, La. His professional interests include pulmonary hypertension, venous thromboembolic disease, and critical care medicine. He is a member of the American College of Chest Physicians and a participant in the ACCP's Pulmonary Vascular Disease One Network.
Chad Miller, MD earned undergraduate degrees in biology and philosophy from the University of Alabama at Birmingham. He completed his medical degree at the University of Alabama School of Medicine in Birmingham. He did his internal medicine residency and his pulmonary and critical care fellowship training at the University of Alabama at Birmingham, during which he also did additional subspecialty training in pulmonary hypertension and echocardiography.
Diagnosing Pulmonary Hypertension in the ICU: Insights from Clinical Experts
Pulmonary hypertension (PH) is a complex, often devastating disease that challenges even experienced critical care providers. In this episode of the Pulmcast Podcast, Dr. Chad Miller and Dr. Craig Patterson share their expertise on the diagnosis of pulmonary hypertension, offering practical insights, clinical pearls, and a reminder of just how important thoughtful evaluation is in patient care.
Why Early Diagnosis of Pulmonary Hypertension Matters
Pulmonary hypertension is defined as an elevated mean pulmonary arterial pressure, typically >25 mmHg on right heart catheterization. While the initial insult begins in the pulmonary vasculature, outcomes are closely tied to right ventricular (RV) function.
Despite advances in awareness, the time from symptom onset to diagnosis has not improved significantly in 20 years. Delays are common because PH is rare, presents with nonspecific symptoms such as dyspnea, and overlaps with a wide range of cardiopulmonary diseases. Early, accurate diagnosis is crucial because untreated pulmonary arterial hypertension (PAH) carries a worse five-year survival than breast or colon cancer.
Common Causes and Clinical Clues
Pulmonary hypertension is an umbrella term, and not all PH is PAH. The World Health Organization (WHO) classifies PH into five groups:
| Group | Cause | Examples |
|---|---|---|
| Group 1 | Pulmonary Arterial Hypertension (PAH) | Idiopathic, connective tissue disease, drugs/toxins, HIV, portal hypertension |
| Group 2 | PH due to Left Heart Disease | Heart failure, valvular disease |
| Group 3 | PH due to Lung Disease / Hypoxia | COPD, interstitial lung disease, sleep apnea |
| Group 4 | Chronic Thromboembolic PH (CTEPH) | Chronic pulmonary emboli, residual clots |
| Group 5 | Multifactorial / Unclear | Hematologic, systemic, metabolic, renal disorders |
In the U.S., left heart disease and lung disease are the most common culprits (Groups 2 and 3). Most referrals for PH evaluation involve patients with heart failure or COPD who remain symptomatic despite treatment.
Echocardiography: The First-Line Test
Echocardiography is often the first test prompting a referral for PH. Elevated right ventricular systolic pressure (RVSP), right atrial/ventricular enlargement, or abnormal septal motion can suggest PH.
However, echo alone cannot establish a definitive diagnosis of PAH. It provides valuable clues but must be followed by invasive testing and broader evaluation to exclude left heart or lung disease.
Interpreting Echo Findings in ICU Patients
Expert interpretation is critical. A patient with reduced ejection fraction (EF 25%) and COPD may have elevated RVSP on echo, but their PH is almost always multifactorial. In such cases, optimal management of underlying conditions (afterload reduction, diuretics, bronchodilators, supplemental oxygen) is the first step before considering advanced PH therapies.
When to Perform Right Heart Catheterization
The gold standard for diagnosing pulmonary arterial hypertension is right heart catheterization (RHC).
Confirms elevated pulmonary pressures
Differentiates pre-capillary (PAH) from post-capillary (left heart disease) causes
Assesses pulmonary vascular resistance and cardiac output
As Dr. Miller emphasized: “This disease is never, and I mean ever, diagnosed off an echo.”
Integrating Hemodynamics with Clinical Judgment
Diagnosis of PH requires synthesis of multiple data points:
Echocardiography
Right heart catheterization
Pulmonary function tests
High-resolution chest CT
Serologies for connective tissue disease
Liver function testing (to evaluate for portopulmonary hypertension)
No single test is definitive; clinicians must integrate physiology, imaging, and history to distinguish PAH from WHO Group 2–4 conditions.
Practical Steps for the Busy ICU Clinician
Start broad: Consider all WHO groups before assuming PAH.
Use RHC early: Confirm physiology and exclude left heart disease.
Look for comorbidities: COPD, OSA, interstitial lung disease, cirrhosis, or connective tissue disease may drive PH.
Don’t forget CTEPH: Always order a V/Q scan—it’s more sensitive than CT angiography for detecting chronic emboli and identifies patients eligible for curative thromboendarterectomy.
Stay systematic: Ask the key question—is this a disease of the pulmonary vessels, or high pressure caused by another process?
Key Takeaways
Not all pulmonary hypertension is pulmonary arterial hypertension. Always walk through WHO groups.
Right heart catheterization is required for a definitive PAH diagnosis.
Echocardiography guides but does not confirm the diagnosis.
Comorbid heart and lung disease are common drivers of PH and must be addressed first.
CTEPH is curable—order a V/Q scan in every PH workup.
Pulmonary hypertension remains one of the most challenging diagnoses in critical care. But with a systematic approach and attention to physiology, clinicians can improve diagnostic accuracy, initiate appropriate therapy, and ultimately improve outcomes for their patients.
