Is a mean pulmonary arterial pressure of 35 mm Hg considered severe pulmonary hypertension?

Is mPAP of 35 mmHg Severe Pulmonary Hypertension?

No, a mean pulmonary arterial pressure (mPAP) of 35 mmHg is not classified as severe pulmonary hypertension—it falls into the moderate range, representing an intermediate risk category that requires treatment but is not considered an absolute contraindication to procedures like liver transplantation.

Severity Classification Framework

The current guidelines do not use traditional "mild/moderate/severe" terminology uniformly, but rather stratify PH by hemodynamic thresholds that correlate with clinical outcomes and treatment decisions:

Hemodynamic Thresholds

• PH Definition: mPAP ≥25 mmHg at rest 1, 2
• Moderate PH: mPAP 35-45 mmHg 3, 4, 3
• Severe PH: mPAP >45 mmHg 3, 4, 3

Your patient with mPAP of 35 mmHg sits at the lower boundary of the moderate range.

Clinical Context: Portopulmonary Hypertension

The most explicit severity stratification comes from liver transplantation guidelines, which provide clear cutoffs 3:

Risk Stratification for Surgical Procedures

• mPAP <35 mmHg: Lower risk, generally acceptable for major surgery
• mPAP 35-45 mmHg: Moderate risk, increased mortality but not absolute contraindication if pulmonary vascular resistance (PVR) <3 Wood units 3
• mPAP >45 mmHg: Severe PH, absolute contraindication to liver transplantation even with vasomodulator therapy 3

Treatment Implications at mPAP 35 mmHg

Vasomodulator therapy should be offered to all patients with mPAP >35 mmHg and PVR >3 Wood units 3. This threshold indicates that 35 mmHg represents a clinically significant level requiring intervention, but not the severe category.

Important Caveats

Complete Hemodynamic Assessment Required

mPAP alone is insufficient for full characterization. You must also assess:

• Pulmonary vascular resistance (PVR): Essential for PAH diagnosis (must be >3 Wood units) 1, 2
• Pulmonary artery wedge pressure (PAWP): Must be ≤15 mmHg to diagnose pre-capillary PH 1, 2
• Right ventricular function: RV dysfunction elevates risk independent of pressure 3

Context-Dependent Risk

The clinical significance of mPAP 35 mmHg varies by:

• Underlying etiology: PAH vs. secondary PH
• Clinical scenario: Pre-operative assessment vs. chronic management
• Functional status: WHO functional class and 6-minute walk distance
• Response to therapy: Patients requiring assessment for transplant need documented response to vasomodulators 3

Practical Algorithm

For a patient with mPAP 35 mmHg:

1. Confirm complete hemodynamics (PVR, PAWP, cardiac output)
2. Classify PH type using clinical classification 1, 2
3. Assess functional status (WHO class, 6MWD, NT-proBNP)
4. Initiate vasomodulator therapy if PVR >3 Wood units 3
5. Refer to PH specialist center for ongoing management 1, 2
6. Reassess hemodynamics after treatment initiation to guide further therapy

The designation of "moderate" rather than "severe" at this pressure level reflects both the treatment algorithms and surgical risk stratification consistently applied across multiple guideline documents.