1. What is Transpulmonary Gradient?

The transpulmonary gradient (TPG) is the difference between mean pulmonary arterial pressure (mPAP) and pulmonary artery wedge pressure (PAWP). It represents the pressure gradient across the pulmonary vascular bed and is used to assess pulmonary vascular resistance.

2. How Does the Calculator Work?

The calculator uses the simple equation:

Where:

• \( mPAP \) — Mean pulmonary arterial pressure (mmHg)
• \( PAWP \) — Pulmonary artery wedge pressure (mmHg)

Explanation: The TPG helps differentiate between pre-capillary and post-capillary pulmonary hypertension.

3. Importance of TPG Calculation

Details: TPG is crucial for diagnosing pulmonary hypertension types and guiding treatment decisions. A TPG >12 mmHg suggests increased pulmonary vascular resistance.

4. Using the Calculator

Tips: Enter mPAP and PAWP values in mmHg. Both values must be positive numbers obtained from right heart catheterization.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal TPG value?
A: Normal TPG is typically ≤12 mmHg. Values above this suggest pulmonary vascular disease.

Q2: How does TPG differ from PVR?
A: TPG is the pressure difference while PVR (pulmonary vascular resistance) is calculated as TPG divided by cardiac output.

Q3: When is TPG measurement most useful?
A: Most valuable in distinguishing between Group 1 (pre-capillary) and Group 2 (post-capillary) pulmonary hypertension.

Q4: What are limitations of TPG?
A: Doesn't account for flow (cardiac output). For complete assessment, calculate PVR and consider diastolic pressure gradient.

Q5: How often should TPG be measured?
A: Typically during diagnostic right heart catheterization and for follow-up in pulmonary hypertension patients.