PVR Calculator
Pulmonary Vascular Resistance — clinical hemodynamic analysis with severity classification
Normal: 10–20 mmHg
Normal: 10–20 mmHg. Measured directly via pulmonary artery catheter. Pulmonary hypertension defined as mPAP ≥ 25 mmHg.
Normal: 6–12 mmHg
Normal: 6–12 mmHg. Balloon-occluded PA pressure; estimates left atrial pressure. Must be lower than mPAP.
Normal: 4–8 L/min
Normal: 4–8 L/min. Measured by thermodilution or Fick method. Required for PVR calculation.
Typical adult: 1.6–2.0 m²
Optional: enter BSA in m² to calculate PVRI and Cardiac Index. Leave blank to skip PVRI.
Enter Hemodynamic Values
Input mean pulmonary artery pressure, left atrial pressure, and cardiac output to calculate pulmonary vascular resistance.
How to Use This Calculator
Enter Measured Hemodynamic Values
Input the three values obtained from right heart catheterization: mean pulmonary arterial pressure (mPAP in mmHg), pulmonary capillary wedge pressure (PCWP in mmHg), and cardiac output (CO in L/min). These values are measured using a Swan-Ganz pulmonary artery catheter. Use the clinical preset examples to explore representative scenarios if you are studying hemodynamics.
Enter Body Surface Area for PVRI
Optionally enter the patient's body surface area (BSA in m²) to calculate the Pulmonary Vascular Resistance Index (PVRI) and Cardiac Index (CI). PVRI is the BSA-normalized form of PVR and is particularly important for pediatric patients and for transplant candidacy assessment. BSA can be calculated from height and weight using the Dubois or Mosteller formula.
Review PVR Results and Severity Classification
The calculator instantly displays PVR in both Wood units and dyn·s/cm⁵, along with the transpulmonary gradient (TPG) and clinical severity category (Normal, Mildly Elevated, Moderately Elevated, or Severely Elevated). The severity gauge chart shows where PVR falls on the clinical spectrum. The pre-capillary vs post-capillary classification helps identify the likely mechanism of pulmonary hypertension.
Export or Print for Clinical Documentation
Use the Print Results button to generate a print-friendly summary of all hemodynamic values for inclusion in clinical notes or patient records. The Export CSV button downloads all calculated values in a spreadsheet-compatible format suitable for research or audit documentation. All calculations are performed locally in your browser; no data is transmitted or stored.
Frequently Asked Questions
What is a normal PVR value?
Normal pulmonary vascular resistance ranges from 0.6 to 2.0 Wood units (48 to 160 dynes·sec/cm⁵) in adults at rest. Values in this range indicate a healthy pulmonary circulation where the right ventricle can pump blood through the lungs with minimal effort. Clinically, a PVR below 3 Wood units is generally considered the threshold below which most patients tolerate surgical procedures and transplantation well. A PVR of 2.1 to 3.0 WU is considered mildly elevated and may warrant further investigation or monitoring. Values above 5 Wood units (400 dyn·s/cm⁵) indicate severely elevated PVR with significant implications for right ventricular function, exercise capacity, and long-term prognosis. PVR can vary slightly with body position, lung volume, and cardiac output state.
What is the difference between PVR and PVRI?
PVR (Pulmonary Vascular Resistance) is the absolute resistance in the pulmonary circulation, calculated as (mPAP − PCWP) / CO, and expressed in Wood units or dyn·s/cm⁵. PVRI (Pulmonary Vascular Resistance Index) normalizes PVR to body surface area by multiplying PVR by BSA (or dividing the pressure gradient by Cardiac Index instead of Cardiac Output). This indexing accounts for differences in body size, making PVRI more comparable across patients of different sizes — particularly children versus adults. Normal PVRI is 3.2 to 3.6 WU·m² (255–285 dyn·s/cm⁵·m²). PVRI is the preferred metric in pediatric cardiology, in congenital heart disease surgery planning, and for transplant candidacy assessment, where PVRI thresholds (e.g., 6 WU·m²) are used in decision-making algorithms.
What does the transpulmonary gradient (TPG) mean?
The transpulmonary gradient (TPG) is the difference between mean pulmonary arterial pressure and pulmonary capillary wedge pressure: TPG = mPAP − PCWP. It represents the pressure drop specifically across the pulmonary vascular bed, excluding the contribution of elevated left-sided filling pressures. A normal TPG is below 12 mmHg. An elevated TPG (≥ 12 mmHg) combined with an elevated PCWP (> 15 mmHg) suggests that pulmonary vascular remodeling is occurring in addition to passive congestion from left heart disease — this is called combined pre- and post-capillary pulmonary hypertension. The TPG helps identify patients with long-standing left heart failure who have developed secondary reactive pulmonary vascular disease, which may affect transplant candidacy and prognosis differently from pure left heart failure.
What is the difference between pre-capillary and post-capillary pulmonary hypertension?
Pre-capillary pulmonary hypertension occurs when mPAP is elevated (≥ 25 mmHg) but PCWP is normal or low (≤ 15 mmHg), meaning the problem lies within the pulmonary arteries themselves — from vascular remodeling, vasoconstriction, thrombosis, or other intrinsic pulmonary vascular disease. This category includes pulmonary arterial hypertension, PH due to lung disease, chronic thromboembolic PH, and others. Post-capillary PH occurs when elevated pulmonary artery pressures are driven by elevated left-sided filling pressures (PCWP > 15 mmHg) from left ventricular failure, valvular heart disease, or diastolic dysfunction. The distinction is crucial because pulmonary vasodilators (prostacyclins, endothelin antagonists, PDE5 inhibitors) are appropriate for pre-capillary PH but are not recommended as primary treatment for isolated post-capillary PH.
How are mPAP, PCWP, and cardiac output measured?
All three values are obtained during right heart catheterization using a Swan-Ganz (pulmonary artery) catheter inserted through a central vein (typically internal jugular or femoral vein) and floated through the right atrium, right ventricle, and into the pulmonary artery. Mean pulmonary arterial pressure (mPAP) is measured directly from the catheter tip position in the pulmonary artery. Pulmonary capillary wedge pressure (PCWP) is obtained by inflating a small balloon at the catheter tip, which wedges the catheter in a small pulmonary artery branch and reflects left atrial pressure through the downstream pulmonary capillaries. Cardiac output is typically measured by thermodilution (injecting cold saline and measuring temperature change) or by the Fick principle (using oxygen consumption and arteriovenous oxygen difference). This procedure is performed in a cardiac catheterization laboratory under fluoroscopic guidance.
What PVR levels affect transplant candidacy or surgical decisions?
Pulmonary vascular resistance thresholds play a critical role in transplant candidacy assessment. For heart transplantation, a PVRI greater than 6 WU·m² (or PVR > 5 WU with a TPG > 16 mmHg or pulmonary artery systolic pressure > 60 mmHg) is generally considered a relative contraindication to isolated orthotopic heart transplantation because the donor right ventricle may not tolerate the elevated afterload. Some programs accept candidates up to PVRI of 8 WU·m² if vasodilator testing shows reversibility. For congenital heart disease surgery (closure of ASD, VSD, PDA), a PVRI below 6 WU·m² in children is generally considered acceptable for repair. Values of 7–8 WU·m² may still allow repair in simple shunts if vasodilator testing demonstrates adequate hemodynamic response. These thresholds should always be interpreted in the context of the full clinical picture and institutional protocols.