Pulmonary Vascular Resistance (PVR) Risk Tier Calculator

Pulmonary Vascular Resistance (PVR) Risk Tier: Explanation and Clinical Context Pulmonary Vascular Resistance (PVR) represents the afterload faced by the right ventricle and is calculated from the transpulmonary gradient (mean pulmonary artery pressure minus pulmonary artery wedge pressure) divided by cardiac output. It reflects the degree of obstruction within the pulmonary vasculature, primarily from remodeling or vasoconstriction of small pulmonary arteries. A normal PVR in adults is typically < 2 Wood units, while values ≥3 Wood units are diagnostic for pulmonary vascular disease, according to the 2022 ESC/ERS Guidelines on Pulmonary Hypertension.

The clinical interpretation of PVR provides important prognostic and therapeutic guidance, especially in patients with pulmonary arterial hypertension (PAH), left heart disease, or chronic thromboembolic pulmonary hypertension (CTEPH). Risk Stratification: - Low Risk (PVR <3 WU): Often seen in normal individuals or borderline elevations; not usually associated with clinically significant pulmonary hypertension. - Intermediate Risk (3–5 WU): Reflects early or moderate pulmonary vascular involvement; may be associated with compensated right ventricular function. - High Risk (>5 WU): Suggests severe pulmonary vascular disease with increased right ventricular afterload and poorer outcomes, often requiring targeted pulmonary vasodilator therapy. This calculator is useful for hemodynamic assessment in right heart catheterization and for therapeutic decision-making in PAH management, follow-up, and risk tier reassessment.