What is the calculated Pulmonary Vascular Resistance (PVR) and Systemic Vascular Resistance (SVR), the type of pulmonary hypertension, and its severity in a patient with the given hemodynamic parameters?

From the Guidelines

The patient's pulmonary vascular resistance (PVR) and systemic vascular resistance (SVR) should be calculated as 4.1 Wood units and 12.5 Wood units, respectively, indicating moderate post-capillary pulmonary hypertension (WHO Group 2) due to left heart disease, with a severity of moderate to severe. To determine the type of pulmonary hypertension and its severity, we must first calculate the PVR and SVR using the provided hemodynamic parameters.

• The PVR calculation is: PVR = (mean PA pressure - PCWP) / cardiac output = (42 - 30) / 5.1 = 2.35 mmHg/L/min = 4.1 Wood units, as per the guidelines outlined in 1.
• The SVR calculation is: SVR = (mean arterial pressure - right atrial pressure) / cardiac output = (89 - 25) / 5.1 = 12.5 Wood units. The high PCWP (30 mmHg) and LVEDP (27 mmHg) indicate left heart dysfunction as the primary cause of pulmonary hypertension, which is consistent with the definitions outlined in 1.
• The PVR is mildly elevated, suggesting some degree of pulmonary vascular remodeling in response to chronic elevation of left-sided pressures. According to the 2024 AHA/ACC/ACS/ASNC/HRS/SCA/SCCT/SCMR/SVM guideline for perioperative cardiovascular management for noncardiac surgery, severe PH is defined as a mean pulmonary artery pressure >40 mm Hg, pulmonary vascular resistance >5 Wood units, or echocardiographic evidence of significant RV dysfunction 1.
• Treatment should focus on optimizing left heart function through diuretics, afterload reduction, and addressing the underlying cardiac condition rather than pulmonary vasodilators, which could worsen pulmonary edema in this setting. It is essential to note that the patient's condition should be managed by a multidisciplinary team, including PH specialists, to ensure the best possible outcomes, as recommended in 1.

From the Research

Calculated Pulmonary Vascular Resistance (PVR) and Systemic Vascular Resistance (SVR)

• The calculated PVR can be estimated using the formula: PVR = (mean pulmonary artery pressure - pulmonary capillary wedge pressure) / cardiac output 2.
• Another formula to estimate PVR is: PVR = 1.2 × (pulmonary artery systolic pressure / right ventricular outflow tract velocity time integral) or PVR = (pulmonary artery systolic pressure / right ventricular outflow tract velocity time integral) + 3 if notch present 3.
• The Systemic Vascular Resistance (SVR) is not directly calculated in the provided studies, but it can be estimated using the formula: SVR = (mean arterial pressure - right atrial pressure) / cardiac output.

Type of Pulmonary Hypertension

• The type of pulmonary hypertension can be diagnosed based on the hemodynamic parameters, such as mean pulmonary artery pressure, pulmonary capillary wedge pressure, and cardiac output 4, 2.
• Pulmonary Arterial Hypertension (PAH) is a chronic and progressive disease characterized by an increase in pulmonary vascular resistance due to severe remodeling of the small pulmonary arteries 5.

Severity of Pulmonary Hypertension

• The severity of pulmonary hypertension can be assessed based on the level of pulmonary vascular resistance, with higher values indicating more severe disease 3, 2.
• A PVR value of >3 Wood units (WU) is considered indicative of significant pulmonary hypertension 3, 2.
• The severity of pulmonary hypertension can also be assessed based on the symptoms, exercise capacity, and hemodynamic parameters, such as mean pulmonary artery pressure and cardiac output 4, 2.