Pulmonary Hypertension and Pulmonary Vascular Disease
Pulmonary vascular disease
Pulmonary hypertension is elevated mean pulmonary artery pressure with increased pulmonary vascular resistance. In children, causes include idiopathic and heritable disease, congenital heart disease with left-to-right shunt, chronic lung disease, and persistent pulmonary hypertension of the newborn. Eisenmenger syndrome is reversal of a long-standing shunt with cyanosis and fixed pulmonary vascular disease. Vasoreactivity testing in the catheterization laboratory helps identify patients who may respond to calcium channel blockers; most children require pulmonary vasodilator therapy such as phosphodiesterase-5 inhibitors, endothelin receptor antagonists, or prostacyclins.
Traps
Oxygen saturation alone does not quantify pulmonary vascular disease. A large shunt with equal pressures may still have reversible resistance; closure decisions require hemodynamic data. Do not stop pulmonary vasodilators abruptly. In Eisenmenger syndrome, pregnancy carries high maternal risk, and defect closure is contraindicated.
Worked example
A child with a large VSD has a mean pulmonary artery pressure of 45 mm Hg, PCWP 10 mm Hg, and cardiac index 4 L/min/m2. PVR = (45 − 10)/4 = 8.75 Wood units·m2. This is elevated; vasoreactivity testing and multidisciplinary discussion are needed before considering closure. Rule of thumb: PVR = (mean PAP − PCWP)/cardiac output; index it to body surface area in children.