Figure
23j
Eisenmenger's Syndrome.
In patients with Eisenmenger's syndrome, in response to substantial
left-to-right shunting, morphplogic alterations occur in the small pulmonary
aretries and arterioles(inset), leading to pulmonary hypertension and
the resulant reversal of the intracardiac shunt(arrow). In the small
pulmonary arteries and arterioles, medial hypertrohy,intimal cellular
proliferation,and fibrosis lead to narrowing or closure of the vessel
lumen.With sustained pulmonary hypertension, extensive atherosclerosis
and calcification often develop in the large pulmonary aretries. Eisenmenger's
syndrome may occur in association with a ventricular defect(as shown),
but it also may occur in association with an atrial septal defect or
a patent ductus arteriosus.