Looking at the ISSVA classification of vascular anomalies, it is not the slow-flow malformations that are associated with cardiac complications. Fast-flow vascular anomalies, including vascular tumors such as infantile and congenital hemangiomas and fast-flow malformations, including arteriovenous malformations and arteriovenous fistulas, can be associated with significant cardiac complications if not treated early and appropriately.
In syndromic vascular anomalies from the subgroup of “malformations associated with other anomalies”, additional cardiac malformations or dysplasias may occur in rare cases. These are, in particular, associated valvular heart disease and/or an open atrial or ventricular septum. These anomalies should be detected or excluded early after birth by ultrasound examination of the heart.
Over time patients with progressive arteriovenous malformations may develop heart failure due to the large-volume shunts between the arterial and venous pathways, without passage through an intervening capillary bed. This happens only in the case of very large AVMs.
Congenital cerebral arteriovenous malformations with very high shunt volumes, such as vein of Galen malformation, as well as very large peripheral arteriovenous malformations already symptomatic at birth, often show severe high-output cardiac failure with a poor prognosis already at the intrauterine stage.