Table 3.

Microscopic features of the ductus arteriosus.

Case	Intimal Flap	Intima	Media-Adventitia	Inflammation	Apoptosis (TUNEL)
1	Absent	No subendothelial cushions, thrombotic lumen occlusion	Outer dissecting hematoma, no cystic medial necrosis	Absent	+
2	Present	No subendothelial cushions	Outer dissecting hematoma, cystic medial necrosis	Absent	+++
3	Present	Subendothelial cushions, thrombus stratification	Outer dissecting hematoma, cystic medial necrosis	Absent	+
4	Present	No subendothelial cushions	Outer dissecting hematoma, no cystic medial necrosis	Absent	+++
5	Present	Subendothelial cushions	Dissecting hematoma, cystic medial necrosis	Absent	+