Table 2.

Comparison of achievement of the LR ratio of > 50% across the different categories

	The number of cases achieving the LR ratio of > 50%
	Category 1 (n = 21)		Category 2 − 3 (n = 8)
Day 0	13	(61.9%)	2	(25.0%)
Day 1	6	(28.6%)	4	(50.0%)
Day 2	2	(9.5%)	0	(0.0%)
Day 3	0	(0.0%)	1	(12.5%)
Day 4	0	(0.0%)	1	(12.5%)

LR ratio, the percentage of velocity–time integral (VTI) of the left-to-right (LR) flow of patent ductus arteriosus against the overall VTI containing the LR and right-to-left (RL) flows by echocardiography