Predictive value of second-trimester ophthalmic artery Doppler for identifying women at risk for preeclampsia

Table 3 Distribution of ophthalmic artery Doppler indices according to receiver operating characteristic-derived cut-off values (n = 90)

Parameter	Category	n (%)	mean ± SD
RI	Low RI	46 (51.1)	0.71 ± 0.10
	Not low RI	44 (48.9)
P1	Low P1	4 (4.4)	61.9 ± 14.6 cm/s
	Not low P1	86 (95.6)
PI	Low PI	29 (32.2)	2.0 ± 0.3
	Not low PI	61 (67.8)
P2	High P2	78 (86.7)	33.9 ± 10.2 cm/s
	Not high P2	12 (13.3)
PR	High PR	16 (17.8)	0.5 ± 0.1
	Not high PR	74 (82.2)

Cutoff values for categorization were derived using receiver operating characteristic curve analysis and the Youden index. The following thresholds were used: RI < 0.60, PR > 0.60, PI < 1.80, P1 < 50 cm/second, and P2 > 30 cm/s.

P1: First systolic peak velocity; P2: Second systolic peak velocity; PI: Pulsatility index; PR: Peak ratio; RI: Resistive index.