The impact of gestational sac size on the effectiveness and safety of high intensity focused ultrasound combined with ultrasound-guided suction curettage treatment for caesarean scar pregnancy

Figures & data

Figure 1. Ultrasound image and MRI obtained from a patient with CSP. A, The transabdominal ultrasound image showed a gestational sac (white arrow) embedding at the scar site of the previous CS with empty uterus cavity and cervical canal. Color Doppler reveals a rich blood supply surrounding gestational sac. B, A saggittal view MR image showed a gestational sac (white arrow) embedding at the site of the previous CS scar.

Figure 2. Contrast-enhanced ultrasound obtained from a patient treated with HIFU. A, abundant blood supply in myometrium of CSP scar (white arrow) around gestational sac before HIFU ablation; B, significantly reduced blood supply in myometrium of CSP scar (white arrow) around gestational sac after HIFU ablation.

Table 1. Comparison of baseline characteristics of CSP patients in three groups.

	Group 1	Group 2	Group 3	F/H	p value
	(n = 16)	(n = 28)	(n = 32)
Age (y)	30.81 ± 5.31	31.68 ± 5.01	31.78 ± 4.28	0.238	.789
BMI (kg/m^2)	21.62 ± 3.27	22.68 ± 2.78	21.97 ± 3.47	0.661	.519
Symptoms (n, %)
Asymptomatic	3, 18.75%	15, 53.57%	7, 21.88%
Abdominal pain	0, 0.00%	1, 3.57%	0, 0.00%
Painless vaginal bleeding	13, 81.25%	9, 32.14%	22, 68.75%
Vaginal bleeding and Abdominal pain	0, 0.00%	3, 10.71%	3, 9.38%
Days of amenorrhoea (d)	40.5 (35.0, 50.5)	42.0 (40.0, 48.0)	48.5 (41.5, 56.5)	6.742	.034
Pre-treatment serum β-hCG (mIU/mL)	18994.95	32226.80	42248.60	3.339	.188
	(8247.50, 39439.05)	(17545.65, 53039.35)	(15896.00, 93493.35)
Gravidity (n)	5 (3, 6)	4 (4, 5)	4 (3, 6)
Parity (n)	1 (1, 2)	2 (1, 2)	2 (1, 2)
Previous caesarean pregnancies (n, %)
1	13,81.25%	14, 50.00%	18, 56.25%
2	3,18.75%	14, 50.00%	14, 43.75%
Thickness of gestational sac	4.8	4.2	4.1	1.646	.439
embedding myometrium (mm)	(4, 5.5)	(3, 5.5)	(3.5, 5.5)
Interval from last CS (y)	7.5 (4, 9)	5.0 (2.5, 6.5)	3.5 (2, 7)	4.411	.110

Table 2. Comparison of HIFU treatment results for CSP patients in three groups.

	Group 1	Group 2	Group 3	F/H	p value
	(n = 16)	(n = 28)	(n = 32)
Median treatment power (w)	390 (326, 399)	399 (392, 400)*	400 (399, 400)*	16.402	<.001
Median treatment time (min)	39.5 (31.0, 60.5)	48.5 (37.0, 79.5)	65.0 (45.0, 92.0)*	7.179	.028
Median sonication time (s)	290 (202, 534)	400 (250, 500)	556 (413, 815)*#	11.325	.003
Average treatment intensity (s/h)	449.55 ± 121.34	474.21 ± 109.78	540.17 ± 112.82*	4.276	.018

P.S: *, compared with Group 1, p < .05; #, compared with Group 2, p < .05.

Table 3. Adverse events during HIFU treatment in three groups.

	Group 1	Group 2	Group 3	χ^2	p value
	(n = 16)	(n = 28)	(n = 32)
Sciatic/buttock pain (n, %)	2, 12.5%	6, 21.4%	10, 21.3%	2.200	.333
Treatment area pain (n, %)	2, 12.5%	3, 10.7%	5, 15.6%	0.402	.907
Vomit (n, %)	0, 0%	1, 3.6%	0, 0%
Leg pain (n, %)	0, 0%	0, 0%	0, 0%
Skin burn (n, %)	0, 0%	0, 0%	0, 0%

Table 4. Comparison of USg-suction curettage results and follow-up in three groups.

	Group 1	Group 2	Group 3	F/H	p value
	(n = 16)	(n = 28)	(n = 32)
Median blood loss (mL)	20.0 (15.0, 22.5)	20.0 (20.0, 30.0)	30.0 (22.5, 50.0)*#	16.667	<.001
Follow-up
Median duration of vaginal bleeding post-curettage (d)	6.0 (4.5, 8.0)	5.5 (4.0, 8.0)	7.0 (5.0, 9.5)	2.725	.256
Median serum β-hCG 1 week post-curettage (mIU/mL)	826.20 (292.05, 2295.70)	1497.05 (608.10, 3155.10)	2249.10 (437.30, 7856.35)	2.733	.255
Average time for serum β-hCG return to nomal level (d)	28.6 ± 5.6	31.4 ± 7.8	33.6 ± 10.8	1.729	.185

P.S: *, compared with Group 1, p < .05; #, compared with Group 2, p < .05.

Table 5. Correlation between the size of gestational sac (mm) and parameters of HIFU treatment and USg-suction curettage (n = 76).

Variables	R value	p value
Treatment power (w)	0.452	<.001
Ttreatment time (min)	0.312	.006
Sonication time (s)	0.385	.001
Treatment intensity (s/h)	0.337	.003
Blood loss during USg-suction curettage (mL)	0.419	<.001