Maternal and fetal cardiometabolic recovery following ultrasound-guided high-intensity focused ultrasound placental vascular occlusion

Experimental Evaluation of an Ultrasound-Guided High-Intensity-Focused Ultrasound Probe for Sonication of Artery

OBJECTIVES

This study aimed to develop an ultrasound-guided high-intensity-focused ultrasound (USgHIFU) probe for arterial sonication and to evaluate vascular contraction.

METHODS

The USgHIFU probe comprised two confocal spherical transducers for sonication and a US color Doppler flow imaging probe for guidance. A vessel-mimicking phantom was sonicated in two directions. In the vascular radial direction, an isolated rabbit aorta embedded in ex vivo pork liver was sonicated at different acoustic powers (245 and 519 W), flow rates (25, 30, and 50 mL/minute), and sonication energies (519, 980, and 1038 J). Changes in the postsonication vessels were evaluated using US imaging, microscopic observation, and histopathological analysis.

RESULTS

Beam focusing along the vascular radial direction caused significant deformation of both tube walls (n = 4), whereas focusing along the axial direction only affected the contraction of the anterior wall (n = 4). The contraction index (Dc) of the vessel sonicated at 245 W and 980 J was 56.2 ± 9.7% (n = 12) with 25 mL/minute. The Dc of the vessel sonicated at 519 W and 1038 J was 56.5 ± 7.8% (n = 17). The Dc of the vessel sonicated at 519 J total energy was 18.3 ± 5.1% (n = 12).

CONCLUSION

The developed USgHIFU probe induced greater vascular contractions by covering a larger area of the vessel wall in the radial direction. Sonication energy affects vascular contraction through temperature elevation of the vessel wall. When the acoustic power was high, an increase in acoustic power, even with comparable sonication energy, did not result in greater vessel contraction.

Guidelines for assessing maternal cardiovascular physiology during pregnancy and postpartum

Maternal mortality rates are at an all-time high across the world and are set to increase in subsequent years. Cardiovascular disease is the leading cause of death during pregnancy and postpartum, especially in the United States. Therefore, understanding the physiological changes in the cardiovascular system during normal pregnancy is necessary to understand disease-related pathology. Significant systemic and cardiovascular physiological changes occur during pregnancy that are essential for supporting the maternal-fetal dyad. The physiological impact of pregnancy on the cardiovascular system has been examined in both experimental animal models and in humans. However, there is a continued need in this field of study to provide increased rigor and reproducibility. Therefore, these guidelines aim to provide information regarding best practices and recommendations to accurately and rigorously measure cardiovascular physiology during normal and cardiovascular disease-complicated pregnancies in human and animal models.

Parameter effects on arterial vessel sonicated by high-intensity focused ultrasound: an ex vivo vascular phantom study

Objective. This study is aimed to explore the effects of vascular and sonication parameters on ex vivo vessel sonicated by high-intensity focused ultrasound. Approach. The vascular phantom embedding the polyolefin tube or ex vivo vessel was sonicated. The vascular phantom with 1.6 and 3.2 mm tubes was sonicated at three acoustic powers (2.0, 3.5, 5.3 W). The occlusion level of post-sonication tubes was evaluated using ultrasound imaging. The vascular phantom with the ex vivo abdominal aorta of rabbit for three flow rates (0, 5, 10 cm s−1) was sonicated at two acoustic powers (3.5 and 5.3 W). Different distances between focus and posterior wall (2, 4, 6 mm) and cooling times (0 and 10 s) were also evaluated. The diameter of the sonicated vessel was measured by B-mode imaging and microscopic photography. Histological examination was performed for the sonicated vessels. Main results. For the 5 cm s−1 flow rate, the contraction index of vascular diameter (Dc) with 5.3 W and 10 s cooling time at 2 mm distance was 39 ± 9% (n = 9). With the same parameters except for 0 cm s−1 flow rate, the Dc was increased to 45 ± 7% (n = 4). At 3.5 W, the Dc with 5 cm s−1 flow rate was 23 ± 15% (n = 4). The distance and cooling time influenced the lesion along the vessel wall. Significance. This study has demonstrated the flow rate and acoustic power have the great impact on the vessel contraction. Besides, the larger lesion covering the vessel wall would promote the vessel contraction. And the in vivo validation is required in the future study.

High-intensity focused ultrasound for noninvasive fetal therapy

High-intensity focused ultrasound (HIFU) consists of an ultrasonic beam that is focused within the body to induce tissue necrosis through both heat energy and as a result of cavitation, which occurs without damaging any intervening tissues. Therefore, it is possible to cauterize and treat tumors without surgical invasion by administering HIFU irradiation from outside the body. This approach has been clinically applied in various fields in recent years, and fetal therapy is no exception, with several clinical applications reported, mainly in basic experiments. This review summarizes the recent basic and clinical findings focusing on fetal treatment with HIFU.

Early-onset twin-twin transfusion syndrome: Case series and systematic review

Introduction

Data on the outcomes of early-onset twin-twin transfusion syndrome (TTTS), diagnosed before 18 weeks gestational age (GA), are sparse. We aimed to review the diagnosis, management and outcomes of early-onset TTTS.

Material and methods

Pregnancy records at a single referral unit 2010-6 were reviewed. In early-onset TTTS cases, data for pregnancy characteristics, interventions and outcomes were collected. PubMed and Scopus databases were searched for studies including pregnant women with early-onset TTTS. The primary outcome measure was livebirths.

Results

Case series: 58 cases of early-onset TTTS 2010-6, with full outcome data in 44. Diagnostic criteria were variable. Median GA at intervention was 17⁺⁴ (range 15⁺⁰-28⁺¹); 67% of patients had laser therapy (39/58). Overall survival: 60% (53/88). At least one livebirth: 86% (38/44), Two livebirths: 34% (15/44); No survivors: 14% (6/44). GA at delivery was 32^+1.5 (range 16⁺²-37⁺⁴). Systematic review: 16 studies included (n = 171 pregnancies). Diagnostic criteria varied widely: 79% of studies used Quintero staging. Most offered laser (89%) at median 17⁺⁰ weeks (range 16⁺⁰-21⁺⁶). GA at delivery was 23⁺⁰-39⁺⁵ weeks. Overall survival: 69% (129/186). At least one livebirth: 74% (127/171). Two livebirths: 59% (55/93). No survivors: 26% (44/171).

Conclusions

In comparison with the commonly accepted overall survival for TTTS treated after 18 weeks of 60-90%, outcomes in early-onset TTTS were at the lower bound of this range. Gestational age at intervention is similar to that of later onset TTTS, indicating a lack of therapeutic options when a diagnosis is made before 18 weeks.