Prenatal diagnosis of vascular ring: evaluation of fetal diagnosis and postnatal outcomes

Funding Acknowledgements

Type of funding sources: None.

Background

The performance of fetal echocardiogram in diagnosing vascular ring (VR) and its impact on postnatal outcomes has not been well examined.

Methods

We reviewed all patients with VR diagnosis from 2000-2020.

Results

50 patients with antenatal diagnosis of VR; 42(84%) with right aortic arch aberrant left subclavian artery and left-sided ductus arteriosus ((RAA-ALS) and 8(16%) with double aortic arch (DAA) were compared to 120 patients with postnatal diagnosis; 90(75%) with DAA, 22(18%) with RAA-ALS (Table 1). Prenatal diagnosis of VR increased over study period; 4 vs 31, 10 vs 29, 14 vs 25, 22 vs 35 between 2000-2005, 2005-2010, 2010-2015, and 2015-2020 respectively, p< 0.01. Prenatal diagnosis of VR was associated with less symptoms [26(52%) vs 72(60%), p < 0.003] and less cross-sectional imaging [22(44%) vs 82(69%), p = 0.0001]. Postnatal diagnosis of VR was associated with more surgical interventions (102(85%) vs 28(56%), p = 0.002), later surgical repair (22.9 ± 35 vs 12.6 ± 10.2 months, p < 0.01), more postoperative complications [8/102 (7.8%) vs 1/28 (3.5%), p = 0.04] and more residual symptoms (2/28(7%) vs 30/102(29%), p = 0.001 respectively].

Conclusion

Prenatal diagnosis of VR has evolved over time. RAA-ALS versus DAA were dominant in the prenatally and postnatally diagnosed cohorts respectively. Prenatal diagnosis of VR was associated less symptoms, less cross-sectional imaging, earlier age of surgical intervention and less residual symptoms.

Table 1 Prenatal Diagnosis (N = 50) Postnatal Diagnosis (N = 120) p-value Gestational Age (weeks) 39 ± 3 38 ± 2 0.9 Male (%) 31 (62%) 69(58%) 0.8 Subtype of vascular ring: Double aortic arch RAA-ALSA Others 8 (16%) 42 (80 %) 0 (0 %) 90 (72%) 22 (17%) 8 (11%) 0.002 0.01 Associated intracardiac CHD: VSD TOF DORV AVSD Coarctation of aorta Others 11 (22%) 1 1 3 0 3 3 24 (20%) 5 7 2 2 3 5 0.8 Associated genetic diagnosis: 22q11 deletion Trisomy 21 Others 9 (18%) 6 3 0 32 (26%) 29 3 0 0.1 Symptomatic presentation: Respiratory Gastrointestinal 26 (52 %) 15 11 72 (60 %) 57 15 <0.03 Age at first symptoms (month) 3.2 ± 2.8 21.6 ± 37 0.01 Diagnostic modalities: Fetal echocardiogram Postnatal echocardiogram Barium swallow Bronchoscopy CT scan MRI 50 (100%) 50 (100%) 2 (4%) 3 (6%) 18 (36 %) 4 (8%) 0 (0%) 120 (100%) 23 (25 %) 18 (15 %) 65 (54%) 7 (14%) Surgical repair 28 (56%) 102 (85%) 0.02 Age at surgical repair (month) 12.6 ± 10.2 22.9 ± 35 <0.01 Postoperative complications 1 (3%) 8 (7%) 0.03 Residual symptoms 2 (1%) 30 (25%) 0.001 Age at most recent follow up (mo) 26 ± 7 60 ± 7 0.02 Table 1: Comparison of patients with prenatal versus postnatal diagnosis of vascular ring

Bicuspid aortic valve flow dynamics using blood speckle tracking in children

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Labatt Family Heart Centre

Background

Bicuspid aortic valves (BAV) are the most common form of congenital heart disease with a prevalence of up to 2%. Fusion of the aortic cusps result in complex flow patterns in the aortic root which may contribute to the risk of progressive dilation. Imaging these patterns with conventional echocardiography is challenging due to the angle dependency of colour Doppler. Blood speckle tracking (BST) is a novel method based on high-frame rate ultrasound that is less angle-independent and developed to evaluate complex flow.

Purpose

The aims of this study were to 1) describe and quantify flow patterns in the aortic root using blood speckle tracking and 2) quantitatively compare flow parameters (energy loss, vorticity, kinetic energy) between paediatric patients with BAVs and those with normal aortic valves.

Methods

Clinical and routine echocardiographic parameters were collected for children with normal and BAVs.  Children were imaged using a commercially available clinical scanner with research software enabling the acquisition of high-frame rate imaging and blood speckle tracking. Aortic root energy loss, vorticity and kinetic energy were measured in the parasternal long axis view.

Results

Data from 46 patients were analyzed (31 normal aortic valves, 15 BAVs) with no significant difference in age, height, weight or BSA between groups. Nine patients (60%) had right-left fusion; 6 (40%) had right-non fusion. Qualitative flow assessment in aortic root demonstrated disturbed flow in the BAV group (see figure) generally directed towards the non-fused cusp (i.e non coronary cusp in right-left fusion). Patients with a BAV had higher aortic valve peak velocity (2.1 m/s vs 0.9 m/s, p< 0.001);  aortic root systolic energy loss (4.29 mW/m vs 1.79 mW/m, p< 0. 001), vorticity (38.7 1/s vs 31.1 1/s, p< 0.01) and kinetic energy (34.5  mJ/m vs 24.5 mJ/m, p = 0.04) compared to those with normal aortic valves.

Conclusion(s)

Blood speckle tracking can demonstrate altered flow patterns in the aortic root in patients with BAV. These patients have increased energy losses, vorticity and kinetic energy when compared to age matched patients with normal aortic valves however the relationship of theses parameters to aortic root dilation remains to be demonstrated.

Abstract Figure. Flow patterns (A-C) and analysis (D-F)

Treatment of fetal circular shunt with non-steroidal anti-inflammatory drugs

A circular shunt (CS) is a life-threatening condition involving massive shunting of systemic arterial blood via the ductus arteriosus to the left ventricle without traversing the lungs. In the prenatal setting, it occurs mainly in fetuses with severe forms of Ebstein's anomaly (EA) owing to unrestricted ductal flow and significant pulmonary and tricuspid regurgitation. We aimed to improve the fetal hemodynamics and chances of survival of affected fetuses by inducing ductal constriction using transplacental non-steroidal anti-inflammatory drugs (NSAIDs). Following initiation of treatment between 26 and 34 weeks' gestation, three (75%) of four fetuses with EA/CS responded with sustained ductal constriction and improved hemodynamic function, which allowed continuation of pregnancy for 3-7 weeks and elective delivery. All successfully treated cases underwent neonatal surgery immediately after birth to eliminate the CS and survived. This included two neonates that underwent single-ventricle palliation surgery that required postoperative extracorporeal membrane oxygenation and hemofiltration for transient respiratory and renal failure. The one case that did not respond to treatment with NSAIDs was delivered prematurely for progressive fetal compromise and died shortly after birth. Transplacental treatment with NSAIDs represents a novel approach to controlling fetal CS, avoiding in-utero death and prolonging the pregnancy to a more advanced gestational age, thereby potentially increasing the chances of neonatal survival. This treatment should be considered and initiated at an early stage of systemic steal to prevent brain injury due to hypoperfusion. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.