Objective

To determine normal four-extremity blood pressure (BP) in the neonatal intensive care unit (NICU) at birth and the utility of upper (UE) and lower extremity (LE) BP difference to screen for coarctation of the aorta (Co-A) and interrupted the aortic arch (IAA).

Study design

Retrospective study of BP at birth (n=866), and case-control study of Co-A/IAA infants and matched controls (1:2).

Result

Although BP increased with gestational age (R(2)=0.3, P<0.0001), the pressure gradient between UE and LE did not change with gestation (P=0.68). Forty-six cases of Co-A/IAA were identified, with 92 controls. Pressure gradient was significantly higher in patients with Co-A/IAA (7.6±14.8 versus 0.4±10 mm Hg, P=0.004). However, there was overlap between cases and controls resulting in low sensitivity (41.3% with ⩾10 mm Hg gradient cutoff).

Conclusion

Evaluation of UE-LE BP gradient at birth is a poor screening test for Co-A/IAA with low sensitivity. Repeating four-limb BP after ductal closure at 24 to 48 h along with SpO2 screening for critical congenital heart disease may increase sensitivity.

This Letter reports the observation of WZγ production and a measurement of its cross section using 140.1±1.2  fb^{-1} of proton-proton collision data recorded at a center-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. The WZγ production cross section, with both the W and Z bosons decaying leptonically, pp→WZγ→ℓ^{'}^{±}νℓ^{+}ℓ^{-}γ (ℓ^{(^{'})}=e, μ), is measured in a fiducial phase-space region defined such that the leptons and the photon have high transverse momentum and the photon is isolated. The cross section is found to be 2.01±0.30(stat)±0.16(syst)  fb. The corresponding standard model predicted cross section calculated at next-to-leading order in perturbative quantum chromodynamics and at leading order in the electroweak coupling constant is 1.50±0.06  fb. The observed significance of the WZγ signal is 6.3σ, compared with an expected significance of 5.0σ.