The "double dunk" technique for a right ventricle to pulmonary artery conduit implantation during the Norwood procedure reduces unintended shunt-related events.

BACKGROUND: The introduction of a right ventricle to pulmonary artery conduit (RVPAc) during the Norwood procedure (NP) for hypoplastic left heart syndrome (HLHS) resulted in a higher survival rate, but also in an increased number of unintended pulmonary and shunt-related interventions. AIM: To analyse how several modifications employed in RVPAc implantation during NP may influence the interstage course, unintended surgical or catheter-based interventions, and pulmonary artery development in a cohort of patients with HLHS. METHODS: We retrospectively analysed three groups of non-selected, consecutive neonates who underwent the NP between 2011 and 2014, with different RVPAc surgical techniques employed: Group I (n = 32) - left RVPAc with distal homograft cuff, Group II (n = 28) - right RVPAc with distal homograft cuff, and Group III (n = 41) - "double dunk," right reinforced RVPAc (n = 41). RESULTS: There were no intergroup differences in terms of age, weight, prevalence of aortic atresia, diameter of the ascending aorta, deep hypothermic circulatory arrest time, and hospital mortality rate (9.3% vs. 14.2% vs. 7.3%, respectively). There was a significant difference between the groups in the number of catheter-based interventions during the interstage period (34% vs. 25% vs. 0%, respectively, p < 0.05) and/or concomitant surgical interventions (17.2% vs. 4.1% vs. 2.6%, respectively). The diameter of the pulmonary arteries was most homogenous in the third group. CONCLUSIONS: The modified strategy of using the "double dunk," right reinforced RVPAc during the NP for HLHS significantly reduces the number of unintended catheter-based and surgical shunt-related reinterventions during the interstage period. This technique allows a more homogenous development of pulmonary arteries before the second, surgical stage.

Counter-ions dynamics in highly plastic and conducting compounds of poly(aniline). A quasi-elastic neutron scattering study.

Proton dynamics in films of poly(aniline) "plastdoped" with di-esters of sulfophthalic (or sulfosuccinic) acids have been investigated by using quasi-elastic neutron scattering techniques. A broad time range (10(-13)-10(-9) s) has been explored by using four different spectrometers. In this time range, the dynamics is exclusively due to protons attached to the flexible tails of the counter-ions. A model of limited diffusion in spheres whose radii are distributed in size gives a realistic view of the geometry of molecular motions. However, it is found that the characteristic times of these motions are widely distributed over several orders of magnitude. The time decay of the intermediate scattering function is well described by a time power law. This behaviour is qualitatively discussed in connection with the structure of the systems and by comparison with other so-called complex systems.