Serial exercise testing in children, adolescents and young adults with Senning repair for transposition of the great arteries

<p>Abstract</p> <p>Background</p> <p>Patients with Senning repair for complete transposition of the great arteries (d-TGA) show an impaired exercise tolerance. Our aim was to investigate changes in exercise capacity in children, adolescents and adults with Senning operation.</p> <p>Methods</p> <p>Peak oxygen uptake (peak VO₂), oxygen pulse and heart rate were assessed by cardiopulmonary exercise tests (CPET) and compared to normal values. Rates of change were calculated by linear regression analysis. Right ventricular (RV) function was assessed by echocardiography.</p> <p>Results</p> <p>Thirty-four patients (22 male) performed 3.5 (range 3–6) CPET with an interval of ≥ 6 months. Mean age at first assessment was 16.4 ± 4.27 years. Follow-up period averaged 6.8 ± 2 years. Exercise capacity was reduced (p<0.0005) and the decline of peak VO₂ (−1.3 ± 3.7 %/year; p=0.015) and peak oxygen pulse (−1.4 ± 3.0 %/year; p=0.011) was larger than normal, especially before adulthood and in female patients (p<0.01). During adulthood, RV contractility changes were significantly correlated with the decline of peak oxygen pulse (r= −0.504; p=0.047).</p> <p>Conclusions</p> <p>In patients with Senning operation for d-TGA, peak VO₂ and peak oxygen pulse decrease faster with age compared to healthy controls. This decline is most obvious during childhood and adolescence, and suggests the inability to increase stroke volume to the same extent as healthy peers during growth. Peak VO₂ and peak oxygen pulse remain relatively stable during early adulthood. However, when RV contractility decreases, a faster decline in peak oxygen pulse is observed.</p

Computational fluid dynamics application in reducing complications of patent ductus arteriosus stenting

In some cases, especially in neonates, ductus arteriosus needs to remain patent for multiple medical purposes. In order to achieve this, current practice involves inserting stent in the ductus arteriosus. This condition is called patent duc-tus arteriosus (PDA). For this process, stents such as coronary stent are commonly used due to unavailability of customized stent for PDA in neonates. The usage of coronary stent however, opens the possibility of acute stent thrombosis and other complications. Therefore, there is a high need of special and customized stents to be used for PDA in neonates. This customized stent has to be able to sustain the hemodynamic effects of the flow inside the PDA. The stent has to be able to support the ductus wall compression and contraction due to arterial compliance. What is more important is that the stent must properly fit into various morphologies of the ductus. There are several different morphologies of PDA identified and the stents must be able to sustain the various shapes and tortuosity. In addition, the stent has to be tested for biocompatibility and practicality. Therefore, the customized design of the PDA stents can be derived from the concept of coronary stents and in compliance with all the mentioned characteristics. However, further analysis has to be completed ensure proper compatibility with neonates. In conclusion, the biggest challenge is to customize a stent that fits all the PDA morphologies