Ferns SJ, Zein CE, Subramanian S, Husayni T, Ilbawi MN.Asian Cardiovasc Thorac Ann. 2020 Dec 25:218492320984095. doi: 10.1177/0218492320984095. Online ahead of print.PMID: 33356352
Take Home Points:
- The additional pulmonary flow in BCPS physiology facilitates the PA growth between Stage 2 and 3.
- PA growth are also shown after Fontan operation even if the additional flow was eliminated.
- No adverse effects, such as decreased ventricular function due to volume overload was shown even after Fontan operation.
Commentary from Dr. Yasuhiro Kotani (Okayama, Japan), section editor of Congenital Heart Surgery Journal Watch:
Ferns and colleagues investigated the long-term effect of the additional antegrade pulmonary flow in 212 patients undergoing Fontan operation. The patients were divided into 2 groups based on the presence of additional flow (Pulsatile group (N=33) and Non-pulsatile group (N=70)). The key finding was that patients with an additional flow had a significant increase in PA size before Fontan and this continued after Fontan operation even eliminated an antegrade flow. They also showed an equivalent outcome between the groups, regarding with ventricular function, AVVR, and other complications.
It is still unclear that how the additional pulmonary flow affects PA growth between stage 2 and 3. This study clearly showed that Nakata index, i.e., PA size significantly increased in patients with an additional flow.
Previous reports describe both advantages and disadvantages of having the additional flow in BCPS. Advantages include better oxygen saturations, improved PA growth, and prevention of pulmonary arteriovenous malformations. Downsides include an elevated BCPS pressure and an increased ventricular volume overload. This study demonstrated the better PA growth even after Fontan operation and no adverse effects, such as impaired ventricular function was noted. However, it is important to know that the proportion of having HLHS in Non-pulsatile Group is much higher. In generally, patients with HLHS tends to have a smaller PA and a decreased ventricular function with significant AVVR, indicating this result should be carefully interpreted. Pulsatile Groups included more standard risk patients who are not likely to develop ventricular dysfunction and late complications and this may have affected the result of this study. An additional flow may not be a good option in patients with an impaired ventricular function, even non-HLHS. Therefore, indication of additional flow should be carefully considered in the group of single ventricle as they have a wide variety of anatomy and physiology and behave differently.