Computational fluid dynamics simulations of flow distribution and graft designs in apicoaortic bypass.
OBJECTIVE
Apicoaortic bypass has double outlets and its graft design is similar to that of a left ventricular assist device (LVAD). The left ventricular apex to the descending aorta (LV-DsAo) bypass is widely used in apicoaortic bypass. In contrast, the left ventricular apex to the ascending aorta (LV-AsAo) bypass is standard in LVAD surgery. This study aimed to evaluate the graft designs of apicoaortic bypass and their effects on flow distribution and energy loss (EL).


METHODS
A simulation study using computational fluid dynamics was performed on the geometry and hemodynamics data obtained from a 30-year-old patient who underwent a LV-DsAo bypass. The ratio of the cardiac output (CO) through the ascending aorta (AsAo) and apicoaortic conduit was set at 50:50, 30:70, and 10:90. Regional blood flow (RBF) and EL were calculated for the different distribution ratios. As an alternative to the LV-DsAo bypass, a virtual LV-AsAo bypass surgery was performed, and each parameter was compared with that of the LV-DsAo bypass.


RESULTS
At a distribution ratio of 50:50, the RBF to the head and EL were 16.4% of the total CO and 62.0 mW in the LV-DsAo bypass, and 32.3% and 81.5 mW in the LV-AsAo bypass, respectively. The RBF to the head decreased with the CO through the AsAo in the LV-DsAo bypass, but it was constant in the LV-AsAo bypass. The EL increased inversely with the CO through the AsAo in both graft designs.


CONCLUSION
The regional blood flow distribution was different, but the trend of the EL which increased inversely with the CO through the AsAo was similar between the LV-DsAo and LV-AsAo bypasses.
['Sasaki|Takashi|T|http://orcid.org/0000-0002-4313-1102', 'Ueda|Hitomi|H|', 'Itatani|Keiichi|K|', 'Suzuki|Kenji|K|', 'Kurita|Jiro|J|', 'Sakamoto|Shun-Ichiro|SI|', 'Miyagi|Yasuo|Y|', 'Ishii|Yosuke|Y|', 'Morota|Tetsuro|T|', 'Nitta|Takashi|T|']
D000328:Adult D001011:Aorta D006352:Heart Ventricles D006353:Heart-Assist Devices D006439:Hemodynamics D006801:Humans D057446:Hydrodynamics
Computational fluid dynamics Flow distribution Graft design Apicoaortic bypass Energy loss Cerebral perfusion