Intraoperative transit time flow measurement
The transit time flow of the grafts was measured by The VeriQ system
TTFM device (MediStim Inc., Oslo, Norway), equipped with2,3 or 4-mm
probes, depending on the size of the graft,under stable haemodynamic
conditions without the support of a mechanical device such as
cardiopulmonary bypass or an intra-aortic balloon pump. The parameter
yielded by TTFM system including(i) the mean graft flow volume (MGF,
ml/min), (ii) the pulse index
calculated as (PI, maximum flow volume—minimum flow volume)/(mean flow
volume) and (iii) the DF, calculated as (flow volume of the diastolic
phase)/(flow volume of the systolic phase + flow volume of the diastolic
phase). Satisfactory blood flow parameters criteria : 1,ACI>50%;2,The
shape of blood flow waveform is stable and
repeatable;3,PI<5,MGF>15ml/min. If sufficient graft flow was not
obtained, graft revision was considered and performed until diastolic
graft flow was confirmed.