Predictive value of intraoperative transit-time flow measurement for short-term graft patency in coronary surgery.

Objective: The aim of this retrospective study was to evaluate the possibility to
predict postoperative graft patency in coronary surgery by means of intraoperative
transit-time flow measurement.
Methods: Of 3567 patients submitted to isolated myocardial revascularization from
June 1997 through June 2003, 157 (4.4%) underwent both intraoperative transittime
flow measurement and angiography at follow-up. Thirty-six have been revascularized
on a beating heart. Three hundred four grafts, 227 arterial conduits, and 77
saphenous vein grafts were checked.
Results: No patients died, and none of them had an acute myocardial infarction
within 12 months after the operation. After a mean of 6.7 4.8 months from the
operation, 266 grafts (group A) were completely functioning, whereas 38 grafts
(group B) had failed. The transit-time flow parameters recorded in the latter group
had significantly lower mean flow and higher pulsatility index and percentage of
backward flow values at both univariate and multivariate analysis. Moreover, mean
flow values of 15 mL/min or less, pulsatility index values of 3.0 or greater, and
percentage of backward flow values of 3.0% or greater were found to be independent
variables for higher incidence of graft failure.
Conclusions: Transit-time flow measurement represents a quick, easy, and reproducible
method for intraoperative evaluation of graft function. The combination of
the 3 major parameters (mean flow, pulsatility index, and percentage of backward
flow) results in the chance to predict