Thromboelastography is a Suboptimal Test for Determination of the Underlying Cause of Bleeding Associated with Cardiopulmonary Bypass and May Not Predict a Hypercoagulable State

OBJECTIVES:

Patients undergoing cardiac surgery
with cardiopulmonary bypass (CPB) are at risk of bleeding. The goal of
this investigation was to compare thromboelastography (TEG) with
standard coagulation tests (prothrombin time [PT], partial
thromboplastin time [PTT], fibrinogen, and D-dimer) in patients with
active bleeding.

METHODS:

A retrospective study of patients who underwent cardiac surgery with CPB was performed. A second analysis was performed to determine if a shortened TEG R time is associated with thrombosis.

RESULTS:

Paired
TEG and standard coagulation tests were available from 21 bleeding
patients; of the 15 patients with normal TEG values and three with a
shortened R time, all had abnormalities of standard coagulation tests.
Eighteen of 67 patients who underwent surgery
with CPB had an episode of postoperative bleeding. The TEG R time and
coagulation index, PT, and PTT collected after CPB were associated with
postoperative bleeding in the univariate analysis, but only PT was
independently associated with postoperative bleeding in the multivariate
analysis. In the second analysis, three of 38 patients with a normal
TEG and four of 43 patients with a shortened R time had a thrombotic
event during hospitalization (P = 1.00).

CONCLUSIONS:

TEG
had limited utility in identifying the underlying cause of bleeding and
was not predictive of postoperative bleeding associated with cardiac surgery compared with conventional coagulation tests. A shortened TEG R time may not represent a hypercoagulable state.