Utility of Sonoclot analysis and tranexamic acid in tetralogy of Fallot patients undergoing intracardiac repair

Sonoclot analysis is a point of care test to monitor the coagulation process, presenting a comprehensive evaluation of the clot formation and retraction as well as platelet function. This randomized double-blinded study was designed to investigate the utility of Sonoclot analysis in monitoring the coagulation profile as also the antifibrinolytic effects of tranexamic acid administered in patients with tetralogy of Fallot undergoing intracardiac repair. Eighty of a total 94 patients were randomly divided into two groups of 40 each. In the study group, TA was administered thrice at a dosage of 10 mg/kg, i.e. before CPB, on CPB and after CPB, whereas in the control group, placebo was administered at the same time intervals. Sonoclot analysis and D-dimer measurement were performed at baseline and following heparin neutralisation. An additional variable, DR15 (diminishing rate of clot strength at 15 min postmaximal clot strength), was calculated from the Sonoclot graph and was compared with d-dimer levels as a measure of fibrinolysis. The three Sonoclot variables, i.e. activated clotting time, clot rate and platelet function, were deranged at baseline in all the patients. Post-CPB, the change in these variables was not significant. ACT, clot rate and platelet function showed no significant (P > 0.05) difference in both the groups at both the time intervals. DR15 and d-dimer values were comparable at baseline in both the groups. However, a significant (P < 0.05) difference was seen in these variables in the control group as compared with the TA group following heparin neutralisation. To conclude, Sonoclot analysis is a useful, point of care method for the monitoring of coagulation and fibrinolysis in patients with tetralogy of Fallot undergoing intracardiac repair.