Thromboelastography for predicting bleeding in patients with aortic stenosis treated with transcatheter aortic valve implantation

Background: Bleeding complications are frequent and independently impact mortality after transcatheter aortic valve implantation (TAVI). Thromboelastography (TEG) measures viscoelastic properties of clot formation and is currently best known for perioperative management to reduce blood transfusion in cardiac surgery. Aim: We sought to determine whether TEG may be predictive of bleeding in patients treated with TAVI. Methods and results: Overall, 54 consecutive patients with severe aortic stenosis treated with TAVI were prospectively included. In all patients, two blood samples were obtained for TEG measurement (the first - 12 h prior to procedure tested with citrated kaolin [CK] TEG assay, and the second - immediately after prosthesis deployment tested with CK and citrated heparinised kaolin assay [CHK]). Major or life-threatening bleeding (MLTB) was diagnosed in 13 (24%) patients. In receiver-operating characteristic (ROC) curve analysis the only TEG parameters showing significant sensitivity and specificity for predicting MLTB were those obtained in the CK sample at the end of the procedure: R value (reaction time, time to initiation of clot formation) area under the curve (AUC) 0.69, 95% confidence interval (CI) 0.49-0.88, p = 0.04; angle (the rate of clot formation), AUC 0.75, 95% CI 0.59-0.92, p = 0.007, and maximum amplitude (MA, ultimate strength of fibrin clot), AUC 0.77, 95% CI 0.62-0.93, p = 0.003. After controlling for confounding factors on multivariate logistic regression, MA remained as the only TEG parameter that significantly correlated with bleeding after TAVI, both as a continuous variable (p = 0.004; 95% CI 0.92-0.98; odds ratio [OR] 0.95 per 1 mm increment) and after using the cut-off value derived from ROC analysis; MA < 46.6 mm (OR 10.4; 95% CI 2.1-51.8; p = 0.004). Conclusions: Low strength of fibrin clot measured by TEG immediately after TAVI may serve as an independent predictor of short-term major and life-threatening bleeding complications.