Hypercoagulability and fibrinolysis assessment in acute myocardial infarction: focus on high risk patients

Despite significant advances in antithrombotic treatment of acute coronary syndrome (ACS), morbidity and mortality in patients suffering from myocardial infarction are still high, with recurrent thrombotic events accounting for a great proportion of the subsequent, long-term complications of these patients. Indeed, great research efforts have focused on high-risk patients with ACS, striving for improvements in their prognosis, through optimisation of antithrombotic treatment.¹ Notwithstanding, there is still an unmet need for tools to refine risk assessment in ACS patients, as well as to improve our ability to integrate clinical and laboratory data in the prognostic evaluation of these patients.

The recently published paper from Lee and colleagues² reports the findings of an observational investigation, aiming to evaluate the association between thrombogenicity indexes (as measured by thromboelastography [TEG]), clinical presentation of ACS, and long-term risk of major adverse cardiovascular events. Among 2705 patients undergoing percutaneous coronary intervention (PCI) included in the analysis, the authors found that higher platelet-fibrin clot strength and lower fibrinolytic activity were associated with both index presentation as acute myocardial infarction, and 4-years risk of MACE post-PCI; spline regression curves suggested also a potential non-linear association between the two indexes and the risk of MACE. When considering the concomitant occurrence of hypercoagulability and impaired fibrinolytic activity, the authors found a significant increase in the long-term risk of MACE (aHR:  1.781, 95%CI: 1.130-2.808), compared to patients with normal indexes.

Despite the limitation of this study – acknowledged by the authors, and including potential selection bias and the existence of other unaccounted confounders, and the overall hypothesis-generating nature of the findings – the results offer an interesting outlook on the potential application of assessing thrombogenicity indexes in patients suffering ACS. Indeed, the identification of patients with hypercoagulability and/or impaired fibrinolysis may be useful for risk-refinement and, specifically, to identify those high-risk subjects who may benefit from more intensive management (e.g., more intensive antithrombotic regimens), and who may require closer follow-up.

These results are in line with previous studies, which showed an association between thrombogenicity indexes and long-term risk of adverse outcomes,^3,4 and with a sub-analysis of the PLATO trial.⁵ Indeed, 

the study by Lee and colleagues further expand our knowledge on this topic, and provide further evidence of the potential usefulness of the evaluation of these indexes in the risk stratification of ACS. These findings open several research and clinical scenario, particularly related to the development of individualised-treatment strategies, taking into account thrombogenicity, beyond clinical risk factors. Whether (and to what extent) this approach could translate into clinical practice remains a matter of debate, and would require extensive and thorough investigation, including evaluation of the potential limitations of the various techniques, the interaction with antithrombotic treatments, and the cost-effectiveness of such approaches.

Nonetheless, this study opens interesting scenarios which may have significant implications for clinical practice in the future. Further studies are needed to confirm these findings and to provide supporting evidence on the potential role of thrombogenicity assessment in the prognostic refinement in patients with ACS, and particularly on the potential therapeutic targeting of enhanced thrombogenicity (including the role of emerging drugs, such as TAFI-inhibitors, and novel antithrombotic strategies).