Increased Thrombogenicity is Associated With Coronary Microvascular Dysfunction in Patients With STEMI—A Proof‐of‐Concept Study

Background Up to 50% of patients with ST‐segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI) develop coronary microvascular dysfunction (CMD). Aims This study aims to assess whether a prothrombotic state of coronary blood, defined by thromboelastography (TEG), is associated with post‐pPCI CMD in STEMI. Methods TEG analysis of infarct‐related coronary artery (IRA) blood was performed in 25 consecutive STEMI patients before and after successful pPCI. CMD was defined by high values of the angiography‐derived index of microcirculatory resistance (IMR angio ≥ 40 units). Results The median age was 59 (IQR 51−71) years. CMD was observed in 13 (52%) patients. Pre‐pPCI Reaction (R) and Kinetic (K) time of the coronary blood from the IRA were inversely correlated with IMR angio (rho −0.45, p = 0.02; rho −0.62, p = 0.002 respectively). R time was significantly shorter in patients who developed CMD (10.7 [IQR 8.8, 13.1] vs. 18.2 [IQR 12.6, 24.2], p = 0.05), and it provided an overall good diagnostic accuracy in predicting CMD (AUC 0.75, [95% CI 0.53−0.96] p = 0.05). Similar relationship was founded for K time: 3.5 [IQR 2.2−4.6] versus 10.6 [IQR 4.5−30.0] min, p = 0.01; AUC 0.82, [95% CI 0.64−0.99] p = 0.01. Moreover, α angle was significantly larger (57.4 [IQR 46.5−64.8] vs. 40.0 [IQR 39.0−49.5], p = 0.03) in patients with CMD (AUC 0.78, [95% CI 0.57−0.98], p = 0.03). Coronary post‐pPCI TEG parameters were not associated with CMD. Conclusions In this proof‐of‐concept study, a prothrombotic state of coronary blood from the IRA is associated with CMD. Further studies are warranted to evaluate if TEG may enhance individualized therapies in patients with STEMI at risk of CMD.