Pre-stenting residual thrombotic volume assessed by dual quantitative coronary angiography predicts microvascular obstruction in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

BACKGROUND: Microvascular obstruction (MVO) is a frequent occurrence after primary percutaneous coronary intervention (pPCI), and is associated with adverse left ventricular remodeling and worse clinical outcome. Distal embolization of thrombotic material is one of the most important underlying mechanisms. The aim of this study was to investigate the relation between the thrombotic volume evaluated by dual quantitative coronary angiography (QCA) prior to stenting and the occurrence of MVOas assessed by cardiac magnetic resonance (CMR). METHODS: Forty-eight patients with ST-segment elevation myocardial infarction (STEMI) undergoing pPCIand receiving CMRwithin 7 days from admission were included. Pre-stenting residual thrombus volume at the site of the culprit lesion was measured by applying automated edge detection and video-assisted densitometry techniques (i.e., dual- QCA), and patients were categorized into tertiles of thrombus volume. The presence of delayed-enhancement MVO, as well as its extent (MVOmass), were assessed by CMR. RESULTS: Pre-stenting dual-QCA thrombus volume was significantly greater in patients with MVO than in those without (5.85 mm3 [2.05-16.71] vs. 1.88 mm3 [1.03-6.92], P=0.009). Patients in the highest tertile showed greater MVOmass compared to those in the mid and lowest tertiles (113.3 gr [0.0-203.8] vs. 58.5 g [0.00-144.4] vs. 0.0 g [0.0-60.225], respectively; P=0.031). The best cut-off value of dual-QCAthrombus volume for prediction of MVOwas 2.07 mm3 (AUC: 0.720). The addition of dual-QCA thrombus volume to the traditional angiographic indices of no-reflow enhanced the prediction of MVOby CMR(R=0.752). CONCLUSIONS: Pre-stenting dual-QCAthrombus volume is associated with the presence and extent of MVOdetected by CMR in patients with STEMI. This methodology may aid the identification of patients at higher risk of MVO and guide adoption of preventive strategies.