Abstract 12177: Quantitative Flow Ratio is a Great Predictor of Microvascular Obstruction in ST-Segment Elevation Myocardial Infarction After Percutaneous Coronary Intervention

Backgrounds: Compare the predictive effects of ST-segment resolution (STR) and quantitative flow ratio (QFR) in the detection of MVO in STEMI patients after PCI.

Research Questions: To investigate the efficacy of STR/QFR in the evaluation of MVO detected by CMR in STEMI after PCI.

Methods: A prospective cohort study enrolled 208 consecutive patients with STEMI. The degree of STR post procedure and predischarge after reperfusion was calculated. QFR were measured according to the angiography, CMR was performed within median time 5 days after revascularization to determine MVO. Clinical factors were enrolled to predict the incidence of MVO.

Results: The MVO/LV mass is 1.42±2.28 in 126 patients with MVO according to CMR, and the area under ROC curves (AUC) identified QFR is the best predictor (AUC: 0.784, P <0.001). Factors including QFR, STR, TIMI flow, CK-MB, cTnI, WBC, and HsCRP showed good predictive effects for the incidence of MVO ( P <0.05). Except for peak cTnI, QFR (%) was the best predictor (AUC: 0.784, P <0.001) ( Figure 1 ). A nomogram for predicting MVO was done (c-index: 0.894) ( Figure 2 ). A significant correlation was observed between STR and various parameters ( P <0.05), except for the correlation between predischarge STR and MVO/LV mass at 6 months. Predischarge STR has the best correlation with infarct size after the 6-month follow-up ( r =-0.509, P <0.001) ( Figure 3 ). Regression analysis indicated that postoperative STR (β=-0.248, P =0.007) was a significant predictor of MVO/LV mass ( Figure 3 ). Figure 4 further analyzed heart function from in-hospital CMR between different postoperative STR levels, and from 6 months CMR between predischarge STR subgroups. Higher STR predicted less cardiac injury and more ideal index of cardiac remodeling.

Conclusions: In STEMI patients after PPCI, QFR demonstrated better predictive effect of the incidence of MVO than STR. Predischarge STR is closely related to infarct size and ejection fraction after 6-month follow-up.