The Extent of Myocardial Damage Evaluated by Cardiac MRI in Patients with ST- Segment Elevation Myocardial Infarction: Predictors and Outcomes - The 65th Annual Conference of the Israel Heart Society & The Israel Society of Cardiothoracic Surgery, 24-25 April 2018

Eyas Massalha Intensive Cardiac Care Unit, Cardiology., Leviev Heart Center, Chaim Sheba Medical Center, Ramat Gan, Israel, Israel Orly Goitein Intensive Cardiac Care Unit, Cardiology., Leviev Heart Center, Chaim Sheba Medical Center, Ramat Gan, Israel, Israel Israel Mazin Intensive Cardiac Care Unit, Cardiology., Leviev Heart Center, Chaim Sheba Medical Center, Ramat Gan, Israel, Israel Ronen Goldkorn Intensive Cardiac Care Unit, Cardiology., Leviev Heart Center, Chaim Sheba Medical Center, Ramat Gan, Israel, Israel Sharon Natanzon Intensive Cardiac Care Unit, Cardiology., Leviev Heart Center, Chaim Sheba Medical Center, Ramat Gan, Israel, Israel Avishay Grupper Intensive Cardiac Care Unit, Cardiology., Leviev Heart Center, Chaim Sheba Medical Center, Ramat Gan, Israel, Israel Roy Beigel Intensive Cardiac Care Unit, Cardiology., Leviev Heart Center, Chaim Sheba Medical Center, Ramat Gan, Israel, Israel Shlomi Matetzky Intensive Cardiac Care Unit, Cardiology., Leviev Heart Center, Chaim Sheba Medical Center, Ramat Gan, Israel, Israel

Background: The extent of myocardial damage is the most important prognostic factor in predicting both early and long term prognosis. Yet, the evaluation of infarct size early post reperfusion by the routinely used tools including myocardial bio-markers as well as echocardiography might not reflect accurately the extent of irreversible myocardial damage. Our aim was to evaluate the extent of delayed enhancement (DE) upon cardiac MRI (CMRI), which reflects the fibrosis and irreversibly damaged myocardium.

Methods: We prospectively evaluated 138 consecutive patients without known prior coronary disease who underwent primary PCI for STEMI. All patients underwent 2D-echocardiography upon admission and CMRI at day 5 ± 1. ECG was evaluated for sum ST-elevation on admission and for early ST-resolution (> 70%) post PPCI. Platelet reactivity to ADP ,Arachidonic Acid(AA),Epeniphrine was obtained at 72-96 hours post admission using conventional aggregometry. Sub-optimal response to antiplatelet therapy was defined as AA-platelet aggregation (PA) >20% and\or ADP-PA >50% and\or EPI-PA>50%. CMRI was evaluated for the extent of DE and micro-vascular damage (MVO), both expressed as % of left-ventricle. Patients were stratified into three tertiles According to DE. Patients in the higher tertile were defined as having large MI and were compared with patients in the two lower tertiles.

Results: Patients with large MI had higher sum ST-elevation on admission ECG (P=0.0015), were more likely to present with an anterior wall MI (P< 0.004), and had lower initial TIMI-grade (P<0.001). Post PPCI patients with large MI were significantly less likely to demonstrate early STR (P=0.003) and had more distal embolization (P=0.027). Patients with large MI on CMRI had significantly more elevated cardiac bio-markers: Peak CPK (P<0.001), Peak Troponin (P <0.001) and Lower LVEF on 2Decho (P=0.001). On CMRI patients with large MI had higher extent of LV involvement on T2 (suggesting larger jeopardized area) as well as larger extent of microvascular damage (MVO). Interestingly, patients with large MI on CMRI were more likely to show sub-optimal response to antiplatelet therapy (P=0.024).

Conclusions: Large MI in STEMI patients as shown on routine CMRI was associated with larger jeopardized area (sum STE, anterior location) and markers of incomplete myocardial reperfusion (angiographic distal embolization, absence of STR, larger extent of MVO on CMRI).