We describe three patients aged 57-65 years old presenting with STEMI, one of whom was an out of hospital cardiac arrest with sustained inferior ST-elevations on ECG after ROSC. All three patients were sent to the catherization laboratory emergently for primary percutaneous coronary intervention. 

In all three patients, coronary angiography revealed 100% thrombotic occlusion in either the proximal right coronary artery (2/3 cases) or left anterior descending coronary artery (1/3 cases). 

Initial management included aspiration thrombectomy and lesion preparation with balloon angioplasty. Despite this, a significant thrombus burden persisted on both coronary angiography and intravascular ultrasound. To minimize the risk of distal embolization, a filter wire was carefully deployed distal to the lesion before stent placement. The wire served as a distal embolic protection device, capturing debris dislodged during stent deployment and post-dilation. There was no peri-procedural ST-segment elevation. The filter wire was removed without complication after post-dilation. Post-procedure angiography confirmed TIMI III flow in all three cases, with no angiographic or clinical evidence of distal embolization. 

STEMI due to large thrombus burden are not infrequent. Recent studies have shown that failed thrombus aspiration including distal embolization is associated with reduced myocardial perfusion by occlusion of distal microvasculature, reduced LVEF, and adverse clinical outcomes. In this case series, we have demonstrated the safe use of filter wire in native vessels in STEMI with residual high thrombus burden after conventional treatment as a distal embolic protection device. TIMI III flow was restored despite high thrombus burden without evidence of distal embolization. This highlights the potential use of distal embolization protection devices to potentially prevent no reflow phenomenon.