Thrombus aspiration reduces microvascular obstruction after primary coronary intervention: a myocardial contrast echocardiography substudy of the REMEDIA Trial

OBJECTIVES: The aim of this study was to clarify the role of microembolization in the genesis of microvascular obstruction (MO) after percutaneous coronary intervention (PCI). BACKGROUND: Fifty consecutive patients entered the myocardial contrast echocardiography (MCE) substudy of the REMEDIA (Randomized Evaluation of the Effect of Mechanical Reduction of Distal Embolization by Thrombus Aspiration in Primary and Rescue Angioplasty) trial, which defined the role of a new thrombus-aspirating device in preventing distal microembolization after PCI. METHODS: A total of 25 patients were randomized to be pretreated with thrombus aspiration before PCI of the culprit lesion and 25 received standard PCI. At 24 h, 1 week, and 6 months after PCI, MCE was performed by Sonovue, and real-time imaging was performed by contrast pulse sequencing technology. Regional wall motion score index (WMSI), contrast score index (CSI), endocardial length of wall motion abnormality (WML) and contrast defect (CDL), end-diastolic and end-systolic left ventricular (LV) volumes, and ejection fraction were calculated. RESULTS: At each time point, in patients treated with a thrombus-aspiration filter device, WMSI, CSI, WML, and CDL were significantly lower and ejection fraction higher (p < 0.05 vs. control patients), whereas LV volumes were slightly but not significantly smaller compared with control patients. In the overall study population, the extent of MO significantly correlated with temporal changes in LV volumes. CONCLUSIONS: Thrombus aspiration used at the time of PCI significantly reduces the extent of MO and myocardial dysfunction, although it does not have a significant favorable effect in preventing LV remodeling. Thus, the beneficial effect of thrombus aspiration occurs at the microvascular level, but additional mechanisms may play a role in influencing the final extent of MO, which strictly correlates with post-infarct LV remodeling.