Small randomized trials in patients with ST-elevation myocardial infarction have shown that aspiration thrombectomy improves angiographic outcomes and may improve clinical outcomes. However, there remains a lack of reports on device-related complications. We report a case of a device complication involving the left main coronary artery where a large burden of thrombus was brought back into the left main coronary artery from the circumflex during aspiration thrombectomy.