Treatment of a large thrombus containing lesion with the MGuard™ protective net coronary stent system: optical coherence tomographic evidence of complete plaque sealing

Abstract

Avoidance of distal embolization is the key of success in the percutaneous treatment of patients with ST elevation myocardial infarction. Embolization may lead to microvascular obstruction, and consequently impairment of myocardial perfusion with increased infarct size and mortality [1, 2]. Different types of devices have been proposed to avoid this issue. Prospective randomized clinical trials have shown the beneficial effect of thrombus aspiration devices in the setting of primary percutaneous coronary intervention (PCI) [3, 4]. Recently, the use of MGuard net coronary stent system (MGS, Inspire-MD, Tel Aviv, Israel) in the setting of primary PCI has shown high rate of myocardial reperfusion and angiographic procedural success [5]. MGS is a new stainless-steel closed-cell design stent concept. Other than conventional available bare-metal stents (BMS), it has an ultrathin flexible polyethylene terephthalate mesh sleeve that is anchored to the external surface of the struts. This biocompatible microfiber net (string diameter 10–22 lm) has minimal effects on stent crossing profile and deliverability (Fig. 1). During stent deployment, the net stretches and slides over the expanding stent struts, creating custom designed pores of &200 lm in diameter. The idea of this design is to entrap the thrombus burden between stent mesh and the wall of the artery, isolating the high-thrombogenic intima components and preventing the ‘‘snow plug effect’’. This is the first time, at our knowledge, that the optical coherence tomography (OCT) assessment of MGS implantation for the treatment of a large thrombus burden right coronary artery (RCA) lesion is being reported. A 78-year-old female with mild hypertension and dislipidemia, previously treated with dual chamber pacemaker implant, was admitted at our hospital for coronary angiography following an inferior ST elevation myocardial infarction treated with a partial effective systemic thrombolytic therapy with reteplase. At the time of coronary angiography, the patient was already on double antiplatelet therapy (600 mg loading dose of clopidogrel and 300 mg loading dose of acetylsalicylic acid). The angiography showed a significant mid-RCA lesion with large thrombus burden (Fig. 2a), while there were no lesions on the left coronary system. PCI was then performed using the standard approach. A bolus of 80 UI/kg of unfractioned heparin was given at the start of procedure. No glycoprotein IIb/IIIa inhibitors were given during the procedure to avoid bleeding complications related to the already administered anti-platelet therapy and patient’s age. After cannulation of the RCA with a 7 French side holes Judking right 4 guiding catheter, a BMW guide wire (Abbott Vascular, Redwood City, CA, USA) was advanced until the distal postero-lateral branch and an OCT scan using the C7XR OCT image system (LightLab Imaging Inc., Westford, MA, USA) was then performed using the nonocclusive flushing technique [6]. The OCT pullback showed a tight stenosis of RCA with a very large intraluminal stratified red thrombus (Fig. 2b). Subsequently, it was decided to perform a direct stenting with 4.0/24 mm MGS implantation, which was deployed at 16 atm. The OCT was repeated thereafter showing a malapposition at the mid part of the stent. Therefore, post-dilatation was A. La Manna S. D. Tomasello C. Tamburino Clinical Division of Cardiology, Department of Internal Medicine and Systemic Disease, Ferrarotto Hospital, University of Catania, Catania, Italy