Successful Retrieval of a Pathologically Proven Calcified Thrombus Using Nimbus: A Case Report

Mechanical thrombectomy can be challenging in cases of hard or calcified thrombi that are resistant to conventional aspiration and stent-retriever techniques. The Nimbus stent retriever (Johnson & Johnson, Warsaw, IN, USA) is designed to improve outcomes in cases with hard clots.

An 80-year-old woman presented with an acute ischemic stroke due to left M2 occlusion. Preprocedural imaging revealed a markedly hyperattenuating lesion on CT and a susceptibility effect on T2*-weighted imaging at the occlusion site. During lesion crossing, marked resistance was encountered when advancing the microguidewire and microcatheter. Aspiration and conventional combined techniques failed to achieve recanalization. A Nimbus stent retriever was used as a rescue device. The stent retriever was deployed across the thrombus while aligning its proximal segment with the clot and partially re-sheathed until resistance was encountered, followed by retrieval of the stent retriever and aspiration catheter as a single unit under continuous aspiration. Successful recanalization was achieved (modified Thrombolysis in Cerebral Infarction score 2B). Histopathological examination of the resected specimen revealed a calcified thrombus. Transthoracic echocardiography and chest CT revealed mitral valve calcification.

Nimbus may be particularly useful for retrieving calcified or unusually firm thrombi that are resistant to conventional thrombectomy techniques.