Microguidewire Looping Technique to Traverse an MCA Occlusion Through the Largest and Straightest Branch (or Following the Path of the Clot): A Good Tip for Safely Dealing with the Usually Unknown Arterial Anatomy Beyond the Stump

Looping a distal microguidewire tip is a commonly used maneuver for crossing occlusions. Rounding the microguidewire tip in a loop configuration minimizes the risk of both arterial trauma and unwanted tip advancement into small arterial branches. Given the anatomic variability of MCA patterns, this technique can be used to safely catheterize the largest and straightest branch beyond a proximal MCA occlusion. A 76-year-old overweight man with a history of arterial hypertension, diabetes mellitus, dyslipidemia, and advanced ischemic heart disease required three percutaneous coronary interventions in the past 5 years had experienced palpitations and an isolated episode of syncope over the previous week. He was evaluated in the emergency department and discharged several hours later after a brief period of hemodynamic and cardiologic monitoring. Blood tests were normal, and the electrocardiogram (ECG) showed no relevant arrhythmia. He was managed with the addition of antihypertensive medications and discharged on his regular dual antiplatelet and statin medications. Five days later, he was brought to the emergency department 4 h after his wife had last seen him normal. On arrival, he was drowsy, responded to stimuli with marked agitation, and had conjugate left gaze deviation, mixed aphasia, and right-sided dense hemiparesis. His National Institutes of Health Stroke Scale (NIHSS) score was 26. Admission CT showed microvascular brain disease with hypodense areas in the basal ganglia or cortical region, corresponding to an Alberta Stroke Program Early CT Score (ASPECTS) of 10. CT perfusion (CTP) images showed a 51 ml left temporal region with total cerebral blood flow reduced to less than 30% of expected levels and a larger 176 ml region with time-to-maximum prolongation >6 s. The mismatch volume was 125 ml and the mismatch ratio was 3.5. CT angiography (CTA) images demonstrated occlusion of the proximal left middle cerebral artery (MCA). Intravenous tissue plasminogen activator (IV-tPA) was not administered because the patient was found on the floor and his relative thought that a traumatic injury might have occurred. The patient underwent urgent stentriever-assisted mechanical thrombectomy (MT), which achieved rapid complete reperfusion with distal filling of all branches of the MCA (modified thrombolysis in cerebral infarction [mTICI] 3) with rapid postprocedural clinical improvement. During this procedure, a microguidewire looping technique was used to cross the MCA occlusion. This technique facilitated safe catheterization of the largest MCA branch and allowed for rapid and effective MT. ECG monitoring during the procedure and during the patient’s hospital stay demonstrated sinus rhythm. The patient achieved complete neurological recovery (modified Rankin Scale [mRS] score of 0) and was discharged directly to home. In this chapter, we describe the microguidewire looping technique used during mechanical thrombectomy and discuss the different MCA variants most commonly encountered during neuroendovascular interventions.