A Case of Development and Rapid Increase in the Microbleeds after Pipeline Placement for an Intracranial Unruptured Aneurysm.

Flow diverter stents are used for the treatment of intracranial aneurysms and require long-term antiplatelet therapy, which has been associated with complications such as intracranial hemorrhage. We encountered a case in which rapid increases in the size and number of cerebral microbleeds were observed shortly after flow diverter stent placement. It is known that microthrombosis within a stent can occur after flow diverter stent placement, and this microthrombosis is thought to cause cerebral microbleeds. The patient was a 77-year-old man who underwent flow diverter stent placement for an unruptured intracranial aneurysm. Postoperatively, he developed disorientation and limb paralysis, with magnetic resonance imaging showing diffuse cerebral infarction but no hemorrhagic lesions. Subsequent imaging revealed numerous cerebral microbleeds that were not present earlier and progressively worsened despite dual antiplatelet therapy and blood pressure management. Adjustments to medications, including delaying aspirin and adding antihypertensives, were made. Sodium ozagrel was introduced but later discontinued due to further increases in cerebral microbleeds. At 30 days post-surgery, imaging showed stabilization. By 3 months, residual cerebral microbleeds remained without further progression, and the patient had a modified Rankin scale score of 1. By adjusting antiplatelet medication and controlling blood pressure, it was possible to somewhat manage cerebral hemorrhage. Even when antiplatelet medications are maintained within the optimal therapeutic range, there remains a risk of cerebral hemorrhage. This risk must be carefully considered, and appropriate adjustments to antiplatelet therapy are essential during the perioperative period.