Severance professor leads guideline revision on stroke blood pressure management

Severance Hospital said Thursday that Professor Nam Hyo-suk of the Neurology Department has led revisions to major acute ischemic stroke treatment guidelines issued by the American Heart Association (AHA) and the Korean Stroke Society, following new clinical evidence showing that excessively low blood pressure after arterial reperfusion therapy can worsen patient outcomes.

Acute ischemic stroke is caused by a clot blocking blood flow to the brain, leading to tissue damage and potentially severe complications such as hemiplegia and speech impairment. When large clots are present, physicians perform arterial reperfusion therapy, inserting a catheter to remove the clot and restore blood flow. After the vessel is reopened, careful management of systolic blood pressure is essential to prevent hemorrhage caused by excessive blood flow through the treated vessel.

Until now, U.S. and European guidelines recommended keeping systolic blood pressure below 180 mmHg following reperfusion therapy. Retrospective studies suggested that tighter control might improve outcomes, and in clinical practice many doctors had already been targeting lower values.

However, a 2023 randomized clinical trial led by Professor Nam and published in JAMA found that lowering blood pressure too aggressively -- below 140 mmHg -- increased the risk of poor outcomes by 1.84 times compared with guideline-recommended levels in patients who underwent arterial reperfusion.

Based on this high-quality evidence, both the AHA and the Korean Stroke Society updated their 2025 guidelines to state that maintaining systolic blood pressure below 140 mmHg after reperfusion therapy is dangerous. The recommendation received Level A and Level Ia evidence ratings from the respective societies, the highest possible grades.

“Our randomized trial showing the risks of excessively lowering blood pressure after arterial reperfusion directly resulted in changes to the clinical guidelines,” Professor Nam said. “Since systolic blood pressure below 140 mmHg was shown to be harmful, the appropriate target range after successful reperfusion should be 140–180 mmHg.”