Extremely high blood pressure–180/120 mmHg or higher–can damage blood vessels and lead to stroke. However, studies show that the incidence of stroke gradually increases as the blood pressure rises above 110/75 mmHg. If you experience a severe increase in your blood pressure, seek immediate medical attention.
Reference:
Pub Med: https://pubmed.ncbi.nlm.nih.gov/1969518/
Pub Med: https://pubmed.ncbi.nlm.nih.gov/1969518/