The effect of blood pressure (BP) reduction on cerebral blood flow (CBF) in acute ischemic stroke is unknown. We measured regional CBF with perfusion-weighted MRI before and after BP treatment in a three-armed non-randomized prospective controlled trial. Treatment arm assignment was based on acute mean arterial pressure (MAP). Patients with (MAP) >120 mmHg (n = 14) were treated with intravenous labetalol and sublingual (SL) nitroglycerin (labetalol group). Those with MAP 100-120 mmHg (n = 17) were treated with SL nitroglycerin (0.3 mg) ('NTG Group') and those with baseline MAP<100 mmHg (n = 18) were not treated with antihypertensive drugs (untreated group). Forty-nine patients (18 female, mean age 65.3 ± 12.9 years) were serially imaged. Labetalol reduced MAP by 12.5 (5.7-17.7) mmHg, p = 0.0002. MAP remained stable in the NTG (6.0 (0.4-16, p = 0.3) mmHg and untreated groups (-0.3 (-2.3-7.0, p = 0.2) mmHg. The volume of total hypoperfused tissue (CBF<18 ml/100 g/min) did not increase after labetalol (-1.1 ((-6.5)-(-0.2)) ml, p = 0.1), NTG (0 ((-1.5)-4.5) ml, p = 0.72), or no treatment 0.25 ((-10.1)-4.5) ml, p = 0.87). Antihypertensive therapy, based on presenting BP, in acute stroke patients was not associated with an increased volume of total hypoperfused tissue.
Keywords: Blood pressure; acute ischemic stroke; cerebral blood flow; labetalol; nitroglycerin.