Acute treatment of hypertension increases infarct sizes in spontaneously hypertensive rats.

We studied the effect of dihydralazine treatment of hypertension in spontaneously hypertensive stroke-prone rats in a model of permanent focal cerebral ischemia (stroke). After occlusion of the middle cerebral artery systemic arterial pressure (SAP) was lowered with a computer controlled infusion device from 163 to 135 or 117 mm Hg for 24h. In the control group SAP was not manipulated. Reduction of SAP to normotension (117 mm Hg) significantly worsened outcome and increased infarct volume measured 7 days after induction of ischemia, whereas a mild reduction of SAP (to 137 mm Hg) had no statistically significant effect on outcome or infarct volume. We conclude that pharmacological treatment of hypertension may negatively affect neurological outcome and infarct volume in a rat stroke model.