Background and Purpose--Angiotensin-converting enzyme (ACE) inhibitor-based therapy reduces the recurrence of stroke. The present study assessed the effects of long-term ACE inhibitor therapy on cerebral circulation in patients with previous minor stroke.

Methods--After a run-in period, 19 patients were randomized to ACE inhibitor therapy (n=9; 4 mg of perindopril daily; mean age, 64±8 years; mean systolic/diastolic blood pressure [BP]±SD, 133±12/77±9 mm Hg) or placebo therapy (n=10; mean age, 66±9 years; mean BP, 139±10/78±8 mm Hg). Cerebral blood flow (CBF) was measured during hypercapnia, normocapnia, and hypocapnia using a positron emission tomography with H₂¹⁵O at entry into the study and after 3 to 12 months. Cerebral perfusion reserve (CPR) was defined as percent CBF response to a 1 mm Hg change in arterial partial pressure of CO₂ between hypercapnia and hypocapnia.

Results--Systolic/diastolic BP and CBF during normocapnia showed no significant changes between entry and completion of the trial in the perindopril and placebo groups. Mean value of CPR showed a significant increase in the perindopril group (from 3.7±1.7%/mm Hg to 4.8±1.7%/mm Hg; P<0.05) but not in the placebo group (from 4.1±0.8%/mm Hg to 4.2±0.6%/mm Hg; NS). Statistical parametric mapping analysis also showed global and significant increase (P<0.01, uncorrected) in CPR in the perindopril group alone.

Conclusions--Long-term ACE inhibitor-based therapy had a beneficial effect on the cerebral circulation by improving CPR in patients with previous minor stroke.