SPECT EVALUATION OF CEREBRAL PERFUSION IN UNCOMPLICATED ESSENTIAL HYPERTENSIVES AND EFFECTS OF ENALAPRIL

A semiquantitative evaluation of regional cerebral blood flow was perf ormed by means of single photon emission computed tomography and Tc-99 m-hexamethylpropyleneamine oxime in 25 neurologically asymptomatic pat ients with essential hypertension and in 10 normotensive controls. Mea n flow velocities and pulsatility indexes of intracranial arteries and the vasomotor reactivity of the middle cerebral artery after hyperven tilation were assessed by means of transcranial Doppler sonography (TC D). The pattern of cerebral perfusion in hypertensive patients was sim ilar to that of normotensive controls. However, the semiquantitative e xamination of the CBF flow maps revealed significantly different front al, temporal and occipital asymmetry indexes in hypertensive patients, as an expression of disturbed perfusion. TCD did not reveal any signi ficant difference in flow velocities between hypertensives and normote nsive controls. In 10 randomly selected hypertensive patients the stud y was repeated after a 4-week oral treatment with the angiotensin-conv erting enzyme (ACE) inhibitor enalapril. Blood pressure fell significa ntly without any decrease in cerebral perfusion. The basal asymmetry i ndex was also unaffected, confirming the absence of any steal effect. Thus, there are indications that focal hypoperfusion is a frequent fin ding among neurologically normal essential hypertensives and that the ACE inhibitor enalapril does not negatively affect cerebral blood flow in the asymptomatic essential hypertensive patients.