Stroke, Vol 15, 1017-1020, Copyright © 1984 by American Heart Association
R Leblanc, W Feindel, LY Yamamoto, JG Milton, MM Frojmovic and CP Hodge
We have studied the effects of the calcium antagonist verapamil on the
epicerebral arteriovenous transit time and regional epicerebral circulation
of dogs by direct measurement of arterial diameters, fluorescein
angiography, and krypton-85 regional epicerebral blood flow analysis. A
large craniectomy was performed and vasoconstriction was induced by the
subarachnoid injection of human platelet-rich plasma (PRP) pretreated with
25 mu M of ADP to cause maximum aggregation. Once vasoconstriction was
established, verapamil (0.1 mg/kg) was topically applied to the perforated
arachnoid. The PRP-ADP produced a mean decrease in the arterial diameters
of 38.2 +/- 1.6% (p less than 0.01) at 10 minutes after its injection and
verapamil produced a mean dilatation of 19.5 +/- 2.5% (p less than 0.01),
compared to control values. Regional epicerebral blood flow was 54.9 +/-
3.4 ml/100 g/min in the control state, 34.8 +/- 3.2 ml/100 g/min (p less
than 0.01) during vasospasm, and 78.2 +/- 4.5 ml/100 g/min (p less than
0.01) after verapamil. Fluorescein angiography, after verapamil,
demonstrated a mean acceleration of the arteriovenous circulation time of
4.5 +/- 0.8 seconds (p less than 0.01) compared to the spasm value. We
concluded that the topical application of verapamil can dilate previously
constricted cortical arteries and that this dilatation is associated with
acceleration of the epicerebral transit time and increased cerebral blood
flow.
ARTICLES
The effects of calcium antagonism on the epicerebral circulation in early vasospasm