[Dilation of the brachial artery in response to sublingual nitroglycerin can predict the antihypertensive effects of valsartan: a study using novel high-frequency high-frame-rate ultrasound imaging].
OBJECTIVE
The efficacy of antihypertensive agents can vary in patients. Four to 8 weeks may be required before antihypertensive agents become fully effective. Predicting the efficacy can help agent selection and dose setting. This study determined whether nitroglycerin-induced vasodilation of brachial arteries can predict the antihypertensive action of angiotensin II receptor antagonist.


METHODS
Untreated uncomplicated patients with essential hypertension, who gave informed consent, were studied (n = 20, mean age 55 years). Before antihypertensive treatment, nitroglycerin-induced vasodilation of the brachial arteries was measured using a novel method of 15 MHz high-frequency high-frame-rate ultrasound imaging (Hitachi EUB8000). Diameter of the brachial artery at the end-systolic phase was measured before and after 0.3 mg nitroglycerin sublingual spray and percentage vasodilation (%D-N) was calculated. The reduction of mean blood pressure after nitroglycerin (%BP-N) was calculated. Valsartan monotherapy (40-80 mg/day)was administered for 3-6 months (mean 132 days). Reduction of mean blood pressure after valsartan monotherapy (%BP-V) was calculated.


RESULTS
Valsartan decreased systolic blood pressure from 138 +/- 13 to 130 +/- 17 mmHg, and diastolic blood pressure from 83 +/- 11 to 78 +/- 11 mmHg (p < 0.05). %D-N was correlated closely with %BP-V (r = - 0.70, p < 0.001). %BP-N had no correlation with %BP-V (r = 0.13, p = 0.58).


CONCLUSIONS
Direct vasodilatory action of nitroglycerin on vascular smooth muscle cells may predict the chronic antihypertensive effect of angiotensin II receptor antagonist.
Clinical Laboratory, Hokkaido University Hospital, Sapporo.
Mamiko
M
Inoue
Satoshi
S
Fujii
Mikami
M
Taisei
Tomoo
T
Furumoto
Sanae
S
Kaga
Hiroshi
H
Komatsu
Kazutomo
K
Goto
Kaoru
K
Komuro
Satoshi
S
Yamada
Hisao
H
Onozuka
Akira
A
Kitabatake
Hiroyuki
H
Tsutsui
D047228:Angiotensin II Type 1 Receptor Blockers / Q000627:therapeutic use*; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001916:Brachial Artery / Q000000981:diagnostic imaging* / Q000187:drug effects / Q000473:pathology; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D005996:Nitroglycerin / Q000494:pharmacology*; D011237:Predictive Value of Tests; D013777:Tetrazoles / Q000627:therapeutic use*; D014463:Ultrasonography; D014633:Valine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000068756:Valsartan; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology*
D047228:Angiotensin II Type 1 Receptor Blockers; D000959:Antihypertensive Agents; D013777:Tetrazoles; D014665:Vasodilator Agents; D000068756:Valsartan; D005996:Nitroglycerin; D014633:Valine