A new study published in the
current Journal of the American Society of Hypertension demonstrates that
the hypertension treatment olmesartan medoxomil was effective in reversing
the narrowing of the arteries that occurs in patients with hypertension.
The study, titled VIOS (Vascular Improvement with Olmesartan medoxomil
Study) was a one-year, exploratory study that evaluated the effects of an
angiotensin receptor blocker (olmesartan medoxomil) vs. a beta-blocker
(atenolol) on vascular function and structure in patients with Stage 1
hypertension, independent of the blood pressure lowering effects of these
agents.(1)
In the VIOS trial, olmesartan medoxomil, through early blockade of
angiotensin II, improved the structure abnormalities of resistance arteries
in patients with hypertension as measured by arterial wall to lumen ratio
(W/L), returning arterial architecture to normal levels after one year of
treatment. This protective effect was not seen with the comparator agent in
the study, atenolol.(2) Olmesartan medoxomil is marketed in the United
States by Daiichi Sankyo, Inc., as BENICAR(R). BENICAR and BENICAR HCT(R)
(olmesartan medoxomil/hydrochlorothiazide) are indicated for the treatment
of hypertension. They may be used alone or in combination with other
antihypertensive agents. BENICAR HCT is not indicated for initial therapy.
BENICAR and BENICAR HCT have not been FDA approved for other indications
such as end organ disease or other hypertension related morbidity.
"We believe the VIOS data add to the growing evidence for the role of
angiotensin receptor blockers in preventing or reversing vascular damage at
many stages during this disease process," said Carlos M. Ferrario, M.D.,
one of the study's lead investigators and Professor and Director of
Hypertension and Vascular Research Center, Wake Forest University School of
Medicine.
Angiotensin II has been linked to vascular dysfunction and end-organ
damage, including cardiac hypertrophy and renal injury.(3,4,5) Previous
studies have demonstrated a beneficial effect of ACE inhibitors or other
angiotension II receptor blockers (ARBs) in the reversal of vascular
hypertrophy in hypertensive subjects.(6,7,8,9,10,11,12)
Hypertension is one of the most prevalent conditions in the United
States, affecting one in three Americans.(13) Long-standing, uncontrolled
hypertension can damage the brain, the eyes, the heart and the kidney.(14)
Antihypertensive agents that inhibit the renin-angiotensin system, such as
angiotensin-converting enzyme inhibitors or ARBs, have demonstrated
substantially greater effects on end-organ repair in the kidney and the
heart.(15,16,17,18)
VIOS Study Design
The study was a randomized, controlled, open-label, one-year study. The
primary endpoint of this study was the change in the morphological
characteristics of resistance arteries as determined by differences in the
wall (media)/lumen (W/L) ratio. This parameter was measured using a
pressurized myograph procedure on arteriole biopsy samples obtained from a
sub-group of 49 patients receiving treatment (27 were on olmesartan and 22
were on atenolol) and from 11 normotensive control subjects.(19)
Non-diabetic patients with Stage 1 hypertension (61% male; age 38 to 67
years) were randomized after a 4-week washout period to olmesartan
medoximil 20 to 40 mg or atenolol 50 to 100 mg plus additional agents
(hydrochlorothiazide 12.5-25 mg, amlodipine 5-10 mg, or hydralazine 50-100
mg twice daily) as needed for a goal BP of < 140/90).(20) Stage 1
hypertension is defined by the JNC 7 as systolic blood pressure (SBP) of
140-159 mm Hg or diastolic blood pressure (DBP) of 90-99 mm Hg.(21)
VIOS Study Results
The arteriolar dimensions (W/L Ratios) in the olmesartan medoxomil and
atenolol-based treatment groups were similar prior to drug treatment (14.9%
and 16% respectively) whereas arteries from the normotensive subjects had
significantly smaller W/L ratios (11%). At the end of the study the W/L
ratio in the olmesartan medoxomil-based treatment group was significantly
reduced (from 14.9% to a mean of 11.1%; P