CARDIOVASCULAR JOURNAL OF AFRICA • Vol 24, No 7, August 2013
AFRICA
255
Does vitamin C or its combination with vitamin E improve
radial artery endothelium-dependent vasodilatation in
patients awaiting coronary artery bypass surgery?
ALPER UZUN, UMIT YENER, OMER FARUK CICEK, OZLEM YENER, ADNAN YALCINKAYA, ADEM DIKEN,
TURGUT OZKAN, AYSEL TURKVATAN, MAHMUT ULAS
Abstract
Background:
We evaluated the vasodilatory effects of two
antioxidants, vitamins C (ascorbic acid) and E (
α
-tocopherol),
on radial artery and endothelium-dependent responses in
patients awaiting coronary artery bypass surgery.
Methods:
The study was performed in three groups. The
first group took 2 g of vitamin C orally (
n
=
31, vitamin C
group), the second group took 2 g of vitamin C with 600 mg
of vitamin E orally (
n
=
31, vitamins C
+
E group), and the
third group took no medication (
n
=
31, control group). After
baseline measurements were taken of the radial artery lumen
diameter, flow volume and lumen area in the non-dominant
radial artery, occlusion was maintained for five minutes with
a pressure cuff placed around the arm. The measurements
were taken again at the time of deflating the cuff, and 60
seconds later. The measurements were repeated after medica-
tion in two of the groups and after placebo in the third group.
Results:
We compared values of the vitamin C group with
those of the vitamins C
+
E group, and found that the latter
were higher than those of the vitamin C group but not statis-
tically significant. In the control group, there was no statisti-
cal difference.
Conclusion:
Vitamin C or its combination with vitamin E
significantly enhanced endothelium-dependent vasodilata-
tion in the radial circulation of patients with coronary artery
disease. Its combination with vitamin E was superior to vita-
min C administration alone for endothelial enhancement but
this difference was not statistically significant. We hypoth-
esised that vitamin C or its combination with vitamin E may
be used as antioxidants for arterial graft patency in patients
undergoing coronary artery surgery.
Keywords:
antioxidants, vitamin C, vitamin E, atherosclerosis
Submitted 14/4/13, accepted 7/6/13
Cardiovasc J Afr
2013;
24
: 255–259
DOI: 10.5830/CVJA-2013-046
In patients with atherosclerosis, there is biochemical evidence to
suggest increased oxidative stress, which results from an altered
balance of endogenous pro- and antioxidants.Vitamin C, the main
water-soluble antioxidant in human plasma, has been shown to
reverse endothelial dysfunction in patients with ischaemic heart
disease in the same way as vitamin E.
1
It effectively scavenges
superoxide and other reactive oxygen species, and plays an
important role in regulation of the intracellular redox state
through its interaction with glutathione.
2
The Health Professionals Follow-up study demonstrated an
inverse relationship between vitamin E intake and coronary
artery disease (CAD) events.
3
In this study, risk for CAD events
in subjects in the highest quintile of vitamin E intake (median
419.0 IU/day) was significantly reduced by 41%, compared with
the subjects in the lowest quintile of vitamin E intake (median
6.4 IU/day).
3,4
Other studies suggest that a high dietary intake of flavonoids
(polyphenolic antioxidants) naturally present in vegetables,
fruits, tea and vitamin E is associated with a decline in
CAD events.
5
Nonetheless, in a subgroup analysis of patients
who had undergone previous coronary artery bypass surgery,
coronary artery lesion progression was less in subjects with
a supplementary vitamin E intake of 100 IU per day or more,
compared with patients with a lower intake.
6
Therefore, we hypothesised that vitamin C and E would
improve abnormal endothelium-dependent vasomotor function
in patients with atherosclerosis. We tested this hypothesis by
examining endothelium-dependent, flow-mediated radial artery
dilatation before and two hours after oral administration of
vitamin C or vitamin C plus vitamin E in two groups of patients
awaiting coronary artery bypass surgery, compared with the
control group.
Methods
A total of 93 patients were randomly divided into three groups:
group 1, vitamin C group,
n
=
31; group 2, vitamins C
+
E group,
n
=
31; group 3, control group,
n
=
31. Patients referred to our
clinic were screened for enrolment, and patients with significant
coronary artery disease were eligible for the study. In all
patients, the presence of coronary artery disease was confirmed
angiographically (at least one coronary stenosis
>
70%).
All patients gave informed consent. The study was conducted
in accordance with the policies and procedures of the Education
Department of Cardiovascular Surgery, Ankara Education
and Research Hospital, Ankara, Turkey
ALPER UZUN, MD
Department of Cardiovascular Surgery, Turkey Yuksek
Ihtisas Education and Research Hospital, Ankara, Turkey
UMIT YENER, MD
OMER FARUK CICEK, MD,
ADNAN YALCINKAYA, MD
ADEM DIKEN, MD
TURGUT OZKAN, MD
MAHMUT ULAS, MD
Department of Radiology, Turkey Yuksek Ihtisas Education
and Research Hospital, Ankara, Turkey
OZLEM YENER, MD
AYSEL TURKVATAN, MD
