Cardiovascular Journal of Africa: Vol 28 No 1 (January/February 2016)

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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 28, No 1, January/February 2017 14 AFRICA
Non-dipper hypertension is associated with slow coronary
flow among hypertensives with normal coronary angiogram
Ercan Aksit, Erdal Gursul, Fatih Aydin, Murat Samsa, Fatih Ozcelik
Abstract
Aim: A person with a drop of more than 10% in nocturnal
arterial blood pressure during the circadian rhythm is referred
to as a dipper and one with a smaller decrease is referred
to as a non-dipper. In our study, we aimed to compare the
thrombolysis in myocardial infarction (TIMI) frame count in
non-dipper and dipper hypertensive patient groups who had
normal coronary artery angiography.
Methods: Patients with normal coronary arteries and with
ambulatory blood pressure monitoring follow ups were retro-
spectively investigated and 60 patients (35%, female) were
included in our study. The patients were grouped as dipper (n
= 30) and non-dipper (n = 30) hypertensives.
Results: The TIMI frame counts in all three coronary arteries
and the mean TIMI frame count in the dipper hypertensive
patient group were significantly lower than those of the
non-dipper hypertensives (right coronary artery TIMI frame
count: 16.83 ± 3.70; 21.63 ± 3.44, p < 0.001; circumflex artery
TIMI frame count: 21.28 ± 3.52; 25.65 ± 3.61, p < 0.001; left
anterior descending artery TIMI frame count: 34.20 ± 2.80;
37.05 ± 3.30, p = 0.001; corrected left anterior descending
artery TIMI frame count: 20.05 ± 1.63; 21.74 ± 1.95, p =
0.001; mean TIMI frame count: 19.31 ± 2.3; 22.94 ± 2.61, p
< 0.001). The body mass index (BMI) was 23.79 ± 2.81 kg/m2
in the dipper patient group, while it was 25.47 ± 2.92 in the
non-dippers. BMI was found to be significantly higher in the
non-dipper group than in the dipper group (p = 0.027).
Conclusion: In this study, TIMI frame count, which is a
simple, productive, objective and reproducible method for
determination of microvascular changes, was found to be
higher in non-dipper hypertensive patients than in the dipper
patients.
Keywords: hypertension, coronary angiography, TIMI frame
count, dipper, non-dipper
Submitted 20/10/15, accepted 3/4/16
Published online 13/5/16
Cardiovasc J Afr 2017; 28: 14–18
DOI: 10.5830/CVJA-2016-045
Hypertension is a significant risk factor for stroke, myocardial
infarction, renal diseases and other vascular disorders. Treatment
of high blood pressure may lower the incidence of complications
and enable a longer life. Cardiovacular parameters such as blood
pressure, heart rate and coronary tonus change with the daily
circadian rhythm. 1
Development of ambulatory blood pressure-monitoring
(ABPM) has provided an understanding of diurnal blood
pressure variations.2 According to ABPM data obtained from
healthy subjects, blood pressure reaches its highest levels in the
morning, decreases slowly during the day and maintains lowest
levels during the night.3 This circadian rhythm in blood pressure
has led to a novel classification. In this ABPM-dependent
classificiation, if nocturnal blood pressure decreases more than
10% of the day-time levels, it is called dipper hypertension
and if the drop is less than 10%, it is considered non-dipper
hypertension.4
The mechanism of diurnal blood pressure variation disorders
is not clear. At night, the balance in the autonomous nervous
system probably shifts towards the sympathetic nervous system.5
If the blood pressure decrease is less than 10 to 20% during
sleep, it is connected with target-organ damage. Particularly
in non-dipper hypertensive patients, it is common to see left
ventricular hypertrophy, congestive heart failure, myocardial
infarction, stroke and renal failure (albuminuria and end-stage
renal failure).6,7
The thrombolysis in myocardial infarction (TIMI) frame
count is the sum of the ciné-angiographic squares obtained, after
infusing opaque substance into the coronaries, from the time
when the dye is seen at the level of the coronary artery ostium
to when it reaches the distal part. The TIMI frame count, which
is a simple, objective and reproducible method, is a quantitative
predictor of coronary flow rate. A high TIMI frame count is a
predictor of slow coronary flow and endothelial dysfunction.8
The aim of this study was to compare the TIMI frame count
in dipper and non-dipper hypertensive patients with normal
coronary artery angiography (CAG).
Methods
This retrospective, single-centre study was performed in a
tertiary healthcare centre. The study data were obtained between
15 February 2010 and 15 February 2012 from hypertensive
patients aged between 18 and 80 years who had normal CAG
and who had arterial blood pressure follow up with ABPM.
Department of Cardiology, Biga State Hospital, Canakkale,
Turkey
Ercan Aksit, MD
Erdal Gursul, MD,
Department of Cardiology, Kocaeli State Hospital, Kocaeli,
Turkey
Fatih Aydin, MD
Department of Cardiology, Selcuk State Hospital, Izmir,
Turkey
Murat Samsa, MD
Department of Cardiology, Trakya University Hospital,
Edirne, Turkey
Fatih Ozcelik, MD