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SA JOURNAL OF DIABETES & VASCULAR DISEASE
RESEARCH ARTICLE
VOLUME 15 NUMBER 2 • NOVEMBER 2018
65
calculated automatically by the echocardiography machine from
M-mode-derived LV dimensions, using Teicholz’s formula:
LVEDV or LVESV = 7.0 × LVID
3
2.4 + LVID
Ejection fraction (EF) was calculated using the formula:
EF = EDV – ESV
EDV
× 100
The LV systolic function was considered normal if the EF was
greater than 50% and/or FS was greater than 25%.
14
The LV
diastolic function was assessed using Doppler modalities. Early
(E) and atrial (A) velocities as well as deceleration time (DT) were
measured using pulsed-wave Doppler by placing the sample
volume at the tips of the mitral leaflets in apical four-chamber view.
Isovolumic relaxation time (IVRT) was measured as the time interval
from the end of LV outflow and start of LV inflow, as indicated by
simultaneous registration of outflow and inflow signals by high-
frequency pulsed-wave Doppler.
Pulmonary venous flow (PVF), systolic (S), diastolic (D) and atrial
reversal (Ar) velocities were obtained by placing a pulsedwave
Doppler sample volume 1–2 cm into the pulmonary vein, proximal
to its insertion into the left atrium. E/A and S/D were calculated.
Diastolic function (DF) was categorised into grades according to
its progression to diastolic dysfunction (DD):
• normal DF: E/A between 1 and 2, IVRT 60–100 ms and DT 160–
240 ms
• grade 1 DD: E/A < 1, IVRT > 100 ms, DT > 240 ms
• grade 2 DD: E/A 1– 2, IVRT 60–100 ms, DT 150–220 ms, PVFS/D
< 1
• grade 3 DD: E/A > 2, IVRT < 60 ms, DT < 160 ms.15 where
DT is deceleration time and PVFS is pulmonary venous flow S
velocity.
Pulmonary artery systolic pressure (PASP) was estimated from
peak tricuspid regurgitant flow using continuous-wave Doppler.
Tissue Doppler echocardiography was not used because, at the
time the study was conducted, the echo machine used did not have
the facility.
Statistical analysis
Data obtained were analysed using STATA 10. Continous variables
are expressed as mean (± standard deviation) and categorical
variables as percentages. Categorical variables were analysed
using the chi-squared test. Student’s
t
-test and analysis of variance
(ANOVA) were used to analyse continuous variables. Correlates of
LV function were determined using Pearson’s rank correlation and
predictors were assessed using logistic regressions. A
p
-value ≤
0.05 was considered statistically significant.
Results
One hundred and ninety-three participants comprising 63 T2DM
patients with normoalbuminuria, 71 T2DM with microalbuminuria
and 59 controls were studied. The mean age for all participants
was 50 years and the three groups were age and gender matched.
Table 1 shows the clinical characteristics of the three study groups.
The duration since diagnosis of DM was significantly longer in the
microalbuminuric than in the normoalbuminuric diabetics (
p
=
0.02). WC, SBP and PR showed a significant stepwise increase from
control to microalbuminuric group (
p
< 0.001,
p
= 0.03,
p
= 0.03,
respectively). Weight, BMI, WHR, DBP and PP were comparable
among the three groups.
on oral antidiabetic drugs, and 59 non-diabetic age- and gender-
matched controls completed the study.
Exclusion criteria were hypertension (blood pressure ≥ 140/90
mmHg or use of antihypertensive drugs), age above 65 years,
macroalbuminuria, serum creatinine of ≥ 1.5 mg/dl, chest deformity
or long-standing chest disease evidenced on chest X-ray, sickle
cell disease, urinary tract infection, pregnancy, cardiac conditions
such as arrhythmia, heart failure, valvular heart disease, pericardial
disease, congenital heart disease, and ischaemic heart disease as
evidenced by clinical,electrocardiographic and echocardiographic
features.
Age, gender and duration of diabetes were recorded for each
subject. Weight was determined in kilograms (kg) using a weighing
scale, height using a stadiometer, and waist and hip circumferences
(WC and HC) were measured in centimetres (cm) using a tape
measure. Body mass index (BMI), body surface area (BSA) and
waist:hip ratio (WHR) were calculated.
Blood pressure was measured using an Accosson mercury
sphygmomanometer with appropriate sized cuff at the brachial
artery, Korotkoff phase 1 was used for systolic (SBP) and phase
5 for diastolic blood pressure (DBP) after at least 15 minutes of
rest in a sitting position. Pulse rate (PR) was measured at the radial
artery. The mean of three consecutive measurements, taken at five-
minute intervals, was recorded. An overnight fasting venous blood
sample was collected for measurement of levels of plasma glucose,
creatinine and urea, and lipid profile using standard protocols.
A two-step microalbuminuria screening process was conducted.
Combur 10 test strip (Roche Diagnostics, Mannheim, Germany), a
visual colorimetric semi-quantitative urine test strip, was used to
test for protein, blood, nitrite and leucocyte levels. If all were absent
then detection of microalbuminuria was performed on the same
urine sample.
Microalbuminuria was determined using Micral test strips, an
optically read semi-quantitative immunoassay method (Roche
Diagnostics, Australia) with a sensitivity and specificity of 80 and
88%, respectively.
11
There are four colour blocks on the test strip
corresponding to negative (or 0), 20, 50 and 100 mg/l of albumin.
The test was done on two occasions; the first was random urine
samples (RUS) and the second was first morning void (FMV) urine
samples of the subjects.
Microalbuminuria was considered to be present when the two
urine samples produced a reaction colour corresponding to 20 mg/l
or more. The result from the FMV urine sample was recorded as
the MCA status of the subject. It has been suggested that MCA
detected in the FMV urine sample corresponds better with 24-hour
urinary albumin excretion (UAE) than microalbuminuria measured in
a RUS, because it is less influenced by physical exercise and diet.
12
Echocardiographic examination was performed with the patient
in the left lateral decubitus position using a Hewlett- Packard Sonos
4500 echocardiography machine with a 3.5-MHz transducer.
Measurements were taken under two-dimensional guided M-mode,
as recommended by the American Society of Echocardiography
(ASE).
13
Endocardialfractionalshortening(FS)wascalculatedautomatically
by the echocardiography machine using the formula:
14
FS = LVIDd – LVIDs
LVIDd
× 100
where LVIDd is left ventricular internal dimension in diastole and and
LVIDs is left ventricular internal dimension in systole Left ventricular
end-diastolic and end-systolic volumes (LVEDV and LVESV) were