Methods
This study included a total of 170 cross-sectionally chosen CKD patients
older than 18 years belonging to our clinic between September 2016 to
July 2017. The definition and the diagnostic criteria for chronic kidney
disease were proposed in the K/DOQI guidelines: estimated glomerular
filtration rate (GFR ml/min/1.73 m2) calculated by the
MDRD formula (18). Patients were divided into five groups according to
their GFR values (Stage-I=76 (GFR>90), Stage-II=39
(GFR=60-89), Stage-III=25 (GFR=30-59), Stage-IV=15 (GFR=15-29),
Stage-V=15 (GFR<15)). Patients with the following conditions
were excluded from the study: uncontrolled hypertension, left
ventricular systolic dysfunction, valvular pathology, any effusion,
aortic aneurysms, acute coronary syndromes, chronic lung disease,
hepatic dysfunction, known malignancy, systemic infection or
inflammatory disorders, and dialysis application. Informed consent was
obtained from all patients before the study. This study was performed
according to the principles stated in the Declaration of Helsinki and
was approved by the local ethics committee of the Van Training and
Research Hospital.
Physical examinations, including anthropometric measurements, history,
and basic laboratory tests, were performed. After an overnight fast of
at least 8 hours, blood samples were taken from the antecubital vein
with an atraumatic puncture and sent to the laboratory for analysis.
Routine electrocardiography (ECG) was recorded in each patient. Each
patient underwent complete transthoracic echocardiography following the
American Society of Echocardiography guidelines. The transthoracic
echocardiography was performed at rest, with the patient in the left
lateral decubitus position, using an echocardiographic device (Vivid S6,
General Electric, Horton, Norway) with a 3.0-MHz transducer. Two
experienced cardiologists blinded to clinical data performed the
echocardiography. Echocardiographic images were also recorded, and
offline measurements were performed.
Color M-mode Doppler recordings were obtained from the suprasternal
window in the supine position. The cursor was placed parallel to the
main direction of flow in the descending aorta. The Nyquist limit was
adapted to 30–50 cm/s, switching to the M-mode with a recorder sweep
rate of 200 mm/s. If the slope of the flame was unclear, baseline
shifting was used to change the aliasing velocity until a clear
delineation of the velocity slope was obtained (Figure 1). AVP was then
calculated by dividing the distance between the points corresponding to
the beginning and end of the propagation slope by the duration between
the corresponding time points. Thus, AVP corresponds to the velocity at
which the flow is propagating down the artery. The mean of at least three
measurements was recorded as the AVP.
The EFT was measured on the free wall of the right ventricle from the
parasternal long-axis view, using the aortic annulus as an anatomic
reference. The thickness of the free right ventricular wall was measured
at the end-systolic period. When space was found without an echogenic
view between visceral pericardium and myocardium, it was estimated as
epicardial fat. To measure EFT, the thickest area was chosen to measure,
preferably the right supraventricular area (Figure 2). The average value
of the three cardiac cycles was noted.
Carotid arteries were evaluated using a Logiq 7 (General Electronic,
Waukesha, WI, USA) with a 7.5-MHz transducer. All examinations were
performed by two experienced radiologists who were blinded to the
patients’ clinical information. Measurements were performed for the
right and left carotid arteries and involved primary transverse and
longitudinal scanning of the common carotid artery, bifurcation, and
internal carotid. The patient was lying in a supine position with their
head directed away from the side of interest and neck slightly extended.
The CIMT was measured on the far wall, 1 cm from the bifurcation of the
common carotid artery, as the distance between the lumen intima
interface and the media-adventitia interface. The CIMT was measured from
the frozen frame of a suitable longitudinal image. At least three
measurements were performed on both sides, and the average measurement
was taken as the CIMT. All measurements were made at a plaque-free site.