Echocardiography, 2-D Clinical Trial
Official title:
Feasibility of Speckle Tracking Echocardiography for Estimation of Left Ventricular Filling Pressures in Cardiac Surgery Patients: a Transoesophageal Study
Determining the LV filling pressure is a key element in the diagnosis and management of
patients with suspected decompensated heart failure. The aim of the present study is to
assess whether a systolic 2D-STEderived parameter, global longitudinal peak systolic strain
(GLPSS), acquired by transoesophageal echocardiography (TEE) is superior to the E/Ea ratio in
the estimation of the LVFP measured as the pulmonary capillary wedge pressure (PCWP) in
patients during cardiac surgery. Automated function image (AFI) algorithm is a novel method
based on 2D strain imaging that enables the simultaneous quantification of myocardial strain
in different left ventricular segments; its 3-click method minimizes variability related to a
manual training of endocardial border required in an usual 2D-strain analysis.
AFI provides GLPSS by averaging mid-oesophageal 4-, 2- chamber and long axis views. The study
is a prospective observational single-center cohort study. 30 Patients scheduled for elective
cardiac surgery will be included in the study group. The study is designed to assess whether
GLPSS measured during cardiac surgery using AFI is superior to E/Ea ratio in estimation of
LVFP measured as PCWP.
For normal cardiac performance, the left ventricle (LV) must be able to eject an adequate
stroke volume at arterial pressure (systolic function) and fill without requiring an elevated
left atrial (LA) pressure (diastolic function). These systolic and diastolic functions must
be adequate to meet the needs of the body. Systolic function is conveniently (although not
always accurately) measured as the ejection fraction (EF), calculated as stroke volume
divided by end-diastolic volume. Diastolic function has been more difficult to evaluate and
is characterized by changed left ventricular (LV) filling dynamics. The mean LA pressure is
the source pressure for LV filling. Determining the LV filling pressure is a key element in
the diagnosis and management of patients with suspected decompensated heart failure.
Measurement of the pulmonary capillary wedge pressure (PCWP) with the Swan-Ganz catheter has
become the gold standard for determining LV filling pressure. Invasively measured pulmonary
capillary wedge pressure (PCWP) has been widely used as a surrogate for left ventricular
filling pressure (LVFP) and is directly associated with functional capacity and prognosis in
patients with heart failure. On the other hand, invasive procedures can produce
complications, especially in critically ill patients and randomized clinical studies found no
benefit from the use of the Swan-Ganz catheter to manage critically ill patients. Thus,
efforts to find a noninvasive method of determining LV filling pressure have continued. One
of the basic non-invasive parameters which reflect the LVFP is the ratio of peak early
diastolic transmitral flow velocity (E) to peak early diastolic velocity of mitral annular
motion (Ea) derived from conventional pulsed-wave and Doppler tissue echocardiography. The
E/Ea ratio has been found to be superior to individual Doppler tissue imaging (DTI)
parameters and to conventional pulsed-wave Doppler parameters assessing LV filling or
pulmonary venous flow both in predicting the increase in LVFP and assessing of patient
prognosis. However, DTI has inherent limitations which may have a negative impact on the
accuracy of Ea measurements. Specifically, DTI is angle-dependent, and is affected by
tethering, myocardial translation, and respiration motions. Recently, 2-dimensional speckle
tracking echocardiography (2DSTE) has been introduced for the measurement of systolic and
diastolic strain and strain rates (SRs) which does not have the above-mentioned limitations.
Since most echocardiographic studies evaluating LVFP were performed with transthoracic
echocardiography (TTE) in a cardiological setting and primarily diastolic 2D-STE parameters
were described, the aim of the present study is to assess whether a systolic 2D-STEderived
parameter, global longitudinal peak systolic strain (GLPSS), acquired by transoesophageal
echocardiography (TEE) is superior to the E/Ea ratio in the estimation of the LVFP measured
as the pulmonary capillary wedge pressure (PCWP) in patients during cardiac surgery.
Automated function image (AFI) algorithm is a novel method based on 2D strain imaging that
enables the simultaneous quantification of myocardial strain in different left ventricular
segments; its 3-click method minimizes variability related to a manual training of
endocardial border required in an usual 2D-strain analysis.
AFI provides GLPSS by averaging mid-oesophageal 4-, 2- chamber and long axis views. The study
is a prospective observational single-center cohort study. Patients scheduled for elective
cardiac surgery will be included in the study group. Written informed consent will be
obtained from all patients before surgery. 30 consecutive patients scheduled for elective
cardiac surgery who do not meet the exclusion criteria. The study is designed to assess
whether GLPSS measured during cardiac surgery using AFI in 45 consecutive patients is
superior to E/Ea ratio in estimation of LVFP measured as PCWP.
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