Introduction
Pulmonary hypertension (PHT) is a disease characterized by complex
proliferation and progressive pulmonary vascular remodeling in the
pulmonary vascular endothelium (1). With use of transthoracic
echocardiography(TTE), it has become possible to estimate pulmonary
artery pressure(PAP) by a noninvasive method. According to Bernoulli
Equation, systolic PAP is obtained by adding estimated right atrial
pressure (RAP) to the multiply of square of tricuspid regurgitation(TR)
flow rate by four (2). When the estimated RAP is added to the
transtricuspid gradient, calculated using the maximum jet of TR, the
calculated values are very close to the values of right ventricular(RV)
systolic pressure measured by right heart catheterization(RHC) (3).
Estimated RAP is determined by TTE based on inferior vena cava (IVC)
diameter and collapse.
Normal value of RAP is 1-7 mmHg (4). RAP is most commonly estimated
according to IVC diameter and inspiratory collapse (5). As RAP
increases, this increase is transmitted to IVC, resulting in IVC
dilatation and reduction of inspiratory collapse. With the combination
of these two parameters, we can predict RAP in most patients.
Both IVC and coronary sinus(CS) open directly into the right atrium(RA).
CS is a tubular structure that draws a route in the atrioventricular
groove located at the posterior of the heart and where large cardiac
veins are poured. The diameter of the ostium varies between 4-5 mm and
9-15 mm(6). Echocardiographically, CS is best evaluated in apical
four-chamber imaging (7).
There are some studies evaluating the relationship of RAP, estimated by
non-invasive methods and systolic PAP with CS(8,9). However, there is no
study comparing invasively measured RAP with CS diameter and collapse
and evaluating the utility of CS in noninvasive RAP estimation. The aim
of our study is to evaluate the utility of CS diameter and collapse,
which is a noninvasive method, for estimating RAP. In this way, new
echocardiographic parameters will be defined for estimating RAP and PAP
value will be determined more accurately and easily.