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.