Methods
136 patients over the age of 18, who admitted to Akdeniz University Hospital Cardiology Department between March 2017 and March 2018 and were scheduled to undergo right heart catheterization(RHC) for any reason were included the study. Patients with congenital heart disease, who had undergone surgery due to congenital heart disease in childhood, whose echocardiographic evaluations could not be made due to poor echogenicity and patients with missing RHC data were excluded from the study.
Each individual included in the study was informed about the study and a written consent form was read and signed. The study protocol was approved by the local ethics committee and was performed in accordance with the Declaration of Helsinki.
RAP, RV end-diastolic pressure, RV systolic pressure, PA pressures (systolic, mean, diastolic) and pulmonary capillary wedge pressure (PCWP) were measured by RHC. Measurements were evaluated at the end of expiration.
Echocardiographic examinations of the patients were performed by an experienced specialist at the Echocardiography Laboratory of the Akdeniz University Cardiology Department. The patients were placed in the left lateral decubitus position. Echocardiographic evaluations were performed in the presence of electrocardiographic rhythm monitoring. Standard two-dimensional echocardiography, M-mode echocardiography and doppler examinations were performed through apical, parasternal and subcostal windows in accordance with the recommendations of the American Echocardiography Society. Parameters were taken in accordance with these guideline recommendations and relevant measurements were calculated according to these guideline recommendations (10). The CS diameter was visualized in the posterior region between LA and LV, with a slight posterior tilting of the probe at the level of the mitral annulus in apical 4-chamber window. Maximum and minimum diameter of CS was measured by M-Mode echocardiography method (Figure-1). CS collapse index (CSCI) was calculated by the following formula:
= % [(CSDmax – CSDmin)] / CSDmax x 100 CSDmax: Maximum CS diameter, CSDmin: minimum CS diameter
IVC measurements were made through a standard subcostal echocardiographic window. The intrahepatic region where IVC joins to the RA was visualized. After expiration, IVC’ s maximum diameter, minimum diameter and respiratory change were measured 1-2 cm near the point where the IVC joins the RA. IVC collapse index (IVCCI) was calculated by the following formula:
= % [(IVCDmax – IVCDmin)] / IVCDmax x 100
IVCDmax: Maximum IVC diameter, IVCDmin: minimum IVC diameter
Body surface areas (BSA) of the patients were calculated and CS and IVC parameters were also analyzed by indexing with BSA.
Descriptive statistics are presented with mean, percentage and standard deviation values. Fisher’s Exact Test or Pearson’s chi-square test was used in the analysis of the relationships between categorical variables. In the analysis of the difference between the measurement values of the two groups, Mann-Whitney U test was used when the distribution of the data did not comply with the normal distribution and Student’s t test was used if it did. Spearman correlation test was used for continuous variables not conforming to ordered or normal distribution and Pearson correlation test was used for continuous variables that conforming to normal distribution. p values less than 0.05 were considered statistically significant. In order to estimate the increase in RAP measured by catheterization, ”Receiver-Operating Characteristic (ROC)” curves were created for each IVC and CS parameter and optimal cut-off values were determined from them. In addition, sensitivity, specificity, positive and negative predictive values were found for the increased RAP value. Study data were analyzed in ”MedCalc” and ”SPSS 25.0 for Windows” programs.