Pulmonary hypertension and elevated right atrial(RA) pressure cause dilation of the coronary sinus(CS), which is well-visualized on 2D echocardiography. Congenitally persistent connection of the left superior vena cava(LSVC) to the CS occurs in ∼0.3% of the population, and causes dilation of the CS. This study evaluates the usefulness of coronary sinus cross-sectional area(CSCSA) and eccentricity index(EI) in differentiating RA pressure overload from persistent left SVC in patients with dilated CS.
We prospectively identified 13 patients with a dilated CS on echo over one year. Off-line analysis was used to measure (1) CSCSA at end-diastole in the parasternal long axis plane, and (2) CS eccentricity index (CSEI) in the same plane. This was defined as B/A, where A is the widest diameter and major axis of the CS, and B is the diameter of the minor axis (perpendicular to and bisecting A at its midpoint). Group 1(7 pts) had dilated CS with documented RA pressure overload. Group 2 (6 pts) had persistent LSVC, confirmed by either computed tomography or injection of agitated saline in the left antecubital vein. Tricuspid regurgitation(TR) velocities and IVC diameters were measured in all patients.
Tricuspid regurgitation (TR) velocity in Group 1 was 4.0 ± 0.7m/s, compared to 2.7 ± 0.6 in Group 2 (p = 0.02). IVC diameters were 2.5 ± 0.9 cm in Group 1 and 1.8 ± 0.3 cm in Group 2 (p = 0.3). CSCSA was significantly smaller in Group 1 (1.8 ± 1.9 cm2) than in Group 2 (5.0 ± 2.8 cm2, p = 0.045). Also, CSEI was higher in Group 1 than in Group 2 (0.9 ± 0.03 vs. 0.6 ± 0.1, p = 0.001). Between these 2 latter parameters, CSEI was more accurate in discriminating patients with elevated RA pressure vs. persistent LSVC: CSEI was > 0.8 in all Group 1 pts and < 0.8 in all Group 2 pts (sensitivity and specificity=100%).
CSCSA and EI vary in patients with dilated CS. Patients with persistent LSVC have a significantly higher CS CSA than those with elevated RA pressure.
Coronary sinus cross-sectional area and eccentricity index can be effectively used to differentiate right atrial pressure overload from congenitally persistent LSVC.
Brian Kolski, No Financial Disclosure Information; No Product/Research Disclosure Information