Dilation of the coronary sinus on echocardiogram: prevalence and significance in patients with chronic pulmonary hypertension.

BACKGROUND Although rarely seen in healthy patients, the coronary sinus (CS) is often visualized on echocardiography in patients with right-sided heart disease. However, the prevalence of this finding and its relation to right-sided heart structure and pressure remains undefined. METHODS We examined the transthoracic echocardiograms of 43 consecutive patients referred for the evaluation of pulmonary hypertension (26 men, 17 women) with a mean age of 53 +/- 15 years (range 21 to 82 years). Structural abnormalities of the tricuspid valve were absent. All patients underwent right heart catheterization within 48 hours of their echocardiogram, which revealed the following pressures: mean pulmonary artery (50 mm Hg, range 31 to 84 mm Hg) and right atrial (RA) (mean 10, range 1 to 24 mm Hg). Echocardiograms were analyzed for CS size (identified as the smallest diameter of a circular structure in the left atrioventricular groove in the parasternal long-axis view), as well as RA and right ventricular (RV) sizes. The presence and severity (grades 1 through 3) of tricuspid regurgitation (TR) were also recorded. RESULTS The CS was visualized in 35 (81%) of 43 patients, and measurements ranged from 0.4 to 1.6 cm (mean 0.8 cm). No difference in RA size, RV size, TR grade, RA pressure (RAP), RV pressure (RVP), mean pulmonary artery pressure (PAP), or pulmonary vascular resistance (PVR) was observed between patients with a visualized and nonvisualized CS. Coronary sinus size correlated significantly with RA size (r = 0.60, P <.001) and pressure (r = 0.59, P <.001), but not with RV size, degree of TR, RVP, PAP, or PVR. Nineteen of 35 patients with a visualized CS underwent pulmonary artery thromboendarterectomy (PTE), and their CS size and RAP were unchanged (0.8 cm and 12 mm Hg, respectively, preand post-PTE; both P = NS [not significant]), though a decrease was observed in other measurements: RA size (4.2 versus 4.8 cm, P =.02), RV size (4.2 versus 5.1 cm, P =.0004), mean PAP (37 versus 72 mm Hg, P <.0001), and PVR (230 versus 899 mm Hg, P <.0001). CONCLUSIONS Coronary sinus dilation was observed in 81% of a selected group of patients with pulmonary hypertension in the absence of structural disease of the tricuspid valve. Coronary sinus dilation is related to RAP and RA size, but not to RV size, degree of TR, RVP, PA pressure, or PVR. Once dilated, CS size does not change shortly after decreases of RA size, RV size, or PA pressure produced by PTE.