Background/aims: The use of transesophageal contrast echocardiography (TOCE) in the diagnosis of intrapulmonary vascular dilatation (IVD) and hepatopulmonary syndrome (HPS) needs to be studied. We tested the specificity of TOCE using traditional criteria and the value of a new method based on TOCE, a grading scale and a selected contrast.
Methods: 1) Several solutions were tested and two were selected: 20% mannitol and 0.9% saline. 2) 71 cirrhotic patients and 20 controls were studied. Left atrium opacification with contrast was classified into 6 degrees by TOCE. Mild and significant IVD were considered in relation to results in controls. Patients were studied with saline and mannitol-TOCE. Results were compared to transthoracic contrast echocardiography (TTCE), to gas exchange abnormalities and to Child class.
Results: The reproducibility of TOCE grading was excellent, (Kappa >0.9). IVD detection using TTCE, mannitol-TOCE and saline-TOCE was 29.5%, 55% (25% mild and 30% significant), and 45% (38% mild and 7% significant), respectively. The best agreement with TTCE (reference method) was obtained with mannitol-TOCE, using significant IVD as the cut point. By this criterion, 18% reached the criteria of HPS using TTCE and 22% using mannitol-TOCE. Patients with IVD by TTCE had non-significant changes in gas exchange determinations. Patients with significant IVD by saline TOCE had lower mean PaO2 levels (67.3+/-14 vs. 79.5+/-11 mm Hg, p<0.05) than patients without IVD. Patients with significant IVD by mannitol TOCE had higher mean AaPO2 (29.3+/-14 vs. 19.7+/-9 mm Hg; p<0.005) and lower mean PaCO2 levels (30.1+/-4.4 vs. 33.4+/-4.8 mm Hg; p<0.05) than patients without IVD. Severity of IVD by TOCE correlated to Child class (r = 0.43; p<0.001).
Conclusions: The presence of contrast in the left atrium cannot be a criterion of IVD when TOCE is used. Our semi-quantitative scale has proved to be feasible and reproducible, presenting a good agreement with TTCE, and has shown better correlation with gas exchange abnormalities and Child class. Saline TOCE appears to be more specific in the detection of hypoxemic patients with IVD, but mannitol TOCE adds sensitivity.