ABC | Volume 113, Nº5, November 2019

Original Article Gouveta et al. cTEE in pulmonary artery dilation in HSS Arq Bras Cardiol. 2019; 113(5):915-922 Figure 2 – Bicaval view of contrast transesophageal echocardiography. Opacification of the right atrium after injection of saline contrast, with small, scattered microbubbles (mild contrast test) in the left atrium after four cardiac cycles Distribution of clinical, laboratory and echocardiographic characteristics of patients with HSS by the presence or absence of IPVD is presented in Table 3. Age, time of treatment, body surface, and clinical and laboratory data were not different between the patients with and without IPVD. Although A-aO 2 was not different between the groups, a tendency for higher PaO 2 values, with significantly higher SatO 2 and significantly lower PaCO 2 in the subgroup of patients with and without IPVD. Considering echocardiographic results, there was a tendency for greater size of the left chambers and for greater left atrial volumes in the subgroup of patients with IPVD, compared with those without IPVD. No significant differences in left ventricular ejection fraction or pulmonary systolic pressure were found between the two subgroups. The diagnosis of HPS was confirmed in one (5%) patient according to the transthoracic echocardiographic criteria, and in five patients (including the one diagnosed by cTTE; 26%, p = 0.09). Discussion This is the first study to use cTEE for diagnosis of IPVD in HSS. Previous studies have reported the use of cTEE and cTTE for detection of IPVD in cirrhotic patients. 2,8 Comparison between these two methods for detection of IPVD in cirrhotic patients with portal hypertension was first reported by Vedrinne et al. 10 According to these authors, cTEE showed higher sensitivity in detecting intrapulmonary shunt compared with the cTTE and is thereby indicated for all patients with suspected IPVD that was not detected by cTTE. In a similar study, Fischer et al. 11 also found that cTEE was able to quantify and classify the appearance of microbubbles in the left chambers in different grades (minimal to significant), and observed a direct relationship between the level of contrast appearance and pulmonary gas exchange abnormalities. 11 These studies showed that the use of cTEE was advantageous, since the quality of transthoracic images may make it difficult to visualize the contrast with microbubbles, which is compensated by the transesophageal window. The presence of intracardiac shunt, originated from a PFO, can be also well identified by cTEE. 9,19,20 PFO was present in three of the patients excluded from our series after the cTEE and may have been the cause of the passage of contrast to the left chambers and of eventual overestimation of the frequency of IPVD. This shows the superiority of the transesophageal method in the diagnosis of this condition. The main finding of the present study on HSS patients and relatively preserved liver function was the occurrence of subclinical IPVD and unaltered gas exchange, detected by cTEE in a significantly higher frequency compared with cTTE. In our HSS patients, cTEE was able to detect slight pulmonary vascular changes compatible with initial stages of the disease. The presence of IPVD in HSS had been previously described in our setting by Ferreira et al. 4 in similar proportion to that observed in our series, but using the transthoracic method only. In our study, the cTEE enabled the detection of IPVD in additional nine patients that had not been diagnosed with the disease by cTTE, which highlights the role of the transesophageal technique in the indirect characterization of this vascular alteration. Therefore, in agreement with previous findings in cirrhotic patients, cTEE in HSS patients was more sensitive as compared with the cTTE for the diagnosis of IPVD, corroborating its superiority in this sense in HSS. In cirrhotic patients with portal hypertension, the prevalence of IPVD was considerably higher according to cTEE than cTTE, 51-75% and 13-47%, respectively. 10-12,21 In our study, some of the individuals of the control group showed a mild (grade I) contrast enhancement, probably due to a physiological pulmonary shunt, which facilitates the passage of small contrast microbubbles, capable of passing the pulmonary capillary barrier and reach the chambers. For this reason, grades ≥ II were considered positive for IPVD. 918