Intrapulmonary vascular dilatations (IPVD), diagnosed by transthoracic contrast-enhanced echocardiography (CEE), can be observed in 13% to 47% of individuals with liver cirrhosis. 1,2 Despite the presence of IPVD, most patients are not characterized as having hepatopulmonary syndrome (HPS), since the diagnosis of this syndrome requires the presence of abnormal arterial oxygenation (partial pressure of arterial oxygen Ο½ 70 mm Hg, or alveolar arterial oxygen gradient ΟΎ 20 mm Hg). 3,4 One of the major controversies is whether cirrhotic individuals with IPVD but without changes in arterial oxygenation are affected by HPS in the early phase and whether these alterations would appear during followup. 5 To our knowledge, there are no prospective studies of the evolution of pulmonary parameters in cirrhotic individuals with IPVD but without changes in arterial oxygenation. Would these patients fulfill HPS criteria during follow-up?
In our series 6 of 56 cirrhotic patients on a waiting list for orthotopic liver transplantation, the frequency of IPVD was 45% (25 patients). Among these patients, 16 (64%) did not fulfill the criteria for HPS, confirming the high frequency of IPVD in cirrhotic subjects without HPS. These patients were followed prospectively to assess the evolution of pulmonary parameters. Of 16 cirrhotic patients with IPVD without changes in arterial oxygenation, 12 were excluded from the study, 11 due to death (after exploratory laparotomy [1], cancer of the larynx [1], digestive hemorrhage [5], spontaneous bacterial peritonitis [2], orthotopic liver transplantation [1 sepsis and 1 hemorrhage]) and 1 because he was submitted to orthotopic liver transplantation. Mean follow-up of the excluded patients was 13.8 months (2-28 months). The complementary tests were not repeated in any of the excluded patients. Thus, the final series consisted of 4 patients with a mean follow-up of 24 months (21-30 months). All patients were submitted to contrastenhanced echocardiography and measurement of arterial blood gases at the beginning and at the end of follow-up. The results are presented in Table 1. The contrast-enhanced echocardiography remained positive in all patients. No patient presented significant changes in arterial oxygenation that would characterize him as having HPS. The present data suggest stability of the pulmonary parameters during the 2-year follow-up period.
The causes of the high mortality rate of our patients did not seem to be related to the presence of HPS, both because of the absence of pulmonary causes and because of the short period of time between the diagnosis of IPVD and death. Schenk et al. 7 demonstrated that not only the presence but also the severity of HPS are related to the survival of cirrhotic patients. It should be emphasized that our patients did not have HPS nor did they present alterations in gas exchanges. In addition, our patients with HPS 6 tend to have mild degrees of the syndrome, in contrast to the data reported by Schenk et al. 7 However, although this is unlikely, we cannot exclude the possibility of progression to HPS in the patients who died. In conclusion, the present results suggest that gas ex-change abnormalities did not develop uniformly and IPVD persisted during a mean follow-up of 24 months.