Evaluation of intrapulmonary vascular dilatation in hepatosplenic schistosomiasis patients by lung perfusion scan

Objectives The hepatopulmonary syndrome is defined as a triad, represented by intrapulmonary vascular dilatation (IPVD) associated with an alveolar-arterial oxygen tension difference (A-aDO2) ≥ 15 mmHg or a PaO2 < 80 mmHg and liver disease and/or portal hypertension. In the northeastern of Brazil, the hepatosplenic schistosomiasis (HSS) is main cause of portal hypertension. In cirrhotics, the presence of hepatopulmonary syndrome influences survival and candidacy for liver transplantation. However, hepatopulmonary syndrome was poorly studied in HSS patients, specially using lung perfusion scan with 99mTc-macroaggregated albumin (99mTc-MAA) for diagnosing IPVD. The aim of this study was to evaluate the use of lung perfusion scan in detecting IPVD in HSS patients.

Methods Nine consecutive HSS patients were submitted to arterial blood gas analysis, and lung perfusion scan with 99mTc-MAA. The diagnostic of IPVD was considered when 99mTc-MAA brain uptake ≥6%. No patient had lung disease or cardiac shunt.

Results The patients were mean age of 56+/-11 years and 56% were males. The mean PaO2 and A-aDO2 were 78 +/- 10 mmHg and 28 +/- 15 mmHg, respectively. The patients presented a brain uptake mean of 5.21 +/- 0.02%. Five (56%) patients had IPVD and four of them A-aDO2 ≥ 15 mmHg, possibly characterizing hepatopulmonary syndrome.

Conclusions The lung perfusion scan can help to evaluate IPVD in HSS patients. Its presence was associated with elevated A-aDO2 and hepatopulmonary syndrome. This syndrome could be a marker of poor prognostic in these patients