The utility of the macro-aggregated albumin lung perfusion scan in the diagnosis and prognosis of hepatopulmonary syndrome in cirrhotic patients candidates for liver transplantation.

BACKGROUND The macro-aggregated albumin lung perfusion scan (99mTc-MAA) is a diagnostic method for hepatopulmonary syndrome (HPS). GOAL To determine the sensitivity of 99mTc-MAA in diagnosing HPS, to establish the utility of 99mTc-MAA in determining the influence of HPS on hypoxemia in patients with concomitant pulmonary disease and to determine the correlation between 99mTc-MAA values and other respiratory parameters. METHODS Data from 115 cirrhotic patients who were eligible for liver transplantation (LT) were prospectively analyzed. A transthoracic contrast echocardiography and 99mTc-MAA were performed in 85 patients, and 74 patients were diagnosed with HPS. RESULTS The overall sensitivity of 99mTc-MAA for the diagnosis of HPS was 18.9% (14/74) in all of the HPS cases and 66.7% (4/6) in the severe to very severe cases. In HPS patients who did not have lung disease, the degree of brain uptake of 99mTc-MAA was correlated with the alveolar-arterial oxygen gradient (A-a PO2) (r = 0.32, p < 0.05) and estimated oxygen shunt (r = 0.41, p < 0.05) and inversely correlated with partial pressure of arterial oxygen (PaO2) while breathing 100% O2 (r = -0.43, p < 0.05). The 99mTc-MAA was positive in 20.6% (7/36) of the patients with HPS and lung disease. The brain uptake of 99mTc-MAA was not associated with mortality and normalized in all cases six months after LT. CONCLUSIONS The 99mTc-MAA is a low sensitivity test for the diagnosis of HPS that can be useful in patients who have concomitant lung disease and in severe to very severe cases of HPS. It was not related to mortality, and brain uptake normalized after LT.