ABSTRACT
Introduction: Hepatopulmonary syndrome [HPS] is characterized by the clinical triad of liver disease, arterial deoxygenation, and widespread pulmonary vascular dilatation. Various threshold values defining arterial hypoxaemia have been recommended and used in previous publications: PaO2 <70 mm Hg, PaO2 <80 mm Hg, AaDO2 >15 mm Hg, and AaDO2 >20 mm Hg. These different threshold values may result in a different prevalence of HPS
The aims of our study are: [l] to clarify how the prevalence of HPS in a sample of patients with chronic liver disease varies according to previously used different cut off values for arterial hypoxaemia; and [2] to determine the predictive value of those out off values in the diagnosis of HPS
Patients and Methods: Nighty patients with liver cirrhosis were studied for the presence of HPS using two-dimensional transthoracic air contrast echocardiography, pulmonary function tests, and arterial blood gas analysis. Those patients in whom contrast echocardiogram showed intrapulmonary vascular dilatations were classified as the positive group while others were labeled as the negative group
Results: Among the studied group, 24 [26.66%] had a positive contrast echocardiography; 12 [13.33%] of them were found to have PaO2<70 mmHg and were qualified for the diagnosis of [clinically significant] HPS; and the other 12[13.33%] with PaO2>70 mmHg were diagnosed as [subclinical HPS]. Using an increased alveolar-arterial difference for the partial pressure oxygen [AaDO2] as an indication of hypoxaemia, the prevalence of HPS was considerably higher [26.66% at > 15 mgHg and 22.22% at > 20mmHg]; than when using partial pressure of arterial oxygen [PaO2] as an indicator [20% at <80 mmHg and 13.33% at <70 mmHg]. For AaDO2 as the indicator, the positive predictive value for a diagnosis of HPS was low at both out vaiues [35.29%, and 38.46% respectively]. In contrast, PaO2 as an indicator had considerably higher positive predictive values [52.94%, and 75% respectively]. Introducing PaO2 <60 mm Hg as the cut off, the positive predictive value increased 100%. Dyspnoea was more oRen present in patients with [clinically significant] HPS [100%] compared with [subclinical PS] [50%], and patients without HPS [42.4%]. Cyanosis [p=0.000], clubbing [p=0.000] and orthodeoxia [p=0.000] were significantly commoner in the12 patients of clinically significant HPS. Presence of spider naevi was significantly related to the presence of subclinical HPS [intrapulmonary vascular dilatations]. The Child-Pugh score correlated signihcantly with the severity of HPS