İzleyiciler

14 Kasım 2017 Salı

HEPATOPULMONARY SYNDROM


HEPATO PULMONARY SYNDROM (HPS) is a life-threatening condition with a triad of liver disease, arterial deoxygenation and intrapulmonary vascular dilatation. There is no multicenter study of actual prevalence.
Although HPS is mostly seen in patients with portal hypertension and cirrhosis, it may also occur in portal hypertension or non-cirrhotic acute and chronic hepatitis, or in the case of nonsirotic portal HT.
In the early stages of HPS, the arterial oxygen pressure may be misleading as normal. In the case of cirrhosis hyperventilation and consequently reduced arterial CO2 occur frequently, and alveolo-arterial oxygen gradient for deoxygenation is a more sensitive determinant. In the case of cirrhosis hyperventilation and consequently reduced arterial CO2 occur frequently, and alveolo-arterial oxygen gradient for deoxygenation is a more sensitive determinant.
Degraded oxygenation results from ventilation-perfusion incompetence resulting from microvascular dilatations in the pulmonary arterial circulation.
Dyspnea occurring in a patient with chronic liver disease is a common presentation of HPS.
Although platypnea, orthodeoxy, spider nevi and clubbing are more frequent in HPS patients, they are not specific for HPS.
There is no relationship between the severity of HPS and the severity of hepatic disease.
Pulse oxymetry saturation is a simple method, with 100% sensitivity for HPS, with 65% specificity. Nevertheless, it is necessary to perform an arterial blood gas measurement in order to be able to make a diagnosis. Contrast-enhanced echocardiography (CEE) and a positive bubble test are recommended for the diagnostic criteria.
In the presence of concurrent cardiovascular disease, pulmonary perfusion imaging with Tecnesium-labeled albumin macroaggregates (99mTcMAA) may help assess the degree of hypoxemia caused by intrinsic pulmonary vascular diatation (IPVD).
MAA-Lung-brain perfusion scintigraphy has limitations. The sensitivity of MAA is lower than that of CEE and it fails to distinguish intracardiac shunts from inrapulmonary shunts.
Portopulmonary hypertension can also be found at the same time as HPS and is a situation that confuses the diagnosis. Portopulmonary hypertension is caused by obstruction of pulmonary artery flow in the presence of portal HT. Right cardiac catheterization is required in the diagnosis. Diagnostic criteria include: mean pulmonary artery pressure (mPAP)> 25 mmHg, pulmonary vascular resistance (PVR)> 3 Wood units, and normal pulmonary artery wedge pressure. Dispne is often present, but it is nonspecific. AaPO2 is usually elevated, but hypoxemia is usually mild even in severe disease. Unlike in HPS, treatments targeting pulmonary HT are also useful for functional capacity in portopulmonary hypertension.
At present, no specific medical treatment has been established for HPS. Although it is advisable to increase the oxygen saturation above> 88%, it is not scientifically proven.
Although pentoxifylline improved in HPS with inhibition of TNF-alpha in animal experiments, human studies are not available. Although a portosystemic shunt with the use of TIPS has been proposed, it is not fully established and may actually aggravate HPS as it will increase hyperdynamic circulation.
Although, although, althoughs…..
OLT (orthotopic KC-T) is the only effective treatment with oxygenation and survival.