Hepatopulmonary syndrome: an update

Abstract

Hepatopulmonary syndrome (HPS) is a clinical threesome composed of liver disease, intrapulmonary vascular dilatation (IPVD) and arterial gas abnormalities. Its occurrence has been described in up to 32% of cirrhotic candidates for liver transplantation. It also affects non-cirrhotic patients with portal hypertension. Its pathogenesis is not well defined, but an association of factors such as imbalance in the endothelin receptor response, pulmonary microvascular remodeling and genetic predisposition is thought to lead to IPVD. Diagnosis is based on imaging methods that identify these dilatations, such as contrast echocardiography or perfusion scintigraphy with RESUMOA síndrome hepatopulmonar (SHP) é considerada uma tríade clínica composta de doença hepática, dilatações vasculares intrapulmonares (IPVD) e alterações de gases arteriais. Há descrição de sua ocorrência em até 32% dos cirróticos candidatos ao transplante de fígado, acometendo também não cirróticos com hipertensão portal. Sua etiopatogenia não está bem definida, mas se especula que a associação de fatores como o desequilíbrio na resposta dos receptores vasculares de endotelina, o remodelamento microvascular pulmonar e a predisposição genética propiciem as IPVD. O diagnóstico baseia-se em métodos de imagem que identifiquem essas dilatações, como a ecocardiografia com contraste ou a cintilografia de perfusão com 99m Tc, além da análise de gases arteriais, para identificar elevação da diferença alvéolo-arterial de O 2 ou hipoxemia. Não existe tratamento medicamentoso eficaz e sua resolução completa ocorre apenas com o transplante de fígado. A importância do diagnóstico da SHP está em priorizar os candidatos ao transplante, uma vez que sua presença está associada ao pior prognóstico. O objetivo deste artigo é fazer revisão das teorias de etiopatogenia da

Evaluation of normality and reproducibility parameters of scintigraphy with 99mTc-MAA in the diagnosis of intrapulmonary vascular dilatations

“…In 99m Tc-MAA scintigraphy, radiolabeled particles, which typically are more than 20 lm in diameter, are injected and retained in the pulmonary vasculature, since capillaries measure 8-15 lm in diameter [5]. In the presence of IPVD, as vasodilation occurs, a fraction of these particles is transferred into the systemic circulation, which can be quantified by the ratio between radioactivity in the intra and extrapulmonary circulation [1].…”

Intrapulmonary Vascular Dilatation Evaluated by 99mTc-MAA Scintigraphy and Its Association with Portal Hypertension in Schistosomiasis

“…In 99m Tc-MAA scintigraphy, radiolabeled particles, which usually have more than 20 µm in diameter, are injected and remain retained in the pulmonary vasculature, since capillaries measure 8 to 15 µm in diameter [12]. In the presence of IPVD, as in vasodilation, a fraction of these particles migrate to the systemic circulation, which can be quantified by radioactivity in the intra- and extrapulmonary circulation [6].…”

Assessment of Biometal Profile in Children with Autism Spectrum Disorder, with Attention Deficit Hyperactivity Disorder, or with Other Psychiatric Diagnoses: A Comparative Outpatient Study

“…Contrast echocardiography evidence of pulmonary shunting (appearance of agitated saline in the left atrium after 3 cardiac cycles) [33,34].…”

“…Treatment of HPS is based on correction of hypoxemia with oxygen and liver transplantation which is the only measure to alter the natural course of the disease and improve the hypoxemia [33]. However, persistent hypoxemia in patients with HPS carry a high morbidity and mortality in cirrhotic patients who contemplating liver transplantation [33].…”