Ultrasound diagnosis of a bernathy malformation in adult patients with idiopathic pulmonary hypertension

Tóm tắt

Background

Abernethy malformation is a congenital defect of the portal system, in which visceral venous blood, bypassing the liver, enters the large circulation through abnormal extrahepatic portosystemic shunts. The Abernethy malformation is anatomically classified as type I, characterized by the absence of a portal vein and two variants of congenital portocaval shunts:Ia ‐ splenic vein and superior mesenteric vein are drained separately into the inferior vena cava and Ib-drained by a common trunk. Type II is defined as congenital portocaval shunts "side to side" with the preserved trunk of the portal vein.The available thematic publications are mainly presented by clinical observations of congenital portocaval shunts in children.The rare occurrence of the defect, the absence of a concensus in the name and evaluation of anatomical variants of congenital portocaval shunts, the possibility of an asymptomatic course is caused by the complexity of diagnosis and the uncertainty of the management tactics of such patients.The authors of all publications of congenital port-caval shunts are recognized as the cause of severe systemic diseases, the mechanisms and real frequency of which remain unknown.It has been established that congenital portocaval shunts can be associated with the development of pulmonary arterial hypertension.Modern clinical classification of pulmonary arterial hypertension, necessary for standardization of diagnostic and therapeutic approaches to patient management, includes associated forms of the disease. Pulmonary arterial hypertension associated with portal hypertension is one of the specific forms of the disease. The importance of differential diagnosis is due to a more unfavorable prognosis in patients with arterial hypertension compared with patients with idiopathic pulmonary hypertension. Ultrasound examination with Doppler assessment of blood flow is recognized as the method of choice of diagnostics of congenital portocaval shunts. Computer tomography is recommended to confirm the results and clarify the anatomical variant of congenital portocaval shunts.

OBJECTIVE: To show the diagnostic value of ultrasound in the detection of congenital portocaval shunts at the stage of primary examination of adult patients with idiopathic pulmonary hypertension.

Methods

The article presents 3 observations of patients with the established diagnosis of idiopathic pulmonary hypertension who were treated at the Chazov National Research Medical Center for the period from 2021 to 2023, in whom congenital portocaval shunts were diagnosed during routine ultrasound examination of the abdominal cavity. All patients were female, aged 39 to 58 years.  Ultrasound examination was performed on the Voluson E-8 device with a convexic sensor with a frequency of 3.5 MG in In-mode and with color Doppler mapping, in the back position and lateral access. The results of the ultrasound examination were compared with the data of echocardiography and multispiral computed tomography with contrast.

Results

In all patients, symptoms of pulmonary arterial hypertension were diagnosed in adolescence and had a progressive course. There was no anamnestic information about liver diseases, clinical and laboratory symptoms of hepatic dysfunction. The leading complaint was shortness of breath with little physical exertion (climbing 1-2 floors).The patients were examined according to established standards, according to the results of which idiopathic pulmonary hypertension was diagnosed. Ultrasound examination of abdominal organs was performed in accordance with the recommendations on the strategy of diagnosing patients with pulmonary arterial hypertension to exclude liver pathology and portal hypertension. Normally, with standard ultrasound examination of the right hypochondrium in adult patients, the following are visualized: the trunk of the portal vein, the right and left branches of the portal vein, the splenic vein and the superior mesenteric vein, forming the zonukonfluence, 3 hepatic veins flowing into the inferior vena cava. Assessment of the size and structure of the liver showed no pathological changes. The principal point of ultrasound examination in these patients was the absence of the trunk of the portal vein and its intrahepatic branches. The confluence zone, the splenic vein and the superior mesenteric vein were preserved. The splenic vein had a normal diameter (no more than 8mm), there was no enlargement of the spleen. The superior mesenteric vein was unevenly expanded (up to 12-14mm) with a convoluted course and flowed into the inferior vena cava in two cases, into the left renal vein in one case. Anatomical features of the identified congenital portocaval shunts corresponded to type 1 Abernethy malformation and the prehepatic level of the portal block according to the classification of portal hypertension. In all cases, there was a compensatory expansion of the hepatic artery up to 7-8mm with high-speed blood flow –Vmax  to 120-180 sm/s. Dilatation of hepatic veins was noted. Echocardiography revealed enlarged right chambers of the heart and increased central venous pressure. The results of multispiral computed tomography with contrast confirmed the presence of congenital portocaval shunts in all observations and clarified the anatomical type of Abernethy malformation: Ia - in one case and Ib - in two observations.

Conclusion

1. The detection of congenital portocaval shunts during ultrasound examination in adult patients with idiopathic pulmonary hypertension had the character of a diagnostic finding, allowed to establish the anatomical type of Abernethy malformation and the level of the portal block.

2. The revealed compensatory reaction of arterial blood flow against the background of liver deportalization explained the absence of hepatic dysfunction in these patients.

3. Extrahepatic localization of congenital portocaval shunts corresponded to the prehepatic variant of the portal block and was combined with signs of stagnation in a large circle of blood circulation according to the results of echocardiography.

4. The data obtained confirm the expediency of using ultrasound as the primary method of differential diagnosis of congenital portocaval shunts in patients with idiopathic pulmonary hypertension and the need for further research to identify mechanisms to confirm the pathogenetic relationship of Abernathy malformation and pulmonary arterial hypertension as an associated pathological condition.