Relationship between portopulmonary hypertension and splenectomy: Mayo Clinic experience and review of published works

A rare case of idiopathic portal hypertension with portopulmonary hypertension occurred following splenectomy with a change in portal hemodynamics

A 22-year-old female was referred to our hospital due to thrombocytopenia and esophagogastric varices (EGV) [LmF2CbRC1, Lg-c,F1RC0], therefore we performed endoscopic variceal ligation. Dynamic abdominal computed tomography showed giant portosystemic shunts (PSSs) from the left gastric vein to the superior vena cava and splenomegaly despite normal hepatic contour. Blood tests showed thrombocytopenia and hypoalbuminemia, but there were no abnormalities in hepatic function. Retrograde hepatic venography and transjugular liver biopsy were subsequently performed in order to further examine liver pathology. These examinations revealed anastomosis between the right and middle hepatic veins, with no features to suggest cirrhosis, therefore diagnosed as idiopathic portal hypertension. Splenectomy was performed for the treatment of hypersplenism with thrombocytopenia. Nine months after undergoing a splenectomy, the patient consulted a cardiologist due to exertional dyspnea with WHO functional class II. Echocardiography revealed a mild dilatated right ventricle (RV) with an estimated systolic pressure of 55 mmHg, consistent with pulmonary hypertension. Right heart catheterization determined an increased mean pulmonary arterial pressure of 40 mmHg and pulmonary vascular resistance of 7.5 wood units, but a normal pulmonary capillary wedge pressure value of 7 mmHg, resulting in the diagnosis of portopulmonary hypertension (PoPH). Administration of oral macitentan 5 mg/day was initiated. Exertional dyspnea and the findings from right heart catheterization were improved with macitentan 10 mg/day. No report exists of PoPH occurring within one year after splenectomy, however we report here a very rare case in which a splenectomy brought about the onset of PoPH.

Association between Body Composition and the Risk of Portopulmonary Hypertension Assessed by Computed Tomography in Patients with Liver Cirrhosis

The aim of this study is to investigate the impact of body composition on the risk of portopulmonary hypertension using computed tomography (CT) in patients with liver cirrhosis. We retrospectively included 148 patients with cirrhosis treated at our hospital between March 2012 and December 2020. POPH high-risk was defined as main pulmonary artery diameter (mPA-D) ≥ 29 mm or mPA-D to ascending aorta diameter ratio ≥ 1.0, based on chest CT. Body composition was assessed using CT images of the third lumbar vertebra. The factors associated with POPH high-risk were evaluated using logistic regression and decision tree analyses, respectively. Among the 148 patients, 50% were females, and 31% were found to be high-risk cases on evaluation of chest CT images. Patients with a body mass index (BMI) of ≥25 mg/m2 had a significantly higher prevalence of POPH high-risk than those with a BMI < 25 mg/m2 (47% vs. 25%, p = 0.019). After adjusting for confounding factors, BMI (odds ratio [OR], 1.21; 95% confidence interval [CI], 1.10-1.33), subcutaneous adipose tissue index (OR, 1.02; 95% CI, 1.01-1.03), and visceral adipose tissue index (OR, 1.03; 95% CI, 1.01-1.04) were associated with POPH high-risk, respectively. In the decision tree analysis, the strongest classifier of POPH high-risk was BMI, followed by the skeletal muscle index. Body composition may affect the risk of POPH based on chest CT assessment in patients with cirrhosis. Since the present study lacked data on right heart catheterization, further studies are required to confirm the results of our study.

Prevalence and characteristics of portopulmonary hypertension in cirrhotic patients who underwent both hepatic vein and pulmonary artery catheterization

Portopulmonary hypertension (PoPH) is a well-known complication of liver cirrhosis. The aim of this study was to clarify the pulmonary hemodynamics and the prevalence and characteristics of PoPH in patients with portal hypertension.

METHODS

The subjects were 335 patients with portal hypertension diagnosed by hepatic vein pressure gradient (HVPG). Among them, 186 patients received measurements of pulmonary artery pressure (PAP), pulmonary artery wedge pressure (PAWP) and pulmonary vascular resistance (PVR). PoPH was diagnosed by PAP >20 mmHg, PVR ≥3 Wood units (WU) and PAWP ≤15 mmHg.

RESULTS

The Child-Pugh classification was class A in 53, B in 92 and C in 41 patients. Median (range) values of HVPG, PAP, PVR and PAWP were 18.4 (5.5-39.0) mmHg, 12.9 (6.6-40.8) mmHg, 0.8 (0.1-4.5) WU and 7.5 (2.2-15.4) mmHg, respectively. Of six patients with PAP >20 mmHg, four had autoimmune hepatitis or primary biliary cholangitis, with the prevalence being significantly higher than that in patients with PAP ≤20 mmHg. Meanwhile, no significant difference was noted in the hepatic functional reserve or HVPG between patients with PAP >20 mmHg and ≤20 mmHg. Only two patients met the diagnostic criteria of PoPH and both patients were Child-Pugh B. The Child-Pugh score and HVPG were not associated with PoPH.

CONCLUSIONS

Our study demonstrated that only two patients were complicated by PoPH. High PAP values were noted in patients with primary biliary cholangitis or autoimmune hepatitis. However, the presence of PoPH and high PAP were not associated with the degree of hepatic functional reserve or HVPG.

Association between splenectomy and portal hypertension in the development of pulmonary hypertension

Both portal hypertension and splenectomy are risk factors for pulmonary hypertension. However, the interactions between portal hypertension and splenectomy in the development of pulmonary hypertension remain unclear. Twelve newly diagnosed pulmonary hypertension patients with a previous history of splenectomy induced by portal hypertension were recruited between November 2008 and May 2017. We compared their clinical features, hemodynamics, and prognosis with idiopathic pulmonary arterial hypertension patients, who were matched by cardiac index, mean pulmonary arterial pressure, and pulmonary vascular resistance. We also compared the clinical characteristics of portal hypertension-post-splenectomy-pulmonary hypertension patients with eight portopulmonary hypertension patients. Compared with the matched idiopathic pulmonary arterial hypertension patients, the portal hypertension-post-splenectomy-pulmonary hypertension patients showed significantly wider red blood cell distribution width (16.7 ± 2.8% versus 13.3 ± 1.7%, p = 0.004), higher total bilirubin concentration (31.0 ± 13.8 µmol/l versus 18.9 ± 10.0 µmol/l, p = 0.010), and higher lactate dehydrogenase concentration (321.5 ± 41.2 IU/l versus 229.2 ± 69.4 IU/l, p = 0.001). Kaplan-Meier survival analyses showed that the portal hypertension-post-splenectomy-pulmonary hypertension patients tended to have poorer prognosis than the matched idiopathic pulmonary arterial hypertension patients (log-rank test: p = 0.010). Compared with the portal hypertension-post-splenectomy-pulmonary hypertension patients, the portopulmonary hypertension cohort appeared to exhibit poorer clinical conditions, including significantly lower mixed venous oxygen saturation (62.9 ± 8.0% versus 73.9 ± 6.5%, p = 0.004) and a significantly higher proportion of pericardial effusion (75.0% versus 8.3%, p = 0.004), even though the two cohorts showed similar hemodynamics. The mean intervals from diagnosis of portal hypertension to pulmonary hypertension in portopulmonary hypertension patients were significantly shorter than the intervals from splenectomy to diagnosis of pulmonary hypertension in portal hypertension-post-splenectomy-pulmonary hypertension patients (5.5 ± 5.2 years versus 13.1 ± 5.9 years, p = 0.008). Splenectomy might be involved in the initiation and development of pulmonary hypertension in patients with portal hypertension, although the precise mechanisms involved remain unknown. Portal hypertension-post-splenectomy-pulmonary hypertension patients might have poorer prognosis even with mild hemodynamics.

Inflammatory Macrophage Expansion in Pulmonary Hypertension Depends upon Mobilization of Blood-Borne Monocytes

Pulmonary inflammation, which is characterized by the presence of perivascular macrophages, has been proposed as a key pathogenic driver of pulmonary hypertension (PH), a vascular disease with increasing global significance. However, the mechanisms of expansion of lung macrophages and the role of blood-borne monocytes in PH are poorly understood. Using multicolor flow cytometric analysis of blood in mouse and rat models of PH and patients with PH, an increase in blood monocytes was observed. In parallel, lung tissue displayed increased chemokine transcript expression, including those responsible for monocyte recruitment, such as Ccl2 and Cx₃cl1, accompanied by an expansion of interstitial lung macrophages. These data indicate that blood monocytes are recruited to lung perivascular spaces and differentiate into inflammatory macrophages. Correspondingly, parabiosis between congenically different hypoxic mice demonstrated that most interstitial macrophages originated from blood monocytes. To define the actions of these cells in PH in vivo, we reduced blood monocyte numbers via genetic deficiency of cx₃cr1 or ccr2 in chronically hypoxic male mice and by pharmacologic inhibition of Cx₃cl1 in monocrotaline-exposed rats. Both models exhibited decreased inflammatory blood monocytes, as well as interstitial macrophages, leading to a substantial decrease in arteriolar remodeling but with a less robust hemodynamic effect. This study defines a direct mechanism by which interstitial macrophages expand in PH. It also demonstrates a pathway for pulmonary vascular remodeling in PH that depends upon interstitial macrophage-dependent inflammation yet is dissociated, at least in part, from hemodynamic consequences, thus offering guidance on future anti-inflammatory therapeutic strategies in this disease.