Use Liver Fibrosis Index for Hints About PAH Progression, Study Says

Liver fibrosis index (LFI) should be considered as a possible predictive marker for the clinical progression of pulmonary arterial hypertension (PAH), according to a recent study.

The authors said they undertook the research because “few studies have reported on cardiohepatic interactions in right heart failure patients, a condition that is an important prognostic factor.” It is already known that liver problems play a key role in the prognosis of left heart failure patients.

The researchers said they believe it is the first study to show the presence of hepatic fibrosis in patients with chronic right heart failure accompanied by PAH using liver ultrasound elastography.

Writing in Heart and Vessels, the authors said the prospective study enrolled 60 consecutive patients with PAH in a hospital in Tokyo from June 2016 to December 2017. The patients recently had right heart catheterization and were included for analysis if they had mean pulmonary artery pressure (mPAP) ≥ 25 mmHg, pulmonary artery wedge pressure ≤ 15 mmHg, and pulmonary vascular resistance ([PVR] > 3 WU). They also had to be adults aged 18 or over and clinically stable for more than 6 months after receiving PAH treatment.

After 25 patients were excluded, 35 were assessed for hepatic fibrosis using real-time tissue elastography, a noninvasive abdominal ultrasonic examination technique, within 24 hours of the right heart catheterization. In RTE, firm areas of tissue are displayed in a color map.

They were also assessed for clinical deterioration, which was defined as when one of the following occurred:

• A ≥ 15% decrease in the distance of the 6-minute walk test (6MWT) accompanied by worsening of the New York Heart Association functional classification
• Need for additional treatment for PAH
• A ≥ 20% upregulation in mPAP and/or PVR
• A ≥ 20% reduction in cardiac output and/or cardiac index

Sixteen controls matched by age and sex were also included for comparison.

The 6MWT was performed and blood samples, taken on the same day as the right heart catheterization, were analyzed for prognostic and liver dysfunction markers in patients with PAH.

The LFI, indicating the extent of hepatic fibrosis, was measured by a single blinded examiner using RTE.

In the first key finding from the study, the authors said results showed the LFI was significantly higher in PAH patients than in healthy controls (1.214 [0.047] vs. 0.911 [0.059], P < .001), suggesting that PAH patients exhibited mild liver fibrosis.

In the second key finding, patients with clinical deterioration (vs. no deterioration) had significantly higher LFI values (1.507 [0.078] vs. 1.080 [0.034], P < .001), independent from other established liver function parameters. In addition, a receiver operating characteristic curve analysis showed that an LFI ≥ 1.275 indicated a significant probability of clinical deterioration (HR, 8.4; 95% CI, 1.5–45.4, P = .012), independent from other known PAH prognostic factors.

Therefore, “the LFI can serve as both a noninvasive evaluation of liver fibrosis and a predictive marker for the deterioration of PAH patients,” the authors wrote.

As a noninvasive test, an RTE is easier on patients and allows for more early detections and early interventions, and as such could improve a patient’s prognosis and lower medical costs by decreasing hospitalizations, they said.

Two of the limitations of the study is that it was conducted at a single center and also that no liver biopsies were performed.

Reference

Furukawa A, Tamura Y, Yamada K, et al. Liver fibrosis index as a novel prognostic factor in patients with pulmonary arterial hypertension. Heart Vessels. Published online October 7, 2021. doi: 10.1007/s00380-021-01951-7