Three-Year mpUS Readout of Post-COVID Liver Changes

Key Takeaways

• In the post-COVID cohort, SWE and SWD trended downward and ATI trended upward over three years, but none of those within-group shifts was statistically significant.
• Controls showed little movement in stiffness and dispersion measures, while attenuation increased significantly over time across both follow-up subgroups.
• Higher stiffness tracked with GGT, ALT, and BMI, and cardiovascular disease plus age remained independent predictors, aligning the imaging findings more closely with metabolic factors than with direct viral injury.

Over three years, liver stiffness in a post-COVID cohort shifted from 5.04 ± 1.74 kPa to 4.59 ± 0.81 kPa without a significant within-group change in a three-year prospective study from Latvia. Attenuation rose modestly and dispersion fell, but the overall imaging pattern remained stable after hospitalization for COVID-19.

This longitudinal prospective single-center study ran from 2020 to 2023 with ethics approval and informed consent. Investigators enrolled 90 randomly selected adults hospitalized during a first COVID-19 episode and 39 clinically healthy controls, excluding participants with previously known liver disease. Baseline assessment took place 3 to 6 months after infection, and 58 post-COVID participants plus all 39 controls returned at three years. The protocol paired biochemical testing with multiparametric ultrasound measures of SWE, ATI, and SWD to compare recovered patients with controls over time.

Among recovered participants, multiparametric ultrasound showed SWE changing from 5.04 ± 1.74 to 4.59 ± 0.81 kPa and SWD from 11.88 ± 1.73 to 10.83 ± 1.49 m/s/kHz. ATI moved from 0.56 ± 0.09 to 0.60 ± 0.09 dB/cm/MHz, and all within-group p values remained above 0.05. Controls were stratified by whether COVID-19 occurred during follow-up, and their SWE and SWD changed only slightly. ATI, by contrast, increased significantly from 0.57 ± 0.08 dB/cm/MHz to 0.62 ± 0.09 and 0.65 ± 0.07 dB/cm/MHz in the two control subgroups, with p less than 0.05.

Higher hepatic stiffness correlated with GGT at rs = 0.37 and p = 0.005, ALT at rs = 0.31 and p = 0.02, and BMI at rs = 0.49 with p below 0.001. ATI also tracked with higher BMI, with p below 0.001, and BMI increased significantly in both control subgroups over time. Regression analysis identified cardiovascular disease and age as independent predictors of increased liver stiffness. The data also showed a positive SWE-to-SWD relationship, with OR 1.407, 95% CI 1.011–1.960, and p = 0.001.

The authors concluded that persistent liver damage attributable to COVID-19 was not evident in this cohort and that longer-term mpUS changes more likely reflected lifestyle or metabolic factors. They also reported no hepatic steatosis, normal SWE, reduced dispersion in the initially affected group, and no hepatic venous congestion on hepatic or systemic Doppler ultrasound.

Limitations included a moderate sample size, follow-up losses in the research group, and no imaging before COVID-19.