Ultrasound Pressure Estimation for Diagnosing Portal Hypertension in Patients Undergoing Dialysis for Chronic Kidney Disease

Abstract

Objectives-Hepatic venous pressure gradient (HVPG) is considered the standard in quantifying portal hypertension, but can be unreliable in dialysis patients. A noninvasive ultrasound technique, subharmonic-aided pressure estimation (SHAPE), may be a valuable surrogate of these pressure estimates. This study compared SHAPE and HVPG with pathology findings for fibrosis in dialysis patients.Methods-This was a subgroup study from an IRB-approved trial that included 20 patients on dialysis undergoing SHAPE examinations of portal and hepatic veins using a modified Logiq 9 scanner (GE, Waukesha, WI), during infusion of Sonazoid (GE Healthcare, Oslo, Norway). SHAPE was compared to HVPG and pathology findings using the Ludwig-Batts scoring system for fibrosis. Logistic regression, ROC analysis, and t-tests were used to compare HVPG and SHAPE with pathological findings of fibrosis.Results-Of 20 cases, 5 had HVPG values corresponding to subclinical and clinical portal hypertension (≥6 and ≥10 mmHg, respectively) while 15 had normal HVPG values (≤5 mmHg). SHAPE and HVPG correlated moderately (r = 0.45; P = .047). SHAPE showed a trend toward correlating with fibrosis (r = 0.42; P = .068), while HVPG did not (r = 0.18; P = .45). SHAPE could differentiate between mild (stage 0-1) and moderate to severe (stage 2-4) fibrosis (À10.4 AE 4.9 dB versus À5.4 AE 3.2 dB; P = .035), HVPG could not (3.0 AE 0.6 mmHg versus 4.8 AE 0.7 mmHg; P = .30). ROC curves showed a diagnostic accuracy for SHAPE of 80%, while HVPG reached 76%.Conclusion-Liver fibrosis staging in dialysis patients evaluated for portal hypertension appears to be more accurately predicted by SHAPE than by HVPG; albeit in a small sample size.Key Words-chronic kidney disease; contrast-enhanced ultrasound; dialysis; portal hypertension; subharmonic imaging; subharmonic pressure estimation L iver cirrhosis is the final common pathological pathway of liver damage arising from a wide variety of chronic liver diseases. [1][2][3][4][5][6][7][8][9] Histologically, it is characterized by diffuse nodular regeneration and dense fibrotic septa evolving to parenchymal extinction and collapse of liver structures. [1][2][3][4][5][6][7][8][9] Distortion of hepatic vascular architecture and increased resistance to portal blood flow leads to portal hypertension and hepatic synthetic dysfunction. [1][2][3][4][6][7][8][9][10]

Subharmonic aided pressure estimation in portal hypertension: A noninvasive ultrasound‐based technique to assess portal pressure gradient

“…First, optimization of parameters to improve the correlation coefficient. A trial 5 in 20 patients undergoing dialysis for chronic kidney disease showed a moderate correlation between SHAPE and HVPG ( r = 0.45), which is lower than the previous one. The cause of the variable and unsatisfied correlation coefficient needed to be solved.…”

“…Monodisperse microbubbles specifically designed for SHAPE using a commercially available microfluidics device (Solstice Pharmaceuticals) have the potential to greatly increase sensitivity to hydrostatic pressure compared to relying on polydisperse agents designed for diagnostic imaging. In addition, the variable correlation coefficient between SHAPE and liver fibrosis is presented in PH patients with other comorbidity (e.g., chronic kidney disease) 5 . Further large‐scale prospective studies are needed to perform to evaluate the clinical application of SHAPE.…”

“…In addition, the variable correlation coefficient between SHAPE and liver fibrosis is presented in PH patients with other comorbidity (e.g., chronic kidney disease). 5 Further large-scale prospective studies are needed to perform to evaluate the clinical application of SHAPE.…”

AIUM Practice Parameter for the Performance of Contrast‐Enhanced Ultrasound

“…Evaluate vasculature and portal pressures. [1][2][3][4][5][6] a. Determine hepatic artery, portal vein, and hepatic vein patency.…”

Contrast-enhanced ultrasonography for the management of portal hypertension in cirrhosis

“…According to the data using SHAPE to differentiate between mild (stage 0–1) and moderate to severe (stage 2–4) fibrosis in patients with dialysis, SHAPE succeeded (-10.4 ± 4.9 dB vs.−5.4 ± 3.2 dB; P = 0.035), but HVPG failed (3.0 ± 0.6 mmHg vs. 4.8 ± 0.7 mmHg; P = 0.30) ( 25 ). The diagnostic accuracy by SHAPE was 80%, whereas that by HVPG was 76%.…”