Controlled attenuation parameter: A measure of hepatic steatosis in patients with cystic fibrosis

Abstract

Background: Hepatic steatosis is a common manifestation of CF-related liver disease(CFLD). Controlled attenuation parameter(CAP) measurement during transient elastography(TE) semiquantifies liver steatosis. We examined the relationship between CAP and CFLD severity, clinical factors and liver stiffness measurements(LSM). Methods: This is a cross-sectional study of CF patients seen for outpatient care between January 2013-March 2014. CFLD severity was categorized as no CFLD, CFLD without portal hypertension(PHTN) and CFLD with PHTN, based on published criteria. Results: 129 patients (median 18.4y; 57% male) had valid CAP. 70(54%) had no CFLD, 44(34%) CFLD without PHTN, and 15(12%) CFLD with PHTN. The median CAP was 210 dB/m (IQR 181-239). Steatosis(CAP ≥230 dB/m) was seen in 27% of subjects without CFLD, 48% in CFLD but no PHTN, and 20% in with CFLD and PHTN(P = .04). CAP was higher for subjects with CFLD without PHTN (P b .05). There was no CAP difference between subjects with no CFLD and those with CFLD and PHTN (P ≥ .65). LSM was not different between no CFLD and CFLD without PHTN (P = .07), but each of these groups had lower LSM compared to subjects with CFLD and PHTN(P b .001 for each). Except for direct bilirubin, CAP was not associated with clinical markers of liver disease. Conclusion: CAP was normal in 86(67%) of patients with CF and was not associated with standard clinical markers of liver disease. CAP was higher in patients with liver disease, which could possibly reflect the loss of steatosis observed with progression to cirrhosis and portal hypertension.

Association Between Transient Elastography and Controlled Attenuated Parameter and Liver Ultrasound in Children With Cystic Fibrosis

“…Interestingly, there appeared to be a step-wise increase in LSM from NL to HTG to NOD. Although several studies have evaluated the use of LSM by FibroScan in CF, (2,(10)(11)(12)(13)(14)(15)(22)(23)(24)(25)(26)(27)(28) our study aimed to determine the association between LSM and US patterns in a multicenter and well-characterized pediatric CF cohort. Furthermore, our study further expands on the previously noted association between increased LSM and decreased platelet count among patients with CF.…”

Cystic fibrosis year in review 2018, part 2

“…A novel noninvasive measure of hepatic steatosis, the controlled attenuation parameter (CAP), which is based on radiofrequency ultrasound signal acquired by the transient elastography device was evaluated in one pediatric center in patients age 6 to 25 years. CAP found hepatic steatosis in 1/3 of patients, which correlated with ultrasound findings but not clinical or biochemical markers of liver disease . Another novel method, MRI based elastography (MRE), can evaluate liver stiffness.…”

“…CAP found hepatic steatosis in 1/3 of patients, which correlated with ultrasound findings but not clinical or biochemical markers of liver disease. 43 Another novel method, MRI based elastography (MRE), can evaluate liver stiffness. In a brief report of four patients, elevated MRE liver stiffness was found, despite the patients having minimal elevations in liver function tests and one with a normal ultrasound.…”

“…IQR] 1301 kcal/d vs 686; P < .0001) and proportion of energy intake (median [IQR] 44%[34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51] vs 31%[24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43]; P < .0001). Thus, while children with CF met their energy requirements and ate ample fat, this was largely due to ingestion of EDNP foods.…”

The Emergence of Elastography for Cystic Fibrosis Liver Disease

“…The low frequency waves are generated by a mechanical drum placed over the abdominal wall overlying the liver interestingly report higher CAP in those with CFLD (n = 44), but not in those with evidence of cirrhosis and portal hypertension (n = 15), suggesting that steatosis may be replaced with fibrosis in more advanced CFLD [18] . While informative, small studies such as these need validation in larger prospective studies.…”