Preliminary study of a new pathological evolution-based clinical hepatolithiasis classification

Risk Factors for Systemic Inflammatory Response Syndrome After Percutaneous Transhepatic Cholangioscopic Lithotripsy

Background

There is a lack of validated predictive models for the occurrence of systemic inflammatory response syndrome (SIRS) after percutaneous transhepatic cholangioscopic lithotripsy (PTCSL) for the treatment of hepatolithiasis. This is the first study to estimate the incidence of SIRS after PTCSL.

Methods

A retrospective analysis of 284 PTCSL sessions for the treatment of hepatolithiasis at our institution between January 2019 and January 2023 was performed. The development of SIRS after PTCSL was the primary study endpoint. Independent risk factors for SIRS after PTCSL were identified using univariate and multivariate logistic regression analyses. A nomogram prediction model was constructed using these independent risk factors, and the predictive value was assessed using receiver operating characteristic (ROC) curves.

Results

The incidence of SIRS after PTCSL was 20.77%. According to multivariate analysis, the number of PTCSL sessions (odds ratio [OR]=0.399, 95% confidence interval [CI]=0.202-0.786, p=0.008), stone location (OR=2.194, 95% CI=1.107-4.347, p=0.024), intraoperative use of norepinephrine (OR=0.301, 95% CI=0.131-0.689, p=0.004), intraoperative puncture (OR=3.476, 95% CI=1.749-6.906, P<0.001), preoperative gamma-glutamyltransferase (OR=1.002, 95% CI=1.001-1.004, p=0.009), and preoperative total lymphocyte count (OR=1.820, 95% CI=1.110-2.985, p=0.018) were found to be independent risk factors for the development of SIRS after PTCSL. These six independent risk factors were used to construct a nomogram prediction model, which showed satisfactory accuracy with an area under the ROC curve of 0.776 (95% CI: 0.702-0.850).

Conclusion

The number of PTCSL sessions, stone location, intraoperative use of norepinephrine, intraoperative puncture, preoperative gamma-glutamyltransferase, and preoperative total lymphocyte count may predict the occurrence of SIRS after PTCSL. This prediction model may help clinicians identify high-risk patients in advance.

Clinical, histopathological, and immunohistochemical spectrum of hepatolithiasis: a tertiary care center-based study from north India

Hepatolithiasis (HL), an uncommon disease among Indians, occurs due to a complex interplay of various structural and functional factors. We retrospectively evaluated the clinical and histopathological spectrum of HL (N = 19) with immunohistochemical evaluation for biliary apomucins and canalicular transporter proteins, both crucial for lithogenesis. Nineteen surgically resected cases were included. Histopathology was systematically evaluated. Immunohistochemistry for apomucins (MUC1, MUC2, MUC4, MUC5AC, and MUC6) and canalicular transporter proteins (BSEP and MDR3) was applied to all cases. The median age was 51 years with female preponderance (F:M = 1.4:1). The stone was cholesterol-rich in 71.4% and pigmented in 28.6% (n = 14). Histopathology showed variable large bile-duct thickening due to fibrosis and inflammation with peribiliary gland hyperplasia. Structural causes (Caroli disease, choledochal cyst, and post-surgical complication) were noted in 15.8% of cases (secondary HL). Expression of gel-forming apomucin MUC1, MUC2, and MUC5AC was seen in either bile duct epithelia or peribiliary glands in 84.2%, 10.5%, and 84.2% cases respectively. Loss of canalicular expression of MDR3 was noted in 42.1% of cases while BSEP was retained in all. Primary HL in the north Indian population can be associated with the loss of MDR3 expression (with retained BSEP) and/ or a shift in the phenotype of biliary apomucins to gel-forming apomucins. The former factor alters the bile acid/ phospholipid ratio while the latter parameter promulgates crystallization. In conjunction, these factors are responsible for the dominantly cholesterol-rich stones in the index population.

Nomogram predicting surgical risk of laparoscopic left-sided hepatectomy for hepatolithiasis

OBJECTIVE

To explore the surgical risk factors of laparoscopic left-sided hepatectomy for hepatolithiasis and establish and validate a nomogram to estimate the corresponding surgical risks.

METHODS

Patients with hepatolithiasis who underwent laparoscopic left-sided hepatectomy were retrospectively enrolled. Demographic data, clinicopathological parameters, and surgical factors were collected. Three hundred fifty-three patients were enrolled and randomly divided into training set (n=267) and validation set (n=86) by 3:1. Conversion to laparotomy was used as a surrogate index to evaluate the surgical risk. Univariate analysis was used to screen potential surgical risk factors, and multivariate analysis using logistic regression model was used to screen independent surgical risk factors. Nomogram predicting the surgical risks was established based on the independent risk factors. Discrimination, calibration, decision curve, and clinical impact analyses were used to evaluate the performance of the nomogram on the statistical and clinical aspects both in the training and validation sets.

RESULTS

Five independent surgical risk factors were identified in the training set, including recurrent abdominal pain, bile duct stricture, ASA classification ≥2, extent of liver resection, and biliary tract T tube drainage. No collinearity was found among these five factors, and a nomogram was established. Performance analyses of the nomogram showed good discrimination (AUC=0.850 and 0.817) and calibration (Hosmer-Lemeshow test, p=0.530 and 0.930) capabilities both in the training and validation sets. Decision curve and clinical impact analyses also showed that the prediction performance was clinically valuable.

CONCLUSIONS

A nomogram was established and validated to be effective in evaluating and predicting the surgical risk of patients undergoing laparoscopic left-sided hepatectomies for hepatolithiasis.

Postoperative jaundice related to UGT1A1 and ABCB11 gene mutations: A case report and literature review

BACKGROUND

Patients with obstructive jaundice caused by intrahepatic bile duct stones can be effectively managed by surgery. However, some patients may develop postoperative complications, liver failure, and other life-threatening situations. Here, we report a patient with mutations in the uridine 5’-diphospho-glucuronosyltransferase 1A1 (UGT1A1) and bile salt export pump (adenosine triphosphate-binding cassette subfamily B member 11, ABCB11) genes who presented multiple intrahepatic bile duct stones and cholestasis, and the jaundice of the patient increased after partial hepatectomy.

CASE SUMMARY

A 52-year-old male patient admitted to the hospital on October 23, 2021, with a progressive exacerbation of jaundice, was found to have multiple intrahepatic bile duct stones with the diagnoses of obstructive jaundice and acute cholecystitis. Subsequently, the patient underwent left hepatectomy with biliary exploration, stone extraction, T-tube drainage, and cholecystectomy without developing any intraoperative complications. The patient had a dark urine color with worsening jaundice postoperatively and did not respond well to plasma exchange and other symptomatic and supportive treatments. Since the progressive increase in postoperative bilirubin could not be clinically explained with any potential reason, including, if not at all, viral infection, cholangitis, autoimmune liver disease, and other causes, the patient underwent whole-exon screening for any genetic diseases, which surprisingly identified UGT1A1 and ABCB11 gene mutations related to glucuronidation of indirect bilirubin as well as bile acid transport in hepatocytes, respectively. Thus, we hypothesized that postoperative refractory cholestasis might result from UGT1A1 and ABCB11 gene mutations and further recommended liver transplantation to the patient, who eventually declined it and died from liver failure six months later.

CONCLUSION

Surgery may aggravate cholestasis in patients with multiple intrahepatic bile duct stones and cholestasis associated with UGT1A1 and ABCB11 gene mutations. A liver transplant may be the best option if active medical treatment fails.

The value of three-dimensional visualization techniques in hepatectomy for complicated hepatolithiasis: A propensity score matching study

OBJECTIVE

The present study aimed to investigate the safety, feasibility, and efficacy of three-dimensional visualization technique (3DVT)-guided hepatectomy in the treatment of complicated hepatolithiasis.

METHODS

The clinical and follow-up data of 279 patients with complicated hepatolithiasis were retrospectively analyzed. The patients were divided into a 3DVT group (group A, 66 cases) and a non-3DVT group (group B, 213 cases). After baseline data were balanced using propensity score matching (PSM), the clinical characteristics and follow-up data of the two groups were observed.

RESULTS

After 1:1 PSM, 58 patients in each group were successfully matched with each other. When the groups were compared, the surgical duration (p = 0.033) and intraoperative blood loss (p = 0.002) of group A were lower than those of group B. The immediate stone clearance rate (91.4% vs. 75.9%, p = 0.024) and quality of life outcome (p = 0.034) of group A were significantly higher than those of group B. Logistic regression analysis showed that history of two or more biliary tract operations (odds ratio [OR] = 6.544, 95% confidence interval [CI] = 1.193-35.890, p = 0.031), bilateral stone distribution (OR = 4.198, 95% CI = 1.186-14.854, p = 0.026), and Geng grade III or IV (OR = 12.262, 95% CI = 2.224-67.617, p = 0.004) were independent risk factors for poor outcomes in patients with complicated hepatolithiasis.

CONCLUSION

Compared to conventional imaging examinations, 3DVT can be used to guide and achieve accurate preoperative diagnosis of complicated hepatolithiasis and has good safety, feasibility, and efficacy.

Hepatolithiasis Classification Based on Anatomical Hepatectomy

BACKGROUND

This study aims to propose a novel classification system to standardize the treatment of hepatolithiasis.

METHODS

A hepatolithiasis classification named LHO was proposed to represent the distribution of stones in the segmental bile ducts and the hepatic atrophy associated with the stones (L), the existence of stones or strictures in the hilar bile duct (H), and dysfunction of the Oddi sphincter (O), which can be used to formulate ideal surgical protocols. One hundred and forty-seven primary hepatolithiasis patients treated between 2013 and 2018 were classified into different types and divided into two groups. If the patient's actual surgical procedure matched the ideal surgical protocol, the patients were included in the matching group; otherwise, patients were included in the nonmatching group. The rates of residual stones, recurrence, and a good quality of life (QOL) were analyzed among the patients in the matching and nonmatching groups and previous reports.

RESULTS

According to the classification of each patient, 77.6% of the patients were included in the matching group, and 22.4% were included in the nonmatching group. The rates of residual stones, recurrence, and a good QOL were significantly better in the matching group than in the nonmatching group (9.6% vs. 27.3%; 8.0% vs. 35.0%; 89.5% vs. 65.4%); the rates of residual stones and a good QOL were also better than those in previous reports (9.6% vs. 19.1%; 89.5% vs. 61.6%).

CONCLUSIONS

The LHO classification can comprehensively reflect the key points of treatment, which is beneficial for formulating effective and standardized surgical plans of hepatolithiasis.

Long-term outcomes of surgical approaches for bilateral hepatolithiasis: A real-world six-decade experience at a single center

BACKGROUND

Bilateral hepatolithiasis is an intractable disease and repeated attacks of acute cholangitis seriously threaten patient health. The surgical approaches evolve along with gradually greater understanding of its pathophysiology.

METHODS

This is a retrospective cohort study for bilateral hepatolithiasis from January 1958 to December 2018. Before May 1993 (Group A, n = 70), three surgical approaches were adopted: 37 patients with common bile duct exploration (CBDE), 29 with choledochoenterostomy (CE) and four with partial hepatectomy (PH). After June 1993 (Group B, n = 150), 101 patients underwent Oddi sphincter-preserved cholangioplasty with hepatico-subcutaneous stoma (OSPCHS), and 16 with CBDE, 21 with CE, 12 with PH. The perioperative and long-term outcomes were compared.

RESULTS

After 1993, the cholangitis recurrence rate significantly decreased from 49.2% to 20.9%, and the stone recurrence rate from 76.3% to 37.1% (both P < .001). Also, the stone-/cholangitis-free durations were prolonged significantly (median: 50.8 vs 26.4/49.6 vs 16.2 months, both P < .001). Preoperative cholangitis was an independent risk factor for stone recurrence (hazard ratio [HR] = 1.863, P = .018), and residual stone for cholangitis recurrence (HR = 2.838, P < .001). OSPCHS and PH were protective surgical approaches for recurrent stone (CBDE: reference; OSPCHS: HR = .469, P = .016, PH: HR = .219, P = .018) and cholangitis (CBDE: reference; OSPCHS: HR = .421, P = .010, PH: HR = .283, P = .093).

CONCLUSIONS

For bilateral hepatolithiasis, the management should focus on hepatobiliary lesion eradication and Oddi sphincter function preservation.

New clinical pathological classification and treatment system for hepatolithiasis

Hepatolithiasis is a complex disease with extensive lesions. There are currently many clinical classifications available. However, these classifications cannot accurately reflect the pathological changes and degree of hepatolithiasis, and are not conducive to communication. Various methods are used for treatment of hepatolithiasis, but they are often misused. We tried to establish a new HLDO classification based on the clinicopathological characteristics of hepatolithiasis and a treatment system based on this classification, so as to comprehensively and accurately describe the pathological changes and degree, scientifically and reasonably treat it, and reduce its residual stone rate and recurrence rate.

Hepatolithiasis: clinical series, review and current management strategy

Objectives

Hepatolithiasis (HL) continues to be a problem due to its local and systemic complications, insufficiency in treatment modalities and high risk of recurrence. There are various surgical options available, ranging from endoscopic interventions to a small segment resection and ultimately to transplantation. In this article, patients with the diagnosis of HL and our treatment strategies were evaluated in the light of literature.

Material and Methods

The patients diagnosed with HL in our clinic between 2014-2019 were evaluated retrospectively by examining the patient files. Demographic characteristics of the patients, causes of the disease, complications and treatment options were evaluated.

Results

17 patients were included into the study. Mean age of the patients was 64.3 years (range 32-89 years). Seven patients had previous cholecystectomies. Stenosis was found to be developed in hepaticojejunostomy (HJ) site in three patients (two had HJ due to bile duct injury and one had HJ following the Whipple procedure), and in hepaticoduodenostomy site in one patient who had the history of biliary tract injury during cholecystectomy. Two patients with HL without previous cholecystectomies had no gallbladder stones. Nine patients underwent surgery. Left hepatectomy was performed in two patients and lateral sector resection was performed in 2 patients. Two patients with anastomotic stenosis underwent HJ revision and two patients with anastomotic stenosis and one patient with stent ingrowth underwent bifurcation resection and neo-hepaticojejunostomy. Eight patients were followed-up nonoperatively with medical and endoscopic approaches.

Conclusion

Hepatolithiasis is a serious condition that needs to be treated with a multimodal approach. Stenting and anastomotic stenosis facilitate the development of hepatolithiasis and increase the risk of its occurrence. In particular, by performing functional hepaticojejunostomy, the development of this complication will be decreased.

Surgical resection for non-Asian intrahepatic lithiasis: The Brazilian experience

BACKGROUND

Intrahepatic lithiasis (IHL) is a rare disease in the western world. Complications associated with IHL include acute cholangitis, liver atrophy, secondary biliary cirrhosis, and risk for intrahepatic cholangiocarcinoma. Liver resection is considered the treatment of choice for IHL. The objective of this study was to analyze patients who underwent liver resection for non-Asian hepatolithiasis.

METHODS

127 patients with symptomatic non-Asian hepatolithiasis underwent resection in six institutions. Demographic data, clinical presentation, diagnosis, classification according to stone location, presence of atrophy, bile duct stricture, biliary cirrhosis, incidence of cholangiocarcinoma, treatment and postoperative course were evaluated.

RESULTS

52 patients (40.9%) were male and the mean age was 46.1 years. Sixty-six patients (51.9%) presented with history of cholangitis. Stones were located in the left lobe in 63 (49.6%), and right lobe in 28 patients (22.0%). Atrophy was observed in 31 patients (24.4%) and biliary stenosis in 18 patients (14.1%). The most common procedure performed was left lateral sectionectomy in 63 (49.6%) patients, followed by left hepatectomy in 36 (28.3%), right hepatectomy in 19 (15.0%), and associated hepaticojejunostomy in 28 (22.0%). Forty-two patients (33.0%) presented postoperative complications and the most common were biliary fistula (13.3%) and surgical site infection (7.0%). Postoperative mortality was 0.7%. Intrahepatic cholangiocarcinoma was observed in 2 patients (1.5%). Recurrence was identified in 10 patients (7.8%), mostly with bilateral stones and/or hepaticojejunostomy.

CONCLUSION

Liver resection is the standard treatment for symptomatic unilateral or complicated IHL with good operative results. Risk of cholangiocarcinoma was low in non-Asian patients.

T-tube drainage versus choledochojejunostomy in hepatolithiasis patients with sphincter of Oddi laxity: study protocol for a randomized controlled trial

Background

Residual and recurrent stones remain one of the most important challenges of hepatolithiasis and are reported in 20 to 50% of patients treated for this condition. To date, the two most common surgical procedures performed for hepatolithiasis are choledochojejunostomy and T-tube drainage for biliary drainage. The goal of the present study was to evaluate the therapeutic safety and perioperative and long-term outcomes of choledochojejunostomy versus T-tube drainage for hepatolithiasis patients with sphincter of Oddi laxity (SOL).

Methods/design

In total, 210 patients who met the following eligibility criteria were included and were randomized to the choledochojejunostomy arm or T-tube drainage arm in a 1:1 ratio: (1) diagnosed with hepatolithiasis with SOL during surgery; (2) underwent foci removal, stone extraction and stricture correction during the operation; (3) provided written informed consent; (4) was willing to complete a 3-year follow-up; and (5) aged between 18 and 70 years. The primary efficacy endpoint of the trial will be the incidence of biliary complications (stone recurrence, biliary stricture, cholangitis) during the 3 years after surgery. The secondary outcomes will be the surgical, perioperative and long-term follow-up outcomes.

Discussion

This is a prospective, single-centre and randomized controlled two-group parallel trial designed to demonstrate which drainage method (Roux-en-Y hepaticojejunostomy or T-tube drainage) can better reduce biliary complications (stone recurrence, biliary stricture, cholangitis) in hepatolithiasis patients with SOL.

Trial registration

Clinical Trials.gov: NCT04218669. Registered on 6 January 2020.

LIVER RESECTION FOR NON-ORIENTAL HEPATOLITHIASIS

Background:

Primary intrahepatic lithiasis is defined when the stones are formed in the liver and associated with local dilatation and biliary stricture. Liver resection is the ideal procedure.

Aim:

To evaluate the results of liver resection in the treatment of non-oriental intrahepatic lithiasis.

Methods:

Fifty-one patients with symptomatic benign non-oriental hepatolithiasis underwent surgical resection in six institutions in Brazil. Demography data, clinical symptoms, classification, diagnosis, management and postoperative course were analyzed.

Results:

Of the 51 patients, 28 were male (54.9%), with a mean age of 49.3 years. History of cholangitis was observed in 15 (29.4%). The types of intrahepatic lithiasis were type I in 39 (76.5%) and type IIb in 12 (23.5%), with additional type Ea in six (11.8%). Liver function test were normal in 42 patients (82.4%). Segmental atrophy was observed in 12 (23.5%). Treatments included left lateral sectionectomy in 24 (47.1%), left hepatectomy in 14 (27.5%) and right hepatectomy in eight (15.7%), with associated hepaticojejunostomy in four (7.8%). Laparoscopic liver resection was performed in eight (15.7%). Postoperative complications were observed in 20 (39.2%) with no mortality.

Conclusion:

Liver resection in patients with hepatolithiasis is the ideal procedure as it removes stones, stricture, atrophic parenchyma, and minimizes the risk of cholangiocarcinoma.

Biliary tract exploration through a common bile duct incision or left hepatic duct stump in laparoscopic left hemihepatectomy for left side hepatolithiasis: which is better?: A single-center retrospective case-control study

Laparoscopic left hemihepatectomy (LLH) followed by biliary tract exploration is used to treat left-sided hepatolithiasis (LSH). The purpose of this study was to compare the efficacy of 2 methods of biliary tract exploration in LLH:biliary tract exploration through a common bile duct (CBD) incision (with T-tube drainage) or through the left hepatic duct (LHD) stump (without T-tube drainage).LSH patients (113 patients) were recruited retrospectively in our hospital from December 2008 to January 2016. To compare different methods of biliary tract exploration during LLH, the patients were divided into 2 groups: 41 patients underwent biliary tract exploration through the LHD stump (LHD group), and 72 patients underwent biliary tract exploration through a CBD incision (CBD group). Baseline characteristics, surgical outcomes, surgery-related complications, postoperative hospital stay (PHS) and long-term results were compared between the 2 groups.There was no unplanned reoperation in the 2 groups. One patient in the CBD group had a residual stone, which was removed by choledochoscopy 2 months postoperation. Two patients in the LHD group and 3 patients in the CBD group had bile leakage and were cured with abdominal drainage. There were no significant differences in the total operation time, incidence of residual stones and bile leakage between the 2 groups (P > .05). The PHS and the incidence of hypokalemia or hyponatremia in the LHD group were significantly lower than those in the CBD group (P < .05). T-tube-related complications occurred in 13.9% (10/72) of the CBD patients. The mean follow-up period was 37.2 ± 13.8 months. There were no significant differences in the incidence of recurrence stones or cholangitis (P > .05) between the 2 groups.Exploration of the biliary tract through the LHD stump without T-tube drainage is safe with satisfactory short- and long-term results for selected LSH patients.

Liver transplantation for hepatolithiasis: Is terminal hepatolithiasis suitable for liver transplantation?

Hepatolithiasis, originally as oriental cholangiohepatitis, especially prevails in Asia, but globalization and intercontinental migration have also converted the endemic disease dynamics around the world. Characterized by its high incidence of ineffective treatment and recurrence, hepatolithiasis, always, poses a therapeutic challenge to global doctors. Although the improved surgical and non-surgical techniques have evolved over the past decade, incomplete clearance and recurrence of calculi are always so common and disease-related mortality from liver failure and concurrent cholangiocarcinoma still exists in the treatment of hepatolithiasis. In the late stage of hepatolithiasis, is it suitable for liver transplantation (LT)? Herein, we propose a comprehensive review and analysis of the LTx currently in potential use to treat hepatolithiasis. In our subjective opinion, and as is objective from the literatures so far, also given the strict indications, LT remains one of the definitive treatments for terminal hepatolithiasis.

Negative short-term impact of intraoperative biliary lavage in patients with hepatolithiasis

AIM: To evaluate short-term outcomes following intraoperative biliary lavage for hepatolithiasis.

METHODS: A total of 932 patients who were admitted to the West China Medical Center of Sichuan University between January 2010 and January 2014 and underwent bile duct exploration and lithotomy were retrospectively included in our study. The patients were divided into the lavage group and the control group. Related pre-, intra-, and postoperative factors were recorded, analyzed, and compared between the two groups in order to verify the effects of biliary lavage on the short-term outcome of patients with hepatolithiasis.

RESULTS: Amongst the patients who were included, 678 patients with hepatolithiasis were included in the lavage group, and the other 254 patients were enrolled in the control group. Data analyses revealed that preoperative baseline and related intraoperative variables were not significantly different. However, patients who underwent intraoperative biliary lavage had prolonged postoperative hospital stays (6.67 d vs 7.82 d, P = 0.024), higher hospitalization fees (RMB 28437.1 vs RMB 32264.2, P = 0.043), higher positive rates of bacterial cultures from blood (13.3% vs 25.8%, P = 0.001) and bile (23.6% vs 40.7%, P = 0.001) samples, and increased usage of advanced antibiotics (26.3% vs 38.2%, P = 0.001). In addition, in the lavage group, more patients had fever (> 37.5 °C, 81.4% vs 91.1%, P = 0.001) and hyperthermia (> 38.5°C，39.7% vs 54.9%, P = 0.001), and higher white blood cell counts within 7 d after the operation compared to the control group.

CONCLUSION: Intraoperative biliary lavage might increase the risk of postoperative infection, while not significantly increasing gallstone removal rate.

Hepatolithiasis and intrahepatic cholangiocarcinoma: A review

Although the incidence of hepatolithiasis is decreasing as the pattern of gallstone disease changes in Asia, the prevalence of hepatolithiasis is persistently high, especially in Far Eastern countries. Hepatolithiasis is an established risk factor for cholangiocarcinoma (CCA), and chronic proliferative inflammation may be involved in biliary carcinogenesis and in inducing the upregulation of cell-proliferating factors. With the use of advanced imaging modalities, there has been much improvement in the management of hepatolithiasis and the diagnosis of hepatolithiasis-associated CCA (HL-CCA). However, there are many problems in managing the strictures in hepatolithiasis and differentiating them from infiltrating types of CCA. Surgical resection is recommended in cases of single lobe hepatolithiasis with atrophy, uncontrolled stricture, symptom duration of more than 10 years, and long history of biliary-enteric anastomosis. Even after resection, patients should be followed with caution for development of HL-CCA, because HL-CCA is an independent prognostic factor for survival. It is not yet clear whether hepatic resection can reduce the occurrence of subsequent HL-CCA. Furthermore, there are no consistent findings regarding prediction of subsequent HL-CCA in patients with hepatolithiasis. In the management of hepatolithiasis, important factors are the reduction of recurrence of cholangitis and suspicion of unrecognized HL-CCA.