Identifying the early predictors of non-response to steroids in patients with flare of autoimmune hepatitis causing acute-on-chronic liver failure.

BACKGROUND AND AIMS: Early identification of non-response to steroids is critical in patients with autoimmune hepatitis (AIH) causing acute-on-chronic liver failure (ACLF). We assessed if this non-response can be accurately identified within first few days of treatment. METHODS: Patients with AIH-ACLF without baseline infection/hepatic encephalopathy were identified from APASL ACLF research consortium (AARC) database. Diagnosis of AIH-ACLF was based mainly on histology. Those treated with steroids were assessed for non-response (defined as death or liver transplant at 90 days for present study). Laboratory parameters, AARC, and model for end-stage liver disease (MELD) scores were assessed at baseline and day 3 to identify early non-response. Utility of dynamic SURFASA score [- 6.80 + 1.92*(D0-INR) + 1.94*(∆%3-INR) + 1.64*(∆%3-bilirubin)] was also evaluated. The performance of early predictors was compared with changes in MELD score at 2 weeks. RESULTS: Fifty-five out of one hundred and sixty-five patients (age-38.2 ± 15.0 years, 67.2% females) with AIH-ACLF [median MELD 24 (IQR: 22-27); median AARC score 7 (6-9)] given oral prednisolone 40 (20-40) mg per day were analyzed. The 90 day transplant-free survival in this cohort was 45.7% with worse outcomes in those with incident infections (56% vs 28.0%, p = 0.03). The AUROC of pre-therapy AARC score [0.842 (95% CI 0.754-0.93)], MELD [0.837 (95% CI 0.733-0.94)] score and SURFASA score [0.795 (95% CI 0.678-0.911)] were as accurate as ∆MELD at 2 weeks [0.770 (95% CI 0.687-0.845), p = 0.526] and better than ∆MELD at 3 days [0.541 (95% CI 0.395, 0.687), p < 0.001] to predict non-response. Combination of AARC score > 6, MELD score > 24 with SURFASA score ≥ - 1.2, could identify non-responders at day 3 (concomitant- 75% vs either - 42%, p < 0.001). CONCLUSION: Baseline AARC score, MELD score, and the dynamic SURFASA score on day 3 can accurately identify early non-response to steroids in AIH-ACLF.

Estimation of liver volume in the western Indian population.

BACKGROUND: A number of formulae to estimate standard liver volume (SLV) exist. However, studies have shown that only certain formulae are applicable to a particular patient population, whereas the other formulae have not been accurate in estimating the SLV. Aim of this study was to assess which formula is most accurate in estimating SLV in the western Indian population. METHODS: Data for donors of living donor liver transplantation from September 2014 to July 2015 was analyzed. Liver volumes were measured using computed tomography volumetry (CTV). SLV was calculated using formulae by the currently existing formulae. The mean SLV and CTV, percentage error in the SLV, and the correlation between SLV and CTV were calculated. RESULTS: Fifty-nine healthy subjects underwent donor hepatectomy [28 (47.5 %) males]. The mean age, mean body mass index (BMI), and mean body surface area (BSA) were 31.8 ± 8.8 years, 23.8 ± 3.7 kg/m(2), and 1.6 ± 0.4, respectively. Mean CTV was 1178 ± 246.8 mL. Difference between mean SLV and mean CTV ranged from -133.5 (±189) mL to 632.2 (±190.2) mL. Mean SLV was significantly different from CTV by all the formulae except Urata. Percentage of population whose SLV was within 15 % of the mean CTV ranged from 1.7 % to 67.8 %, with the highest percentage obtained by using Fu-Gui's formula. However, there was wide inter-individual variation on scatter plots between SLV and CTV by both these formulae. CONCLUSION: Currently existing formulae were not accurate in estimating SLV in our population.

The Impact of Ischemia/Reperfusion Injury on Liver Allografts from Deceased after Cardiac Death versus Deceased after Brain Death Donors.

BACKGROUND AND AIMS: The shortage of organs for transplantation has led to increased use of organs procured from donors after cardiac death (DCD). The effects of cardiac death on the liver remain poorly understood, however. Using livers obtained from DCD versus donors after brain death (DBD), we aimed to understand how ischemia/reperfusion (I/R) injury alters expression of pro-inflammatory markers ceramides and influences graft leukocyte infiltration. METHODS: Hepatocyte inflammation, as assessed by ceramide expression, was evaluated in DCD (n = 13) and DBD (n = 10) livers. Allograft expression of inflammatory and cell death markers, and allograft leukocyte infiltration were evaluated from a contemporaneous independent cohort of DCD (n = 22) and DBD (n = 13) livers. RESULTS: When examining the differences between transplant stages in each group, C18, C20, C24 ceramides showed significant difference in DBD (p<0.05) and C22 ceramide (p<0.05) were more pronounced for DCD. C18 ceramide is correlated to bilirubin, INR, and creatinine after transplant in DCD. Prior to transplantation, DCD livers have reduced leukocyte infiltration compared to DBD allografts. Following reperfusion, the neutrophil infiltration and platelet deposition was less prevalent in DCD grafts while cell death and recipients levels of serum aspartate aminotransferase (AST) of DCD allografts had significantly increased. CONCLUSION: These data suggest that I/R injury generate necrosis in the absence of a strong inflammatory response in DCD livers with an appreciable effect on early graft function. The long-term consequences of increased inflammation in DBD and increased cell death in DCD allografts are unknown and warrant further investigation.

Benign histology after pancreaticoduodenectomy for suspected malignancy. Lessons to be learned--a single centre experience.

UNLABELLED: The aim of the study was to perform a comprehensive analysis of patients with a benign final histology after pancreaticoduodenectomies (PD) for suspected pancreatic and periampullary cancer. MATERIAL AND METHODS: We searched the pathology database at the King's College Hospital for negative PD specimens submitted between January 2004-December 2010. Clinical, diagnostic, surgical,histopathological and outcome data were collected retrospectively. Pathology specimens and imaging results have been re-evaluated. A literature review was performed to identify factors affecting the incidence across centres. RESULTS: 469 PD were performed for presumed cancer. The incidence of benign disease encountered in this group was 7.25% (34/469). Autoimmune pancreatitis (AIP) was a finding in 26.47% (9/34) of cases. 17.65% of PD were complicated by a pancreatic leak and the overall mortality rate was 8.82%(3/34). Radiologists revised over 75% of pre-operative diagnoses. The incidence of benign disease was correlated with the overall centre experience and utilisation of CT imaging, but not ERCP or EUS. CONCLUSIONS: It is impossible with current diagnostics to entirely avoid cases of benign disease inpatients undergoing PD for suspected cancer. The mortality rate is higher in this group, but it is possible to avoid unnecessary procedures in experienced centres. AIP represents an important diagnostic entity, which should be actively pursued pre-operatively.

Tuberculosis in liver transplant recipients: experience of a South Indian liver transplant center.

Tuberculosis (TB) is a serious disease for liver transplant recipients (LTRs). Data on post-liver transplant TB from high-burden countries are scant. The aims of this study were to describe the prevalence of TB in LTRs from a high-prevalence area and to analyze the risk factors for the development of post-liver transplant TB. We performed a retrospective review of our database and a case-control study of identified cases with TB and age-matched LTRs without TB. The overall prevalence of TB in LTRs was comparable to the prevalence of TB in LTRs from low-prevalence countries (5/214 or 2.3%). A low rate of interferon-γ release assay (IGRA) testing before liver transplantation was observed (68/214 or 31%). Most patients were screened clinically and with chest radiography alone before transplantation. TB developed variably after transplantation [median = 72 days, interquartile range (IQR) = 534 days]. The presentation was mostly extrapulmonary and/or disseminated (4/5 or 80%). When cases with posttransplant TB were compared with matched healthy LTRs, the presence of unexplained granulomas in explants (2/5 or 40%, P = 0.01) was the only factor associated with the development of TB. When all explants showing granulomas were reviewed, TB (52.9%) remained the most common cause; however, in almost half (47.1%), other attributable causes were found. Patients were treated with a standard daily regimen for a median of 12 months (IQR = 7.5 months). Posttransplant TB was associated with a high mortality rate (2/5 or 40%). In conclusion, we observed a low prevalence of TB in LTRs from a high-prevalence region. The presence of granulomas suggestive of TB in liver explants warrants isoniazid prophylaxis in the absence of disease. Post-liver transplant TB is associated with a high mortality rate. The roles of routine IGRA testing and isoniazid prophylaxis in a high-prevalence setting urgently need to be studied.

Lessons from look-back in acute liver failure? A single centre experience of 3300 patients.

BACKGROUND & AIMS: Acute liver failure (ALF) is a rapidly progressive critical illness with high mortality. Complex intensive care unit (ICU) protocols and emergency liver transplantation (ELT) are now often available, but rarity and severity of illness have limited its study and evidence-base for care. We reviewed patients treated over a 35-year period at a specialist high-volume ICU, quantifying changes in disease aetiology, severity and evolution of ICU support and ELT use and outcome. METHODS: Review of adult patients admitted during the period 1973-2008, with acute liver dysfunction and coagulopathy with overt hepatic encephalopathy (ALF) and those without (acute liver injury; ALI). RESULTS: 3305 patients fulfilled inclusion criteria, 2095 with ALF. Overall hospital survival increased from 30% in 1973-78 to 76% in 2004-08; in ALF from 17% to 62% (both p<0.0001). In ALF patients treated without ELT, survival rose from 17% to 48% (p<0.0001); in those undergoing ELT (n=387) from 56% in 1984-88 to 86% in 2004-08 (p<0.01). Coincident with drug sales-restriction, paracetamol-related admissions fell significantly. Viral admissions fell from 56% to 17% of non-paracetamol cases (p<0.0001). Admission markers of liver injury severity fell significantly and the proportion of patients with intracranial hypertension (ICH) fell from 76% in 1984-88 to 20% in 2004-08 (p<0.0001). In those with ICH, mortality fell from 95% to 55% (p<0.0001). CONCLUSIONS: The nature and outcome of ALF have transformed over 35 years, with major improvements in survival and a fall in prevalence of cerebral oedema and ICH, likely consequent upon earlier illness recognition, improved ICU care, and use of ELT.

The impact of inflammatory bowel disease post-liver transplantation for primary sclerosing cholangitis.

BACKGROUND: An association between primary sclerosing cholangitis (PSC) and inflammatory bowel disease (IBD) is well recognized. However, the disease course of IBD following liver transplantation (LT) for PSC remains ill-defined. AIMS AND METHODS: We aimed to assess the impact of IBD in patients that had undergone LT for PSC to help identify risk factors for flare and to assess the impact of IBD on graft survival. RESULTS: 110 patients underwent LT for PSC (Oct 1990-Aug 2009) at King's College Hospital. 74 (67%) patients had concurrent IBD and 36 had PSC alone prior to transplant. 39 patients developed IBD (flare of IBD and de-novo) post transplant. Cumulative risk for IBD at 1-, 2-, 5- and 10-years was 16%, 24%, 38% and 72% respectively. Flare of IBD occurred in 33 patients with a mean time to flare of 30 ± 28 months. De-novo IBD occurred in 6 patients (all UC). Mean time to diagnosis was 29 ± 25 months. Multivariate cox-regression analysis identified active IBD at time of LT as a significant predictor of graft failure post LT (HR 10, CI 3-39, P = 0.001) and smoking at time of transplantation and subsequent cessation predictive of recurrent IBD post transplantation (HR 17, 2-180, P = 0.02). CONCLUSION: In conclusion, smoking at time of LT was predictive of flare of IBD and active IBD at time of transplantation had a significant effect on graft survival. Medical therapy needs to be maximised in the pre-LT period. Patients with poorly controlled IBD refractory to medical therapy should be considered for colectomy at time of transplantation.

The effect of body position on compartmental intra-abdominal pressure following liver transplantation.

BACKGROUND: Current assumptions rely on intra-abdominal pressure (IAP) being uniform across the abdominal cavity. The abdominal contents are, however, a heterogeneous mix of solid, liquid and gas, and pressure transmission may not be uniform. The current study examines the upper and lower IAP following liver transplantation. METHODS: IAP was measured directly via intra-peritoneal catheters placed at the liver and outside the bladder. Compartmental pressure data were recorded at 10-min intervals for up to 72 h following surgery, and the effect of intermittent posture change on compartmental pressures was also studied. Pelvic intra-peritoneal pressure was compared to intra-bladder pressure measured via a FoleyManometer. RESULTS: A significant variation in upper and lower IAP of 18% was observed with a range of differences of 0 to 16 mmHg. A sustained difference in inter-compartmental pressure of 4 mmHg or more was present for 23% of the study time. Head-up positioning at 30° provided a protective effect on upper intra-abdominal pressure, resulting in a significant reduction in all patients. There was excellent agreement between intra-bladder and pelvic pressure. CONCLUSIONS: A clinically significant variation in inter-compartmental pressure exists following liver transplantation, which can be manipulated by changes to body position. The existence of regional pressure differences suggests that IAP monitoring at the bladder alone may under-diagnose intra-abdominal hypertension and abdominal compartment syndrome in these patients. The upper and lower abdomen may need to be considered as separate entities in certain conditions.

Liver transplantation for propionic acidemia in children.

Propionic acidemia (PA) is a rare inherited disorder of branched chain amino acid metabolism; despite improvements in conventional medical management, the long-term outcome remains disappointing. Liver transplantation (LT) has been proposed to minimize the risk of further metabolic decompensations and to improve the quality of life. We performed a retrospective review of all children with PA who underwent LT between 1987 and 2008. Five children were identified with a median age of 1.2 years (range = 0.7-4.1 years) at referral. Four of the children presented clinically at 3 weeks of age or less, and 1 child was diagnosed prenatally. All had metabolic acidosis and hyperammonemia. Two had seizures and required intensive care; this care included inotropic support and continuous venovenous hemofiltration in 1 child. The children were considered for elective LT for the following reasons: frequent metabolic decompensations (2), previous sibling death (2), and elective management (1). One child underwent auxiliary LT, and 4 children received orthotopic grafts (1 living related graft). The median age at LT was 1.5 years (range = 0.8-7.0 years). There was 1 retransplant 3 months after LT due to hepatic artery thrombosis. One year after LT, 1 patient suffered a metabolic stroke with minimal residual neurology. After a median follow-up of 7.3 years (range = 2.2-15.0 years), all the children had normal graft function and a good quality of life with a protein-unrestricted diet and no further metabolic decompensations. In conclusion, LT has a role in the management of PA: it reduces the risk of metabolic decompensation and improves the quality of life. The potential for the development of metabolic sequelae is not completely eliminated.

Long-term outcome and management of hepatopulmonary syndrome in children.

UNLABELLED: We aim to report a single center experience of the management and long term outcome of HPS in pediatric liver transplant recipients. A retrospective review of children with HPS from 1990 to 2004. INCLUSION CRITERIA: liver disease or portal hypertension, hypoxemia (PaO(2) < 70 mmHg or SaO(2) < 95%) and intrapulmonary shunting documented by macroaggregated albumin scan ratio of >4% (classified mild group [<20%], moderate group [20-40%] and severe group [>40%]). Resolution of HPS post-liver transplant was defined as PaO(2) > 70 mmHg or SaO(2) > 95%. Eighteen children (six male [34%], median age at diagnosis of HPS 8.6 [1-15.5] yr) had HPS: biliary atresia (n = 8), idiopathic biliary cirrhosis (n = 4), progressive intrahepatic cholestasis (n = 2), miscellaneous (n = 4). The majority had mild shunting (n = 8). Fourteen underwent transplantation with resolution of HPS in 13. Six developed complications: hepatic artery thrombosis (n = 4), biliary (n = 2). Four children died (28%), two pretransplant. There was a tendency towards shunt fraction worsening to a slower degree over time. One-yr survival rate post-transplant was 93%. Median PaO(2) was significantly lower in non-survivors compared to survivors (43 vs. 55.2 mmHg, p = 0.03). There was correlation between oxygen parameters pretransplant and time to HPS resolution post-transplant. HPS is reversible after transplant, but is associated with increasing mortality and morbidity.

Pediatric liver transplantation for metabolic liver disease: experience at King's College Hospital.

AIMS: The aims of this article were to report a single-center experience of pediatric liver transplantation for liver-based metabolic disorders and to compare the outcome of cirrhotic versus noncirrhotic metabolic liver disease. METHODS: The medical records of 96 patients younger than 18 years undergoing transplantation for liver-based metabolic disorders from 1989 to 2005 were reviewed. RESULTS: Hundred twelve transplants were performed in 96 patients at a median age of 59.7 months (range, 0-208 months). The cumulative 1-, 5-, and 10-year graft and patient survival rates were 83%, 77%, and 62% and 91%, 86%, and 82%, respectively. Acute liver failure at first presentation (hazard ratio [HR] 3.0; 95% confidence interval [CI] 1.1-8.1), age less than 1 year at time of transplantation (HR 4.6; 95% CI 1.7-12.4) and hospitalization (HR 3.2; 95% CI 1.1-9.3) were significant predictors of worse patient survival. For noncirrhotic disorders, the long-term patient (100% vs. 100%, 90% vs. 100%, and 90% vs. 75%, P=0.87) and graft survivals (93% vs. 100%, 70% vs. 100%, and 70 vs. 75%, P=0.12) at 1, 5, and 7 years for auxiliary versus orthotopic transplantation were not significantly different. CONCLUSIONS: Long-term patient survival after transplantation for metabolic disorders is excellent for both cirrhotic and noncirrhotic metabolic disorders. For noncirrhotic metabolic disorders, auxiliary transplantation has similar patient and graft survival compared with orthotopic transplantation, but further research is recommended.

Outcome after wait-listing for emergency liver transplantation in acute liver failure: a single centre experience.

BACKGROUND/AIMS: Though emergency liver transplantation (ELT) is an established treatment for severe acute liver failure (ALF), outcomes are inferior to elective surgery. Despite prioritization, many patients deteriorate, becoming unsuitable for ELT. METHODS: We examined a single-centre experience of 310 adult patients with ALF registered for ELT over a 10-year period to determine factors associated with failure to transplant, and in those patients undergoing ELT, those associated with 90-day mortality. RESULTS: One hundred and thirty-two (43%) patients had ALF resulting from paracetamol and 178 (57%) from non-paracetamol causes. Seventy-four patients (24%) did not undergo surgery; 92% of these died. Failure to transplant was more likely in patients requiring vasopressors at listing (hazard ratio 1.9 (95% CI 1.1-3.6)) paracetamol aetiology (2.5 (1.4-4.6)) but less likely in blood group A (0.5 (0.3-0.9)). Post-ELT survival at 90-days and one-year increased from 66% and 63% in 1994-1999 to 81% and 79% in 2000-2004 (p<0.01). Four variables were associated with post-ELT mortality; age >45 years (3 (1.7-5.3)), vasopressor requirement (2.2 (1.3-3.8), transplantation before 2000 (1.9 (1.1-3.3)) and use of high-risk grafts (2.3 (1.3-4.2). CONCLUSIONS: The data indicate improved outcomes in the later era, despite higher level patient dependency and greater use of high-risk grafts, through improved graft/recipient matching.

Safety and efficacy of combined use of sildenafil, bosentan, and iloprost before and after liver transplantation in severe portopulmonary hypertension.

Portopulmonary hypertension (PPHTN) represents a constrictive pulmonary vasculopathy in patients with portal hypertension. Liver transplantation (LT) may be curative and is usually restricted to patients with mild-to-moderate disease severity characterized by a mean pulmonary artery pressure (mPAP < 35 mm Hg). Patients with severe disease (mPAP > 50 mm Hg) are usually excluded from transplantation. We describe a patient with severe PPHTN, initiated on sequential and ultimately combination therapy of prostacyclin, sildenafil, and bosentan (PSB) pretransplantation and continued for 2 years posttransplantation. Peak mPAP on PSB therapy was dramatically reduced from 70 mm Hg to 32 mm Hg pretransplantation, and continued therapy facilitated a further fall in mPAP to 28 mm Hg posttransplantation. The pulmonary vascular resistance index fell from 604 to 291 dyne second(-1) cm(-5). The perioperative mPAP rose to 100 mm Hg following an episode of sepsis and fell with optimization of PSB therapy. In conclusion, this is the first reported patient with severe PPHTN using this combination of vasodilator therapy as a bridge to LT and then as maintenance in the posttransplantation phase. This regimen may enable LT in similar patients in the future, without long-term consequences.

Liver transplantation in patients over 60 and 65 years: an evaluation of long-term outcomes and survival.

With increased demand for liver transplantation (LT), outcomes of older recipients have been subjected to greater scrutiny, as previous studies have demonstrated poorer survival outcomes. Outcomes of 77 patients aged>65 yr (group 1) who underwent transplantation between 1988 and 2003 at King's College Hospital, London, were compared with all recipients aged between 60 and 64 yr (group 2, n=137) and 202 time-matched control patients with chronic liver disease aged between 18-59 yr (group 3). Patient survival at 30-days for groups 1, 2, and 3 were 99%, 94%, and 94%, respectively (P=not significant [NS]). At 1-yr, survival in the 3 groups was 82%, 86%, and 83%, respectively (P=NS), and at 5-yr patient survival was comparable (73%, 80%, and 78%, respectively) (P=NS). Episodes of acute cellular rejection (ACR) were fewer in the older cohorts (43% vs. 45% vs. 61%, P=0.0016), although there was no significant difference identified in the numbers of patients in each group who experienced ACR (P=0.16). A similar but nonsignificant trend was identified for rates of chronic rejection among the groups. In conclusion, these data suggest that survival of patients over 60 and 65 yr undergoing LT is satisfactory, at least in the first 5-yr posttransplantation. In addition, patients over 65 yr experience less rejection, with good graft survival. Thus, LT should not be denied to patients>65 yr on the basis of age alone, once a comprehensive screen for comorbidity has been undertaken.

Change in model for end-stage liver disease score on the transplant waiting list predicts survival in patients undergoing liver transplantation.

Allocation of donor livers through the model for end-stage liver disease (MELD) score has resulted in a fall in waiting list deaths in the United States. Change in MELD score (DeltaMELD) whilst awaiting transplant has been suggested as a method of refining organ allocation. Our aims were to analyse the effect of DeltaMELD between listing and transplant, and examine its impact on patient survival, intensive care stay and hospital stay in 402 patients transplanted for chronic liver disease at a single centre. Patients who had a DeltaMELD score of >+1 point were more likely to die in hospital following transplant (P < 0.05) and had a significantly worse 12- and 36-month survival post transplant (P < 0.0001) when compared with patients with DeltaMELD

Pregnancy outcome after liver transplantation: a single-center experience of 71 pregnancies in 45 recipients.

Infertility is common in women with end-stage liver disease. Successful liver transplant (LT), however, can restore childbearing potential. Controversy exists regarding the most appropriate immunosuppressive regimen and timing of conception following LT. We report the outcomes of a review of all pregnancies occurring following LT at King's College Hospital, London, from 1988 to 2004. Seventy-one pregnancies were recorded in 45 women. Tacrolimus (60%) and cyclosporin A (38%) were the predominant primary immunosuppressive agents used. Median age at conception was 29 years (range, 19-42), with a median time from LT to conception of 40 months (range, 1-111). There were 50 live births, and no maternal or fetal deaths related to pregnancy. There were no graft losses. Median gestation was 37 weeks (range, 24-42) with a median birth weight of 2,690 g (range, 554-4,260). Caesarean section was performed in 40% of pregnancies. Complications included pregnancy-induced hypertension in 20%, preeclampsia in 13%, acute cellular rejection in 17%, and renal impairment in 11%. There was no statistically significant difference in complication rates observed between immunosuppressive groups. Pregnancies occurring within 1-year posttransplant had an increased incidence of prematurity, low birth weight, and acute cellular rejection compared to those occurring later than 1 year. In conclusion, this study confirms that favorable outcomes of pregnancy post-LT can be expected for the majority of patients. However, delaying pregnancy until after 1-year post-LT is advisable, since doing so maybe associated with a lower risk of prematurity.

Systematic review and validation of prognostic models in liver transplantation.

A model that can accurately predict post-liver transplant mortality would be useful for clinical decision making, would help to provide patients with prognostic information, and would facilitate fair comparisons of surgical performance between transplant units. A systematic review of the literature was carried out to assess the quality of the studies that developed and validated prognostic models for mortality after liver transplantation and to validate existing models in a large data set of patients transplanted in the United Kingdom (UK) and Ireland between March 1994 and September 2003. Five prognostic model papers were identified. The quality of the development and validation of all prognostic models was suboptimal according to an explicit assessment tool of the internal, external, and statistical validity, model evaluation, and practicality. The discriminatory ability of the identified models in the UK and Ireland data set was poor (area under the receiver operating characteristic curve always smaller than 0.7 for adult populations). Due to the poor quality of the reporting, the methodology used for the development of the model could not always be determined. In conclusion, these findings demonstrate that currently available prognostic models of mortality after liver transplantation can have only a limited role in clinical practice, audit, and research.