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DESARROLLO EXPERIMENTAL

In document Instituto Politécnico Nacional (página 53-120)

6.3.1 Introduction

AH often precipitates decompensation in patients with alcoholic cirrhosis and this

may lead to associated organ failure. It has also been suggested that histological

necrosis and an acute inflammatory infiltrate contributes to the worsening of portal

hypertension in these patients (132). Our previous study on the effects of anti-TNF

therapy and those o f others(147) suggest that the inflammatory mediators of AH,

especially pro-inflammatory cytokines such as TNFa, are especially important, and

modulation of these factors may result in an amelioration o f portal pressure. This

implies that portal hypertension in the setting o f acute AH may possibly be more

labile and amenable to therapeutic interventions compared to that in alcoholic

cirrhosis without evidence of hepatic inflammation. Moreover, an increased risk of

variceal bleeding due to AH would have potentially more serious consequences with

respect to outcome due to the associated decompensation. Albumin dialysis using the

Molecular Adsorbents Recirculating System (MARS; Teraklin AG, Rostock,

Germany) has been used mainly in the treatment of liver failure (148), and our group

had previously shown its potential benefit in patients with severe acute AH. (149)

in four patients with acute-on-chronic liver failure (ACLF) after the first session of

MARS, which increased before the second session but again underwent reduction,

albeit less steep, after the second session (150). A noteworthy point is the fact that all

four patients had evidence o f hepatic inflammation (AH-3, non-alcoholic

steatohepatitis-1). The aim of this study, was thus to evaluate the acute effects of

albumin dialysis, using MARS, on portal haemodynamics in patients with severe

acute AH. Patients treated with haemofiltration alone were investigated using the

same protocol to establish whether changes observed were specific to albumin

dialysis or just an effect of extracorporeal therapy.

6.3.2 Methods

6.3.2.1 Patient selection

Inclusion criteria: (i) Patients were included with severe AH, which was defined by

a history o f alcohol abuse, clinical and laboratory stigmata o f acute AH and

supported by histological evidence, (ii) Acute-on-Chronic Liver Failure (ACLF),

defined as acute deterioration in liver function over 2-4 weeks due to a defined

precipitant leading to severe, progressive clinical deterioration despite supportive

care (over 72 hours) with (a) increasing jaundice (bilirubin>85pmol/L), and (b)

either hyperbilirubinaemia>300pM and/or encephalopathy (>grade 2) (151) and/or

renal failure, (iii) Clinically significant portal hypertension: (HVPG >12mmHg).

Exclusion criteria: Patients were excluded if they were <18 or >75 years old,

adequate consent could not be obtained, were already enrolled in another study

protocol, had uncontrolled variceal bleeding or uncontrolled infection over the past

48 hours, had known hepatic/extrahepatic malignancy, were pregnant, had co­

6.3.2.2 Study design

Eleven patients were finally included and received a 6-hour session of extracorporeal

therapy. Eight patients received MARS treatment in conjunction with

haemofiltration. Three others did not consent to MARS but agreed to haemodynamic

assessment and haemofiltration, and received a 6-hour session o f veno-venous

haemofiltration alone. HVPG changes at 6 and 24 hours were the primary end­

points.

6.3.2.3 Monitoring: The patients were evaluated clinically and biochemically and

The Child Pugh score (87) and discriminant function (89) were calculated. The

severity of encephalopathy was assessed using the West Haven criteria (151). Mean

arterial pressure, electrocardiogram, heart rate and temperature, were monitored

continuously during treatment. The patients were actively warmed to a core

temperature o f 37°C if temperature dropped during treatment. Intravascular volume

was maintained using crystalloids, colloids or red cells as appropriate to maintain

central venous pressure between 8 and 10cm H2O. Blood glucose was maintained

between 5-7mmol/L with infusion of 50% dextrose.

6.3.2.4 Extracorporeal therapy: The MARS system consists of a blood circuit, an

albumin circuit, and a renal circuit, in our studies using continuous veno-venous

haemofiltration (Hospal BSM 22c, Hospal, Lyon, France). Blood is dialysed across

an albumin-impermeable high-flux dialysis membrane (MARS Flux; Teraklin AG).

The albumin circuit contains 600 ml of 20% human albumin, which passes through

the dialysate compartment of the blood dialyser. It subsequently undergoes

haemofiltration and passage through activated charcoal and anion exchange resin

columns to remove acquired toxins. Heparin was used as required (if patient’s INR

were run at 150 ml/min, with 1 L/hour fluid exchange, maintaining equal fluid

balance. Each MARS session was continued for 6-8 hours duration.

6.3.2.5 Haemofiltration: Continuous veno-venous haemofiltration (Hospal BSM 22c)

was performed with similar rates of blood flow (150 ml/min) and fluid exchange (1

L/hour) as that used for MARS.

6.3.2.6 Haemodynamic measurements: Haemodynamic studies were performed at

the time of trans-jugular liver biopsy prior to the extracorporeal session, and this

followed an overnight fast and a 1-hour period during which the patient had been

resting supine. The methodology applied for measurement of HVPG and systemic

haemodynamics was as described previously (chapter 2, section 2.1.2.1-2.1.2.3).

Patients were sedated for the procedure using midazolam (median dose o f 3 [range

2-5] mg; Phoenix Pharma Ltd., Gloucester, UK).

6.3.3 Results

Eleven patients with severe alcoholic hepatitis (median DF >68) were studied who

had been assigned to treatment with MARS (n=8) or standard medical therapy (n=3),

which included haemofiltration, as part of a larger trial on assessment of the efficacy

of MARS [Teraklin AG, Rostock, Germany]. Patients in the 2 groups were

comparable with respect to liver disease severity (discriminant function and MELD

score) but patients in the treatment arm had a significant reduction in bilirubin within

24 hours (p<0.001) and a trend towards a lower serum creatinine. O f interest, there

were no significant differences in CRP, white blood cell count or liver function in

between the groups after MARS treatment. None o f the patients received any

immuno-modulatory treatments as all had contra-indications (sepsis, recent GI bleed

and/or renal failure).

after 6 hours (the end o f a treatment session), and remained at this level by 24 hours.

The reduction in HVPG was greater than 20% reduction from baseline levels in 7/8

patients receiving MARS, both at 6 and 24 hours, as shown in Figure 6.5.

Extracorporeal

In document Instituto Politécnico Nacional (página 53-120)

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