title: Cerebral haemodynamics in cirrhotic patients with hepatic encephalopathy.
abstract: OBJECTIVE
  Factors other than elevated levels of ammonia may be implicated in hepatic encephalopathy (HE) pathophysiology, including abnormal cerebral haemodynamics. Transcranial Doppler ultrasonography (TCD) evaluates cerebrovascular structural integrity and reactivity, through pulsatility index (PI) and breath-holding index (BHI) respectively. The aim of this study was to evaluate cerebral haemodynamics by TCD in patients with compensated and decompensated cirrhosis, and patients with and without HE.
  
  
  METHODS
  We studied 90 subjects by TCD measuring PI and BHI in the middle cerebral artery: 30 with cirrhosis and no HE, 30 with cirrhosis and low-grade HE and 30 healthy subjects. Critical flicker frequency, psychometric hepatic encephalopathy score and West-Haven criteria were performed to assess MHE and HE respectively.
  
  
  RESULTS
  Pulsatility index increased in decompensated cirrhotics (Child ≥ 7) when compared with compensated cirrhotics and healthy subjects [median (IQR) 1.07 (0.95-1.21) vs 0.90 (0.83-1.05) vs 0.87 (0.78-0.96); P < 0.001]. A reverse relationship was observed for BHI among the three groups [0.82 (0.45-1.11) vs 1.20 (0.82-1.52) vs 1.28 (1.06-1.68); P < 0.001]. Similar findings were observed in decompensation [model for end-stage liver disease (MELD) score ≥14]. Patients with HE showed higher PI and lower BHI [1.05 (1.00-1.16) and 0.89 (0.59-1.15)], when compared with patients without HE [0.96 (0.83-1.13) and 1.00 (0.60-1.53)] or controls [0.87 (0.78-0.96) and 1.28 (1.06-1.68)] (P < 0.001 for PI, and P = 0.007 for BHI). In multivariate regression models, only PI predicted HE, but it was outperformed by MELD-sodium and tumour necrosis factor-alpha.
  
  
  CONCLUSIONS
  These results indicate that cerebral haemodynamics are altered in patients with cirrhosis, in relation to severity of disease and HE. Findings on impaired PI and BHI suggest that structural vascular damage and loss of vascular autoregulation are implicated in the pathophysiology of HE.
authors.affiliation: Liver Clinic, Department of Gastroenterology, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", México D.F, Tlalpan, México.
authors.forename: Ricardo U
authors.initials: RU
authors.lastname: Macías-Rodríguez
authors.forename: Andrés
authors.initials: A
authors.lastname: Duarte-Rojo
authors.forename: Carlos
authors.initials: C
authors.lastname: Cantú-Brito
authors.forename: Tilman
authors.initials: T
authors.lastname: Sauerbruch
authors.forename: Astrid
authors.initials: A
authors.lastname: Ruiz-Margáin
authors.forename: Jonel
authors.initials: J
authors.lastname: Trebicka
authors.forename: Marina
authors.initials: M
authors.lastname: Green-Gómez
authors.forename: Jorge B
authors.initials: JB
authors.lastname: Díaz Ramírez
authors.forename: Manuel
authors.initials: M
authors.lastname: Sierra Beltrán
authors.forename: Misael
authors.initials: M
authors.lastname: Uribe-Esquivel
authors.forename: Aldo
authors.initials: A
authors.lastname: Torre
mesh_terms: D015415:Biomarkers / Q000097:blood; D001921:Brain / Q000098:blood supply* / Q000473:pathology; D062485:Breath Holding; D003430:Cross-Sectional Studies; D006439:Hemodynamics / Q000502:physiology*; D006501:Hepatic Encephalopathy / Q000503:physiopathology*; D006801:Humans; D008103:Liver Cirrhosis / Q000150:complications*; D012044:Regression Analysis; D018709:Statistics, Nonparametric; D017585:Ultrasonography, Doppler, Transcranial
chemical_list: D015415:Biomarkers
keywords: cerebral vasoconstriction; cerebrovascular reactivity; cirrhosis; portal hypertension; transcranial Doppler ultrasonography