title: Wireless surveillance for transjugular intrahepatic portosystemic shunts (TIPS): a feasibility study.
abstract: OBJECTIVE
  Shunt surveillance is a critical component of follow-up for patients with cirrhosis with transjugular intrahepatic portosystemic shunts (TIPS). Transabdominal Doppler ultrasound analysis of the shunt has been used as a noninvasive means of assessing shunt function. Doppler ultrasound analysis of the shunt is less sensitive than direct transjugular portosystemic pressure gradient measurement for detecting shunt failure. A wireless, noninvasive means of measuring the portosystemic pressure gradient in the clinic may facilitate follow-up in this group of patients. The aim of this study was to determine if two implanted wireless pressure sensors could accurately transmit a portosystemic pressure gradient across a TIPS.
  
  
  METHODS
  Two wireless microelectromechanical system pressure sensors were placed in a swine model for measuring the portosystemic pressure gradient across a TIPS. Catheter-based pressure transducers were also placed and used as the gold standard. Pressures from both systems were measured concurrently.
  
  
  RESULTS
  Wireless microelectromechanical system portal and systemic pressure measurements were accurate within +/-2 mm Hg (mean, 0.86 mm Hg) of the gold standard.
  
  
  CONCLUSIONS
  The use of wireless sensors may facilitate the surveillance of shunt function in patients with portal hypertension who have undergone placement of TIPS.
authors.affiliation: Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Ken K
authors.initials: KK
authors.lastname: Hirasaki
authors.forename: John A
authors.initials: JA
authors.lastname: Watts
authors.forename: Paul V
authors.initials: PV
authors.lastname: Suhocki
mesh_terms: D001795:Blood Pressure Determination / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D006975:Hypertension, Portal / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation; D018670:Monitoring, Ambulatory / Q000295:instrumentation*; D019168:Portasystemic Shunt, Transjugular Intrahepatic / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013686:Telemetry / Q000295:instrumentation*; D014160:Transducers, Pressure