title: Noninvasive and simple assessment of cardiac output and pulmonary vascular resistance with whole-body impedance cardiography is useful for monitoring patients with pulmonary hypertension.
abstract: BACKGROUND
  Right heart catheterization (RHC) is the gold standard for the diagnosis of pulmonary hypertension (PH) and a useful tool for monitoring PH. However, there are some disadvantages in the regular use of RHC because it is invasive. Noninvasive methods for monitoring hemodynamics are needed to manage patients with PH. In this study, we aimed to evaluate the reliability of noninvasive hemodynamic assessment with whole-body impedance cardiography (Non-Invasive Cardiac System [NICaS]) for PH.
  
  
  RESULTS
  We investigated 65 consecutive patients undergoing RHC. Two-thirds of them had pulmonary arterial hypertension and one-third had chronic thromboembolic PH; 25% of the patients were receiving medical therapy. Cardiac output (CO) was estimated by NICaS (NI-CO), thermodilution (TD-CO), and the Fick method (Fick-CO). There was a strong correlation between NI-CO and TD-CO (r=0.715, P<0.0001) and Fick-CO (r=0.653, P<0.0001). Noninvasive pulmonary vascular resistance (PVR) was estimated using a conventional invasive equation with NI-CO, mean pulmonary arterial pressure was calculated by echocardiographic measurement, and pulmonary capillary wedge pressure was estimated at 10mmHg in all cases. NICaS-derived PVR was very strongly correlated with invasive PVR (TD-PVR: r=0.704, P<0.0001; Fick-PVR: r=0.702, P<0.0001).
  
  
  CONCLUSIONS
  Noninvasive measurement of CO and PVR using NICaS and echocardiography is a useful tool for the assessment of PH.
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine.
authors.forename: Yu
authors.initials: Y
authors.lastname: Taniguchi
authors.forename: Noriaki
authors.initials: N
authors.lastname: Emoto
authors.forename: Kazuya
authors.initials: K
authors.lastname: Miyagawa
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nakayama
authors.forename: Hiroto
authors.initials: H
authors.lastname: Kinutani
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Tanaka
authors.forename: Toshiro
authors.initials: T
authors.lastname: Shinke
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Hirata
mesh_terms: D000368:Aged; D001794:Blood Pressure; D002302:Cardiac Output; D002307:Cardiography, Impedance / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006976:Hypertension, Pulmonary / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods*; D012189:Retrospective Studies; D014655:Vascular Resistance