title: Attenuated right ventricular energetics evaluated using ¹¹C-acetate PET in patients with pulmonary hypertension.
abstract: OBJECTIVE
  The right ventricle (RV) has a high capacity to adapt to pressure or volume overload before failing. However, the mechanisms of RV adaptation, in particular RV energetics, in patients with pulmonary hypertension (PH) are still not well understood. We aimed to evaluate RV energetics including RV oxidative metabolism, power and efficiency to adapt to increasing pressure overload in patients with PH using (11)C-acetate PET.
  
  
  METHODS
  In this prospective study, 27 patients with WHO functional class II/III PH (mean pulmonary arterial pressure 39.8 ± 13.5 mmHg) and 9 healthy individuals underwent (11)C-acetate PET. (11)C-acetate PET was used to simultaneously measure oxidative metabolism (k mono) for the left ventricle (LV) and RV. LV and RV efficiency were also calculated.
  
  
  RESULTS
  The RV ejection fraction in PH patients was lower than in controls (p = 0.0054). There was no statistically significant difference in LV k mono (p = 0.09). In contrast, PH patients showed higher RV k mono than did controls (0.050 ± 0.009 min(-1) vs. 0.030 ± 0.006 min(-1), p < 0.0001). PH patients exhibited significantly increased RV power (p < 0.001) and hence increased RV efficiency compared to controls (0.40 ± 0.14 vs. 0.017 ± 0.12 mmHg·mL·min/g, p = 0.001).
  
  
  CONCLUSIONS
  The RV oxidative metabolic rate was increased in patients with PH. Patients with WHO functional class II/III PH also had increased RV power and efficiency. These findings may indicate a myocardial energetics adaptation response to increasing pulmonary arterial pressure.
authors.affiliation: Department of Molecular Imaging, Hokkaido University Graduate School of Medicine, Kita 15 Nishi 7, Kita-Ku, Sapporo, Hokkaido, Japan, 060-8638, kyoshi@med.hokudai.ac.jp.
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Yoshinaga
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohira
authors.forename: Ichizo
authors.initials: I
authors.lastname: Tsujino
authors.forename: Noriko
authors.initials: N
authors.lastname: Oyama-Manabe
authors.forename: Lisa
authors.initials: L
authors.lastname: Mielniczuk
authors.forename: Rob S B
authors.initials: RS
authors.lastname: Beanlands
authors.forename: Chietsugu
authors.initials: C
authors.lastname: Katoh
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Kasai
authors.forename: Osamu
authors.initials: O
authors.lastname: Manabe
authors.forename: Takahiro
authors.initials: T
authors.lastname: Sato
authors.forename: Satoshi
authors.initials: S
authors.lastname: Fujii
authors.forename: Yoichi M
authors.initials: YM
authors.lastname: Ito
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Tomiyama
authors.forename: Masaharu
authors.initials: M
authors.lastname: Nishimura
authors.forename: Nagara
authors.initials: N
authors.lastname: Tamaki
mesh_terms: D000085:Acetates; D000328:Adult; D000368:Aged; D002244:Carbon; D016022:Case-Control Studies; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000378:metabolism; D006801:Humans; D006976:Hypertension, Pulmonary / Q000000981:diagnostic imaging* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D013318:Stroke Volume; D016278:Ventricular Function, Right
chemical_list: D000085:Acetates; D019275:Radiopharmaceuticals; C438206:carbon-11 acetate; D002244:Carbon