title: Ventricular geometric characteristics and functional benefit of mild right ventricular outflow tract obstruction in patients with significant pulmonary regurgitation after repair of tetralogy of Fallot.
abstract: BACKGROUND
  Right ventricular (RV) outflow tract obstruction (RVOTO) might protect the RV from adverse remodeling caused by significant pulmonary regurgitation (PR) in patients with repaired tetralogy of Fallot (rTOF), but the underlying mechanisms and influences on exercise tolerance remain unclear. This study sought to investigate the impacts from mild RVOTO on ventricular remodeling and exercise capacity in rTOF.
  
  
  METHODS
  Eighty-five rTOF patients with a PR fraction ≥20% were assessed with cardiac magnetic resonance, cardiopulmonary exercise test, and echocardiography. Patients with a peak RVOT pressure gradient 20-50 mmHg were considered to have mild RVOTO (n = 29), while those with a gradient <20 mmHg had isolated PR (n = 56).
  
  
  RESULTS
  Comparing to patients with isolated PR, patients with combined PR and mild RVOTO had smaller RV and RVOT dimension, better RV and left ventricular (LV) ejection fraction (EF), and superior exercise capacity. PR severity and RV mass/volume ratio were similar between these 2 groups. LVEF coupled with RVEF only in patients with isolated PR. In multivariate analysis, smaller RVOT dimension was independently related to smaller RV dimension (P < .001) and higher RVEF (P = .005). Furthermore, mild RVOTO was independently associated with higher peak oxygen consumption (P = .014) and oxygen uptake efficiency slope (P = .005).
  
  
  CONCLUSIONS
  Patients with combined PR and mild RVOTO had better RV remodeling and exercise capacity compared to those with isolated PR. Our findings confirm the benefits from mild residual RVOTO support a policy of conservative RVOTO relief at repair.
authors.affiliation: Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Chun-An
authors.initials: CA
authors.lastname: Chen
authors.affiliation: Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Ssu-Yuan
authors.initials: SY
authors.lastname: Chen
authors.affiliation: Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Jou-Kou
authors.initials: JK
authors.lastname: Wang
authors.affiliation: Center for Optoelectronic Biomedicine, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Wen-Yih Isaac
authors.initials: WY
authors.lastname: Tseng
authors.affiliation: Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan; Department of Pediatrics, Taipei Medical University Hospital, Taipei, Taiwan.
authors.forename: Hsin-Hui
authors.initials: HH
authors.lastname: Chiu
authors.affiliation: Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Chung-I
authors.initials: CI
authors.lastname: Chang
authors.affiliation: Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Ing-Sh
authors.initials: IS
authors.lastname: Chiu
authors.affiliation: Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Yih-Sharng
authors.initials: YS
authors.lastname: Chen
authors.affiliation: Department of Pediatrics, E-DA hospital and I-SHOU University, Kaohsiung, Taiwan.
authors.forename: Ming-Chun
authors.initials: MC
authors.lastname: Yang
authors.affiliation: Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Chun-Wei
authors.initials: CW
authors.lastname: Lu
authors.affiliation: Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Ming-Tai
authors.initials: MT
authors.lastname: Lin
authors.affiliation: Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan. Electronic address: wumh@ntu.edu.tw.
authors.forename: Mei-Hwan
authors.initials: MH
authors.lastname: Wu
mesh_terms: D000328:Adult; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods; D008297:Male; D011183:Postoperative Complications; D011379:Prognosis; D011665:Pulmonary Valve Insufficiency / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013771:Tetralogy of Fallot / Q000503:physiopathology / Q000601:surgery*; D016277:Ventricular Function, Left / Q000502:physiology*; D014694:Ventricular Outflow Obstruction / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D017725:Ventricular Pressure; D020257:Ventricular Remodeling