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Original research article
Right ventricular fibrosis is associated with cardiac remodelling after pulmonary valve replacement
  1. Kenichiro Yamamura1,
  2. Darren Yuen2,3,
  3. Edward J Hickey1,4,
  4. Xiaolin He2,3,
  5. Rajiv R Chaturvedi5,
  6. Mark K Friedberg5,
  7. Lars Grosse-Wortmann5,6,
  8. Kate Hanneman7,
  9. Filio Billia1,
  10. Michael E Farkouh1,
  11. Rachel M Wald1,3,5,7
  1. 1 Toronto Congenital Cardiac Centre for Adults, Peter Munk Cardiac Centre, University of Toronto, Toronto General Hospital, Toronto, Ontario, Canada
  2. 2 Division of Nephrology, Department of Medicine, St. Michael’s Hospital and University of Toronto, Toronto, Ontario, Canada
  3. 3 Keenan Research Centre for Biomedical Science, St. Michael’s Hospital, Toronto, Ontario, Canada
  4. 4 Division of Cardiovascular Surgery, Department of Surgery, University of Toronto, SickKids Hospital, Toronto, Ontario, Canada
  5. 5 Division of Cardiology, Department of Pediatrics, The Labatt Family Heart Center, University of Toronto, SickKids Hospital, Toronto, Ontario, Canada
  6. 6 Department of Diagnostic Imaging, University of Toronto, SickKids Hospital, Toronto, Ontario, Canada
  7. 7 Department of Medical Imaging, University of Toronto, Peter Munk Cardiac Centre, Toronto General Hospital, Toronto, Ontario, Canada
  1. Correspondence to Dr Rachel M Wald, Toronto Congenital Cardiac Centre for Adults, Peter Munk Cardiac Centre, Toronto General Hospital, Toronto, ON M5G 2N2, Canada; Rachel.Wald{at}uhn.ca

Abstract

Objective The relationship between right ventricular (RV) fibrosis and right heart reverse remodelling following pulmonary valve replacement (PVR) has not been well studied in adults with repaired tetralogy of Fallot (rTOF). Our aims were to histologically quantify RV fibrosis and to explore the relationship between fibrosis severity and cardiac remodelling post-PVR.

Methods Adults with rTOF and pre-PVR cardiovascular (CMR) imaging were consented to procurement of RV muscle during PVR. Samples were stained with picrosirius red to quantify collagen volume fraction. Clinical data at baseline and at last follow-up were reviewed. Adverse cardiovascular outcomes included death, sustained arrhythmia and heart failure.

Results Fifty-three patients (male 58%, 38±11 years) were studied. Those with severe fibrosis (collagen volume fraction >11.0%, n=13) had longer aortic cross-clamp times at initial repair compared with the remainder of the population (50 vs 33 min, p=0.018) and increased RV mass:volume ratio pre-PVR (0.20 vs 0.18 g/mL, p=0.028). Post-PVR, the severe fibrosis group had increased indexed RV end-systolic volume index (RVESVi) (74 vs 66 mL/m2, p=0.044), decreased RVESVi change (Δ29 vs Δ45 mL/m2, p=0.005), increased RV mass (34 vs 25 g/m2, p=0.023) and larger right atrial (RA) area (21 vs 17 cm2, p=0.021). A trend towards increased heart failure events was observed in the severe fibrosis group (15% vs 0%, p=0.057).

Conclusions Severe RV fibrosis was associated with increased RVESVi, RV mass and RA area post-PVR in rTOF. Further study is required to define the impact of fibrosis and persistent right heart enlargement on clinical outcomes.

  • cardiac magnetic resonance (cmr) imaging
  • tetralogy of fallot
  • congenital heart disease surgery

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Footnotes

  • Contributors KY and RMW conceived and designed the research, acquired data, performed statistical analysis, drafted the manuscript and critically reviewed the manuscript. DY, EJH, XH and KH acquired data, wrote the first draft and critically reviewed the manuscript. RRC, MKF, LG-W, FB and MEF wrote the first draft and critically reviewed the manuscript. All authors interpreted the results and approved the final version of the manuscript.

  • Funding Canadian Institutes of Health Research Operating Grant (MOP 119353) to RW.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Ethics approval The study protocol was approved by the institutional research ethics board (study number 12–0242).

  • Provenance and peer review Not commissioned; externally peer reviewed.

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