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Original research
Cardiac magnetic resonance systematically overestimates mitral regurgitations by the indirect method
  1. Litten Bertelsen1,
  2. Niels Vejlstrup1,
  3. Laura Andreasen1,2,
  4. Morten Salling Olesen1,2 and
  5. Jesper Hastrup Svendsen1,3
  1. 1Department of Cardiology, Centre for Cardiac, Vascular, Pulmonary and Infectious Diseases, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
  2. 2Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
  3. 3Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
  1. Correspondence to Dr Litten Bertelsen; littenbertelsen{at}gmail.com

Abstract

Objective Cardiac MRI is quickly emerging as the gold standard for assessment of mitral regurgitation, most commonly with the indirect method subtracting forward flow in aorta from volumetric segmentation of the left ventricle. We aimed to investigate how aortic flow measurements with increasing distance from the aortic valve affect calculated mitral regurgitations and whether measurements were influenced by breath-hold regimen.

Methods Free-breathing and breath-hold phase contrast flows were measured in aorta at valve level, sinotubular (ST) junction, mid-ascending aorta and in the pulmonary trunk. Flow measurements were pairwise compared, and subsequently, after exclusion of patients with visible mitral and tricuspid regurgitations for left-sided and right-sided comparisons, respectively, flow-measured stroke volumes were compared with ventricular volumetric segmentations.

Results Thirty-nine participants without arrhythmias or structural abnormalities of the large vessels were included. Stroke volumes measured with free-breathing and breath-hold flow decreased equally with increasing distance to the aortic valves (breath-hold flow: aortic valve 105.6±20.8 mL, ST junction 101.5±20.7 mL, mid-ascending aorta 98.1±21.5 mL). After exclusion of atrioventricular regurgitations, stroke volumes determined by volumetric measurements were higher compared with values determined by flow measurements, corresponding to ‘false’ atrioventricular regurgitations of 8.0%±5.8% with flow measured at valve level, 11.6%±5.2% at the ST junction and 15.3%±5.0% at the mid-ascending aorta.

Conclusions Stroke volumes determined by flow decrease throughout the proximal aorta and are systematically lower than volumetrically measured stroke volumes. The indirect method systematically overestimates mitral regurgitations, especially with increasing distance from the aortic valves.

  • mitral regurgitation
  • cardiovascular examination
  • MRI
  • aorta, great vessels and trauma
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Footnotes

  • Contributors LB conceptualised and designed the study, performed data acquisition and measurements, performed statistical analyses and drafted the manuscript. LA contributed to study design, performed data acquisition and revised the manuscript. NV, MSO and JHS contributed to study design, participated in scientific discussions during the study and revised the manuscript. All authors read and approved the final version of the manuscript.

  • Funding The study is supported by the Innovation Fund Denmark (12-135225) and the Arvid Nilssons Fond (no grant number).

  • Competing interests JHS reports to be a member of Medtronic advisory boards and to have received speaker honoraria and research grants from Medtronic and Gilead not related to this work.

  • Patient consent for publication Not required.

  • Ethics approval The study was approved by the local ethics committee of the Capital Region of Denmark (protocol no. H-1-2011-044).

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

  • Data availability statement Data are available on reasonable request.

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