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Original research
Exploring the mechanisms responsible for reduced systolic function in high-gradient aortic stenosis
  1. Jacques Liebenberg1,
  2. Anton Doubell2,
  3. Jan Steyn3,
  4. Philip Herbst4
  1. 1 Department of Medicine, University of Stellenbosch, Stellenbosch, South Africa
  2. 2 Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, Western Cape, South Africa
  3. 3 Division of Cardiology, Tygerberg Hospital, Stellenbosch University, Stellenbosch, Western Cape, South Africa
  4. 4 Division of Cardiology, Department of Medicine, Faculty of Medicine and Health Sciences, University of Stellenbosch, Cape Town, South Africa
  1. Correspondence to Dr Jacques Liebenberg, Department of Medicine, University of Stellenbosch, Stellenbosch, South Africa; liebjurg{at}gmail.com

Abstract

Objective To characterise the mechanics responsible for the reduced ejection fraction (rEF) in high-gradient severe aortic stenosis (AS).

Methods 21 patients with high-gradient severe AS (aortic valve area (AVA) <1.0 cm2 and mean gradient (MG) >40 mm Hg) were included. They included 9 patients with rEF (EF <50%) and 12 with preserved ejection fraction (pEF) (EF >50%). Valve area and MG were assessed echocardiographically, and myocardial fibrosis was quantified using MRI. Load-independent measures of intrinsic contractility was assessed with pressure-volume haemodynamics.

Results 80% of the cohort was female, with a mean age of 64 years. Patients were matched for age, sex and body surface area. Load-independent contractile function was similar between the rEF and pEF groups: preload recruitable stroke work slope (101 vs 112 mm Hg; p=0.65), end-systolic pressure-volume relationship slope (1.91 vs 1.28 mmHg/mL; p=0.07) and Starling Contractile Index slope (3.47 vs 7.96 mm Hg/mL/s; p=0.31). End-systolic wall stress and valvuloarterial impedance were higher in cases with rEF (150 vs 83.5 N/cm2; p<0.01 and 4.8 vs 3.4 mm Hg/mL; p=0.05), driven by higher degrees of valvular stenosis (valve area 0.46 vs 0.78 cm2; p<0.01). The rEF group was more symptomatic (New York Heart Association 3.3 vs 2.3; p=0.02), with higher pulmonary pressures (50 vs 30 mm Hg; p=0.04) and more fibrosis (24% vs 13% of left ventricular mass; p=0.03).

Conclusion The pathophysiological problem in patients with high-gradient AS with rEF relates to an excessively increased afterload due to more severe valvular stenosis, with preserved intrinsic contractile function. Myocardial fibrosis in the rEF group did not translate into worse muscle function.

  • Aortic Valve Stenosis

Data availability statement

Data are available upon reasonable request.

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Data availability statement

Data are available upon reasonable request.

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Footnotes

  • Contributors All authors contributed equally to the manuscript development, data collection and processing. All authors approved the final submitted version of the abstract. JL is acting as the guarantor for the submitted work.

  • Funding The research project was funded by the SUNHEART research fund.

  • Competing interests None declared.

  • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting or dissemination plans of this research.

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

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.