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Coronary artery disease
Original research article
Diagnostic performance of an acoustic-based system for coronary artery disease risk stratification
  1. Simon Winther1,
  2. Louise Nissen2,
  3. Samuel Emil Schmidt3,
  4. Jelmer Sybren Westra1,
  5. Laust Dupont Rasmussen2,
  6. Lars Lyhne Knudsen2,
  7. Lene Helleskov Madsen2,
  8. Jane Kirk Johansen4,
  9. Bjarke Skogstad Larsen3,
  10. Johannes Jan Struijk3,
  11. Lars Frost4,
  12. Niels Ramsing Holm1,
  13. Evald Høj Christiansen1,
  14. Hans Erik Botker1,
  15. Morten Bøttcher2
  1. 1 Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark
  2. 2 Department of Cardiology, Hospital Unit West, Herning, Denmark
  3. 3 Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
  4. 4 Department of Cardiology, Regional Hospital of Silkeborg, Silkeborg, Denmark
  1. Correspondence to Dr Simon Winther, Department of Cardiology, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, DK-8200 Aarhus, Denmark; sw{at}dadlnet.dk

Abstract

Objective Diagnosing coronary artery disease (CAD) continues to require substantial healthcare resources. Acoustic analysis of transcutaneous heart sounds of cardiac movement and intracoronary turbulence due to obstructive coronary disease could potentially change this. The aim of this study was thus to test the diagnostic accuracy of a new portable acoustic device for detection of CAD.

Methods We included 1675 patients consecutively with low to intermediate likelihood of CAD who had been referred for cardiac CT angiography. If significant obstruction was suspected in any coronary segment, patients were referred to invasive angiography and fractional flow reserve (FFR) assessment. Heart sound analysis was performed in all patients. A predefined acoustic CAD-score algorithm was evaluated; subsequently, we developed and validated an updated CAD-score algorithm that included both acoustic features and clinical risk factors. Low risk is indicated by a CAD-score value ≤20.

Results Haemodynamically significant CAD assessed from FFR was present in 145 (10.0%) patients. In the entire cohort, the predefined CAD-score had a sensitivity of 63% and a specificity of 44%. In total, 50% had an updated CAD-score value ≤20. At this cut-off, sensitivity was 81% (95% CI 73% to 87%), specificity 53% (95% CI 50% to 56%), positive predictive value 16% (95% CI 13% to 18%) and negative predictive value 96% (95% CI 95% to 98%) for diagnosing haemodynamically significant CAD.

Conclusion Sound-based detection of CAD enables risk stratification superior to clinical risk scores. With a negative predictive value of 96%, this new acoustic rule-out system could potentially supplement clinical assessment to guide decisions on the need for further diagnostic investigation.

Trial registration number ClinicalTrials.gov identifier NCT02264717; Results.

  • cardiac imaging and diagnostics
  • coronary artery disease

This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/

https://doi.org/10.1136/heartjnl-2017-311944

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    Footnotes

    • Contributors Substantial contribution to conception and design: SW, LN, SES, NRH, HEB and MB. Collection of data: SW, LN, JSW, LDR, LLK, LHM, JKJ and LF. Analysis and interpretation of data: SW, LN, SES, JSW, BSL, JJS, EHC, HEB and MB. All authors have worked on drafting the article or revising it critically and approved the final version.

    • Funding The research reported here is partly financed by The Danish Heart Foundation (grant no. 15-R99-A5837-22920), The Hede Nielsen Foundation, and by an unrestricted institutional research grant from Acarix A/S.

    • Competing interests The current research is financed partly by Acarix A/S by an unrestricted grant. SES is a minor shareholder and part-time consultant in Acarix A/S. BSL is an industrial student at Acarix A/S. MB is part of the Acarix A/S advisory board. MB and SW received an unrestricted institutional research grant from Acarix A/S.

    • Ethics approval The study was approved by The Central Denmark Region Committees on Health Research Ethics and The Danish Data Protection Agency.

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