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Early Finding of diastolic heart Failure by EchoCardiographic Tissue Stiffness measurements (EFFECTS)

Researchers:  Lana Keijzer,

Principal investigator:   Rik Vos

Dutch grant by NWO-TTW and the Dutch Heart Foundation, call 'Early recognition of Cardiovascular diseases 2016'

Heart failure

Heart failure is a major public health problem in developed countries. There is a poor prognosis in patients with heart failure. Left ventricular diastolic dysfunction is one of the important underlying mechanisms, to a large extent caused by increased stiffness of the heart. Patients with predominantly diastolic dysfunction have a 1-year mortality rate of 25%. Currently, there is no accurate non-invasive method for early diagnosis of heart failure and there is no method of monitoring the therapy.

Shear wave/mechanical wave detection
EFFECTS delivers a technique for early diagnosis of stiffening of the heart, which employs non-invasive ultrasound imaging. The new method is based on the natural shear waves in the heart muscle, which find their origin in the natural "noise-like" mechanical excitations caused by the beating heart, atrial contraction, flowing blood, etc. The propagation velocity of the resulting natural shear waves is dependent on the local stiffness of the heart muscle.

Preclinical studies
In a preclinical study we have analyzed the accuracy of the method when looking at the mechanical waves after  valve closure, i.e., after the same events that generate the heart tones. Albeit that it is suspected that the timing of the mechanical waves may not be optimal (the valves close in the isovolumetric phase where the cardiac stiffness is rapidly changing), we have seen in this study that the propagation velocity is not significantly different from that found with open-chest acoustic-radiation force based shear wave measurements. This leads us to continue this research further.

Figure: Open chest vs. closed chest shear wave measurements in bovine animal model. [Vos et al., ‘Shear wave tracking: open chest versus closed chest’, IEEE Ultras. Symp. 2016]

[Vos et al., ‘Cardiac shear wave velocity detection in the porcine heart’, Ultras. Med. Biol. 2017]

 

Animal study

(open or min. invasive)

Systolic [m/s]

Diastolic

[m/s]

Hollender et al. (2012)

4.1

1.4

Couade et al. (2011)

4.8

1.45

Urban et al. (2013)

4

1.5

Clinical evaluations
We use a very high frame rate (1000 FPS) acquisition system with high penetration depth and high spatial resolution to capture the waves, on a clinical machine that was custom programmed for this project. We are evaluating this method in a study containing both healthy volunteers and patients. In parallel we use a clinical machine in regular TDI mode to assess feasibility in a clinical workflow.

[Strachinaru et al., 'Cardiac shear wave elastography using a clinical ultrasound system', Ultras. Med. Biol. 2017]
[Strachinaru et al., 'Clinical value of high frame rate imaging', ESC EuroEcho , Lisbon, Portugal. 2017]
[Vos et al., 'High frame rate imaging: technique and applications', ESC EuroEcho , Lisbon, Portugal. 2017 - invited]