Use of a novel handheld ultrasound device with continuous-wave doppler capability for the assessment of valvular heart disease

Background/Introduction Echocardiography is the primary non-invasive imaging method for the diagnosis and evaluation of valvular heart disease. Doppler echocardiography provides accurate non-invasive evaluation of valve hemodynamics. Recent technological advancements have enabled the acquisition of echocardiographic images at the point-of-care by using small handheld ultrasound devices (HUDs); their availability and relatively low cost compared to the high-end systems have made these devices attractive to use for rapid medical decision making. However, the inability to quantify flow velocity has been a major limitation for HUDs; the lack of spectral Doppler capability has so far hindered the comprehensive assessment of haemodynamic data and valve function. Purpose To evaluate for the first time the accuracy of a novel HUD with continuous-wave (CW) Doppler capability to measure flow velocity in valvular heart disease. Methods We prospectively included 56 consecutive patients who were referred to the echocardiography laboratory of a tertiary hospital. All patients were scanned with both the Kosmos HUD and the standard echocardiography cart-based system (reference standard) in a randomized order. CW Doppler measurements of maximum velocities (Vmax) were obtained from the apical five-chamber view for the aortic ejection and regurgitation and from the apical four-chamber view for the mitral and tricuspid regurgitation (presence assessed by colour Doppler), maintaining a parallel orientation between the ultrasound beam and the blood flow. All measurements were compared to assess inter-method agreement using linear regression and Bland-Altman analysis. Results The acquisition of CW Doppler signal using the HUD was feasible in 55 out of 56 patients (mean age 66±16 years old, 40% female). Among them, there were 31 cases of (at least mild) aortic stenosis and 23 cases of valvular regurgitation (4 aortic, 6 mitral and 13 tricuspid regurgitations). There was excellent correlation between the HUD and the cart-based system CW Doppler for the aortic Vmax measurements (r=0.99, p<0.001) and for the valvular regurgitation Vmax measurements (r=0.98, p<0.001). The corresponding Bland-Altman plots showed a small underestimation bias of −0.13 m/sec (p<0.001), with limits of agreement ±0.41 m/sec for the aortic Vmax and −0.21 m/sec (p=0.003), with limits of agreement ±0.57 m/sec for the valvular regurgitation Vmax measurements. Conclusion A novel HUD with CW Doppler spectral analysis was able to provide peak jet velocity measurements comparable to the standard cart-based echocardiography systems, in patients with valvular stenosis and regurgitation. Such expanded capabilities of HUDs show clinical potential and may lead to the improvement of the assessment of valvular pathology at the point-of-care. Funding Acknowledgement Type of funding sources: None.