Handheld Ultrasound with CW Doppler: A New Era for TAVI Follow-Up
2026 Research
The global rise in transcatheter aortic valve implantation (TAVI) has created a significant follow-up burden for echocardiography laboratories. While standard transthoracic echocardiography (TTE) remains the gold standard for monitoring these prosthetic valves, owing to guidelines suggesting CW doppler use for measuring peak velocities and gradients to differentiate between valve failure and PVL, the need for portable, bedside solutions is growing.1
A new prospective study published in the International Journal of Cardiovascular Imaging (2026) offers the first real-world evidence that a handheld ultrasound device (HHUD) equipped with Continuous-Wave (CW) Doppler can accurately assess TAVI prostheses, even when used by clinicians with intermediate experience.2
Table of Contents
The Challenge: Beyond “Quick Looks”
Historically, handheld ultrasound devices have been limited by a lack of CW Doppler, which is technologically complex to integrate into small devices. Without CW Doppler, clinicians cannot accurately measure the high-velocity flows across prosthetic valves, limiting handhelds to simple “quick looks” rather than quantitative assessments. The development of the Kosmos ultrasound system by EchoNous has addressed this gap by incorporating diagnostic-grade CW Doppler into a super portable format.
The Study: Handheld vs. High-End Cart
Researchers conducted a single-center prospective study of 67 TAVI patients (3 later excluded due to suboptimal acoustic windows). The goal was to compare measurements from a reference cart-based high-end system (Philips EPIQ CVx) operated by an expert (ASE Level III) against the handheld Kosmos device operated by a clinician with intermediate experience (ASE Level II). The handheld exam was performed immediately after the routine post-TAVI evaluation in a tertiary echocardiography laboratory, with BP/HR measured before each test to minimize hemodynamic drift.
Two independent cardiologists were mutually blinded to ensure a rigorous comparison of key valvular parameters, including transvalvular gradients and velocities, with the Kosmos ultrasound operator also blinded to prior echo studies and clinical history, strengthening internal validity for agreement testing.
Key Findings: High Concordance in Critical Metrics
The results demonstrated “good-to-excellent” agreement between the handheld device and the reference cart for the four primary parameters of valve function with agreement for direct Doppler spectral measurements (Vmax/gradient/VTI) is higher than for LVOT-dependent calculated metrics.
- Maximum Aortic Velocity: ICC = 0.83
- Mean Transvalvular Gradient: ICC = 0.76
- Transvalvular VTI: ICC = 0.87
- LVOT VTI: ICC = 0.8
Interestingly, the study noted a difference in performance based on valve type, showing better agreement in balloon-expandable valves compared to self-expanding models, possibly due to acoustic shadowing or frame geometry, alongside the small number of self-expanding valves.
Clinical Implications: Bedside Triage and Screening
The study concludes that the Kosmos ultrasound, used as a handheld device, can serve as a powerful bedside screening tool. While it is not intended to replace a comprehensive, multi-parametric TTE, its ability to provide accurate hemodynamic data in the hands of intermediate-level users could revolutionize how we triage TAVI patients.
By enabling reliable initial assessments in the clinic or at the bedside, this technology can help “streamline patient referral pathways and potentially reduce the workload of echocardiography laboratories”. This study was supported by an IDIVAL grant, EchoNous did not fund, and authors declared no competing interests.
References
- Baumgartner H, Hung J, Bermejo J, et al. Recommendations on the echocardiographic assessment of aortic valve stenosis: a focused update from the European Association of Cardiovascular Imaging and the American Society of Echocardiography. European Heart Journal – Cardiovascular Imaging. 2017;18(3):254-275. doi:10.1093/ehjci/jew335
- Margarida de Castro, A., Zubiaur, J., Pérez-Barquín, R., et al. Feasibility and agreement study of a handheld ultrasound device with continuous-wave doppler in transcatheter aortic valve implantation patients. Int J Cardiovasc Imaging (2026). https://doi.org/10.1007/s10554-026-03622-y.
Q&A: LVEFQ&A: Handheld Ultrasound in TAVI Patients
Prosthetic valves often have elevated gradients compared to native valves. CW Doppler is required to accurately measure these high-velocity signals. Without it, a handheld device cannot provide the quantitative data (like mean gradient or Vmax) necessary to assess if a TAVI prosthesis is functioning correctly.
The study specifically utilized an operator with “intermediate experience” (ASE Level II) for the handheld evaluations. Even without “expert” status, the operator achieved high concordance with the reference system, suggesting that HHUDs can “up-skill” clinicians for bedside triage.
Yes. In this study, the HHUD detected paravalvular leaks with an 85.9% global agreement (kappa 0.69); (any aortic regurgitation (including paravalvular leak)) compared to the reference expert exam. However, the researchers noted that any suspected pathology or significant dysfunction identified on a handheld should still be confirmed with a comprehensive TTE.
clinical judgment?
Only 4.5% of patients (3 out of 67) were excluded due to poor acoustic windows that prevented adequate measurements. This demonstrates that the technology is feasible for the vast majority of the post-TAVI population, who are often elderly (median age of 81 in this study)
