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Page 10 of 11 Spieker et al. Vessel Plus 2020;4:29 I http://dx.doi.org/10.20517/2574-1209.2020.28

EuroSCORE 22% ± 15%) of whom the majority might have been too unfit to complete bicycle exercise.
The increase in blood pressure during isometric exercise may lead to a mismatch between increasing
mitral closing force and increased mitral tethering resulting from the impact of the rise in afterload on left
[24]
ventricular geometry . Additional mechanisms such as left ventricular dyssynchrony, changed sphericity
and papillary muscle dynamics during exercise, may enhance these forces.

Limitations
The present study was retrospective in design so that we did not include a control group with moderate
MR at rest and exercise-induced severe MR that was managed conservatively with optimal medical therapy.
However, this would be necessary to definitively conclude the clinical benefit of patients with moderate MR
at rest and exercise-induced dynamic MR. Moreover, this study was conducted at a single center. Therefore,
further validation in a larger prospective multicenter study will be necessary to confirm the present
findings. However, this is the largest study including patients with dynamic MR undergoing PMVR, so far.
Since exercise echocardiography was performed upon clinical suspicion of dynamic MR and not on regular
basis in every patient with MR grade 2+, a selection bias towards patients with relatively advanced disease
in MR grade 2+ seems probable. In addition, we only included patients who underwent PMVR and not
those who were not selected for PMVR because of remaining mild or moderate MR during exercise. These
questions need to be addressed in prospective analyses.

In conclusion, our data provide clinical evidence of symptomatic benefit from PMVR (MitraClip)
in patients with dynamic severe MR detected by handgrip echocardiography. These patients equally
benefit from MitraClip implantation as patients with severe MR at rest. Further studies comparing an
interventional strategy (PMVR) vs. conservative management (optimal medical therapy) are necessary to
further evaluate clinical benefit from PMVR in patients with dynamic MR. Handgrip echocardiography
may be integrated in the diagnostic workup of symptomatic patients with moderate MR at rest with
suspicion of dynamic MR based on discrepancy between symptoms and echocardiographic findings at rest.

DECLARATIONS
Authors’ contributions
Designed the study: Spieker M, Hellhammer K, Horn P, Westenfeld R
Responsible for data collection: Spieker M, Hellhammer K
Performed the statistical analysis: Spieker M, Westenfeld R
Involved in data interpretation, critically reviewed and revised the manuscript: Spieker M, Hellhammer K,
Spießhoefer J, Zeus T, Horn P, Kelm M, Westenfeld R

Availability of data and materials
Not applicable.

Financial support and sponsorship
None.

Conflicts of interest
All authors declared that there are no no conflicts of interest.

Ethical approval and consent to participate
The study was part of a registry, which was approved by the ethics committee of the Heinrich-Heine
University Duesseldorf and registered at www.clinicaltrials.gov (NCT02033811). The study was in
accordance with the Declaration of Helsinki. All patients gave informed written consent.