Dynamics of the mean transmitral pressure gradient and its impact on
clinical outcomes after MitraClip
Abstract
Background: The impact of the increased mitral gradient (MG) on outcomes
is ambiguous. Therefore, we aimed to evaluate a) periinterventional
dynamics of MG, b) the impact of intraprocedural MG on clinical
outcomes, and c) predictors for unfavourable MG values after MitraClip.
Methods: We prospectively included patients undergoing MitraClip. All
patients underwent echocardiography at baseline, intraprocedurally, at
discharge, and after six months. 12-month survival was reassessed.
Results: 175 patients (age 81.2±8.2 years, 61.2% male) with severe
mitral regurgitation (MR) were included. We divided our cohort into two
groups with a threshold of intraprocedural MG of 4.5 mmHg, which was
determined by the multivariate analysis for the prediction of 12-month
mortality (<4.5 mmHg: Group 1, 4.5 mmHg: Group 2).
Intraprocedural MG 4.5 mmHg was found to be the strongest independent
predictor for 12-month mortality (HR: 2.33, p=0.03, OR: 1.70, p=0.05)
and ≥3.9 mmHg was associated with adverse functional outcomes (OR: 1.96,
p=0.04). The baseline leaflet-to-annulus index (>1.1) was
found to be the strongest independent predictor (OR: 9.74, p=0.001) for
unfavourable intraprocedural MG, followed by the number of implanted
clips (p=0.01), MG at baseline (p=0.02) and central clip implantation
(p=0.05). Conclusion: MG shows time-varying and condition-depended
dynamics periinterventionally. Patients with persistent increased (≥4.5
mmHg) MG at discharge showed the worst functional outcomes and the
highest 12-month mortality, followed by patients with an intra-hospital
decrease in MG to values below 4.5 mmHg. Pre-interventional
echocardiographic and procedural parameters can predict unfavourable
postprocedural MG.