Implantation of one versus two MitraClips in the German TRAMI registry: Is more always better?

Objectives: To compare baseline characteristics and outcomes in patients treated with either 1 or 2 MitraClips in the German TRAMI (Transcatheter Mitral Valve Interventions) registry.

Background: The MitraClip community seems to silently assume that results should intrinsically be better after implantation of more than one clip, although data is still sparse.

Methods: In 2010-2013, 803 patients were enrolled prospectively into TRAMI (461 one-clip and 312 two-clip procedures). Follow-up was performed centrally at 30 days and 1 year.

Results: Baseline characteristics of TRAMI-patients with two clips differed significantly from single-clip patients regarding constitutional (more men, taller body height) and heart failure-related factors (larger left ventricular dimensions, reduced left ventricular ejection fraction, more severe heart failure). Also, a significant increase in two-clip procedures over time was present. After propensity score matching for differing baseline characteristics, residual moderate mitral regurgitation (MR) occurred more frequently after implantation of two clips, whereas residual severe MR could more frequently be observed after one-clip procedures. However, no or mild residual MR at discharge was present in 71.6% after single-clip and in 70.1% after two-clips implantation (p = .81). After 1 year, no significant differences regarding mortality or New York Heart Association status could be detected in the propensity matched cohorts. However, TRAMI-patients treated with two clips had a significantly higher incidence of cerebral-vascular events (p = .02).

Conclusions: TRAMI data cannot support the theory that implantation of more than one clip is associated with better clinical outcomes. The finding of more cerebral-vascular events after two-clip procedures might be hypothesis-generating.