Harpoon TDS-5
Harpoon Mitral Valve Repair System (Edwards Lifesciences, Irvine, CA) is
a novel transapical off-pump mitral valve repair (MVr) system based on
ePTFE chordal implantation. Differently from Neochord DS 1000 it was
developed and tested to target severe DMR with isolated prolapsing
Posterior Mitral Leaflet (PML). At present indeed, the device has not
been evaluated for the treatment of Anterior Mitral Valve Leaflet (AML)
disease, bileaflet prolapse and flail forms. Currently available for
clinical use in Europe, it gained the CE mark in
20209.
The procedure is performed under transesophageal 2D /3D echocardiography
guidance, general anesthesia, single lumen intubation. Trough anterior
left mini-thoracotomy in the fifth intercostal space, the optimal entry
site on LV apex is identified slightly more anterior than in Neochord
procedure, and confirmed by finger testing under 2D TEE. Two small purse
strings sutures are placed on-site and the ventricle is punctured,
allowing for the positioning of a 14 Fr introducer. This is equipped
with an inner hemostatic valve that allows for LV navigation without
significant blood loss. The TEE X-plane view and 3D imaging assessment
lead the positioning of the delivery system tip under the dome of the
targeted scallop 11Gerosa, G., D’Onofrio, A., Besola, L., &
Colli, A. (2018). Transoesophageal echo-guided mitral valve repair
using the Harpoon system. European Journal of Cardio-Thoracic
Surgery, 53(4), 871-873.. The needle passes through the leaflet
tissue, far from the edge, releasing the suture. Then it’s automatically
withdrawn, tightening the ePTFE coil and forming a double-helix knot on
the atrial surface of the leaflet22Gammie, J. S., Bartus, K.,
Gackowski, A., D’Ambra, M. N., Szymanski, P., Bilewska, A., … &
Duncan, A. (2018). Beating-heart mitral valve repair using a novel
ePTFE cordal implantation device: a prospective trial. Journal of the
American College of Cardiology, 71(1), 25-36. (Figure 3). The device
is subsequently retrieved, carrying outside the neochordal free-end
through the introducer. The procedure is repeated until the desired
number of chords is implanted, using a different delivery system for
each chord. Since the needle throw during device deployment is
approximately 22 mm, Valsalva maneuver may be essential to promote an
increase in left atrial volume and so increase the distance between the
leaflet and the posterior LA wall to >25 mm during the
leaflet piercing33Diprose, P., Fogg, K. J., Pittarello, D.,
Gammie, J. S., & D’Ambra, M. N. (2020). Intensive care and anesthesia
management for HARPOON beating heart mitral valve repair. Annals of
Cardiac Anaesthesia, 23(3), 321.. Under 2D/3D TEE guidance the chords
are finally tightened to reach the best MR reduction, and then secured
to the LV wall44Colli, A., Adams, D., Fiocco, A., Pradegan, N.,
Longinotti, L., Nadali, M., … & Gerosa, G. (2018). Transapical
NeoChord mitral valve repair. Annals of cardiothoracic surgery, 7(6),
812..
To identify patients potentially suitable for the Harpoon MVRS, a
careful preoperative screening is required, including detailed
preoperative three-dimensional TEE. This allows to calculate the ratio
of prolapsing PML length compared to the anteroposterior distance from
the base of PML to the free edge of the AML, which is a predictor of
adequate coaptation when the value is
1.5/155Gammie, J. S.,
Bartus, K., Gackowski, A., D’Ambra, M. N., Szymanski, P., Bilewska,
A., … & Duncan, A. (2018). Beating-heart mitral valve repair using
a novel ePTFE cordal implantation device: a prospective trial. Journal
of the American College of Cardiology, 71(1), 25-36..
Since its first in human application in 201566Gammie, J. S.,
Wilson, P., Bartus, K., Gackowski, A., Hung, J., D’Ambra, M. N., …
& Kapelak, B. (2016). Transapical beating-heart mitral valve repair
with an expanded polytetrafluoroethylene cordal implantation device:
initial clinical experience. Circulation, 134(3), 189-197., the
device demonstrated to be safe and effective in reducing mitral
regurgitation in patients with DMR. The TRACER trial (Mitral TransApical
NeoChordal Echo-Guided Repair; NCT02768870) a prospective non-randomized
multicenter clinical study45, enrolled 30 patients
from April 2016 to November 2017, including subjects from 6 different
European Centers with isolated severe degenerative MR due to P2
prolapse. Data published by Gammie et al. show how primary endpoint
(30-day successful implantation of cords with MR reduction to moderate
or less) was met in 27 out of 30 patients (90%). There were no deaths,
strokes, or permanent pacemaker implantations. At 6 months, MR was mild
or less in 85 % (22 of 26) and severe in 8% (2 of 26). A favorable
cardiac reverse remodeling was demonstrated at 30
days.45 More recent clinical data from the TRACER CE
trial were presented in June 2019 at TVT Structural Heart Summit (data
lock on 17th December 2018).77https://www.tctmd.com/slide/harpoon-transapical-technology-and-clinical-updates
The enrollment reached 65 patients; among them 62 had been successfully
treated with Harpoon, 2 were converted to open surgery and 1 procedure
had been aborted. No perioperative death or stroke were reported. Ten
patients were later lost at follow up (2 of them died and 8 exit from
the study for secondary intervention). Fifty-two patients reached 1 year
of follow up, MR was mild or less in 75% (39 of 52) and severe in 2%
(2 of 26). Positive reverse remodeling (in term of annular diameter and
LEDV reduction) was confirmed at one year. The Harpoon program was also
paused because of 4 additional cases of severe MR recurrence due to
ePTFE chords rupture,9 then restarted and finally
gained the CE mark in May 2020.
Conclusion
Transapical micro-invasive technologies are safe and effective options
to treat MR in selected patients. Limitations are still present, first
of all the lack of knowledge on durability. Moreover, the ability to
treat a single component of the MV apparatus needs to face against the
complexity of the mechanisms involving the disease.
Therefore, the cardiac mitral surgeon will have to fill these gaps by
acting on a double front: on one hand he must extensively embrace
micro-invasive solutions and apply them on well-selected patients; on
the other hand he must gain a complete tool-box which allows for a
tailored valve repair, based on combined multi-targeting procedures.
This evolution can guide the surgeon through the new revolution of MV
micro-invasive tailored repair.