Reply to Hysi and Fabre

We thank Hysi and Fabre [1] and their interest in our work [2]. They raise concerns regarding the reoperation and recurrent mitral regurgitation (MR) rate in the initial European clinical experience with HARPOON beating-heart transventricular artificial cordal implantation. This technology was in its earliest stage of clinical use for the patients we reported. There have been significant learnings in patient selection, target planning, imaging and cordal tensioning as clinical experience has accrued. While the authors refer to Johnston’s results as the gold standard for outcomes in degenerative MR, it is telling that in the Johnston experience, recurrent moderate and severe MR was seen by 2 weeks in 6% and 5% of patients, respectively [3]. The HARPOON system was remarkably safe and not associated with stroke, death, renal failure or blood transfusion, and case times were ½ those of conventional mitral valve operations. Repair versus replacement rates for degenerative MR are highly variable, and in fact only 67–80% of patients in contemporary datasets receive mitral repair [4, 5]; in contrast, in our initial HARPOON experience, no patient was subject to replacement. Another important finding of this initial experience was that implantation of artificial cords with the HARPOON system does not compromise nor complicate future conventional surgical repair. At 1 year, patient survival was 97%, 98% of patients were in New York Heart Association (NYHA) class I or II and 97% had functioning mitral valve repairs. As we move into the next series of HARPOON repairs, we anticipate that improvements in target placement, as well as quantitated image-guided adjustment of cordal length, will enable surgeons to achieve high-quality and durable mitral valve repairs. The ongoing ASCEND post-market study in Europe (NCT04382612) and RESTORE US pivotal trial (NCT04375332) will further inform the value of this exciting therapy.

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