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. 2023 Aug 28;10(9):1016.
doi: 10.3390/bioengineering10091016.

The Development of a Permanent Implantable Spacer with the Function of Size Adjustability for Customized Treatment of Regurgitant Heart Valve Disease

Min-Ku Chon  1 , Su-Jin Jung  2 , Jae-Young Seo  2 , Dong-Hoon Shin  3 , Jun-Hui Park  4 , Hyun-Sook Kim  5 , Joo-Yong Hahn  6 , Eun-Kyoung Kim  6 , Seung-Whan Lee  7 , Yong-Hyun Park  1 , Sang-Hyun Lee  1 , June-Hong Kim  1
Affiliations

The Development of a Permanent Implantable Spacer with the Function of Size Adjustability for Customized Treatment of Regurgitant Heart Valve Disease

Min-Ku Chon et al. Bioengineering (Basel). .

Abstract

The Pivot Mandu is an innovative device featuring a leak-tight adjustable 3D balloon spacer, incorporating inner mesh support, an outer e-PTFE layer, and a compliant balloon in the middle layer with a specialized detachable system. To assess its feasibility, proof of concept was rigorously evaluated through bench testing and survival porcine animal experiments. The results demonstrated successful remote inflation of the balloon system, with the balloon spacer exhibiting sustained patent and functional integrity over an extended observation period of up to 6 months. A noteworthy feature of the newly designed 3D balloon spacer is its capability for easy size adjustment during procedures, enhancing its adaptability and practicality in clinical settings. This three-layered 3D balloon spacer, with its established long-term patency, exhibits highly encouraging outcomes that hold promise in overcoming the current limitations of spacer devices for heart valve diseases. Given the compelling results from preclinical investigations, the translation of the Pivot Mandu into human trials is strongly warranted.

Keywords: biocompatible coating; cardiology; e-PTFE; implantable medical device; nitinol; polyurethane.

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Conflict of interest statement

The corresponding author (June-Hong Kim) has intellectual property of the spacer device and stock of TAU MEDICAL Inc., and is currently working as clinical director of Tau-PNU MEDICAL Co., Ltd. The other authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Structure of Pivot Mandu 3D balloon spacer: (a,b) Pivot-TR system with oven-cavity 3D spacer; (c) illustration of Pivot-TR system; (d–f) Pivot Mandu system 3D balloon spacer with e-PTFE outer layer; (g) illustration of Pivot Mandu system.
Figure 2
Figure 2
Illustration of procedural schema of detachable fluid injection system for Pivot Mandu system: (a) balloon injection tube is inserted into the device, saline can be injected to customize the 3D balloon spacer and expand it to the desired size; (b) balloon injection tube is inserted into the device, size of the 3D balloon spacer can be reduced by draining the saline; (c) detailed representation of 3D balloon spacer with balloon injection tube inserted in Pivot Mandu system; (d) 3D balloon spacer of Pivot Mandu appropriately inflated to the desired size, while balloon injection tube is being withdrawn; (e) balloon injection tube completely removed (once the balloon injection tube is fully removed, the size of the 3D balloon spacer of Pivot Mandu cannot be adjusted); (f) detailed depiction of 3D balloon spacer in Pivot Mandu system when balloon injection tube is retrieved.
Figure 3
Figure 3
Pivot Mandu 3D balloon spacer testing in vivo and in vitro: (a) in vitro expandable testing of Pivot Mandu conducted in a water tank set at 36.5 °C to construct environmental conditions similar to human body; (b) bench testing conducted in water tank (3D balloon spacer size was verified by measuring the amount of injection fluid); (c) in vivo test (3D balloon spacer was easily inflated through the injection lumen without any evidence of rupture or damage); (d) preclinical study (3D balloon spacer was maintained for a duration of 24 weeks); (e) results of 3D balloon spacer patency test evaluated at 8 weeks (data included 16 samples, with 2 missing data points at 8 weeks owing to procedural infections and heart failure caused by severe tricuspid regurgitation (TR)); (f) 3D balloon spacer patency test results conducted at 24 weeks with data available for five samples.
Figure 4
Figure 4
TR reduction effect of Pivot Mandu. (a) Modeling of TR in pigs was performed, and TR grading was assessed throughout the survival period. (b) Baseline echocardiogram of pigs immediately after modeling TR, showing a grade of moderate to severe TR. (c) Echocardiogram immediately after the implantation of Pivot Mandu, showing a grade of mild to moderate TR. (d) Echocardiogram after 24 weeks of Pivot Mandu implantation, showing a grade of moderate TR. 1 = mild, 2 = moderate, 3 = severe, 4 = massive, 5 = torrential.
Figure 5
Figure 5
Examination of harvested samples for tricuspid valve and Pivot Mandu device after implantation into pigs: (a) after 8 weeks (confirmed tissue covering); (b) after 24 weeks; (c) pathology of septal leaflet after 24 weeks; (d) pathology of e-PTFE material on 3D balloon spacer, which comes into contact with the tricuspid valve, after 24 weeks (confirmed formation of endothelium).
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References

    1. Thourani V.H., Kodali S., Makkar R.R., Herrmann H.C., Williams M., Babaliaros V., Smalling R., Lim S., Malaisrie S.C., Kapadia S. Transcatheter aortic valve replacement versus surgical valve replacement in intermediate-risk patients: A propensity score analysis. Lancet. 2016;387:2218–2225. doi: 10.1016/S0140-6736(16)30073-3. - DOI - PubMed
    1. Kim J.-H., Sung S.-C., Chon M.-K., Kim J.-O., Lee S.-H., Lee S.-Y., Je H.-G., Choo K.-S., Hwang J.-M., Kim J.-S. Mitral loop cerclage as a variant form of mitral cerclage annuloplasty that adds a device (CSTV) for preventing potential complications: A preclinical proof of concept and feasibility study. Eurointerv. J. Eur. Collab. Work. Group Interv. Cardiol. Eur. Soc. Cardiol. 2016;11:e1669–e1679. doi: 10.4244/EIJV11I14A319. - DOI - PubMed
    1. Asmarats L., Puri R., Latib A., Navia J.L., Rodés-Cabau J. Transcatheter tricuspid valve interventions: Landscape, challenges, and future directions. J. Am. Coll. Cardiol. 2018;71:2935–2956. doi: 10.1016/j.jacc.2018.04.031. - DOI - PubMed
    1. Asmarats L., Perlman G., Praz F., Hensey M., Chrissoheris M.P., Philippon F., Ofek H., Ye J., Puri R., Pibarot P. Long-term outcomes of the FORMA transcatheter tricuspid valve repair system for the treatment of severe tricuspid regurgitation: Insights from the first-in-human experience. JACC Cardiovasc. Interv. 2019;12:1438–1447. doi: 10.1016/j.jcin.2019.04.038. - DOI - PubMed
    1. Peppas A., Furer A., Wilson J., Yi G., Cheng Y., Van Wygerden K., Seguin C., Shibuya M., Kaluza G.L., Granada J.F. Preclinical in vivo long-term evaluation of the novel Mitra-Spacer technology: Experimental validation in the ovine model. Eurointerv. J. Eur. Collab. Work. Group Interv. Cardiol. Eur. Soc. Cardiol. 2017;13:272–279. doi: 10.4244/EIJ-D-16-00609. - DOI - PubMed

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