Percutaneous mitral repair as treatment in HFrEF (MitraClip/TEER) historical perspective

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Nehal Eid, M.D.[2]

Historical Perspective

Surgical origin and early transcatheter development

Mitral transcatheter edge-to-edge repair (M-TEER) evolved from the surgical Alfieri edge-to-edge repair, developed in the 1990s. Approximation of the middle portions of the anterior and posterior mitral leaflets created a double-orifice valve; transcatheter systems subsequently reproduced this principle through percutaneous leaflet grasping.[1]

The first-in-human implantation in 2003 initiated the EVEREST development program. EVEREST I was completed in 2006 with 55 patients; pooled analysis with 52 EVEREST II roll-in patients (n=107) demonstrated acute procedural success in 84%, one in-hospital death (0.9%), and freedom from major adverse events in 91% at 30 days. Midterm follow-up identified durability of the initial result as a principal limitation: 32 of 107 patients (30%) underwent mitral surgery within 3.2 years.[2][1]

The MitraClip system received CE Mark approval in March 2008, with commercialization beginning in September 2008—approximately five years before United States approval. This interval generated extensive European experience before randomized evidence in secondary mitral regurgitation became available. ACCESS-EU phase I subsequently enrolled 567 patients at 14 centers from April 2009 to April 2011 and reported 12-month outcomes in September 2013. Compared with EVEREST II, it marked a transition toward older, higher-risk patients with predominantly functional MR, impaired ventricular function, and more advanced symptoms.[3][4]

Landmark evidence and regulatory milestones

Evolution of M-TEER
Period Milestone Historical significance
1990s Surgical Alfieri edge-to-edge repair Established the double-orifice leaflet-approximation concept subsequently reproduced by transcatheter devices.[1]
2003–2009 First-in-human implantation and EVEREST feasibility studies Established the feasibility and early safety of transseptal leaflet repair. In the initial 107-patient cohort, acute procedural success was 84%, while 30% underwent mitral surgery during follow-up of up to 3.2 years.[2]
2008–2013 European approval and ACCESS-EU CE Mark approval in March 2008 and commercialization in September 2008 preceded ACCESS-EU phase I enrollment from April 2009 to April 2011; its 12-month results were reported in September 2013. Implant success was 99.6%, but incomplete MR relief remained frequent. At 1 year, residual MR was distributed similarly in functional disease—grade 3–4+ in 21%, 2+ in 47%, and 0–1+ in 32%—and degenerative disease—25%, 42%, and 33%, respectively—suggesting that incomplete relief was not confined to one etiology. Single-leaflet device attachment occurred in 27 patients (4.8%); 10 of these patients underwent a second MitraClip procedure and 6 underwent mitral-valve surgery, with no device embolizations. Across the whole cohort, 36 patients (6.3%) required mitral-valve surgery and 3.4% underwent a second MitraClip procedure within 12 months. Echocardiographic grades were not core-laboratory adjudicated, and the investigators noted that the surgical rate might underestimate residual or recurrent MR because reoperation itself carried high risk in this population.[4] The population differed substantially from EVEREST II: mean age was 74 years, 77% had functional MR, 53% had an ejection fraction of 40% or less, and 85% were in NYHA class III or IV, compared with a mean age of 71 years, 73.4% degenerative MR, mean ejection fraction of 60%, and 52% in NYHA class III or IV in EVEREST II. Two contributing centers reported that 73%–80% of their patients would have met EVEREST II exclusion criteria, predominantly because of ventricular dysfunction.[3][4] An exploratory intention-to-treat subgroup analysis of EVEREST II reported treatment interactions by age (70 years or older versus younger; P=0.009) and MR etiology (functional versus degenerative; P=0.02), with the relative result for percutaneous repair more favorable in the older and functional-MR subgroups. This hypothesis-generating signal paralleled the population that predominated in European post-approval practice.[5][4]
2011–2015 EVEREST II randomized trial and five-year follow-up In 279 patients with grade 3+ or 4+ MR, MitraClip provided superior procedural safety but less effective MR reduction than surgery at 1 year (primary efficacy composite 55% vs 73%; P=0.007), driven by surgery for mitral-valve dysfunction in 20% versus 2.2%. At 5 years, the composite remained lower with MitraClip (44.2% vs 64.3%), driven by reintervention (27.9% vs 8.9%) and grade 3+/4+ MR (12.3% vs 1.8%), while mortality was similar (20.8% vs 26.8%; P=0.4). Because 78% of post-clip surgeries occurred within the first 6 months and event rates were comparable thereafter, the principal limitation was less complete initial correction with early reintervention rather than inferior durability beyond 6 months.[1][6]
2013 Initial United States FDA approval Approval was restricted to selected patients with symptomatic primary degenerative MR at prohibitive surgical risk. This restriction reflected EVEREST II's trade-off between superior procedural safety and less effective MR reduction compared with surgery.[7][8]
2013–2016 European registry experience The German TRAMI registry enrolled 828 patients during 2010–2013 with a median EuroSCORE I of 20.0%. One-year mortality was 20.3%, while 63.3% of patients were in NYHA class I or II at 1 year versus 11.0% at baseline. Procedural failure was the strongest independent predictor of 1-year mortality (HR 4.36), providing an early signal that procedural quality rather than device deployment alone determined outcome.[9] Long-term TRAMI follow-up (n=722; median 1,037 days) showed estimated mortality of 31.9% at 2 years and 53.1% at 4 years, without a significant difference by MR etiology.[10]
2007–2017 United States registry experience and secondary-MR use A subsequent pooled analysis of the pre-randomization EVEREST II Investigational Device Exemption program provided the largest United States secondary-MR dataset. Among 616 patients with grade 3+ or 4+ secondary MR, including 482 at high surgical risk, 30-day death and stroke occurred in 3.6% and 2.3%, respectively; MR grade 2+ or less was achieved in 88.8% at discharge, and Kaplan–Meier freedom from mortality was 76.8% at 1 year. In high-risk patients, annualized heart-failure hospitalization fell from 0.68 to 0.46 during the 12 months before versus after treatment.[11] The original EVEREST II High Risk Study supplied the proximate rationale for randomized testing. Among 78 treated patients (mean age 77 years; more than half with previous cardiac surgery), 46 had functional MR and devices were successfully implanted in 96%. Thirty-day procedure-related mortality was 7.7% in a cohort with a protocol-predicted surgical mortality of 18.2% and an STS-calculator estimate of 14.2%. Twelve-month survival was 76% versus 55% in the nonrandomized, concurrently screened but non-enrolled comparison group (P=0.047). The 2016 AATS consensus update identified these data as the foundation for COAPT.[12][13] At five years, clinical follow-up was obtained in 90% of the 78 patients. Among patients with available effectiveness data, MR was grade 2+ or less in 75%, left-ventricular end-diastolic volume had decreased by 38.2 mL, and improvement in NYHA class was durable. Two patients (2.6%) developed mitral stenosis and two underwent mitral-valve surgery, including one because of mitral stenosis. Forty-two deaths occurred through 5 years; the investigators considered the observed mortality most likely attributable to the advanced age and comorbidity profile of the cohort.[14] The 2017 STS/ACC TVT Registry report linked residual MR grade 3+ or greater to 1-year mortality approaching 50% and a composite of death or heart-failure rehospitalization exceeding 50%; mortality was approximately half as high with residual MR grade 1+ or less, while grade 2+ carried intermediate risk.[15] The TVT Registry population included approximately 9% with secondary MR and another 9% with mixed MR despite the absence of an approved secondary-MR indication or randomized outcome evidence.[16]
2018 MITRA-FR and COAPT MITRA-FR reported no clinical benefit, whereas COAPT demonstrated reductions in heart-failure hospitalization and mortality. This discordance established patient selection, optimization of guideline-directed medical therapy, left-ventricular remodeling, procedural success, and durable MR reduction as central determinants of benefit. In COAPT, the hospitalization benefit emerged within 30 days, whereas the mortality benefit emerged predominantly after 1 year. Both trials used early-generation devices.[17][16][18]
March 2019 FDA indication expanded to secondary MR The United States indication was extended to selected symptomatic patients with secondary MR, with the labeled population reflecting the principal COAPT selection framework.[7]
2019–2021 United States diffusion and institutional experience United States adoption expanded rapidly after the 2019 indication extension. Annual TEER volume rose from 1,152 procedures in 2014 to 10,460 in 2019 across 403 sites, while 30-day mortality fell from 5.6% to 4.1% and 1-year mortality from 27.4% to 22.0%. In-hospital mortality declined from 2.9% to 2.1%, stroke remained below 1%, conversion to open surgery occurred in 0.5%, single-leaflet device attachment in approximately 1%, and median length of stay fell from 3 days to 1 day. Registry investigators attributed these gains to growing operator experience and improved patient selection, noting that the median STS predicted risk of mortality for mitral repair fell below 5% for the first time in 2019. Real-world MR reduction nonetheless lagged the pivotal trial: residual moderate-to-severe MR was 8.7% in the registry versus 5.3% at 1 year in COAPT, although the registry value was site-reported rather than core-laboratory adjudicated.[19][20] Institutional experience also influenced adoption-era outcomes. Procedure time declined substantially across the first 200 institutional cases and remained lower after risk adjustment, whereas the unadjusted improvement in optimal MR reduction lost statistical significance after adjustment, suggesting that changing case selection contributed alongside technical proficiency.[21]
2023 COAPT five-year follow-up Demonstrated persistence of the reduction in heart-failure hospitalization and mortality, with a low incidence of device-specific safety events beyond the early procedural period. Against an acute procedural success rate of 95%, MR recurrence and mitral reintervention were 5.3% and 4.5%, respectively, at 5 years.[22][18]
2024 RESHAPE-HF2 Extended randomized evidence to a population with predominantly moderate-to-severe functional MR, broadening the evidence base beyond the original COAPT population.[23]
2024 MATTERHORN Provided the first randomized comparison of M-TEER with mitral-valve surgery specifically for secondary MR in patients at high surgical risk. Unlike COAPT, MITRA-FR, and RESHAPE-HF2, MATTERHORN enrolled patients across a broad LVEF range (mean 43.0±11.7%); its findings therefore inform procedural selection in secondary MR generally rather than exclusively in heart failure with reduced ejection fraction.[24][25]

Device evolution

The MitraClip platform evolved through the original and NT systems, the NTR/XTR generation introduced in 2018, and the fourth-generation G4 platform. Each generation addressed specific technical constraints. The NT system introduced nitinol grippers capable of opening to a wider angle during leaflet capture. NTR/XTR added delivery-system refinements and longer clip arms with the XTR system (12 mm versus 9 mm for NTR), permitting treatment across a broader anatomic range. G4 added two additional clip sizes with 50%-wider arms (NTW and XTW), independent controlled gripper actuation, an improved deployment sequence, and continuous intraprocedural left-atrial-pressure monitoring. These features addressed limitations of NTR/XTR, including leaflet-injury risk with the longer XTR arms, difficult tissue insertion with shorter NTR arms in wide coaptation gaps, inability to grasp the two leaflets independently, and the availability of only two implant sizes. The improvement with G4 has been attributed specifically to the wider clip sizes and independent grasping mechanism, which permit more complete leaflet approximation in both degenerative and functional MR.[26][27]

The magnitude of generational improvement was concentrated in near-complete MR reduction. MR grade 1+ or less at 1 year was achieved in 42.9%–69.1% of patients across the EVEREST II randomized trial (43.0%; n=184; NT/G1), the EVEREST II REALISM secondary-MR registry (42.9%; n=616; NT/G1), MITRA-FR (49.5%; n=152; NT/G2), and COAPT (69.1%; n=302; NT/G2). This compared with 89.2% at 1 year across the full third-generation EXPAND cohort. In the secondary-MR cohort reported in the comparative tabulation by Lander et al. (n=213), MR grade 1+ or less and grade 2+ or less were achieved in 89.5% and 99.1%, respectively, at 1 year. With the fourth-generation device, EXPAND G4 reported MR grade 1+ or less in 92.6% and grade 2+ or less in 98.5% at 1 year. Because rates of MR grade 2+ or less were already high in earlier trials, the historical shift was principally in the depth rather than the overall frequency of MR reduction. These advances are important when interpreting trials conducted with earlier-generation devices.[28][29][30][31]

Improved acute and 1-year results have not yet translated into demonstrably superior longer-term durability. In pooled analyses stratified by device generation, newer iterations were associated with lower 1-year MR recurrence and reintervention, but durability at 3 years was not significantly improved. Across generations, aggregate M-TEER failure—MR recurrence or mitral reintervention—remained below 13% through 3 years before increasing to approximately 28% at 5 years; weighted 5-year rates were 17% for MR recurrence and 9% for reintervention. Failure was consistently more frequent in primary than secondary MR, with recurrence or reintervention reaching 41% at 5 years in primary MR. These estimates qualify the improvement in initial MR reduction and demonstrate that long-term durability depends on both device performance and the underlying disease process.[18]

Worldwide use increased from more than 30,000 treated patients by 2016 to more than 150,000 by the publication of the REPAIR-MR trial design in 2023.[8][32]

PASCAL and PASCAL Ace emerged as alternative edge-to-edge repair systems through the CLASP program. CLASP IID randomized 300 patients with prohibitive surgical risk and grade 3+ or 4+ degenerative MR to PASCAL or MitraClip and met its 30-day safety and 6-month effectiveness noninferiority endpoints.[33] At 1 year, the devices had similar major clinical outcomes and met noninferiority criteria for MR reduction; however, CLASP IID was a device-comparison trial in degenerative MR, not an independent clinical-outcome trial in secondary MR.[34]

References

  1. ↑ 1.0 1.1 1.2 1.3 Maisano F, La Canna G, Colombo A, Alfieri O (2011). "The Evolution From Surgery to Percutaneous Mitral Valve Interventions: The Role of the Edge-to-Edge Technique". Journal of the American College of Cardiology. 58 (21): 2174–2182. doi:10.1016/j.jacc.2011.07.046.
  2. ↑ 2.0 2.1 Feldman T, Kar S, Rinaldi M; et al. (2009). "Percutaneous Mitral Repair With the MitraClip System: Safety and Midterm Durability in the Initial EVEREST (Endovascular Valve Edge-to-Edge REpair Study) Cohort". Journal of the American College of Cardiology. 54 (8): 686–694. doi:10.1016/j.jacc.2009.03.077. PMID 19679246.
  3. ↑ 3.0 3.1 O'Gara PT, Calhoon JH, Moon MR, Tommaso CL (2014). "Transcatheter Therapies for Mitral Regurgitation: A Professional Society Overview From the American College of Cardiology, the American Association for Thoracic Surgery, Society for Cardiovascular Angiography and Interventions Foundation, and the Society of Thoracic Surgeons". Journal of the American College of Cardiology. 63 (8): 840–852. doi:10.1016/j.jacc.2013.11.014.
  4. ↑ 4.0 4.1 4.2 4.3 Maisano F, Franzen O, Baldus S; et al. (2013). "Percutaneous Mitral Valve Interventions in the Real World: Early and 1-Year Results From the ACCESS-EU, a Prospective, Multicenter, Nonrandomized Post-Approval Study of the MitraClip Therapy in Europe". Journal of the American College of Cardiology. 62 (12): 1052–1061. doi:10.1016/j.jacc.2013.02.094. PMID 23747789.
  5. ↑ Feldman T, Foster E, Glower DD; et al. (2011). "Percutaneous Repair or Surgery for Mitral Regurgitation". The New England Journal of Medicine. 364 (15): 1395–1406. doi:10.1056/NEJMoa1009355. PMID 21463154.
  6. ↑ Feldman T, Kar S, Elmariah S; et al. (2015). "Randomized Comparison of Percutaneous Repair and Surgery for Mitral Regurgitation: 5-Year Results of EVEREST II". Journal of the American College of Cardiology. 66 (25): 2844–2854. doi:10.1016/j.jacc.2015.10.018. PMID 26718672.
  7. ↑ 7.0 7.1 Bonow RO, O'Gara PT, Adams DH; et al. (2020). "2019 AATS/ACC/SCAI/STS Expert Consensus Systems of Care Document: Operator and Institutional Recommendations and Requirements for Transcatheter Mitral Valve Intervention". Journal of the American College of Cardiology. 76 (1): 96–117. doi:10.1016/j.jacc.2019.12.002.
  8. ↑ 8.0 8.1 Nishimura RA, Vahanian A, Eleid MF, Mack MJ (2016). "Mitral Valve Disease—Current Management and Future Challenges". Lancet. 387 (10025): 1324–1334. doi:10.1016/S0140-6736(16)00558-4.
  9. ↑ Puls M, Lubos E, Boekstegers P; et al. (2016). "One-Year Outcomes and Predictors of Mortality After MitraClip Therapy in Contemporary Clinical Practice: Results From the German Transcatheter Mitral Valve Interventions Registry". European Heart Journal. 37 (8): 703–712. doi:10.1093/eurheartj/ehv627. PMID 26614824.
  10. ↑ Kalbacher D, Schäfer U, von Bardeleben RS; et al. (2019). "Long-Term Outcome, Survival and Predictors of Mortality After MitraClip Therapy: Results From the German Transcatheter Mitral Valve Interventions (TRAMI) Registry". International Journal of Cardiology. 277: 35–41. doi:10.1016/j.ijcard.2018.08.023. PMID 30153994.
  11. ↑ Ailawadi G, Lim DS, Mack MJ; et al. (2019). "One-Year Outcomes After MitraClip for Functional Mitral Regurgitation". Circulation. 139 (1): 37–47. doi:10.1161/CIRCULATIONAHA.117.031733. PMID 30586701.
  12. ↑ Whitlow PL, Feldman T, Pedersen WR; et al. (2012). "Acute and 12-Month Results With Catheter-Based Mitral Valve Leaflet Repair: The EVEREST II High Risk Study". Journal of the American College of Cardiology. 59 (2): 130–139. doi:10.1016/j.jacc.2011.08.067. PMID 22222076.
  13. ↑ Kron IL, LaPar DJ, Acker MA; et al. (2017). "2016 Update to The American Association for Thoracic Surgery (AATS) Consensus Guidelines: Ischemic Mitral Valve Regurgitation". The Journal of Thoracic and Cardiovascular Surgery. 153 (5): e97–e114. doi:10.1016/j.jtcvs.2017.01.031. PMID 28411753.
  14. ↑ Kar S, Feldman T, Qasim A; et al. (2019). "Five-Year Outcomes of Transcatheter Reduction of Significant Mitral Regurgitation in High-Surgical-Risk Patients". Heart. 105 (21): 1622–1628. doi:10.1136/heartjnl-2017-312605. PMID 30077993.
  15. ↑ Sorajja P, Vemulapalli S, Feldman T; et al. (2017). "Outcomes With Transcatheter Mitral Valve Repair in the United States: An STS/ACC TVT Registry Report". Journal of the American College of Cardiology. 70 (19): 2315–2327. doi:10.1016/j.jacc.2017.09.015. PMID 29096801.
  16. ↑ 16.0 16.1 Bonow RO, O'Gara PT, Adams DH; et al. (2020). "2020 Focused Update of the 2017 ACC Expert Consensus Decision Pathway on the Management of Mitral Regurgitation". Journal of the American College of Cardiology. 75 (17): 2236–2270. doi:10.1016/j.jacc.2020.02.005.
  17. ↑ Stone GW, Lindenfeld J, Abraham WT; et al. (2018). "Transcatheter Mitral-Valve Repair in Patients with Heart Failure". The New England Journal of Medicine. 379 (24): 2307–2318. doi:10.1056/NEJMoa1806640.
  18. ↑ 18.0 18.1 18.2 Mariani A, Stolz L, von Bardeleben RS; et al. (2026). "Durability of Mitral Valve Transcatheter Edge-to-Edge Repair: An Expert Overview". JACC: Cardiovascular Interventions. 19 (9): 1057–1070. doi:10.1016/j.jcin.2026.02.019. PMID 41837916 Check |pmid= value (help).
  19. ↑ Mack M, Carroll JD, Thourani V; et al. (2021). "Transcatheter Mitral Valve Therapy in the United States: A Report From the STS-ACC TVT Registry". Journal of the American College of Cardiology. 78 (23): 2326–2353. doi:10.1016/j.jacc.2021.07.058. PMID 34711430 Check |pmid= value (help).
  20. ↑ Mack M, Carroll JD, Thourani V; et al. (2022). "Transcatheter Mitral Valve Therapy in the United States: A Report From the STS/ACC TVT Registry". The Annals of Thoracic Surgery. 113 (1): 337–365. doi:10.1016/j.athoracsur.2021.07.030. PMID 34711394 Check |pmid= value (help).
  21. ↑ Chhatriwalla AK, Vemulapalli S, Holmes DR; et al. (2019). "Institutional Experience With Transcatheter Mitral Valve Repair and Clinical Outcomes: Insights From the TVT Registry". JACC: Cardiovascular Interventions. 12 (14): 1342–1352. doi:10.1016/j.jcin.2019.02.039. PMID 31320029.
  22. ↑ Stone GW, Abraham WT, Lindenfeld J; et al. (2023). "Five-Year Follow-up after Transcatheter Repair of Secondary Mitral Regurgitation". The New England Journal of Medicine. 388 (22): 2037–2048. doi:10.1056/NEJMoa2300213.
  23. ↑ Anker SD, Friede T, von Bardeleben RS; et al. (2024). "Transcatheter Valve Repair in Heart Failure with Moderate to Severe Mitral Regurgitation". The New England Journal of Medicine. 391 (19): 1799–1809. doi:10.1056/NEJMoa2314328.
  24. ↑ Baldus S, Doenst T, Pfister R; et al. (2024). "Transcatheter Repair versus Mitral-Valve Surgery for Secondary Mitral Regurgitation". The New England Journal of Medicine. 391 (19): 1787–1798. doi:10.1056/NEJMoa2408739. PMID 39216093 Check |pmid= value (help).
  25. ↑ Stolz L, Stocker TJ, Lurz P, Hausleiter J (2025). "Growing Evidence for Edge-to-Edge Repair in Secondary Mitral Regurgitation: What to Learn From COAPT, MITRA-FR, and RESHAPE-HF2". JACC: Cardiovascular Interventions. 18 (7): 927–932. doi:10.1016/j.jcin.2025.01.429.
  26. ↑ Chakravarty T, Makar M, Patel D; et al. (2020). "Transcatheter Edge-to-Edge Mitral Valve Repair With the MitraClip G4 System". JACC: Cardiovascular Interventions. 13 (20): 2402–2414. doi:10.1016/j.jcin.2020.06.053. PMID 33011141 Check |pmid= value (help).
  27. ↑ von Bardeleben RS, Rogers JH, Mahoney P; et al. (2023). "Real-World Outcomes of Fourth-Generation Mitral Transcatheter Repair: 30-Day Results From EXPAND G4". JACC: Cardiovascular Interventions. 16 (12): 1463–1473. doi:10.1016/j.jcin.2023.05.013. PMID 37380228 Check |pmid= value (help).
  28. ↑ Windecker S, Winkel MG, Praz F (2020). "Adding a Clasp to the Toolbox for Transcatheter Mitral Valve Repair". JACC: Cardiovascular Interventions. 13 (20): 2358–2360. doi:10.1016/j.jcin.2020.06.021.
  29. ↑ Lander MM, Brener MI, Goel K; et al. (2023). "Mitral Interventions in Heart Failure". JACC: Heart Failure. 11 (8 Pt 2): 1055–1069. doi:10.1016/j.jchf.2023.07.016.
  30. ↑ Kar S, von Bardeleben RS, Rottbauer W; et al. (2023). "Contemporary Outcomes Following Transcatheter Edge-to-Edge Repair: 1-Year Results From the EXPAND Study". JACC: Cardiovascular Interventions. 16 (5): 589–602. doi:10.1016/j.jcin.2023.01.010.
  31. ↑ von Bardeleben RS, Mahoney P, Morse MA; et al. (2023). "1-Year Outcomes With Fourth-Generation Mitral Valve Transcatheter Edge-to-Edge Repair From the EXPAND G4 Study". JACC: Cardiovascular Interventions. 16 (21): 2600–2610. doi:10.1016/j.jcin.2023.09.029. PMID 37877913 Check |pmid= value (help).
  32. ↑ McCarthy PM, Whisenant B, Asgar AW; et al. (2023). "Percutaneous MitraClip Device or Surgical Mitral Valve Repair in Patients With Primary Mitral Regurgitation Who Are Candidates for Surgery: Design and Rationale of the REPAIR MR Trial". Journal of the American Heart Association. 12 (4): e027504. doi:10.1161/JAHA.122.027504. PMID 36752231 Check |pmid= value (help).
  33. ↑ Lim DS, Smith RL, Gillam LD; et al. (2022). "Randomized Comparison of Transcatheter Edge-to-Edge Repair for Degenerative Mitral Regurgitation in Prohibitive Surgical Risk Patients". JACC: Cardiovascular Interventions. 15 (24): 2523–2536. doi:10.1016/j.jcin.2022.09.005.
  34. ↑ Zahr F, Smith RL, Gillam LD; et al. (2023). "One-Year Outcomes From the CLASP IID Randomized Trial for Degenerative Mitral Regurgitation". JACC: Cardiovascular Interventions. 16 (23): 2803–2816. doi:10.1016/j.jcin.2023.10.002. PMID 37962288 Check |pmid= value (help).
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