Take Home Message
When the rules of the game are not very clear, particular attention must be paid to the design of the study, and every single situation this entails. When there is no comparison group, the results should not be so liberally extrapolated to real life cases. In these terms, the conclusions should be quite limited.
Cuando las reglas del juego no son suficientemente claras, especial atención debe ser puesta al diseño del estudio, y en cada una de las situaciones específicas que esto implica. Cuando no existe un grupo control comparativo, los resultados no pueden ser extrapolados tan liberalmente a los casos de la vida real. En estos términos, las conclusiones deben ser bastante limitadas.
Quando as regras do jogo não são muito claras, deve-se prestar atenção especial ao desenho do estudo e a tudo o que isso acarreta. Quando não há grupo de comparação, os resultados não devem ser extrapolados tão liberalmente para casos da vida real. Nestes termos, as conclusões devem ser bastante limitadas.
Abstract
By Ovidio A. García-Villarreal, MD
Cardiac Surgery. Consultant in Private Practice. Monterrey, México.
email: ovidiocardiotor@gmail.com
The study by Szerlip et al. [1] states the efficacy of the TEEMVR (transcatheter edge-to-edge mitral valve repair) using the PASCAL device to treat the mitral regurgitation (MR) [1].
To begin with, the selection of patients in this study was made according to the decision by a Heart Team, which constitutes a highly debatable point. Decision-making for this type of pathology should be based on the recommendations from the 2020 ACC / AHA guideline for heart valve disease [2]. In turn, these recommendations are very different for primary MR, compared to those for secondary MR. For primary MR, the only indication to refer a patient to TEEMVR is an STS-PROM ≥8% (high surgical risk). In this study, no reference is made to the STS-PROM of patients with primary MR. In the case of secondary or functional MR, these guidelines clearly indicate the presence of symptoms as a preliminary requirement, and the patient must be in Stage D of heart failure, to be a candidate for the percutaneous approach. In this study, all of the above arguments are not addressed. Therefore, the fact as a “decision based on the Heart Team” is totally out of place, and cannot be accepted as valid in a study of this magnitude. There is a flagrant disruption for adherence to the current clinical guidelines. In the strongest of terms, this can be interpreted as an unethical procedure, requiring the necessity to review the informed consent presented to each patient enrolled in this study.
This is only an observational study, with a post hoc analysis [1]. In addition, it combined two very different population groups; patients with primary and secondary MR were put altogether. However, the most notable feature, is that it does not present any comparative control group. The comparisons in this study are made before and after the installation of the percutaneous device, at 1 and 2 years of follow-up. All the previous studies in the literature referring to TEEMVR that have served as a hallmark of reference, viz, EVEREST II [3], COAPT [4], and MITRA-FR [5], have used comparative control groups in order to establish substantive conclusions regarding usage of the percutaneous device. Furthermore, each of them has primarily focused on a specific subgroup of patients with MR, whether secondary or primary, when making the final conclusions. Thus, the present study, being only observational and without a comparative control group, mixing up two different set of patients, cannot make conclusions of any kind regarding management with TEEMVR for MR.
In this study a total of 124 patients were enrolled (69% for secondary MR, and 31% for primary MR) [1]. As we can identify here, the number of patients for any of the groups is quite small, and insufficient to conclude from any result, to the level of management recommendation.
Also, there is no mention of patient treatment with Guideline‐Directed Medical Therapy (optimal medical treatment) after device installation, especially in the FMR group, which constitutes a crucial aspect in the management of these patients [6].
The only remarkable fact about this study is that the device seems to be safe to use and relatively free of complications at 2 years of follow-up. In this regard, the recurrence of ≥ 3 MR+ was only 3% at 2-yr follow-up, which is subject to discussion, given the background from the surgical group having a recurrence rate for ≥3 MR+ in edge -to-edge up to 20% at two years after the procedure [7].
We should not lose sight that 2 years of follow-up is not the optimal time to draw conclusions about safety regarding the degree of recurrence of MR after TEEMVR. We highly suggest carrying out some RCT for this purpose, before we can emphasize sufficiently solid conclusions in this regard.
- Szerlip M, Spargias KS, Makkar R, et al. 2-Year Outcomes for Transcatheter Repair in Patients With Mitral Regurgitation From the CLASP Study. J Am Coll Cardiol Intv. 2021; 14 (14) 1538-48. https://www.jacc.org/doi/10.1016/j.jcin.2021.04.001.
- Otto CM, Nishimura RA, Bonow RO, et al. 2020 ACC/AHA Guideline for the Management of Patients with Valvular Heart Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation. 2021 Feb 2;143(5):e35-e71. doi: 10.1161/CIR.0000000000000932.
- Feldman T, Kar S, Elmariah S, et al; EVEREST II Investigators. Randomized Comparison of Percutaneous Repair and Surgery for Mitral Regurgitation: 5-Year Results of EVEREST II. J Am Coll Cardiol. 2015;66(25):2844-54. doi: 10.1016/j.jacc.2015.10.018.
- Stone GW, Lindenfeld J, Abraham WT, et al; COAPT Investigators. Transcatheter Mitral-Valve Repair in Patients with Heart Failure. N Engl J Med. 2018; 379(24):2307-2318. doi: 10.1056/NEJMoa1806640.
- Obadia JF, Messika-Zeitoun D, Leurent G, et al; MITRA-FR Investigators. Percutaneous Repair or Medical Treatment for Secondary Mitral Regurgitation. N Engl J Med. 2018;379(24):2297-2306. doi: 10.1056/NEJMoa1805374.
- Samarendra P. GDMT for heart failure and the clinician's conundrum. Clin Cardiol. 2019;42(12):1155-61. doi:10.1002/clc.23268.
- De Bonis M, Taramasso M, Lapenna E, et al. MitraClip therapy and surgical edge-to-edge repair in patients with severe left ventricular dysfunction and secondary mitral regurgitation: mid-term results of a single-centre experience. Eur J Cardiothorac Surg 2015; doi: 10-1093/ejcts/ezv043.