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New tool predicts mortality after percutaneous mitral-valve repair

Journal of the American College of Cardiology
Reuters Health - 17/02/2022 - The eight-item MitraScore tool may help doctors decide which of their patients with severe mitral regurgitation will benefit from transcatheter edge-to-edge mitral-valve repair (TEER), researchers report.

TEER with MitraClip (Abbott Vascular) is an alternative to surgery that has become the first-line intervention for secondary mitral regurgitation in high-risk patients, and second-line therapy for primary mitral regurgitation in high-risk patients, the team notes in the Journal of the American College of Cardiology.

"The simple MitraScore, based on 8 clinical risk factors, can reasonably predict long-term mortality after mitral-valve TEER," Dr. Mohamad Alkhouli of Mayo Clinic Alix School of Medicine in Rochester, Minnesota, told Reuters Health by email. "This is the first purpose-specific risk-prediction scheme for mitral-valve TEER. It highlights the need for judicious use of the procedure and careful consideration of its utility and futility."

"Interestingly, the score had a reasonable discriminative value even without variables related to valve anatomy or procedural outcomes," said Dr. Alkhouli, lead author of an accompanying editorial.

To create and validate the tool, Dr. Sergio Raposeiras-Roubin of University Hospital Alvaro Cunqueiro in Vigo, Spain, and his colleagues used data from the international Percutaneous Mitral Valve Repair and Nutritional Status Registry (MIVNUT) of patients with symptomatic mitral regurgitation who underwent TEER.

Overall, 1,109 patients who were referred for TEER between 2012 and 2020 from 12 centers in Europe and Canada and who had follow-up and vital status data were included in the study. Patients were followed-up from the procedure date to November 2020.

The researchers identified eight independent predictors of mortality over a roughly two-year period following percutaneous mitral-valve repair: age 75 years or over, estimated glomerular filtration rate <60 mL/min/1.73 m2, anemia, left ventricular ejection fraction <40%, peripheral-artery disease, chronic obstructive pulmonary disease, high diuretic dose, and lack of therapy with renin-angiotensin system (RAS) inhibitors.

MitraScore assigned one point to each predictor (c-statistic, 0.70). For each point, the relative risk of mortality increased by 55% (P<0.001). Discrimination and calibration for mortality prediction exceeded those of Society of Thoracic Surgeons (c-statistic, 0.57) and EuroSCORE II (c-statistic, 0.61) scores.

MitraScore showed good performance in the validation cohort of 725 patients from the Italian GIOTTO registry (c-statistic, 0.66). The score also helped predict heart-failure rehospitalization and showed a significant association with the likelihood of clinical improvement.

"This is a first step that helps provide additional data when discussing the procedure with patients in the shared decision-making process, but that needs further refinement," said Dr. Jon R. Resar, a professor of medicine and the director of the Adult Cardiac Catheterization Laboratory at Johns Hopkins Hospital in Baltimore, Maryland. "It is important to remember that this is a risk score derived from a population of patients, and that individual patient outcomes may vary."

"Patients with mitral regurgitation undergoing TEER are a challenging group of patients because the underlying cause of the mitral regurgitation is variable (primary/degenerative vs. secondary/functional), the patients tend to be quite sick, and they often have a number of other comorbidities," Dr. Resar, who was not involved in the study, told Reuters Health by email. "Only if they are high risk for surgery do they undergo TEER. Thus, predicting even intermediate-term outcomes in this patient population is difficult."

"This risk score may be helpful in informing patients how they might feel after the procedure," he added. "Patients with high risk scores may be recommended to have additional medical therapy optimization before undergoing the procedure or may be recommended to not have the procedure at all."

Dr. Guilherme F. Attizzani, an associate professor of medicine at Case Western Reserve University and the interventional director of The Valve and Structural Heart Disease Center of University Hospitals in Cleveland, Ohio, told Reuters Health by email, "Intuitively, one would expect that these variables would impact prognosis. It was important, however, that these results were validated in a robust fashion, addressing the impact of these variables for this specific procedure."

"These robust results, well validated in a large population, might help us refine our patient selection for TEER and improve our understanding of which patients can benefit most from this therapy," added Dr. Attizzini, who also was not involved in the study. "It is very important that we now have a user-friendly score to predict adverse outcomes after a common procedure. These results will definitely have a positive impact on clinical practice."

Dr. Raposeiras-Roubin did not respond to requests for comment.

SOURCE: https://bit.ly/3rNSKvo and https://bit.ly/3gLL1Yf Journal of the American College of Cardiology, online February 15, 2022.

By Lorraine L. Janeczko

© 2023 The Author(s). Published by Medicom Medical Publishers.
User license: Creative Commons Attribution – NonCommercial (CC BY-NC 4.0)

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