Predictive Value of NTproBNP in Patients Undergoing Mitral Valve Transcatheter Edge-to-Edge Repair for Primary Mitral Regurgitation

P. von Stein (Köln)¹, R. Pfister (Köln)¹, S. Ludwig (Hamburg)², J. Weimann (Hamburg)², A. Scotti (New York)³, A. Latib (Ney York)⁴, M. Weber (Bonn)⁵, E. Xhepa (München)⁶, J. Dreyfus (Paris)⁷, J.-M. Paradis (Quebec)⁸, F. Praz (Bern)⁹, T. Modine (Bordeaux)¹⁰, J. Hausleiter (München)¹¹, E. Donal (Rennes)¹², A. Coisne (Lille)¹³, D. Kalbacher (Hamburg)¹⁴, C. Iliadis (Köln)^1
1Herzzentrum der Universität zu Köln Klinik III für Innere Medizin Köln, Deutschland; ²Universitäres Herz- und Gefäßzentrum Hamburg Klinik für Kardiologie Hamburg, Deutschland; ³Montefiore Medical Center, Albert Einstein College of Medicine Montefiore-Einstein Center for Heart and Vascular Care New York, USA; ⁴Montefiore Medical Center, Albert Einstein College of Medicine Montefiore-Einstein Center for Heart and Vascular Care Ney York, USA; ⁵Universitätsklinikum Bonn Medizinische Klinik und Poliklinik II Bonn, Deutschland; ⁶Deutsches Herzzentrum München Klinik für Herz- und Kreislauferkrankungen München, Deutschland; ⁷Centre Cardiologique du Nord Cardiology Department Paris, Frankreich; ⁸Laval University Quebec Heart & Lung Institute Quebec, Kanada; ⁹Inselspital - Universitätsspital Bern Universitätsklinik für Kardiologie Bern, Schweiz; ¹⁰Centre Hospitalier Universitaire Bordeaux Service Médico-Chirurgical: Valvulopathies-Chirurgie Cardiaque-Cardiologie Interventionelle Structurelle Bordeaux, Frankreich; ¹¹LMU Klinikum der Universität München Medizinische Klinik und Poliklinik I München, Deutschland; ¹²University of Rennes CHU Rennes, Inserm, LTSI - UMR 1099 Rennes, Frankreich; ¹³Heart Valve Clinic, CHU Lille Department of Clinical Physiology and Echocardiography Lille, Frankreich; ¹⁴Universitäres Herz- und Gefäßzentrum Hamburg Allgemeine und Interventionelle Kardiologie Hamburg, Deutschland

Background
Mitral valve transcatheter edge-to-edge repair (M-TEER) offers a viable alternative for patients with primary mitral regurgitation (PMR) who face high or prohibitive surgical risk. However, predictors of outcomes in these patients remain scarce, and risk scores are lacking. Therefore, we aimed to assess the prognostic value of baseline NT-proBNP in this population.

Methods
Out of the 3,083 consecutive patients included in the retrospective, multicenter PRIME-MR registry (Outcomes of Patients tReated wIth Mitral Transcatheter Edge-to-edge Repair for Primary Mitral Regurgitation), we selected those with available NT-proBNP levels and follow-up data. The primary endpoint was a composite of all-cause mortality and heart failure hospitalization at 2 years, analyzed as a time to first event. Due to its skewed distribution, NT-proBNP was logarithmized in regression models.

Results
1,382 patients (median age 81 [25th-75th quartile: 76-85] years, 47% female, 82% NYHA class >II, EuroScore II: 4.1 [2.4-6.9]%) were included. Median NT-proBNP level was 1,991 (829-4,260) ng/L. The left atrial volume index measured 66 (48-85) mL/m2, left ventricular ejection fraction was 58 (50-64)%, and the left ventricular end-systolic diameter was 36 (30-43) mm. Pulmonary artery systolic pressure reached a median of 48 (37-60) mmHg, with atrial fibrillation observed in 67% of patients. Main PMR pathologies were flail (47%) and prolapse (45%). Median time to follow-up was 2.1 (95% CI: 1.97-2.34) years. The primary endpoint occurred in 307 patients (Kaplan-Meier estimate: 34.4%). Log-transformed NT-proBNP levels were independently associated with the primary endpoint (adjusted HR: 1.19, 95% CI: 1.07-1.32; p=0.001), after adjusting for creatinine, haemoglobin, diabetes mellitus, atrial fibrillation, NYHA class, and tricuspid regurgitation. These associations were confirmed for patients with isolated PMR, i.e., without a functional mitral regurgitation component (adjusted HR: 1.24, 95% CI: 1.05-1.47, p=0.011) and for glomerular filtration rate corrected NT-proBNP (adjusted HR: 1.14, 95% CI: 1.02-1.28, p=0.021), but not for patients with a body mass index >30 kg/m2 (adjusted HR: 1.12, 95%CI: 0.74-1.67, p=0.60).  

Conclusion
Baseline NT-proBNP levels are independently associated with the combined endpoint of all-cause mortality and heart failure hospitalization at 2 years in patients with PMR undergoing M-TEER, significantly associated in several subgroups, except for obese patients. These associations enable the pre-interventional identification of patients at increased risk, facilitating timely intervention planning.