Introduction <p>Secondary mitral regurgitation (SMR) in patients with heart failure is associated with poor prognosis. Mitral Transcatheter edge-to-edge repair (M-TEER) has become a groundbreaking treatment option for high-risk patients ineligible for conventional surgery, with the MitraClip system standing as the most widely validated and utilized device in this field.</p> Aim <p>This study aimed to evaluate the immediate procedural outcomes and long-term clinical results of MitraClip interventions in Turkish patients with secondary mitral regurgitation. The primary objectives were to determine the rate of procedural success according to standardized Mitral Valve Academic Research Consortium (MVARC) criteria and to assess the proportion of patients achieving optimal mitral regurgitation reduction (MR ≤ 1+) at hospital discharge. The secondary objectives were to identify independent clinical, echocardiographic, and procedural predictors associated with rehospitalization for heart failure and all-cause mortality during follow-up, and to evaluate the durability of mitral regurgitation reduction and functional improvement over the medium-term follow-up period.</p> Materials and methods <p>This retrospective study included 140 Turkish patients with moderate-to-severe (grade 3+) or severe (grade 4+) SMR who underwent MitraClip treatment between 2021 and 2024, with a median follow-up of 23.5 months (interquartile range [IQR]: 14.0–27.0). MR severity was assessed by comprehensive echocardiographic evaluation according to current guidelines, and post-procedure MR was classified as ≤ 1 + or &gt; 1 + for outcome analyses.</p> Results <p>The study population had a median age of 75.0 (IQR: 68.0–78.0) years, with 42.9% being female. Procedural success according to MVARC criteria was achieved in 137 patients (97.9%), while MR ≤ 1 + at discharge was observed in 95 patients (67.9%). During follow-up, 56.4% of patients required rehospitalization, and the mortality rate was 7.1%. Significant improvement in functional capacity was observed, with 88.6% of patients improving by at least one New York Heart Association (NYHA) functional class at 1-month follow-up (from 100% NYHA class III-IV at baseline to 11.4% class III, 70.0% class II, and 18.6% class I post-procedure). Multivariate analysis revealed that estimated glomerular filtration rate (eGFR) (Hazard ratio [HR] 0.95, 95% confidence interval [CI]: 0.91–0.99, <i>p</i> = 0.03), atrial fibrillation (HR 1.62, 95% CI: 1.02–2.57, <i>p</i> = 0.04), and post-procedure MR severity (MR grade &gt; 1 + vs. ≤1+) (HR 1.73, 95% CI: 1.13–2.65, <i>p</i> = 0.01) were associated with rehospitalization. Mortality risk was associated with lower hemoglobin (HR 0.92, 95% CI: 0.86–0.99, <i>p</i> = 0.04), and severe MR (HR 2.54, 95% CI: 1.09–5.92, <i>p</i> = 0.03).</p> Conclusions <p>MitraClip intervention demonstrated high procedural success rates in Turkish patients with SMR, leading to significant reduction in MR severity and improvement in NYHA functional class. While rehospitalization and mortality rates aligned with previous studies, specific clinical factors were identified as being associated with clinical outcomes.</p>