Clinical predictors and impact of postoperative mean gradient on outcome after transcatheter edge-to-edge mitral valve repair

Background: The predictors and clinical significance of increased Doppler-derived mean diastolic gradient (MG) following transcatheter edge-to-edge mitral valve repair (MVTEER) remain controversial. Objective: We sought to examine baseline correlates of Doppler-derived increased MG post-MVTEER and its impact on intermediate-term outcomes. Methods: Patients undergoing MVTEER were analyzed retrospectively. Post-MVTEER increased MG was defined as >5 mmHg or aborted clip implantation due to increased MG intraprocedurally. Baseline MG and 3D-guided mitral valve area (MVA) by planimetry were retrospectively available in 233 and 109 patients. Results: 243 patients were included; 62 (26%) had MG > 5 mmHg post-MVTEER or aborted clip insertion, including 7 (11%) that had aborted clip implantation. Mortality occurred in 63 (26%) during a median follow up of 516 days (IQR 211, 1021). Increased post-MVTEER MG occurred more frequently in females (44% vs. 16%, p < 0.001), those with baseline MVA <4.0 cm² (71% vs. 16%), baseline MG ≥4 mmHg (61% vs. 20%), or multiple clips implanted (33% vs. 21%, p = 0.04). Increased post-MVTEER MG was associated with increased subsequent mortality compared to those with normal gradient (HR 1.91 95% CI 1.15–3.18 p = 0.016) as was aborted clip insertion compared to all others (HR 5.23 95% CI 2.06–13.28 p < 0.001). Conclusions: Smaller baseline MVA and increased baseline MG are associated with increased MG post-MVTEER and patients with a Doppler-derived post-MVTEER MG >5 mmHg suffered excess subsequent mortality. In high risk patients considered for MVTEER, identification of those at risk of iatrogenic mitral stenosis with MVTEER is important as they may be optimally treated with alternate surgical or transcatheter therapies.