Prognostic value of projected transmitral gradient after mitral transcatheter edge-to-edge repair

Background Transcatheter edge-to-edge repair (TEER) reduces the mitral valve orifice area and may result in post-procedural mitral stenosis (MS). The transmitral gradient (TMG), which reflects the effective orifice area, has traditionally been used as a clinical endpoint following TEER. However, the prognostic significance of post-TEER TMG remains unclear. Projected TMG—adjusted for hemodynamic parameters such as heart rate and stroke volume— has been established as a useful risk stratification metric in patients with organic MS. This hemodynamically adjusted TMG may also be valuable for assessing MS following TEER. Purpose To evaluate the prognostic value of projected TMG—adjusted for heart rate and stroke volume—in patients undergoing TEER. Methods This single-center retrospective study included consecutive patients who underwent TEER from January 2019 to December 2023 at our facility. Both original and projected TMG were assessed at baseline and immediately post-procedure. The original TMG was calculated using Doppler echocardiography from the apical view, whereas the projected TMG was derived by adjusting the TMG for heart rate and stroke volume. Patients were stratified into four groups based on the level of post-procedural original or projected TMG and the degree of residual mitral regurgitation (MR). The cut-off values for TMG were defined as the upper tertile of each parameter. The primary endpoint was a composite of all-cause mortality and hospitalization for heart failure (HF). Results A total of 124 patients were included, with a mean age of 77 ± 10 years; 49 (40%) were female. Overall, 88 patients (71%) had secondary MR. The cut-off values for original and projected TMG were 2.70 mmHg and 4.13 mmHg, respectively. During a median follow-up period of 675 days, 38 patients (31%) reached the primary endpoint, including 17 all-cause deaths and 21 HF hospitalizations. Kaplan–Meier curves demonstrated a significant difference in prognosis when patients were stratified by combination of projected TMG and residual MR ≥ moderate (Log-rank p = 0.002), whereas stratification by original TMG and residual MR did not yield significant differences (p = 0.240). Neither residual MR ≥ moderate nor elevated TMG alone (original or projected) was independently associated with adverse outcomes. However, the combination of a projected TMG > 4.13 mmHg and residual MR ≥ moderate was independently associated with worse prognosis (adjusted hazard ration [HR] = 2.57, 95% confidence interval [CI]: 1.05–6.28; p = 0.039). Similar findings were observed in the subgroup analysis of patients with functional MR. Conclusion An elevated projected transmitral gradient—adjusted for heart rate and stroke volume—was independently associated with adverse clinical outcomes in patients with residual MR following TEER. These findings suggest that projected TMG may serve as a valuable risk stratification tool in post-TEER management, particularly in patients with residual MR.