Mitral valve gradient changes associate with outcomes of patients undergoing transcatheter edge-to-edge repair

INTRODUCTION

Transcatheter edge-to-edge repair (TEER) is typically used to treat mitral regurgitation (MR) in patients with high surgical risk. Increased post-procedural mitral valve gradient (MVG) may impact mortality and hospitalizations. We aim to evaluate and compare the absolute postprocedural MVG and the change in the MVG effect on outcomes for patients undergoing TEER therapy.

METHODS

Patients who underwent TEER for severe MR were divided into two groups, initially by postprocedural absolute MVG, TTE-based at discharge, and then by the difference between preprocedural and postprocedural MVG. Primary endpoints included all-cause mortality and heart failure hospitalization (HFH) during one year after the procedure.

RESULTS

The study included 100 patients. The mean MVG increased from 3.39 mmHg immediately after the procedure to 4.83 mmHg the following day, an increase of 1.44 mmHg (p < 0.001). First stratification was by MVG on the day following the procedure - MVG ≤5 mmHg (n = 70) and MVG >5 mmHg (n = 30). There was no significant difference in rates of survival (88.6%, 93.3%, p = 0.716) or HFH (18.6%, 33.3%, p = 0.178). Second stratification was by the difference in preprocedural and postprocedural MVG- delta MVG <3 mmHg (n = 55) and delta MVG ≥3 mmHg (n = 45). While survival rates did not significantly differ (87.3% vs. 93.3%, p = 0.503), delta MVG ≥3 mmHg correlated with higher HFH rates (12.7% vs. 35.6%, p = 0.014).

CONCLUSIONS

The MVG of patients undergoing TEER usually increases on the day after the procedure compared to the immediate post-procedure MVG. Higher delta MVG is associated with higher HFH rate.

Prognostic importance of the transmitral pressure gradient in mitral annular calcification with associated mitral valve dysfunction

AIMS

The aim of this study was to define the natural history of patients with mitral annular calcification (MAC)-related mitral valve dysfunction and to assess the prognostic importance of mean transmitral pressure gradient (MG) and impact of concomitant mitral regurgitation (MR).

METHODS AND RESULTS

The institutional echocardiography database was examined from 2001 to 2019 for all patients with MAC and MG ≥3 mmHg. A total of 5754 patients were stratified by MG in low (3-5 mmHg, n = 3927), mid (5-10 mmHg, n = 1476), and high (≥10 mmHg, n = 351) gradient. The mean age was 78 ± 11 years, and 67% were female. MR was none/trace in 32%, mild in 42%, moderate in 23%, and severe in 3%. Primary outcome was all-cause mortality, and outcome models were adjusted for age, sex, and MAC-related risk factors (hypertension, diabetes, coronary artery disease, chronic kidney disease). Survival at 1, 5, and 10 years was 77%, 42%, and 18% in the low-gradient group; 73%, 38%, and 17% in the mid-gradient group; and 67%, 25%, and 11% in the high-gradient group, respectively (log-rank P < 0.001 between groups). MG was independently associated with mortality (adjusted HR 1.064 per 1 mmHg increase, 95% CI 1.049-1.080). MR severity was associated with mortality at low gradients (P < 0.001) but not at higher gradients (P = 0.166 and 0.372 in the mid- and high-gradient groups, respectively).

CONCLUSION

In MAC-related mitral valve dysfunction, mean transmitral gradient is associated with increased mortality after adjustment for age, sex, and MAC-related risk factors. Concomitant MR is associated with excess mortality in low-gradient ranges (3-5 mmHg) but gradually loses prognostic importance at higher gradients, indicating prognostic utility of transmitral gradient in MAC regardless of MR severity.

Exercise behavior of degenerative mitral stenosis

Mitral annular calcification (MAC) is increasingly encountered, particularly among the elderly and those with chronic kidney disease, and is often associated with a transvalvular gradient. In contrast to rheumatic mitral stenosis relatively little is known about mitral stenosis due to MAC. We aimed to clarify whether exercise limitation in this group is primarily due to valvular obstruction or ventricular dysfunction resulting from multiple comorbidities. 20 patients with severe MAC (bulky calcium deposits which restricted leaflet motion) were submitted to supine bicycle exercise, measuring Doppler and echocardiographic parameters at baseline and during exercise. They were compared 1:1 to subjects matched for age, sex, and left ventricular wall thickness. At baseline MAC subjects had higher mean mitral valve gradients (MVG) than comparison subjects (7.5 ± 3.8 vs 1.6 ± 0.8 mm Hg, p < 0.0001), along with larger indexed left atrial volumes (54.4 ± 14.9 vs 34.0 ± 11.7 mL, p < 0.0001) and reduced left atrial strains (reservoir, conduit, and booster pump). With exercise MAC subjects reached higher levels of MVG (17.3 ± 8.4 vs 5.5 ± 2.5 mm Hg, p < 0.0001), and pulmonary artery systolic pressure (estimated from tricuspid regurgitant jet [TR] velocity) and displayed a moderate correlation between ΔMVG and ΔTR velocity (r² = 0.57). MAC subjects whose exercise MVG was ≥ 15 mm Hg all had a peak pulmonary artery systolic pressure > 60 mm Hg. MAC subjects also had relative chronotropic incompetence. Patients with severe MAC and a transvalvular gradient experience large increases in MVG and pulmonary pressure with exercise, similar to what has been described in rheumatic mitral stenosis. MAC may be an under-recognized cause of dyspnea and exercise intolerance in older patients.