Degenerative Mitral Regurgitation: Impact on Post-Procedural Gradient

Primary or degenerative mitral regurgitation (MR) occurs frequently. Even though surgery continues to be the standard treatment at present, it remains risky for one group of patients, which makes edge-to-edge mitral valve repair (MV-TEER) a viable alternative.

We are well aware that moderate to severe MR is associated with worse prognosis. However, post procedural mean gradient analysis (ppMG) has not been carried out exhaustively and the available data on primary MR remains limited.

The study looked at 371 patients undergoing edge-to-edge repair with MitraClip, from the GISE and GIOTO registries. At the end of the procedure, 187 patients presented <3 mmHg ppMG, 77 >3/=4 mmHg ppMG and 107 >4 mmHg ppMG.

Primary end point was all cause death or hospitalization driven by cardiac failure within 12 months.

There were no significant differences between the three groups of patients. Mean age was 85, and 51% were women. Also, 71.3% were hypertensive, 16.5% diabetic, 21.2% had chronic obstructive pulmonary disease (COPD), 40.4% presented atrial fibrillation, 22% had CAD and 45% had been hospitalized for cardiac failure. Also, 10% had a history of MI, 17% had had prior heart surgery and 70% were in functional class III-IV. STS mortality rate was 3.7%.

Mean ejection fraction was 57%, and 4.6% had ≤35% ejection fraction. Echocardiographic values showed LV diastolic diameter 53, LV systolic diameter 35, end diastolic volume 110 ml and pulmonary artery systolic pressure 45 mmHg.

36% of patients received just one clip, while 59% received two. No relationship was found between the number of clips and higher ppMG. Patients with ppMG >3/=4 presented more residual MR >2+ by the end of the procedure vs the other two groups.

After one year, no differences were found between the three groups in terms of mortality or hospitalization for cardiac failure.

At multivariable analysis, neither ppMG >4mmHg not ≥5 mmHg were predictors of bad evolution, though so the case for ppMG ≥4 mmHg together with residual MR ≥2+ (hazard ratio: 1.98; 95% confidence interval: [1.10–3.58]).

Conclusion

In this cohort of patients with degenerative MR treated with edge-to-edge repair, no link was found between post procedural mean gradient and one-year prognosis. However, a considerable number of patients did experience an increase in post procedural gradient and residual MR, and the combination of both factors seems to be a solid predictor of adverse events.