Edge-to-edge treatment of the mitral valve is currently a valid alternative to surgery in cases of mitral regurgitation.
Different studies have taken residual mitral regurgitation as a parameter of success, but little research has been conducted on the residual gradient once the procedure has been completed.
What has been published is that a mean gradient ≥5 mmHg measured by hemodynamics or ≥4.4 mmHg through transesophageal Doppler echocardiography would be related with a poor evolution, as it causes mitral stenosis. However, in recent studies, this information has been subject to controversy (both in relation with primary and secondary regurgitation).
Researchers analyzed 710 consecutive patients who received percutaneous treatment of the mitral valve using the edge-to-edge strategy. Of them, 265 had degenerative mitral regurgitation (DMR) and 445 had secondary mitral regurgitation (SMR).
In the DMR arm, at the end of the procedure 167 patients presented gradient <5 mmHg and 98 ≥5 mmHg; among those with SMR, 347 had a gradient <5 mmHg and 98 ≥5 mmHg.
The primary endpoint (PEP) was a composite of all-cause mortality and readmission for heart failure at 5 years.
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Regardless of the cause of the failure, patients with a high mean gradient had a smaller ventricular diameter.
Patients with DMR had higher rates of hypertension and atrial fibrillation; in contrast, the subjects evaluated in the SMR arm were younger, mostly men, with higher risk scores and greater presence of renal failure. This arm showed a lower ejection fraction on Doppler echocardiography.
There were no differences in complications during the procedure between both groups.
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There were also no differences in the PEP between the DMR arm (6.3% vs. 74.4%; p = 0.06) and the SMR arm (78.6% vs. 74.8%; p = 0.54). After adjusting for variables, elevated gradient was a predictor of PEP in patients with DMR (hazard ratio [HR]: 1.59; 95% confidence interval [CI]: 1.03-2.45; p = 0.034), but not for patients with SMR (HR: 0.87; 95% CI: 0.63-1.22; p = 0.43).
At 12 and 24 months, functional class improved in all patients regardless of whether they had an elevated gradient, and there was also an improvement in the 6-minute walk test (except in patients with DMR with elevated gradient).
Conclusion
Elevated postprocedural mean gradient is an independent predictor of clinical events in patients with degenerative mitral regurgitation, but not in those with functional mitral regurgitation.
Dr. Carlos Fava.
Member of the Editorial Board of SOLACI.org.
Original Title: Long-Term Outcomes of Patients With Elevated Mitral Valve Pressure Gradient After Mitral Valve Edge-to-Edge Repair.
Reference: Benedikt Koell, et al. J Am Coll Cardiol Intv 2022;15:922–934.
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