End-Tidal CO2 Predicts Reduction in Mitral Regurgitation in Patients Undergoing Percutaneous Mitral Valve Edge-to-Edge Repair

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Objectives: We evaluated end-tidal CO₂ (etCO₂), which has been proposed to assess acute hemodynamic changes, to guide percutaneous edge-to-edge mitral valve repair (PMVR) with the MitraClip system. Methods: Thirty-nine patients (aged 78 ± 14 years) undergoing PMVR for moderate-to-severe mitral regurgitation (MR) of primary and secondary etiology were included. General anesthesia was maintained with sevoflurane and constant ventilation parameters to ensure stable etCO₂ tension. MR grade was determined semiquantitatively by transesophageal echocardiography by 2 experienced operators blinded to etCO₂ measurements. etCO₂ levels were measured 3, 5, 10, and 15 min after final MitraClip placement. Results: Overall, etCO₂ increased from 32.2 ± 1.7 before to 35.4 ± 3.0, 34.6 ± 2.6, and 34.2 ± 2.4 mm Hg 3, 5, and 10 min after implantation. A significant correlation was noted between the echocardiographic reduction in MR grade and the increase in etCO₂. ANOVA for repeated measures confirmed a significant increase in etCO₂ after clip implantation (corrected F = 20.0; p < 0.001) and revealed a significantly greater increase in etCO₂ in patients with MR reduction ≥2 grades as compared to lesser MR reductions (F = 6.47; p = 0.015). Blood pressure changes did not correlate with the degree of MR reduction. Conclusions: We observed a close correlation between the reduction in MR grade during PMVR and etCO₂, which might evolve as a useful parameter to complement treatment guidance during PMVR.