Transcatheter valve-in-valve implantation in a degenerated very small Mitroflow prosthesis.

OBJECTIVES

To assess the feasibility and results of 'valve-in-valve' implantation using the 23-mm CoreValve for the treatment of degenerated 19-mm and 21-mm Mitroflow bioprostheses.

METHODS

We retrospectively analysed all consecutive patients who underwent transcatheter aortic valve implantation for 19-mm and 21-mm Mitroflow bioprostheses. The height of implantation with respect to the ring of the Mitroflow prosthesis was targeted at -6 mm for the first 3 cases. In the following cases, the target was higher to promote free supra-annular movement of the leaflets.

RESULTS

The procedure was successful in 17 of 18 patients (94%). For implantations above the limit of -6 mm, the mean gradient was 10.4 ± 2.6 mmHg compared with 28.1 ± 11.6 mmHg for implantations below the limit of -6 mm (P < 0.01). For patients with severe stenosis as main mechanism of failure of the bioprosthesis, the mean post-procedural gradient was 31.2 ± 11.8 mmHg compared with 12.7 ± 6 mmHg in the absence of severe stenosis (P < 0.01). Patient-prosthesis mismatch (indexed effective orifice area ≤ 0.85 cm2/m2) and severe mismatch (indexed effective orifice area ≤ 0.65 cm2/m2) were present in 83% (15 of 18) and 27% (5 of 18) of patients, respectively. We did not notice any complications following the procedures. Six months after the procedure, functional status was improved in all patients.

CONCLUSIONS

Our short series demonstrates the ability to perform transcatheter 'valve-in-valve' implantation in 19-mm and 21-mm Mitroflow prostheses with satisfactory results, but high post-procedural gradients and patient-prosthesis mismatch remain a relatively frequent problem mostly when severe stenosis is the main mechanism of failure. Implantation in a high position is critical to decrease the rate of high postimplantation gradients.