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.

Predictive factors for thrombosis and major bleeding in an observational study in 181 patients with heparin-induced thrombocytopenia treated with lepirudin.

The antithrombotic efficacy of lepirudin in patients with heparin-induced thrombocytopenia (HIT) is compromised by an increased risk for bleeding. A retrospective observational analysis in 181 patients (median age, 67 years) with confirmed HIT treated in routine practice with lepirudin was performed to identify predictive factors for thrombotic and bleeding complications. Lepirudin was administered at a mean (+/- SD) dose of 0.06 +/- 0.04 mg/kg/h (compared with a recommended initial dose of 0.15 mg/kg/h). Mean activated partial thromboplastin time was greater than 1.5 times baseline value in 99.4% of patients. Median treatment duration was 7.7 days. Until discharge from the hospital, 13.8% and 20.4% of patients experienced a thrombotic or a major bleeding event, respectively. On multivariate analysis, mean lepirudin dose was not a significant predictive factor for thrombosis. In contrast, mean lepirudin dose greater than 0.07 mg/kg/h, long duration of lepirudin treatment, and moderate to severe renal impairment were significant positive factors for major bleeding. Overall, these results suggest that the recommended dose of lepirudin in patients with HIT is too high; the use of reduced doses may be safer with regard to bleeding risk and does not compromise antithrombotic efficacy.