Thromboembolism with low profile bioprosthesis.

Area of Science:

• Cardiovascular Surgery
• Biomaterials Science
• Clinical Cardiology

Background:

• Low profile bioprostheses (LPB) are increasingly used for heart valve replacement.
• Long-term data on the safety and efficacy of LPB, particularly regarding thromboembolic events and tissue degeneration, are crucial.

Purpose of the Study:

• To evaluate the late clinical outcomes of low profile bioprostheses, focusing on thromboembolism and endocarditis.
• To assess the durability and safety of flexible stent-mounted LPB in patients undergoing mitral valve replacement (MVR) and aortic valve replacement (AVR).

Main Methods:

• Retrospective analysis of 415 patients who underwent MVR and/or AVR with LPB (rigid and flexible stents).
• Actuarial probability and linearized incidence rates for thromboembolism and endocarditis were calculated.
• Long-term follow-up, including assessment of tissue degeneration for flexible stent LPB.

Main Results:

• The 6-year actuarial freedom from thromboembolism was 90.3% for the entire cohort.
• Linearized incidence rates for MVR and AVR were 2.5 +/- 0.62 and 1.2 +/- 0.49 per 100 patient-years, respectively.
• Low incidence of endocarditis (0.54 per 100 patient-years) and no observed tissue degeneration in flexible stent LPB after 5 years in patients >35 years.

Conclusions:

• Low profile bioprostheses demonstrate a favorable safety profile with low rates of thromboembolism and endocarditis.
• Flexible stent-mounted LPB show promising durability and safety in the mid-term follow-up.
• The necessity of long-term anticoagulation in patients with atrial fibrillation undergoing MVR with LPB requires further investigation.