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[Biological versus mechanical valves in the mitral position]
Insights
The Björk-Shiley valve showed better long-term event-free survival and freedom from reoperation compared to the Hancock valve in mitral valve replacement patients. Mechanical prostheses are preferred, especially for younger patients.
Area of Science:
- Cardiology
- Cardiac Surgery
- Biomaterials Science
Background:
- Long-term outcomes of prosthetic heart valves are crucial for patient management.
- Comparing mechanical valves like Björk-Shiley (BS) and Hancock (HX) is essential for clinical decision-making.
Purpose of the Study:
- To retrospectively evaluate the long-term late results of isolated mitral valve replacement using Hancock (HX) and Björk-Shiley (BS) valves.
- To compare the survival, thromboembolism, bleeding, endocarditis, and reoperation rates between the two valve types.
Main Methods:
- Retrospective evaluation of 54 patients with Hancock valves and 37 patients with Björk-Shiley valves.
- Total follow-up of 424 patient-years for HX and 366 patient-years for BS.
- Actuarial survival and event-free survival rates were calculated, excluding hospital deaths.
Main Results:
- No significant difference in hospital mortality, thromboembolism, bleeding, or endocarditis between HX and BS groups.
- Actuarial survival at ten years was similar (75.5% HX vs. 80.8% BS).
- Björk-Shiley valves demonstrated significantly higher actuarial freedom from reoperation (93.5% vs. 69.6%) and event-free survival (70.6% vs. 49.2%) at ten years (p < 0.01 and p < 0.05, respectively).
Conclusions:
- The Björk-Shiley mechanical valve showed superior long-term performance regarding reoperation and event-free survival compared to the Hancock valve.
- Mechanical prostheses are preferred, with consideration for biological valves in elderly patients (>65 years) or those with contraindications to anticoagulation.
Abstract:
The long-term late results of isolated mitral valve replacement before April 1981 were retrospectively evaluated in 54 patients receiving a Hancock valve (HX) with a total follow-up of 424 patient-years (py) and 37 patients receiving a Björk-Shiley valve (BS) with a total follow-up of 366 py. There was no significant difference in regard to preoperative age, cardiothoracic ratio, electrocardiogram, or New York Heart Association functional class between the two groups. All of the BS group and 43 of the HX patients received long-term anticoagulant therapy. No significant difference was notable between the two groups in hospital mortality. Actuarial survival rate excluding hospital deaths was 75.5 +/- 6.7% for the HX group, and 80.8 +/- 7.1% for the BS group at ten years (not significant). There was no significant difference between the two groups in overall incidence of thromboembolism (HX 1.4% py, BS 1.9% py), anticoagulant related bleeding (HX 0.5% py, BS 0.8% py), or endocarditis (HX 0.5% py, BS 0.3% py). Actuarial freedom from reoperation at ten years was 69.6 +/- 8.1% for the HX group, and 93.5 +/- 4.4% for the BS group (p less than 0.01). Event free survival excluding hospital deaths at ten years was 49.2 +/- 8.1% for the HX group, 70.6 +/- 8.3% for the BS group (p less than 0.05). We prefer a mechanical prosthesis except in patients over 65 years old, who have a short life expectancy, in whom anticoagulation is thought to be difficult, and who hope a biological valve.