Aortic valve replacement with small-sized disc prostheses (medtronic hall)

Area of Science:

• Cardiac Surgery
• Biomaterials in Medicine
• Prosthetic Valve Design

Background:

• Narrow aortic roots historically present challenges for small prosthetic valve performance.
• Modern low-profile mechanical prostheses offer improved hemodynamics and ease of implantation.
• Elderly patients frequently have narrow aortic roots, increasing the need for suitable prostheses.

Purpose of the Study:

• To evaluate the performance of small Medtronic Hall mechanical prostheses (sizes 20, 21, 22) in patients with narrow aortic annuli (>21 mm).
• To assess hemodynamic performance, morbidity, and mortality associated with these small-sized prostheses.

Main Methods:

• A retrospective study of 332 patients who received Medtronic Hall prostheses (size 20, 21, or 22) between 1988 and 1997.
• Analysis of preoperative and postoperative hemodynamic data, including transvalvular gradients.
• Evaluation of in-hospital and late outcomes, including mortality, morbidity, thromboembolic events, and functional status.

Main Results:

• Peak gradients post-bypass were 13.9 mmHg (size 20), 14.0 mmHg (size 21), and 10.1 mmHg (size 22).
• In-hospital mortality was 1.2% with no significant inter-group differences.
• Late mortality was 9.3% overall, with a trend towards higher rates in smaller prostheses (p=0.01).
• 97% of survivors were in NYHA class I/II at a mean follow-up of 4.3 years.

Conclusions:

• Small Medtronic Hall prostheses demonstrate favorable hemodynamic characteristics in patients with narrow aortic roots.
• These prostheses represent a suitable option for aortic valve replacement in patients with small aortic annuli.
• While late mortality showed a trend with smaller sizes, overall outcomes and functional status in survivors were good.