Can the conventional aortic root replacement be improved?

To improve hemodynamic characteristics of the mechanical conduit, we routinely use our own modification in which valve prosthesis is placed inside a Dacron tube leaving a 5mm margin for suturing to the annulus, thus allowing the use of valve prosthesis larger than the annulus.

Between August 2000 and August 2006, a total of 262 patients (9% with acute aortic dissection and 18% with previous cardiac surgery) underwent aortic root replacement using this graft. Cumulative follow-up time was 691 patient-years and was 100% complete.

The median size of aortic annulus in this patient group was 23mm, for which a standard conduit with a valve prosthesis having a GOA of about 2.55cm² and an estimated EOA of about 2.03cm² would have been possible. However, the median GOA and EOA of the valve prostheses implanted (St. Jude Regent 25), was 4.02 and 3.34cm², respectively. An expected prosthesis-patient mismatch could be avoided in 21 patients. No blood transfusion during the entire hospital stay was required for 150 patients (69%). There were 2 (0.8%) early and 11 (4.2%) late deaths. Nine of deceased patients had had previous cardiac surgery, which was identified as an independent predictor for mortality. Only 5 patients (1.9%) suffered valve-related events during the follow-up. The actuarial event-free survival at 5 years was 90% for all patients.

The modified mechanical valve composite graft with a supraannular position of the valve inside the tube provides improved hemodynamic and hemostatic characteristics leading to excellent early and midterm results.