Routine enlargement of the small aortic root: a preventive strategy to minimize mismatch

We routinely use aortic root enlargement (ARE) as part of one strategy to avoid prosthesis-patient mismatch in patients with relatively small aortic roots who are undergoing aortic valve replacement (AVR).

We performed a retrospective review of 657 consecutive stented AVR patients at a single institution between 1995 to 2001. Of these, 114 (17%) patients underwent ARE. Root enlargement was selectively performed in patients at risk for prosthesis-patient mismatch, defined as calculated projected indexed effective orifice area (iEOA) less than 0.85 cm2/m2. This involved extension of the aortotomy between the left and noncoronary cusps, valve implantation, and Dacron patch closure of the aorta, thus permitting replacement with a valve size appropriate to body surface area.

The mean age of ARE patients was 72.5 +/- 11.0 years, with 32% aged 80 years or more. Of the patients, 61% were female and 27% had undergone previous cardiac operations. Combined procedures included coronary bypass in 57 patients and mitral repair or replacement in 24. The prevalence of mismatch was less than 3%. The ARE required an average of 19 minutes of additional aortic clamp time. The 30-day mortality was 0.9%. Logistic regression showed perfusion time to be the only independent predictor of mortality.

Our results show that ARE can be performed readily and with minimal added risk relative to standard AVR. We also present a preventive strategy to minimize mismatch predicted at time of operation from the reference value of effective orifice area for a given prosthesis and the patient's size. This includes use of ARE to enhance the potential benefit of AVR.