Background and aim of the study: Concern exists regarding progressive root dilatation after the modified Ross procedure. The present prospective echocardiographic study aimed to provide further insight into neo-aortic regurgitation (nAR) and neo-aortic root dimensions over time in adult Rotterdam Ross root patients, and to study potential risk factors for nAR and dilatation.
Methods: All Rotterdam Ross patients aged ≥16 years at surgery were subjected to a prospective biennial standardized echocardiographic protocol. Analysis over time of nAR according to the jet length and jet diameter method, autograft annulus and sinotubular junction (STJ) diameters was carried out using a multilevel linear model in 90 patients who had two or more echocardiographic measurements (mean 5; range 2-9; total 458) up to 14 years (mean 7 years) after surgery.
Results: The mean (± SE) initial postoperative jet length nAR was grade 0.9 ± 0.09, and the annual increase 0.1 ± 0.02 (p <0.001). Initial annulus and STJ diameters were 25 ± 0.5 mm and 36 ± 0.6 mm, while annual increases were 0.4 ± 0.07 mm and 0.5 ± 0.09 mm, respectively (p <0.001). Patients who eventually underwent an autograft reoperation (n = 10) had

significantly greater initial nAR and greater progression of nAR, and a greater initial annulus diameter. The annual annulus and STJ diameter increase was greater in patients who underwent autograft reoperation. Compared to freestanding root replacement, patients with inclusion cylinder aortic root replacement had smaller initial annulus and STJ diameters that did not increase over time. Female gender was associated with a greater initial jet length and jet diameter nAR and a greater increase over time in jet diameter nAR. Preoperative aortic regurgitation or combined aortic stenosis and regurgitation were associated with greater initial annulus and STJ diameters. Neither bicuspid valve disease, patient age, preoperative ascending aorta aneurysm, prior aortic valve surgery nor hypertension had an effect on initial or progression of nAR, annulus, and STJ diameter.
Conclusion: The annual increase in nAR and root dimensions is small, but persistent, after autograft aortic root replacement in adults, and further reoperations should be anticipated. Use of the inclusion cylinder root replacement technique seems to prevent neo-aortic dilatation.

The Journal of Heart Valve Disease 2006;15:100-107