Comparison of pulmonary and aortic root and cusp dimensions in normal adults using computed tomography: potential implications for Ross procedure planning.

Objectives: The Ross procedure is currently receiving renewed interest. Its function and durability depend on preservation of pulmonary valve anatomy; limited data exist on normal pulmonary valve geometry. The objective was to compare aortic and pulmonary root and cusp dimensions in adults with normal tricuspid aortic and pulmonary valves.

Methods: We reviewed 507 coronary computed tomography studies, selecting those with adequate visibility of both pulmonary and aortic roots for further analysis. Diastolic aortic and pulmonary root and cusp dimensions were measured. Root dimensions at different phases of the cardiac cycle were measured in 3 patients.

Results: We analysed studies of 50 patients with the mean age of 54 years [standard deviation (SD): 16]. In end-diastole, pulmonary root had a smaller sinutubular to basal ring ratio than the aortic root [0.82 (SD: 0.09) vs 1.14 (SD: 0.12), P < 0.001]. Aortic and pulmonary cusps had similar dimensions; however, pulmonary cusp effective height was lower [5.9 mm (SD: 1.6) vs 8.4 mm (SD: 1.2), P < 0.001]. Pulmonary basal ring perimeter was largest at end-diastole and smallest at end-systole, with the relative difference of 23.5% (SD: 2.7).

Conclusions: The pulmonary root has a similar cusp size compared to the aortic root, but a different shape, resulting in a lower pulmonary cusp effective height. The perimeter of the pulmonary basal ring changes during the cardiac cycle. These findings suggest that stabilizing the autograft to normal aortic, rather than pulmonary, root dimensions should result in normal autograft cusp configuration. Computed tomography angiography could become a tool for personalized planning of the Ross procedure.