The wide spectrum of aortic root dilatation after the Ross operation.

Introduction

The Ross root replacement is the only technique that guarantees long-term viability of all the component parts of the root. The normal aortic root performs extremely sophisticated functions which are closely linked to its structure, dynamics and viability. This has been shown to translate into clinically-relevant endpoints, such as survival and quality of life. The insertion of the pulmonary autograft as a freestanding root guarantees optimal relationship between the component parts with no distortion. Although the pulmonary valve is known to adapt to the new environment, there is continuing concern about the risk of long-term autograft dilatation and aortic regurgitation. We here describe two patients with considerably different types of changes in shape and size of the aortic root, in comparison to two age- and gender-matched controls.

The patients are: (1) 62-year-old female, 13.4 years after the operation and (2) 47-year-old male, 15.6 years after the operation. The patients were scanned using Toshiba Aquilion 64 multi-slice scanner as part of clinical follow-up. Three-dimensional anatomical models of the aortic root were then reconstructed, by segmenting the luminal volume in reference to the CT image intensity. The shape of the root was visualized as in the figure, and the sinus sizes were quantified in terms of width, bulge and height of each sinus. The mean sinus diameters of the patients 1 and 2, as the average of three cusp-to-commissure lengths, were 31.9 mm and 51.9 mm, respectively. Those of controls were 32.6 mm and 32.8 mm. The 3D model as well as the sinus sizes plot demonstrate asymmetry feature of the autograft roots unlike controls which are symmetrical. The smaller autograft root (Patient 1) has symmetric bulge and height but asymmetric width whereas the larger autograft root (Patient 2) has symmetric width but asymmetric bulge and height, both of which indicate larger right- and non-coronary sinuses than left-coronary sinus (Figure 1).

Figure 1.

Two three-dimensional anatomical models of the aortic root reconstructed from CT angiogram of 62-year-old female (top middle) and 47-year-old male patient (top right) showing broad spectrum of the shape and size. Two normal anatomical models of age- and gender-matched controls as also shown in the middle panel. The sinus morphology was quantified using these models with the parameters in the top left panel (L1: width, L2: depth and L3: height) and the results are shown in the bottom panel. LC, NC and RC stand for left-coronary, non-coronary and right-coronary sinuses, respectively.

Conclusions and future directions

This investigation of two Ross roots shows a wide spectrum of aortic root shape and size as the result of adaptation more than 13 years after the operation. The findings demonstrate the patient-specific nature of the interaction between the tissue valve and the host. More comprehensive analysis over larger patient population is warranted.