Echocardiographic description of the anatomic relations within the normal aortic root

Diagnostic procedures continue to contain much hidden information that may substantially improve the understanding of the mechanisms of aortic valve disease and its treatment planning. The study aim, using transesophageal echocardiography (TEE), was to describe in detail the anatomical and physiological properties of the normal human aortic root in vivo.

The study included 32 patients referred for TEE for suspected cardiac sources of emboli, but diagnosed as normal. Images of the aortic valve in long axis (100-120 degrees) and short-axis (45-60 degrees) views were recorded in mid-systole and end-diastole. Parameters of the aortic root (subaortic diameter, sinotubular junction (STJ), maximal sinus diameter, sinus height, cusp diameter, cusp height, opening, coaptation and intercommissural distance) were measured. For repeatability and reliability, two investigators performed the same series of measurements on a subgroup of 11 patients.

Aortic valve parameters proved to be independent of age, gender, body weight and height, and also of body mass index and body surface area. The subaortic diameter showed no statistically significant connection to maximal sinus diameter or to STJ. No connection was found between STJ and cusp or sinus length in the long-axis view. A simplified regression equation describes the STJ as being three-quarters of the maximal sinus diameter. The valve opening was found to be ca. 80% of the subaortic diameter in systole. Length of coaptation proved to be independent of aortic diameters, but was approximately half of the left coronary (LC) and right coronary (RC) cusp height in diastole. This measurement model proved to be both reliable and reproducible.

This reliable description of normal anatomic and geometric relations within the aortic root, through extended examination of the aortic root by echocardiography, may facilitate a better planning of aortic valve-preserving interventions.