Aortic root and valve proportions: an example of the golden ratio?

Abstract

Calcific aortic stenosis is the most common lesion requiring valve replacement. Transcutaneous procedures (TAVR) are rapidly increasing yet detailed information on aortic valve and root anatomy are sparse.  This study examined gated cardiac CT scans to make observations regarding the size and proportions of the valve leaflets, sinuses of Valsalva, and sinotubular junction. One hundred and fifty gated cardiac CT scans were performed for a variety of clinical indications. Area of each cusp (short axis plane) was measured along with sinus height (from leaflet base to sinotubular junction), sinus width (from central coaptation point to outer sinus edge), annular perimeter, perimeter at mid-sinus level, and perimeter at the sinotubular junction. The right coronary cusp was largest, the left cusp smallest, and the non-coronary cusp intermediate in size. Each cusp was larger in men than women, even after indexing for body surface area.  By contrast, indexed sinus width and height did not differ between genders. No significant differences were noted between races. Annular perimeter did not vary by age while the mid-sinus perimeter and sinotubular junction perimeter increased with age (p=0.01, r2 =0.05 and p=0.002, r2 =0.07).  Interestingly, the ratio of sinus height (average): annular radius was 1.69±0.18, very close to the “golden ratio” of 1.62 found throughout the natural world.  This might be important for proper vortex formation in the sinuses.