Absence of Myocardial Support at the Base of the Left Coronary Aortic Sinus in a Patient With Ehlers-Danlos Syndrome

We diagnosed a spontaneous coronary intramural hematoma in a 32-year-old woman with vascular Ehlers-Danlos syndrome (EDS).¹ Cardiac computed tomography incidentally revealed an additional rare anatomic finding: absence of myocardial support at the base of the left coronary aortic sinus (CAS) (Figure A–C, red dashed circles).

Figure.

(A–D) Absence of myocardial support at the base of the left coronary aortic sinus (CAS) in a patient with vascular Ehlers-Danlos syndrome compared with a normal control (Lower panels).

Normally, more than two-fifths of the normal aortic root circumference that corresponds to part of the right and left CAS bases shows myocardial support (Figure, Lower panels),² involving the ventricular septum and free wall. Accordingly, a substantial part of the left fibrous trigone is covered/replaced by the left ventricular free wall myocardium. However, in this case, the base of the left CAS is supported by a bare left fibrous trigone directly covered by epicardial adipose tissue (Figure A–C). Accordingly, the entire left CAS lacks myocardial support. In this region, called the left ventricular summit, the left ventricular free wall is nothing but a thin fibrous membrane (Figure A–C), and the circumferential extent of myocardial support of the aortic root (black dashed line) is less than that of the normal control (Figure B, Lower panel). The right CAS retains normal myocardial support (yellow dashed circles) from the ventricular septum (Figure A,D).

In a normally developed aortic root, type III collagen predominantly comprises the extracellular matrix.³ Vascular EDS with defective type III procollagen might show deficient myocardial support at the left CAS as an uncommon aortic phenotype. Although absence of myocardial support does not require surgical correction by itself, myocardial support ensures the structural strength of the aortic root. Therefore, this anomaly may be associated with aortopathy in a patient with vascular EDS. During regular follow-up using transthoracic echocardiography, close observation of the left CAS morphology would be required. When the patient needs to undergo any invasive procedures involving the aortic root, this anatomic information must be shared to prevent periprocedural complications.

Acknowledgments

We thank Atsushi Kono, Yoshiaki Watanabe, Takuro Nishio, Tomoki Maebayashi, Kiyosumi Kagawa, and Noriyuki Negi for their support with image acquisition and processing.

Disclosures

K.H. is a member of Circulation Journal’s Editorial Team.

References

• 1.   Toba T, Mori S, Yatani A, Sugisaki Y, Akita T, Sasaki N, et al. Spontaneous coronary artery intramural hematoma in a patient with vascular Ehlers-Danlos syndrome: Serial findings in coronary computed tomographic angiography. J Cardiovasc Comput Tomogr 2017; 11: 324–326.
• 2.   Toh H, Mori S, Tretter JT, Izawa Y, Shimoyama S, Suzuki M, et al. Living anatomy of the ventricular myocardial crescents supporting the coronary aortic sinuses. Semin Thorac Cardiovasc Surg 2020; 32: 230–241.
• 3.   Falla Zuñiga LF, Muñoz Cerón YS, Salazar L. Structural remodelling of the heart valves extracellular matrix during embryo development. Anat Histol Embryol, doi:10.1111/ahe.12603.