A 45-year-old woman with increasing complaints of recurrent angina since 2 years presented to our outpatient clinic. Obstructive coronary artery disease had been ruled out by coronary angiography previously.
The patient was referred for coronary function testing (CFT), including acetylcholine spasm provocation testing. Just distal to first diagonal branch, myocardial bridging (MB) in the left anterior descending (LAD) artery (Panels A and B) was present. At that same location, the CFT demonstrated severe focal epicardial spasm after 100 μg intracoronary infusion of acetylcholine (Panel C).
It has previously been suggested that low endothelial shear stress (ESS) might lead to endothelial dysfunction and atherosclerosis1 and thus potentially to CAS. To assess the influence of ESS on CAS in our patient, a 3D reconstruction of the LAD with diagonal was made, and end-diastolic shear stress was calculated using angiograms from two projections being at least 30° apart with CAAS Workstation WSS prototype (Pie Medical Imaging).
Contradictory, we found a region of high ESS without any atherosclerosis where the MB and CAS were located (Panels D and E). This corroborates with another hypothesis that the intima beneath the MB is stressed by high ESS leading to the intima becoming thinner and consisting of relatively more vascular smooth muscle cells (VSMCs).2 The increased presence of VSMCs might lead to a hyper-reactive vasoconstrictive response to acetylcholine in this scenario.3
In conclusion, this case illustrates a possible different aetiology of CAS in the presence of MB and high ESS.
Contributor Information
Tijn P J Jansen, Cardiology, Radboudumc, Geert Grooteplein Zuid 10, Nijmegen 6525 GA, Netherlands.
Jolanda J Wentzel, Cardiology, Radboudumc, Geert Grooteplein Zuid 10, Nijmegen 6525 GA, Netherlands.
Peter Damman, Cardiology, Radboudumc, Geert Grooteplein Zuid 10, Nijmegen 6525 GA, Netherlands.
We would like to thank Caïa Crooijmans, Shams Totakhel, and Jean Paul Aben for their work contributing to this cardiovascular flashlight.
Supplementary data are not available at European Heart Journal online.
All authors declare no disclosure of interest for this contribution.
No data were generated or analysed for or in support of this paper.
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