Accumulation of Ca+ 2 at arterial segments proximal to myocardial bridging may influence the vascular dynamics of coronary artery

Abstract

We have read the arguments about the undetermined mechanisms of ischemia induced by myocardial bridge (MB) [ 1 Peters S. Unusual case of myocardial bridging of the circumflex artery and initially intractable chest pain. Int. J. Cardiol. 2015; 179: 25-26 Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar , 2 Duygu H. Myocardial bridging of the left circumflex artery: an extremely rare entity Int. J. Cardiol. 2015; 189: 231 Scopus (3) Google Scholar , 3 Gili S. Taha S. Omede P. Moretti C. A bridge over troubled water: functional assessment of a myocardial bridge. Int. J. Cardiol. 2015; 201: 285-287 Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar ]. Gili et al. claimed that the strategies to evaluate the ischemia induced by MB failed due to complex dynamics of coronary flow [ [3] Gili S. Taha S. Omede P. Moretti C. A bridge over troubled water: functional assessment of a myocardial bridge. Int. J. Cardiol. 2015; 201: 285-287 Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar ]. However this dilemma could have been explained by a recent finding. We read that article in which Tohno et al. reported the elevation of Ca, P, Zn, and Na levels in the arterial segments proximal to MB on the LAD artery [ [4] Tohno Y. Tohno S. Minami T. Pakdeewong-Ongkana N. Suwannahoy P. Quiggins R. Different accumulation of elements in proximal and distal parts of the left anterior descending artery beneath the myocardial bridge. Biol. Trace Elem. Res. 2015; https://doi.org/10.1007/s12011-015-0498-x Crossref PubMed Scopus (3) Google Scholar ]. They also reported that defective areas of endothelial lining were observed in those segments. Those findings may explain how those patients are suffering from recurrent chest pain, MI, and ACS even at relatively young ages despite normal angiogram with mild narrowing due to MB or non-critically stenotic plaque accompanied with MB. In our experience, we observed that those young subjects were generally misdiagnosed as myocarditis although they had presented with ST segment elevation on precordial ECG leads and then we diagnosed them as having long segment MB on LAD artery by multidetector computerized tomography angiography [ [5] Aparci M. Ozturk C. Okutucu S. Balta S. Isilak Z. Kardesoglu E. Bozlar U. Anteroseptal myocardial infarctions due to myocardial bridging are generally misdiagnosed as myocarditis in young patients. Am. J. Cardiol. 2015; (Suppl., PP-031): S110-S111 Abstract Full Text Full Text PDF Google Scholar ]. Additionally, case reports and studies presenting the coronary vasospasm associated with MB have been increasing [ 6 Vales L. Kanie Y. Fox J. Coronary artery occlusion and myocardial infarction caused by vasospasm within a myocardial bridge. J. Invasive Cardiol. 2010; 22: E67-E69 PubMed Google Scholar , 7 Teragawa H. Fukuda Y. Matsuda K. Hirao H. Higashi Y. Yamagata T. Oshima T. Matsuura H. Chayama K. Myocardial bridging increases the risk of coronary spasm. Clin. Cardiol. 2003; 26: 377-383 Crossref PubMed Scopus (58) Google Scholar ]. Moreover those patients with MB and coronary vasospasm had poor prognosis due to recurrent chest pain, MI, and life threatening arrhythmia [ [8] Kim S.S. Jeong M.H. Kim H.K. Kim M.C. Cho K.H. Lee M.G. Ko J.S. Park K.H. Sim D.S. Yoon N.S. Yoon H.J. Park H.W. Kim J.H. Hong Y.J. Ahn Y.K. Cho J.G. Park J.C. Kang J.C. Long-term clinical course of patients with isolated myocardial bridge. Circ. J. 2010; 74: 538-543 Crossref PubMed Scopus (23) Google Scholar ].