STEMI in coronary bridging: An unusual scenario

STEMI in coronary bridging: An unusual scenario

G Model IHJCCR-45; No. of Pages 3 ARTICLE IN PRESS IHJ Cardiovascular Case Reports (CVCR) xxx (2017) xxx–xxx Contents lists available at ScienceDire...

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G Model IHJCCR-45; No. of Pages 3

ARTICLE IN PRESS IHJ Cardiovascular Case Reports (CVCR) xxx (2017) xxx–xxx

Contents lists available at ScienceDirect

IHJ Cardiovascular Case Reports (CVCR) journal homepage: www.elsevier.com/locate/ihjccr

Case report

STEMI in coronary bridging: An unusual scenario Shreetal Rajan Nair a,∗ , P. Sheena b a b

Meitra Hospital, Calicut, Kerala, India Department of Pediatrics, Starcare Hospital, Calicut, Kerala, India

a r t i c l e

i n f o

Article history: Received 23 June 2017 Received in revised form 2 September 2017 Accepted 3 September 2017 Available online xxx

Introduction

Discussion

Coronary bridging is defined as cardiac muscle overlying an intramyocardial course of epicardial coronary artery and is frequently asymptomatic, but can present in a myriad number of clinical settings. Bridged coronary segments are usually spared from atherosclerosis, but in very unusual clinical scenario may present as total coronary occlusion.

The first classical description of myocardial bridging was given by Reymann in 1737 and is characteristic of certain species.1 It is a very common cause of anginal like symptoms in human beings and various autopsy series have placed the prevalence of myocardial bridges ranging from 15 to 85%, though angiogram has showed the same to be at 0.5–2.5%.2 Certain sub-populations like hypertrophic cardiomyopathy (HCM) have higher prevalence of myocardial bridges and abnormal ECG patterns. Coronary bridges have to be distinguished between coronary loops and venous bridges which are benign1 . They vary in depth and length and are usually asymptomatic but can manifest in a variety of clinical scenarios ranging from benign to catastrophic consequences and hence the need to identify the same. Various theories of wall shear stress, inflammation and vasoreactivity contribute to the unusual phenomenon.2 Atherosclerosis in an area of coronary bridge occurs not at the entrance but 20–30 mm proximal to the bridge. High wall shear stress (WSS) associated with the collision of the anterograde and retrograde blood stream during peak systole is the primary mechanism responsible for the WSS. Extrinsic compression by the overlying myocardium during systole also adds to the increased plaque burden at the site. However during diastole, WSS decreases throughout the bridge and the adjacent areas. Myocardial bridges have been characteristically described in a variety of ways: ‘milking effect’ in coronary angiogram, half-moon sign on IVUS, finger- tip or spike and dome pattern in intracoronary Doppler, step up and step down phenomenon in multi detector computer tomography (MDCT) and increase in pressure gradients with dobutamine stress fractional flow reserve (FFR)1–3 . Management of coronary bridges depends on the symptoms and the clinical profile of subjects and varies from optimal medical management with beta blockers to surgical options like myotomy or coronary artery bypass grafting (CABG). The management scheme given by Schwartz et al provides answers to several questions faced while dealing with myocardial bridges.2,4 In our case, we could obtain a good result with balloon

The case 48 year old gentleman previously asymptomatic and with no significant risk factors for coronary artery disease (CAD) presented in the ED with typical anginal pain of 2 h duration. His baseline parameters were within normal limits and ECG showed acute anterior wall STEMI (Fig. 1A). Echocardiogram revealed regional wall motion abnormality involving the LAD territory with normal left ventricular systolic function and normal wall thickness. He was taken up for primary percutaneous coronary intervention (PPCI) on an emergency basis. Angiogram revealed total occlusion of mid LAD artery (Fig. 1B; Supplementary video S1). POBA to LAD was performed with good result (Fig. 1C; Supplementary video S2). Intracoronary nitroglycerin (NTG) post POBA unmasked an interesting finding: Grade III coronary bridging at the site of total occlusion (Fig. 1D; supplementary video S3). Coronary stenting was deferred taking into consideration the clinical scenario. Six months post procedure the subject is doing fine and symptom free.

∗ Corresponding author at: Meitra Hospital, Calicut, Kerala, India. E-mail addresses: [email protected] (S.R. Nair), [email protected] (P. Sheena).

http://dx.doi.org/10.1016/j.ihjccr.2017.09.001 2468-600X/© 2017 Cardiological Society of India. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

Please cite this article in press as: Nair SR, Sheena P, STEMI in coronary bridging: An unusual scenario, IHJ Cardiovasc Case Rep. (2017), http://dx.doi.org/10.1016/j.ihjccr.2017.09.001

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ARTICLE IN PRESS S.R. Nair, P. Sheena / IHJ Cardiovascular Case Reports (CVCR) xxx (2017) xxx–xxx

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Fig. 1. (A) Electrocardiogram showing acute anterior wall myocardial infarction. (B) Coronary angiogram showing total occlusion of mid LAD artery (arrow). (C) Balloon angioplasty (POBA) to the site of total occlusion restores flow to distal LAD and systolic frame showing Grade III coronary bridging (arrow).gr3 (D) Grade III coronary bridging unmasked after intra-coronary nitroglycerin injection (arrow).

angioplasty alone and coronary stenting was deferred due to the increased incidence of target vessel and target lesion revascularisations. 1–3 Hence the wiser approach is to go more conservatively. So also, intravascular ultrasound (IVUS) guided strategy should be the rule while placing a coronary stent in the vicinity of a coronary bridge in the best interest of the subject under consideration. In our case, however we did not use IVUS due to logistic reasons. Six months post procedure the subject is asymptomatic and is on optimal medical management with beta blockers, antiplatelet agents and statins. Nitrates are generally avoided in confirmed cases of myocardial bridges as they impair distal coronary perfusion as a result of coronary vasodilatation. Subjects who are symptomatic despite optimal medical management are candidates for surgical management with CABG being preferred over myotomy in certain clinical settings like extensive and deep myocardial bridges and severe grades of bridging.

5. Majority of persons can be managed medically and has excellent long term results.

Conclusion and take home message

Patient consent

1. STEMI in coronary bridging is a very unusual phenomenon. 2. POBA is the best management strategy in such a case. 3. Avoid coronary stenting in a bridged segment as rates of target lesion revascularisation (TLRs) are very high. 4. Surgery (myotomy/CABG) is the best management modality in coronary bridging who are symptomatic with medical management.

Funding sources None to mention. Conflicts of interest None to state. Contributor’s statement Both the authors have contributed equally in manuscript preparation, literature search and compilation, data collection and interpretation and all other related work relating to the article.

Obtained. Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.ihjccr.2017.09. 001.

Please cite this article in press as: Nair SR, Sheena P, STEMI in coronary bridging: An unusual scenario, IHJ Cardiovasc Case Rep. (2017), http://dx.doi.org/10.1016/j.ihjccr.2017.09.001

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References [1]. Mohlenkampp S, Hort W, Ge J, Erbel R. Update on myocardial bridging. Circulation. 2002;106:2616–2622. [2]. Corban MT, Hung OY, Eshtehardi P, et al. Myocardial Bridging: Contemporary Understanding of Pathophysiology with Implications for Diagnostic and Therapeutic Strategies. JACC. 2014;63(22):2346–2355.

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[3]. Bruschke AVG, Veltman CE, de Graaf MA, Vliegen HW. Myocardial bridging: what have we learned in the past and will new diagnostic modalities provide new insights? Neth Heart J. 2013;21:6–13. [4]. Gomberg-Maitland M, Kim MC, Fuster VA. stratified approach to the treatment of a symptomatic myocardial bridge. Clin Cardiol. 2002;25:484–486.

Please cite this article in press as: Nair SR, Sheena P, STEMI in coronary bridging: An unusual scenario, IHJ Cardiovasc Case Rep. (2017), http://dx.doi.org/10.1016/j.ihjccr.2017.09.001