Cardiovascular consequences of myocardial bridging: A meta-analysis and meta-regression

Abstract

Myocardial bridging, a congenital abnormality in which a coronary artery tunnels through the myocardial fibres was usually considered a benign condition. Many studies suggested a potential hemodynamic significance of myocardial bridging and some, usually case reports, implied a possible correlation between it and various cardiovascular pathologies like acute myocardial infarction, ventricular rupture, life-threatening arrhythmias, hypertrophic cardiomyopathy, apical ballooning syndrome or sudden death. The main objective of this article is to evaluate whether myocardial bridging may be associated with significant cardiac effects or if it is strictly a benign anatomical variation. To this purpose, we performed a meta-analysis (performed using the inverse variance heterogeneity model) and meta-regression, on scientific articles selected from three main databases (Scopus, Web of Science, Pubmed). The study included 21 articles. MB was associated with major adverse cardiac events - OR = 1.52 (1.01–2.30), and myocardial ischemia OR = 3.00 (1.02–8.82) but not with acute myocardial infarction, cardiovascular death, ischemia identified using imaging techniques, or positive exercise stress testing. Overall, myocardial bridging may have significant cardiovascular consequences (MACE, myocardial ischemia). More studies are needed to reveal/refute a clear association with MI, sudden death or other cardiovascular pathologies.

Prevalence of Anxiety and Depression Symptoms in Patients with Myocardial Infarction with Non-Obstructive Coronary Arteries

“…The authors concluded that autopsy studies are the gold standard in evaluating the prevalence of MB and that high-resolution CT scanning of coronary arteries should be preferred over coronary angiography studies. It has usually been considered as a benign condition but there are studies suggesting a potential haemodynamic significance of MB and some, usually case reports, indicates a possible association between MB and various cardiac pathologies like AMI, left ventricular rupture, life-threatening arrhythmias, hypertrophic cardiomyopathy, apical ballooning syndrome or sudden death 38 . MB is suggested to be a possible underlying mechanism for MINOCA but a subset of the SMINC-study showed similar prevalence for MB in MINOCA, with or without takotsubo syndrome (TS), as in healthy controls 39 .…”

Myocardial bridge characteristics and coronary atherosclerotic markers

“…Several studies reported that preferential development of atherosclerosis just proximal to bridged segment while the bridged segment itself was free from atherosclerosis. [10][11][12] The reasons for confi nement of atherosclerosis at proximal part of MB while sparing the bridged segment were due to hemodynamic disturbances and signifi cant pressure gradients between the bridged segment and the proximal coronary segment leading to chronic coronary pressure overload with signifi cant endothelial changes. 11 Moreover, the absence of exposure to pericoronary adipose tissue at MB site and increased lymph drainage of the vessel wall, protecting against lipid accumulation within the bridged segment.…”

“…[10][11][12] The reasons for confi nement of atherosclerosis at proximal part of MB while sparing the bridged segment were due to hemodynamic disturbances and signifi cant pressure gradients between the bridged segment and the proximal coronary segment leading to chronic coronary pressure overload with signifi cant endothelial changes. 11 Moreover, the absence of exposure to pericoronary adipose tissue at MB site and increased lymph drainage of the vessel wall, protecting against lipid accumulation within the bridged segment. 8,11 Elmali et al found that a signifi cant association was observed between the MB depth and systolic narrowing, while there was no signifi cant association between the MB length and systolic narrowing and MB depth was related to patient symptoms of chest pain whereby increased MB depth, but not MB length, causing further may not give the true interaction or relationship between cardiac fat and MB characteristics.…”

“…11 Moreover, the absence of exposure to pericoronary adipose tissue at MB site and increased lymph drainage of the vessel wall, protecting against lipid accumulation within the bridged segment. 8,11 Elmali et al found that a signifi cant association was observed between the MB depth and systolic narrowing, while there was no signifi cant association between the MB length and systolic narrowing and MB depth was related to patient symptoms of chest pain whereby increased MB depth, but not MB length, causing further may not give the true interaction or relationship between cardiac fat and MB characteristics. Saidi et al reported that there was prominent perivascular space under the MB characterized by preponderance of fatty tissue that may limit the compressive forces on the bridged segment during systole.…”

Advanced Coronary Atherosclerosis and Fatal Myocardial Infarction in Mild Dyslipidemic, Low Risk Young Man: A Case Report With Literature Reviewed

“…23 However, acute myocardial infarction, [24][25][26] ventricular septal rupture, 27 paroxysmal AV block, 28 ventricular tachycardia during exercise 29 or even sudden death 30 had been reported in MB cases. Recently, Hostiuc S et al, 31 performed a meta-analysis of 21 MB studies and found that MB was associated with major adverse cardiac events, OR = 1.52 (95% CI: 1.01-2.30), and myocardial ischemia, OR = 3.00 (95% CI: 1.02-8.82), but not with acute myocardial infarction, cardiovascular death, ischemia (identified using imaging techniques), or positive exercise stress testing. In summary, MB could have significant cardiovascular consequences (MACE, myocardial ischemia) in three ways; 1) by direct systolic compression of the tunneled artery causes delayed relaxation and reduces blood supply, [32][33][34] 2) by induced atherosclerosis of the proximal segment prior to the MB, [35][36][37] as found in this case, and 3) enhanced vasospasm.…”