Update review on myocardial bridging: New insights

Myocardial bridging (MB) is a common congenital abnormality that remains asymptomatic in a large proportion of patients. The peak of clinical manifestation occurs during the third and fourth decades of life. MB provokes myocardial ischemia through different mechanisms including supply-demand mismatch, endothelial dysfunction, coronary microvascular dysfunction and external mechanical compression. The association between MB and atherosclerotic disease is controversial. Recent studies established a significant association of MB with myocardial infarction and non-obstructive coronary artery disease. The first line medical treatment is based on beta-blockers and calcium channel blockers. Ivabradine is used in second line therapy. Invasive approaches involving percutaneous coronary intervention, coronary artery bypass graft and myotomy are performed in patients with symptoms refractory to maximally tolerated medical treatment. The choice of revascularization technique depends on anatomical characteristics, clinical condition and physician experience. Available data derived from anecdotal evidence view the lack of randomized clinical trials.

Chest Pain During Chemotherapy: A Case of Severe Myocardial Bridging

A cancer patient presented with acute chest pain at rest 40 hours after IV fluorouracil infusion. Angiography showed evidence of myocardial bridging.

[Myocardial bridge as the only cause of acute coronary syndrome among the young patients]

OBJECTIVE

Introduction: Myocardial bridge is an inborn anomaly of coronary artery development, when a part of it is submerged in a myocard, which is pressing the coronary artery to a systola and restrains coronary blood circulation. Generally this feature of coronary blood circulation does not cause any clinical symptoms because the 85% of coronary blood stream of the left ventricle is provided by diastolic filling. Hemodynamic changes in atherosclerosis, tahicardie, hypertrophie of myocard are leading to the manifestation of clinical symptoms of ischemia. The aim: The purpose of the investigation was to discover the features of clinical development of acute coronary syndrome caused by myocardial bridge of young patients without the features of atherosclerotical harm of coronary arteries.

PATIENTS AND METHODS

Materials and methods: Eight causes of acute coronary syndrome among patients of 28±8,5 years with myocardial bridge which was revealed during coronary angiography, were investigated. Standardized examination and conservative treatment of patients was held, except for three who have got interventional therapy.

RESULTS

Results: According to our investigation, myocardial bridge of all investigated patients was located in the middle of the third front interventricular branch of the left coronary artery. Causes of acute coronary syndrome manifestation were tahicardia, spasms of coronary artery, inducted by iatrogenic factors hypertrophie of myocard, hypertrophic cardiomyopatie. Connection between the manifestation of clinical symptoms and length of tunneled segment which did not depend on the level of systolic compres was discovered. The results of conservative and interventional treatment were analyzed.

CONCLUSION

Conclusions: Myocardial bridge can be the cause of myocardial ischemia among patients without signs of coronary atherosclerosis with additional hemodynamic risk facts such as tahicardia, spasms of coronary artery, hypertrophie of myocard. Clinical symptomatology of the acute coronary syndrome is more often observed among patients who's myocsrdial bridge is located in the middle of the third front interventricular branch of the left coronary artery. This is caused by perpendicular location of muscle fibers to coronary artery that increases systolic compression. Diastolic function and blood filling of coronary artery can be improved due to the medication beta-blockers therapy of patients with symptomatic myocardial bridge. A higher risk of appearance of restenosis of the stent is possible due to interventional treatment of young patients with myocardial bridge without atherosclerosis of coronary arteries.

Myocardia ischemia associated with a myocardial bridge with no significant atherosclerotic stenosis

BACKGROUND

Myocardial bridge refers to the myocardial tissue with which the coronary artery is partly covered. Though it has long been regarded to be benign, patients with myocardial bridges may present with myocardial ischemia, acute coronary syndromes, coronary spasm, sudden cardiac arrest or even sudden death.

CASE PRESENTATION

In present study, we reviewed four cases with myocardial bridge and no stenosis of coronary artery, which included acute coronary syndrome and sudden cardiac arrest.

CONCLUSIONS

These cases indicated that cardiac events in patients with myocardial bridge may be associated with coronary spasm, myocardial supply/demand mismatch or cardiac arrest.

Myocardial Noncompaction Presenting With Myocardial Bridge: A Case Report

Myocardial noncompaction, namly isolated noncompaction of the left ventricular myocardium (NVM), is a rare congenital disease. It can be either seen in the absence of other cardiac anomalies, or associated with other congenital cardiac defects, mostly stenotic lesions of the left ventricular outflow tract. A myocardial bridge (MB) is thought being associated with coronary heart disease, such as coronary spasm, arrhythmia, and so on. The significance of MB in association with other congenital cardiac conditions is unknown.We report a novel case who was presented NVM and MB. A 34-year-old man complained of chest prickling-like pain and dizzy for 1 year. His blood pressure was 110/70 mm Hg. Echocardiograph revealed increased trabeculations below the level of papillary muscle of left ventricle (LV); deep intertrabecular recesses in the endocardial wall of LV particularly in apex free wall; and LV ejection fraction of 57%. A coronary computerized tomography scan showed that part, 38.9 cm, of left descending artery tunnel was surrounding by cardiac muscles rather than resting on top of the myocardium.The therapeutics interventions included lifestyle cares, agents of anti-ischemia and improvement myocardial cell metabolism. The patient was followed up for 2.6 years, and his general condition was stable.This case indicates that NVM can be developed with MB, and the complete diagnosis of NVM and MB should be made by different image studies.

Deferring coronary stenting for myocardial bridging by fractional flow reserve and optical coherence tomography

Deciding how to treat acute myocardial infarction (MI) with myocardial bridge is difficult because stent fracture and early restenosis are frequently reported. We present a 50-year-old female patient with acute MI and myocardial bridge. Optical coherence tomography (OCT) and fractional flow reserve were used to reach a decision on treatment.

Metal fatigue in myocardial bridges: stent fracture limits the efficacy of drug-eluting stents

Myocardial bridging (MB) is a common anatomical varient in which a segment of coronary artery takes an intramural path. Occasionally, it can result in symptomatic ischemia. We present four cases in which MB was treated with drug-eluting stents that subsequently fractured, leading to recurrent symptoms.

Coronary artery occlusion and myocardial infarction caused by vasospasm within a myocardial bridge

Myocardial bridging is a common congenital coronary anomaly that is clinically silent in the majority of cases. Case reports suggest myocardial ischemia and infarction can be caused by myocardial bridging. The proposed mechanisms by which myocardial bridging causes myocardial ischemia include compromised coronary blood flow, endothelial dysfunction, thrombus formation and a strong association with coronary vasospasm. We reported a case of myocardial infarction caused by both myocardial bridging and coronary vasospasm. We reviewed the literature and suggest that coronary stenting may have a role in treating myocardial ischemia due to myocardial bridging and coronary spasm that is refractory to medical management.

Stent graft used to rescue coronary rupture during percutaneous coronary intervention for myocardial bridge

Myocardial bridge (MB) is a congenital variation of the coronary arteries and the segment of the coronary artery through myocardium is compressed during systole. Although it is relatively asymptomatic, percutaneous coronary intervention (PCI) may be necessary to relieve symptoms. Perforation or frank rupture of coronary arteries occurs rarely in patients undergoing percutaneous coronary intervention. We report the coronary rupture in a case with myocardial bridge which occurred during percutaneous coronary intervention. We deployed a stent graft to successfully rescue the rupture of the distal segment of left anterior descending coronary artery (LAD-D) with myocardial bridge (MB).

Limitation of fractional flow reserve in evaluating coronary artery myocardial bridge

Symptomatic myocardial bridge is treated with medical therapy, but in refractory cases, percutaneous revascularization has been used. We describe two cases to highlight differences in coronary compression and flow pattern, which make the luminal narrowing associated with a myocardial bridge anatomically and physiologically different from the fixed stenosis of atherosclerotic epicardial disease. Due to these characteristics, evaluating the functional severity of a myocardial bridge using fractional flow reserve as a guide to revascularization may be of limited value. Furthermore, stenting, including drug-eluting stents, may not be the ideal revascularization strategy secondary to a higher risk of in-stent restenosis.

Myocardial infarction in a young female with reninoma induced hypertension and myocardial bridging

We present a case of myocardial infarction in a young female with reninoma induced hypertension and myocardial bridging. Reninoma is a rare and curable cause of secondary hypertension. Currently developed multi-detector computed tomography (MDCT) has permitted better evaluation of myocardial infarction and myocardial bridging. Myocardial infarction associated with reninoma and myocardial bridging has not been reported, and we report this interesting case.

[The evaluation on stent implantation efficacy of myocardial bridge and severe atherosclerosis lesions in the segments proximal to the myocardial bridge]

OBJECTIVE

To assess long term stent implantation efficacy of myocardial bridge and severe atherosclerosis lesions in the segments proximal to the myocardial bridge.

METHODS

The study population consisted of 3 groups (103 patients). Group A included 28 patients with severe atherosclerosis lesion of luminal narrowing of > or = 70% in the segments proximal to the myocardial bridge. Group B included 16 patients with symptomatic myocardial bridge lesion of systolic luminal narrowing of > or = 95%. Group C included 59 patients with severe atherosclerotic lesion of luminal narrowing of > or = 70%. All lesions were successfully treated with stent by standard interventional techniques. Quantitative coronary angiography was performed before and immediately after stent deployment. Follow-up Quantitative coronary angiography was performed at six months or later. Clinical evaluation was done at 20 months after PCI.

RESULTS

There was no significant difference in luminal diameter and stent diameter among 3 groups immediately after stent implantation (P > 0.05). At six months, restenosis occurred in 4 patients in Group A (14.3%), in 7 patients in Group B (43.7%), and in 8 patients in Group C (14.8%), respectively. The rate of restenosis was significantly lower in group A and C than in group B (P < 0.05). No significant difference was found between group A and C. Additional balloon dilating of stent were performed in all restenosis patients. Clinical evaluation at 20 months showed that all patients remained free of angina and cardiac events.

CONCLUSION

The efficacy of intracoronary stent implantation in treating severe atherosclerosis lesion in the segments proximal to the myocardial bridge is not affected by abnormal haemodynamic changes of myocardial bridges. The rate of restenosis in intracoronary stent implantation of myocardial bridges is higher than that of atherosclerotic lesions in the segments proximal to myocardial bridge.