Intramyocardial muscle bridging of the coronary artery--an examination of a diastolic "spike and dome" pattern of coronary flow velocity

Myocardial Bridge and Atherosclerosis, an Intimal Relationship

PURPOSE OF REVIEW

This review investigates the relationship between myocardial bridges (MBs), intimal thickening in coronary arteries, and Atherosclerotic cardiovascular disease. It focuses on the role of mechanical forces, such as circumferential strain, in arterial wall remodeling and aims to clarify how MBs affect coronary artery pathology.

REVIEW FINDINGS

MBs have been identified as influential in modulating coronary artery intimal thickness, demonstrating a protective effect against thickening within the MB segment and an increase in thickness proximal to the MB. This is attributed to changes in mechanical stress and hemodynamics. Research involving arterial hypertension models and vein graft disease has underscored the importance of circumferential strain in vascular remodeling and intimal hyperplasia. Understanding the complex dynamics between MBs, mechanical strain, and vascular remodeling is crucial for advancing our knowledge of coronary artery disease mechanisms. This could lead to improved management strategies for cardiovascular diseases, highlighting the need for further research into MB-related vascular changes.

Myocardial infarction with distal embolization associated with myocardial bridging in a postoperative patient: a case report

Myocardial bridging is associated with myocardial infarction (MI) on rare occasions. The mechanism by which this occurs is unclear; vessel occlusion in this setting may be due to superimposed thrombosis or vasospasm. An unusual case is presented of postoperative MI from thrombosis associated with myocardial bridging and intravascular volume depletion, with subsequent distal embolization. Endothelial injury as a result of myocardial bridging may predispose to thrombus formation. To avoid MI, adequate fluid hydration is recommended during the perioperative period in patients with myocardial bridging.

Self-expanding intracoronary stent for symptomatic myocardial bridging

Myocardial bridging has been recognized as a potential cause of symptoms of angina, arrhythmias and even infarction. Various treatment strategies including beta-blockers, surgery and more recently intra-coronary stents have been used to manage bridging. We report a novel case of use of self-expanding stent for myocardial bridging in a patient with symptoms of angina and ischemia on nuclear imaging. We further present the 18-month follow up showing minimal in-stent stenosis. To our knowledge, this is the first report of using a self-expanding stent in myocardial bridging. The use of self-expanding stents could be a potential treatment for symptomatic myocardial bridging.

Detection of myocardial bridging with ECG-gated MDCT and multiplanar reconstruction

OBJECTIVE

The aim of this study was to evaluate the incidence of myocardial bridging in 626 patients examined with MDCT angiography of the coronary arteries.

MATERIALS AND METHODS

Six hundred twenty-six patients who were referred to Florence Nightingale and Atatürk University Hospitals were involved in this study. These patients had atypical chest pain, symptoms suggestive of coronary artery disease, or no significant cardiac complaint. Patients were in sinus rhythm and were premedicated with metoprolol tartrate (5 mg/mL IV bolus) to decrease the heart rate and nitroglycerin (5 mg sublingual 1 min before the examination) to dilate the coronary arteries. MDCT was performed on two different 16-MDCT scanners.

RESULTS

Among the 626 patients, 22 cases (3.5%) of myocardial bridging were detected. Fifteen cases of myocardial bridging (2.4%) were located at the middle third of the left anterior descending coronary artery (LAD), five (0.8%) were at the distal third of the LAD, and two (0.3%) were at the proximal third of the LAD. In these patients, the length of tunneled artery was between 6 and 22 mm, with a mean of 17 mm, and the depth of tunneled artery was between 1.2 and 3.3 mm, with a mean of 2.5 mm.

CONCLUSION

We found the incidence of myocardial bridging in this patient group to be 3.5%. This result is in agreement with some of the angiographic studies in the literature. Our study showed that MDCT is a reliable and noninvasive tool for diagnosing coronary myocardial bridging. After evaluating resource axial images, it is necessary to also evaluate the sagittal multiplanar reconstruction images for myocardial bridging.

Myocardial Bridge: a clinical review

Human coronary arteries occasionally course intramyocardially--a condition termed Myocardial Bridge. We review the anatomic and pathophysiological basis of the Myocardial Bridge and discuss clinical presentations, prognoses and the current treatment options for this interesting coronary angiographic variant.

Intracoronary stent placement proximal to a myocardial bridge: immediate and long-term results

The intracoronary stent placement in a lesion proximal to a myocardial bridge is of special importance and is considered to be a challenge for the interventional cardiologist. In this study 4 cases of stent implantation proximal to a coronary bridged segment are described. In all cases complications were observed after the procedure. The patients remained free of symptoms and the exercise TI201 test was negative for ischemia 8.5+/-2.6 months later. Although there is skepticism because of the abnormal coronary flow pattern, the endothelial dysfunction and the subsequent thrombogenicity, the stent placement proximal to a myocardial bridge was safe and with favorable long term results in all 4 cases. However, further studies in large populations are necessary.

Transesophageal echocardiographic Doppler study of coronary flow in a patient with myocardial bridging--a case report

A case report of myocardial bridging of the left anterior descending artery is described. Coronary flow proximal to the myocardial bridge was studied with transesophageal echo Doppler. The patient, a 62-year-old farmer who sustained an anterior myocardial infarction, underwent thrombolysis and was admitted. He subsequently underwent coronary angiography and left ventriculography, which showed a severe myocardial bridge of the midshaft of the left anterior descending artery. The ejection fraction improved from 25 to 48% after thrombolysis, as measured by using echocardiography. Transesophageal Doppler study proximal to the myocardial bridge revealed a relative increase of the diastolic coronary flow velocity (increased acceleration), which reached its peak value in early diastole. Despite the presence of severe myocardial bridging, coronary flow reserve increased substantially two minutes after the infusion of dipyridamole (0.56 mg/kg iv for 4 minutes). Transesophageal Doppler study of coronary blood flow proximal to the myocardial bridge in the left anterior descending artery showed a characteristic waveform that may prove to be indicative of this condition.

Acute myocardial infarction caused by a myocardial bridge treated with intracoronary stenting

The clinical significance of myocardial bridges (MBs) is variable, and most patients are asymptomatic. However, angina, myocardial infarction, and sudden death have been reported in association with MBs. Here we describe the use of intracoronary stenting for the treatment of a patient with an anterior myocardial infarction due to an MB.

Myocardial bridging in a survivor of sudden cardiac near-death: role of intracoronary doppler flow measurements and angiography during dobutamine stress in the clinical evaluation

Extensive myocardial bridging in the left anterior descending coronary artery was found in a 46 year old survivor of sudden cardiac near-death. Positron emission tomography and dobutamine stress echocardiography revealed ischaemia in the myocardium distal to the bridging. Spasm was excluded as cause of the ischaemia by intracoronary infusion of acetylcholine. Further evaluation of the haemodynamic importance of the bridging using intracoronary Doppler flow velocity measurements revealed an abnormal flow reserve. Dobutamine stress during coronary angiography caused increased mechanical compression during diastole. This was accompanied by multiple premature ventricular contractions. After a debridging operation the flow velocity reserve was normal. The abnormalities found during dobutamine stress had disappeared. Unexpectedly, a spasm was inducible. This may have been due to local oedema or scar formation after the operation. For the evaluation of the haemodynamic importance of myocardial bridging, intracoronary Doppler flow velocity measurements and angiography during dobutamine stress may be helpful in clinical decision making.

Physiological significance of a proximal coronary artery stenosis on a distal intramyocardial bridge: coronary flow velocity patterns pre- and post-angioplasty

The angiographic incidence of intramyocardial bridging (MB) is 0.7-4.5% [Angelini et al.: Prog Cardiovasc Dis 25:75-88, 1983]. Morphological and physiological patterns of MB have recently been described, observing coronary flow velocity patterns, intravascular ultrasound, and angiography [Flynn et al.: Cathet Cardiovasc Diagn 32:36-39, 1994; Ge et al.: Circ Res 89:1725-1732, 1994]. We describe a reversal of the normal flow velocity characteristics within a MB, due to a hemodynamically significant stenosis in the proximal left anterior descending artery (LAD). After successful percutaneous transluminal coronary angioplasty (PTCA) of the proximal LAD stenosis, there was normalization of the flow velocity pattern within the MB and the appearance of a spike and dome pattern distal to the MB.