Coronary artery bypass grafting for myocardial bridges of the left anterior descending artery

Myocardial Bridge or Something Else?

In this E-Challenge, the authors report on a patient with symptoms of exertional dyspnea and angina, scheduled to have surgical unroofing of an identified myocardial bridge (MB). An MB is very common in patients with hypertrophic cardiomyopathy (HCM). Intraoperative transesophageal echocardiography with provocative maneuvers revealed the patient had a systolic anterior motion of the mitral valve with septal contact and resulting outflow tract obstruction despite the notable absence of significant basal septal hypertrophy. HCM has many phenotypic variants that can make the identification of patients with latent left ventricular outflow tract obstruction difficult in the absence of a high index of suspicion. In this report, the authors discuss the association between MBs and HCM and the importance of recognizing phenotypic variants of HCM.

Minimally invasive coronary artery bypass grafting via a lower ministernotomy for left anterior descending artery myocardial bridging: mid-term results

OBJECTIVES

Coronary artery bypass grafting or supra-arterial myotomy is now suggested as a better therapeutic option in myocardial bridging (MB) when medical treatment fails to control symptoms. For left anterior descending (LAD) MB, minimally invasive coronary artery bypass via a lower ministernotomy can be offered.

METHODS

Forty-four consecutive patients who underwent elective minimally invasive coronary artery bypass surgery from 2005 to 2014 via an inferior sternotomy using the left internal mammary artery as a bypass graft for LAD MB were evaluated retrospectively.

RESULTS

The mean age was 59.1 ± 13.1 years with 26 (59%) men and 18 (41%) women. The mean body mass index was 27.2 ± 3.9 and the mean EuroSCORE II was 1.6 ± 1.8. Routine coronary multislice computed tomography angiography on the 6th postoperative day revealed 97.7% graft patency. During the initial hospital stay, 1 patient (2.3%) underwent a reoperation for early graft failure. Forty patients (91%) could be followed up for a mean period of 64.4 ± 24.5 months after the procedure, during which 2 patients (4.5%) died of non-cardiac causes and 9 patients (20.5%) underwent postoperative coronary angiography with confirmed graft occlusion in only 1 case (2.3%). The improvement in the distribution of patients in the Canadian Cardiovascular Society class 0 was from 4 patients (9%) preoperatively to 37 patients (84%) at the end of the follow-up period (P-value 0.001).

CONCLUSIONS

Minimally invasive coronary artery bypass surgery via a lower ministernotomy may be safe and efficient for treating LAD artery MB with acceptable complication rates, cosmetic benefits and patency rates.

Myocardial Bridge Bypass Graft: A Novel Surgical Procedure for Extensive Myocardial Bridges

In patients with myocardial bridges (MBs) and insufficient medical management, the optimal surgical strategy remains undetermined. Based on computer simulations we developed a novel procedure, MB bypass grafting, that showed better hemodynamics compared with coronary artery bypass grafting in a simulation study. In this novel procedure the left internal mammary artery was used to connect the proximal and distal ends of the MB. For the first time we used MB bypass grafting to treat a patient with extensive MB. The patient recovered well after surgery, and the left internal mammary artery graft remained patent 3 months postoperatively.

Recurrent attack of acute myocardial infarction complicated with ventricular fibrillation due to coronary vasospasm within a myocardial bridge: a case report

BACKGROUND

Myocardial bridge (MB) often an inoffensive condition that goes in one or more of the coronary arteries through the heart muscle instead of lying on its surface. MBs sometimes leads to myocardial ischemic symptoms such as chest pain, even an occurrence of myocardial infarction. However, reports of severe and recurrent cardiac adverse events related to the MBs are rare.

CASE PRESENTATION

A 44-year-old male patient who suffered from a four-hour crushing chest pain ten years ago, was diagnosed as acute anterior ST-elevation myocardial infarction (STEMI). The initial findings of coronary angiography (CAG) showed MB was located in the middle part of the left anterior descending coronary artery (LAD). The patient was managed medically. Another re-attack of similar previous chest pain characteristics occured just after 3 days of discharge. Supra-arterial myotomy and CABG were the next adopted management. Postoperative progression was uneventful. However, 32 months after surgical treatment, the patient experienced an abrupt onset of chest pain accompanied by loss of consciousness. The ECG showed ventricular fibrillation (VF). After electrical cardioversion, an immediate CAG followed by CTA was performed which excluded thrombus or acute occlusion in the native coronary artery and an occlusion was observed at the end of the left internal mammary artery. An implantable cardioverter-defibrillator (ICD) was successfully performed for prevention of malignant arrhythmia. During ten years of follow-up, no complications have been identified.

CONCLUSIONS

Although MB is mostly benign, it may lead to significant cardiovascular consequences. Supra-arterial myotomy is an appropriate treatment option for this patient who failed to optimal medical therapy. Furthermore, ICD implantation must be considered in order to prevent malignant ventricular arrhythmia caused by continuous spasm resulting in ischemia. Further investigations are required to confirm the clinical effectiveness of these procedures.

Combined Myocardial Bridge and Coronary Vessel Disease Requiring Coronary Artery Bypass Grafting and Myotomy of the Myocardial Bridge

Myocardial bridging (MB) describes a band of myocardium that covers the epicardial surface of the coronary artery. This band can vary both in thickness and distance to which it covers the artery. It is broadly classified as superficial or deep, depending on the thickness of the covering muscle layer. It can be asymptomatic, or it could present with different complications. Reported complications have included ischemia and acute coronary syndromes, coronary spasm, ventricular septal rupture, and arrhythmias. MB is most commonly found in the middle segment of the left anterior descending (LAD) coronary artery. There is controversy with regard to therapy for symptomatic patients who are refractory to medical management. Percutaneous coronary intervention and surgical myotomy (unroofing) have been proposed; yet, each one has its pros and cons. MB can be associated with the development of atherosclerosis proximal to the MB segment in the involved coronary artery, and patients can present having both pathologies. We present a case series of six patients with atherosclerotic coronary lesions requiring coronary artery bypass grafting (CABG) with an accidental perioperative finding of MB, which required myotomy.

The Myocardial Bridge: Potential Influences on the Coronary Artery Vasculature

A myocardial bridge (MB) is an anatomical abnormality of the coronary artery and is characterized by the systolic narrowing of the epicardial coronary artery caused by myocardial compression during systole. An MB is frequently observed on cardiac computed tomography or coronary angiography and generally appears to be harmless in the majority of patients. However, the presence of MB is reportedly associated with abnormalities of the cardiovascular system, including coronary artery diseases, arrhythmia, certain types of cardiomyopathy, and cardiac death, indicating that MB serves a pivotal role in the occurrence and/or development of such cardiovascular events. Recently, there has been an increasing interest in the coexistence of MB and coronary spasm in research due to opposing aspects regarding their treatments. For example, monotherapy using β-blockers, which are effective in patients with MB, may worsen symptoms in patients with coronary spasm. By contrast, nitroglycerin, which is an effective treatment option for coronary spasm, may worsen symptoms in patients with MB. This review focuses on the pathophysiology and diagnosis of MB and MB-related cardiovascular diseases, including coronary spasm, and on the treatment strategies for MB.

What is the optimal treatment for symptomatic patients with isolated coronary myocardial bridge? A systematic review and pooled analysis

BACKGROUND

Myocardial bridging is a common coronary anomaly, with few severe adverse events but a relevant symptom burden. Myocardial bridging treatment, however, remains uncertain because of the lack of randomized trials.

MATERIAL

MEDLINE/PubMed was systematically screened for studies reporting on isolated myocardial bridging diagnosed at coronary angiography or with coronary computed tomography in patients admitted for suspected angina or with an acute coronary syndrome. Baseline, treatment and outcome data were appraised and pooled according to treatment (medical therapy, bypass surgery/myotomy or stenting).

RESULTS

A total of 899 patients in 18 studies were included with a low prevalence of traditional risk factors, especially diabetes (15.6%, interquartile range 2.5-21.5). After a median of 31.0 months (interquartile range 12.4-37.1), major cardiovascular events (composite of death, myocardial infarction or target vessel revascularization) occurred in only 3.4% of the study patients and 78.7% [70.5-86.9; 95% confidence intervals (CI)] were managed conservatively and free of symptoms. When an invasive strategy was planned, freedom from angina was higher in patients treated with surgery [84.5% (78.4-90.7; 95% CI)] than in those treated with stenting [54.7% (38.9-70.6; 95% CI)]. Patients in the stenting group experienced a high incidence of major cardiovascular events related to target vessel revascularization [40.07% (19.83-60.32; 95% CI)]. Meta-regression showed that patients treated with beta-blockers or with a history of hypertension were more likely to remain free from angina (B -0.6, P = 0.013; B -0.66, P = 0.006).

CONCLUSION

Patients with symptomatic isolated myocardial bridging generally have a good long-term prognosis. Pharmacological treatment alone, especially with beta-blockers, is able to improve angina in most cases. Surgical treatment appears to be more effective than stenting in nonresponders.

Myocardial bridging with left ventricular hypertrophy presenting as Wellens pattern

The course of epicardial coronary arteries into a muscular tunnel under a bridge of myocardium is known as myocardial bridging (MB). This could be a benign anomaly, nevertheless, it could have a great impact on the quality of life in the setting of severe anginal symptoms. The clinical presentation and diagnosis could be challenging in those patients. The treatment options start from simple medical therapy to surgical intervention in refractory cases, the role of percutaneous coronary intervention (PCI) is limited in MB. We are describing a case of severe MB presenting as Wellens pattern with underlying left ventricular hypertrophy (LVH).

Left Anterior Descending Artery Myocardial Bridging: A Clinical Approach

A myocardial bridge (MB) is the term for the muscle overlying the intramyocardial segment of the epicardial coronary artery (referred to as a tunneled artery). Although MBs can be found in any epicardial artery, most of them involve the left anterior descending artery. These congenital coronary anomalies have long been recognized anatomically, and are traditionally considered a benign condition; however, the association between myocardial ischemia and MBs has increased their clinical relevance. This review summarizes the prevalence, pathophysiology, and diagnostic findings, including morphological, functional assessment, and treatment of patients with MB involving the left anterior descending artery, suggesting a pragmatic clinical approach to this entity.

Myocardial bridging: contemporary understanding of pathophysiology with implications for diagnostic and therapeutic strategies

Patients with myocardial bridging are often asymptomatic, but this anomaly may be associated with exertional angina, acute coronary syndromes, cardiac arrhythmias, syncope, or even sudden cardiac death. This review presents our understanding of the pathophysiology of myocardial bridging and describes prevailing diagnostic modalities and therapeutic options for this challenging clinical entity.

Myocardial bridging: what have we learned in the past and will new diagnostic modalities provide new insights?

The clinical significance of myocardial bridging has been a subject of discussion and controversy since the introduction of coronary arteriography (CAG) in the early 1960s. More recently computed tomography coronary angiography (CTCA) has made it possible to visualise the overlying muscular bands and appears to have a higher sensitivity for detecting myocardial bridging than CAG. Combining CTCA with invasive techniques such as CAG should make it possible to improve our understanding of the pathophysiology of myocardial bridging and to provide answers to hitherto unresolved questions. This paper critically reviews the outcomes of previous studies and defines remaining questions that should be answered to optimise the management of the presumably fast growing number of patients in whom a diagnosis of myocardial bridging has been made.

Is coronary artery bypass grafting an acceptable alternative to myotomy for the treatment of myocardial bridging?

A best evidence topic in cardiothoracic surgery was written according to a structured protocol. The question addressed was 'Is CABG an effective alternative for the treatment of myocardial bridging?' Altogether, only six papers were identified using the reported search that represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes, and results of these papers are tabulated; these studies reported the outcome of myotomy and coronary artery bypass grafting (CABG) for myocardial bridging. All of these studies were retrospective reports of the results of surgical intervention in patients with myocardial bridging. They showed that the incidence of myocardial bridging was less than 1-1.5% in patients with angina requiring angiography, and 7-9% of these patients had refractory angina despite medical treatment and required surgery. The evidence on the treatment of this congenital condition that mainly affects the middle segment of left anterior descending artery is limited, and there are no treatment guidelines currently available. Stenting of the tunnelled segment has shown high failure rates in approximately half of the cases. Current evidence in the literature suggests that surgery is the mainstay treatment for myocardial bridging. Surgery is performed either as supra-arterial myotomy and de-roofing of the muscle bands on- or off-pump, or as coronary artery bypass grafting of the affected coronary artery beyond the tunnelled segment. Although no mortality was reported with either of these operations, surgical myotomy on deep and extensive myocardial bridges carries the risk of entering the right ventricle, bleeding and aneurysm formation. In addition, in a small percentage of the patients undergoing myotomy, angina recurred. Despite the possibility of competitive flow in the native coronary artery after CABG for myocardial bridging, we did not identify any evidence demonstrating graft occlusion after CABG for myocardial bridging. In conclusion, in extensive and deep myocardial bridgings, CABG may be the treatment of choice that carries low risk, limited complications and excellent symptomatic relief.