Prognostic Implications of Resistive Reserve Ratio in Patients With Nonobstructive Coronary Artery Disease With Myocardial Bridging.

BACKGROUND: Myocardial bridging (MB) is accompanied by the dynamic extravascular compression of epicardial coronary arteries, leading to intracoronary hemodynamic disturbance with abnormal coronary flow profiles. We aimed to evaluate the prognostic implications of resistive reserve ratio (RRR), a composite measure of flow and pressure parameters that represents the vasodilatory capacity of the coronary arteries, in patients with angina with nonobstructive coronary artery disease (ANOCA) and MB, in comparison with coronary flow reserve (CFR). METHODS AND RESULTS: In this retrospective cohort study, we included patients with ANOCA who underwent coronary reactivity testing, where MB was identified by transient constriction in coronary artery segments between systole and diastole. Abnormal CFR and RRR were defined as <2.5 and <2.62, respectively. Major adverse cardiac events, including cardiovascular death, stroke, myocardial infarction, heart failure, and late revascularization, served as outcomes. Among 1251 patients with ANOCA, 191 (15.3%) had MB. The prevalence of abnormal CFR or RRR was not significantly different between patients with and without MB (P=0.144 and P=0.398, respectively). Over a median follow-up time of 6.9 years, abnormal RRR predicted major adverse cardiac events in patients with MB (hazard ratio [HR], 4.38 [95% CI, 1.71-11.21]; P=0.002) and without MB (HR, 1.91 [95% CI, 1.38-2.64]; P<0.001). Abnormal CFR predicted major adverse cardiac events in patients without MB (HR, 2.15 [95% CI, 1.54-3.00]; P<0.001), whereas it was not predictive of major adverse cardiac events in patients with MB (HR, 2.29 [95% CI, 0.93-5.65]; P=0.073). CONCLUSIONS: In patients with ANOCA and MB, impaired RRR was superior to impaired CFR in distinguishing patients at a higher risk of future adverse events, suggesting that RRR may serve as a risk stratification tool in patients with MB and ANOCA.

Acute Myocardial Infarction Due to Myocardial Bridge Treated With Surgery: a Case Report.

Myocardial bridging is congenital anomaly characterized by segment of epicardial coronary arteries passing through the myocardium. Various ischemic conditions are related with this pathology. We report a case of myocardial bridging that was complicated with acute anterior myocardial infarction and a review of the literature. The patient was treated successfully with coronary bypass graft surgery after unsuccessful percutaneous intervention.

Clinically significant myocardial bridging.

Myocardial bridging is a common anatomical variant in which a major epicardial coronary artery takes an intramyocardial course, leading to dynamic systolic compression. Because coronary perfusion occurs primarily during diastole, most patients with this anatomical variant have no associated perfusion abnormalities or symptoms. Despite this, there is a subset of patients with myocardial bridging who experience ischaemic symptoms. Determining which anatomical variants are benign and which are clinically relevant remains a challenge. Further complicating the picture, functional factors such as diastolic dysfunction and coronary vasospasm may exacerbate myocardial bridging-related ischaemia. In patients with ischaemic symptoms in the absence of alternative explanations, a detailed assessment of myocardial bridging with invasive physiology should be performed to define the significance of the lesion and guide tailored medical therapy. Patients with refractory symptoms despite maximally tolerated medical therapy should be considered for surgical coronary unroofing.

Clinical Implication and Optimal Management of Myocardial Bridging: Role of Cardiovascular Imaging.

Myocardial bridging (MB) was historically considered a benign structure as most people with MB are clinically asymptomatic. Recently, however, mounting evidence indicates that MB can cause adverse cardiac events owing to arterial systolic compression/diastolic restriction, atherosclerotic plaque progression upstream from MB, and/or vasospastic angina. In MB patients with refractory angina, the optimal treatment strategy should be determined individually based on versatile anatomic and hemodynamical assessments that often require multidisciplinary diagnostic approaches. The present review summarizes the clinical implication and management of MB, highlighting the role of imaging modalities currently available in this arena.

Myocardial bridging is significantly associated to myocardial infarction with non-obstructive coronary arteries.

BACKGROUND: Myocardial infarction with non-obstructive coronary arteries (MINOCA) is a common disorder characterized by the presence of clinical criteria for acute myocardial infarction in the absence of obstructive coronary artery disease on angiography. We aim to investigate the relationship between myocardial bridging (MB) and MINOCA. METHODS AND RESULTS: An observational retrospective study was conducted on 15 036 patients who had been referred for coronary angiography and who fulfilled the Fourth Universal Definition of Myocardial Infarction. The study population was divided into ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI) patients, from which we defined two main groups: the MINOCA group and the coronary artery disease (CAD) group. Statistical analyses were carried out by using SPSS, version 20. The prevalence of angiographic MB among the groups was significantly greater in the MINOCA group (2.9% vs. 0.8%). MINOCA accounted for 14.5% of spontaneous myocardial infarction, and the clinical presentation was more frequently NSTEMI rather than STEMI (84.3% vs. 15.7%). After adjusting for confounders, multivariate analyses showed a positive association between MB and MINOCA [odds ratio = 3.28, 95% CI (2.34; 4.61) P < 0.001]. Cardiovascular risk factors were less common in the MINOCA population, which was younger and more often female. CONCLUSION: MB is a risk factor for MINOCA. Because MB prevalence differed significantly between the controls (CAD group) and cases (MINOCA group), which were positively associated to MB, it seems likely that MB would be a potential cause of MINOCA. Investigations for MB in MINOCA cases and especially in NSTEMI patients seem necessary.

The Curious Case of Pseudo-Wellens' Syndrome and Myocardial Bridging.

Wellens' syndrome is an electrocardiographic harbinger of a critical left anterior descending (LAD) coronary artery stenosis in acute coronary syndromes (ACS), whereas pseudo-Wellens' syndrome typically has angiographically normal coronary arteries. Myocardial bridging (MB) occurs when an epicardial coronary artery segment takes a tunneled intramuscular course. We describe a rare case of MB-induced pseudo-Wellens' syndrome in a young patient presenting with unstable angina (USA).

Myocardial bridging - Sudden unexpected death of a young girl: A case report.

Myocardial bridging (MB) is a relatively uncommon congenital anomaly where a segment of the coronary artery dips inside the myocardium and takes a tunneled course under a bridge of the myocardium. This leads to the compression of the coronary artery during systole resulting in hemodynamic changes and their clinical manifestations. However, it is an incidental finding but can present with multiple complications like myocardial ischemia, infarction, and sudden death, primarily when associated with other risk factors like left ventricular hypertrophy of the heart. Therefore, a careful examination of the heart is essential for evaluating the clinical significance of the MB. Here, we presented a case of a 30-year-old young female who had a sudden death, and her histological examination of the heart showed MB of left anterior descending coronary artery (LAD).

[Surgical treatment of obstructive hypertrophic cardiomyopathy combined with muscle bridging of the left anterior descending artery]. / Khirurgicheskoe lechenie obstruktivnoi gipertroficheskoi kardiomiopatii v sochetanii s miokardial'nym mostikom perednei niskhodyashchei arterii.

Myocardial bridging is often detected during diagnostic coronary angiography in patients with congenital and acquired heart defects. In most cases, muscle bridging does not require surgical treatment. Myocardial bridging and tunnels causing compression of one or more major coronary arteries is a potential cause of myocardial ischemia in patients with hypertrophic cardiomyopathy. The authors report surgical treatment of a patient with obstructive hypertrophic cardiomyopathy and myocardial bridging of the left anterior descending artery.

Myocardial Bridging, the Hidden Risk Factor for Ischemia.

Myocardial bridging is an uncommon cause of a quite common emergency department complaint for chest pain and is often associated with left ventricular hypertrophy. We present a case of an otherwise healthy middle-aged U.S. military service member who presented with acute coronary syndrome which was ultimately determined to be the result of myocardial bridging.

Myocardial Bridging: Diagnosis, Functional Assessment, and Management: JACC State-of-the-Art Review.

Myocardial bridging (MB) is a congenital coronary anomaly in which a segment of the epicardial coronary artery traverses through the myocardium for a portion of its length. The muscle overlying the artery is termed a myocardial bridge, and the intramyocardial segment is referred to as a tunneled artery. MB can occur in any coronary artery, although is most commonly seen in the left anterior descending artery. Although traditionally considered benign in nature, increasing attention is being given to specific subsets of MB associated with ischemic symptomatology. The advent of contemporary functional and anatomic imaging modalities, both invasive and noninvasive, have dramatically improved our understanding of dynamic pathophysiology associated with MBs. This review provides a contemporary overview of epidemiology, pathobiology, diagnosis, functional assessment, and management of MBs.

Interplay Between Myocardial Bridging and Coronary Spasm in Patients With Myocardial Ischemia and Non-Obstructive Coronary Arteries: Pathogenic and Prognostic Implications.

Background Myocardial bridging (MB) may represent a cause of myocardial ischemia in patients with non-obstructive coronary artery disease (NOCAD). Herein, we assessed the interplay between MB and coronary vasomotor disorders, also evaluating their prognostic relevance in patients with myocardial infarction and non-obstructive coronary arteries (MINOCA) or stable NOCAD. Methods and Results We prospectively enrolled patients with NOCAD undergoing intracoronary acetylcholine provocative test. The incidence of major adverse cardiac events, defined as the composite of cardiac death, non-fatal myocardial infarction, and rehospitalization for unstable angina, was assessed at follow-up. We also assessed angina status using Seattle Angina Questionnaires summary score. We enrolled 310 patients (mean age, 60.6±11.9; 136 [43.9%] men; 169 [54.5%] stable NOCAD and 141 [45.5%] MINOCA). MB was found in 53 (17.1%) patients. MB and a positive acetylcholine test coexisted more frequently in patients with MINOCA versus stable NOCAD. MB was an independent predictor of positive acetylcholine test and MINOCA. At follow-up (median, 22 months; interquartile range, 13-32), patients with MB had a higher rate of major adverse cardiac events, mainly driven by a higher rate of hospitalization attributable to angina, and a lower Seattle Angina Questionnaires summary score (all P<0.001) compared with patients without MB. In particular, the group of patients with MB and a positive acetylcholine test had the worst prognosis. Conclusions Among patients with NOCAD, coronary spasm associated with MB may predict a worse clinical presentation with MINOCA and a higher rate of hospitalization attributable to angina at long-term follow-up with a low rate of hard events.

Complications associated with myocardial bridging in four children without underlying cardiac disease: a case series.

BACKGROUND: Myocardial bridging is largely considered to be a benign, symptomless congenital anomaly of the coronary arteries in which the intramyocardial coronary course is partially 'tunnelled' and leads to vessel compression during ventricular systole. There are few data regarding children. OBJECTIVE: To report on myocardial bridging observed in children seeking medical help in the paediatric emergency room. CASE PRESENTATION: A series of four children aged 6-13 years with symptomatic myocardial bridging but no other underlying cardiac abnormalities is reported. They were admitted to the paediatric emergency department during 2013-2016, three with chest pain after physical activity and one with septic shock. RESULTS: Heart computed tomography scan in the first three demonstrated myocardial bridging of the left anterior descendent coronary artery's branches; their 2-year follow-up was uneventful. The fourth patient presented with ventricular fibrillation 24 hours after admission and at autopsy there was an intramyocardial tract 4 cm long on the left anterior descendent coronary artery. CONCLUSIONS: This case series demonstrates that myocardial bridging can be symptomatic in children with no underlying cardiac disorders and should be included in the differential diagnosis of exertional chest pain and/or arrhythmias.Abbreviations: CRP, C-reactive protein; CT, computed tomography; D1, diagonal 1 artery; ECG, electrocardiogram; ED, emergency department; KD, Kawasaki disease; LAD, left anterior descending coronary artery; MB, myocardial bridging; RI, ramus intermedius artery; TN, troponin.

Challenges in Evaluation and Management of Children with Myocardial Bridging.

Myocardial bridging (MB) is a congenital anomaly where a coronary artery branch or group of branches extends inside a tunnel consisting of myocardium. Although it is mostly considered "benign," it is reported that MB may lead to significant cardiac problems and sudden cardiac deaths. While it is a congenital anomaly, its symptoms usually arise at further ages rather than childhood. The literature on MB in children is in the form of case reports or small case series. This is why pediatric cases are assessed in the light of information obtained from adults. This review compiled the literature on MB in adults and children and compared it, as well as discussing questions arising regarding the clinic, diagnosis, and treatment of MB.

Clinical characteristics and factors associated with coronary stenosis proximal to a myocardial bridge: a retrospective study.

BACKGROUND: The association of myocardial bridge (MB) with cardiovascular risk and the possible cardiovascular risk factors remain unclear. This study aimed to explore the clinical characteristics and related factors of coronary stenosis proximal to an MB. METHODS: This was a retrospective study of patients with symptoms of coronary atherosclerotic heart disease admitted between 10/2011 and 12/2014 to the Emergency and Cardiology Department of Bayannur Hospital, who underwent selective coronary angiography (SCAG). The patients were assigned to the non-stenosis and stenosis groups according to whether coronary stenosis was proximal to the MB. RESULTS: Among 244 patients with MB and cardiovascular symptoms, 91 (37.3%) had stenosis proximal to the MB. Compared with the non-stenosis group, there were more males (80.2% vs. 55.6%, P < 0.001) and smokers (including those who had quit smoking) (P < 0.001) in the stenosis group. There were no significant differences in blood lipid-related indexes (TG, TC, HDL-C, LDL-C, and VLDL-C) between the two groups. Multivariable analysis suggested that MB location in the middle distal or distal segment of the left anterior descending artery (LAD) increased the odds of coronary stenosis proximal to the MB (OR = 0.439, 95% CI: 1.57-7.532, P = 0.002), which was then considered an independent factor associated with coronary stenosis proximal to the MB. CONCLUSIONS: In patients diagnosed with an MB by SCAG, only MB located in the middle distal or distal segment of the LAD is independently associated with coronary stenosis proximal to the MB.

Clinical Outcomes of Surgical Unroofing of Myocardial Bridging in Symptomatic Patients.

BACKGROUND: There is a paucity of data regarding results of surgical management of myocardial bridging. Our objective was to evaluate the clinical outcomes of unroofing procedures in patients with myocardial bridging of the left anterior descending (LAD) coronary artery who had chest pain refractory to medical therapy. METHODS: Among 274 adult patients diagnosed with myocardial bridging at our institution (1996-2017), 71 underwent surgical intervention. To understand the potential benefit of unroofing, we excluded patients with concomitant operations for other diagnoses or known obstructive coronary disease. The study included 35 patients with preoperative chest pain and isolated LAD coronary artery bridging who underwent surgical unroofing. We analyzed recurrent symptoms, postoperative medication use, and mortality. RESULTS: Mean age was 48.2 ± 11.2 years (18 men [51%]). All patients underwent preoperative coronary angiography. Endothelial dysfunction in the LAD coronary artery bridged segment was confirmed in 20 of 24 patients (83%). Mean cardiopulmonary bypass and cross-clamp times were 47.6 ± 29.8 minutes and 33.7 ± 22.2 minutes, respectively. Median lengths of hospital and intensive care unit stay were 5 days and 1 day, respectively. During follow-up (median, 31 months; 95% confidence interval, 18-49) there were no cardiac-related deaths, and 22 patients (63%) reported no chest pain. Among 13 symptomatic patients, 10 underwent postoperative noninvasive testing, which was negative for ischemia in all cases. CONCLUSIONS: Myocardial unroofing can be performed safely in patients with chest pain and isolated LAD coronary artery myocardial bridging. However, patients should be aware of the potential for recurrent nonischemic chest pain and continued medical therapy despite relief of coronary compression.