Angiographic differentiation of systolic narrowing of the left anterior descending coronary artery in hypertrophic cardiomyopathy from myocardial bridges

To the Editor： I read with great interest the case report of multiple myocardial bridges affecting both coronary arteries in a patient with hypertrophic cardiomyopathy. However, I differ with the authors in their interpretation of the coronary arteriograms.

Multiple myocardial bridges affecting left anterior descending artery and right coronary artery with hypertrophic cardiomyopathy:a case report

The prevalence of myocardial bridging in hypertrophic cardiomyopathy （HCM） is relatively higher, and it usually occurs in the middle and distal portions of the left anterior descending artery. It is rarely reported that multiple lesions of myocardial bridging affecting not only the left anterior descending artery but also right coronary artery. We reported a 56-year-old man suffering from chest discomfort on exertion. Echocardiography and ventriculography showed hypertrophy of the apex involving the anterior and lateral wall. Coronary angiograph revealed multiple myocardial bridges affecting the left anterior descending artery and the right posterior descending artery.

Bioresorbable stent unloading during percutaneous coronary intervention:Early detection and management

In this letter,we comment on a recent case report by Sun et al in the World Journal of Cardiology.The report describes the successful management of a rare complication:The unloading or detachment of a bioresorbable stent(BRS)during percutaneous coronary intervention(PCI)in a male patient.The unloading of BRS was detected via angiography and intravascular ultrasound(IVUS)imaging of the left coronary artery and left anterior descending artery.Although this case is interesting,the authors’report lacked crucial details.Specifically,insufficient information about the type of BRS used,potential causes of BRS unloading,or whether optical coherence tomography(OCT)imaging for coronary arteries was performed before,during,or after PCI.The OCT imaging of coronary arteries before PCI can potentially prevent BRS unloading due to its higher resolution compared to IVUS.In addition,despite detecting myocardial bridging during the PCI,the authors did not provide any details regarding this variation.Here we discuss the various types of BRS,the importance of OCT in PCI,and the clinical relevance of myocardial bridging.

Quantitative flow ratio and intravascular ultrasound guided percutaneous coronary intervention of left anterior descending lesion concomitant with severe coronary myocardial bridge

Severe coronary stenosis concomitant with congenital coronary myocardial bridge(MB)is a tough scenario for cardiologist to perform revascularization,for which the complication rates including in-stent restenosis,stent fracture,stent thrombosis and even coronary perforation are still high.[1,2]Meanwhile,the necessity of revascularization in such patients is worth prudent evaluation.Cardiac imaging modalities are crucial and helpful in making revascularized decisions and strategies.Herein,we report a case using quantitative flow ratio(QFR)and intravascular ultrasound(IVUS)to facilitate accurate revascularization in a patient with both severe coronary stenosis and deep coronary MB.

Acute myocardial infarction in a child with myocardial bridge

BACKGROUND： Myocardial infarction （MI） is rare in children, and Kawasaki disease is now recognized as the main cause for MI. In this report, we present a child with MI caused by myocardial bridge （MB）.METHODS： A 7.5-year-old boy was admitted to Weifang People’s Hospital on September 16, 2008 for heart disease. By electrocardiogram, coronary CT angiography, emission computed tomography, and other examinations, he was initially diagnosed as having （1） acute inferior myocardial infarction and extensive anterior myocardial infarction; （2） fulminant myocarditis; or （3） coronary myocardial bridge. He was treated with oxygen, thrombolysis, myocardial nutrition, vitamin C （4.0 g per time）, dexamethasone （7.5 mg per time）, a large dose of gamma globulin, and interferon.RESULTS： Myocardial enzymes, liver function, C-reactive protein, and troponin-I returned to normal at 21 days after treatment. At 29 days, electrocardiogram indicated that II, III, aVF, V4 - V6 leads had abnormal Q wave, and ST-T changed. The patient was discharged.CONCLUSION： Myocardial bridge may be one of the causes of MI in children.

Spontaneous coronary artery dissection as a cause of myocardial infarction

Spontaneous coronary artery dissection(SCAD) is a rare disease that is usually seen in young women in left descending coronary artery and result in events like sudden cardiac death and acute myocardial infarction. A 70-year-old man was admitted to the emergency department with chest pain which started 1 h ago during a relative's funeral. The initial electrocardiography demonstrated 2 mm ST-segment depression in leads V1-V3 and the patient underwent emergent coronary angiography. SCAD simultaneously in two different coronary arteries [left anterior descending(LAD) artery and left circumflex(LCx)] artery was detected and SCAD in LCx artery was causing total occlusion which resulted in acute myocardial infarction. Successful stenting was performed thereafter for both lesions. In addition to the existence of SCAD simultaneously in two different coronary arteries, the presence of muscular bridge and SCAD together at the same site of the LAD artery was another interesting point which made us report this case.

Plaque herniation after stenting the culprit lesion with myocardial bridging in ST elevation myocardial infarction: A case report

BACKGROUND Myocardial bridging(MB)is increasingly recognized to stimulate atherogenesis,which may contribute to an acute coronary syndrome.Stenting the coronary segment with MB has been recognized to have an increased risk of in-stent restenosis,stent fracture and coronary perforation.The safety and efficacy of stenting the culprit lesion with overlaying MB in ST elevation myocardial infarction(STEMI)as primary reperfusion therapy has not been established.CASE SUMMARY We reported a patient who presented with inferior STEMI with a culprit lesion of an acute thrombotic occlusion in the right coronary artery and thrombolysis and thrombin inhibition in myocardial infarction 0 flow.After the stent placement during primary percutaneous coronary intervention,intravascular ultrasound revealed MB overlying the stented segment where heavy atherosclerotic plaque were present.Likely due to the combination of plaque herniation or prolapse caused by MB,as well as local increased inflammation and thrombogenicity,acute stent thrombosis occurred at this region,which led to acute stent failure.The patient required an emergent repeated cardiac catheterization and placing a second layer of stent to enhance the radial strength and reduce the inter-strut space.CONCLUSION Plaque herniation or prolapse after stenting a MB segment in STEMI is a potential etiology for acute stent failure.

Evaluation of intracoronary function after reduction of ventricular rate by esmolol in severe stenotic myocardial bridge: A case report

BACKGROUND Severe stenotic myocardial bridges(MBs)have been reported to lead to intracoronary ischaemia,but the physiological evaluation of MBs using intracoronary function evaluation indicators after intraoperative drug treatment has not been fully established.CASE SUMMARY We performed through snuff fossa for coronary angiography in a patient with chest tightness after repeated exercise,and the results showed that the middle part of the anterior descending branch was a MB with 100%systolic compression.The intracoronary function evaluation(defined as the ratio of distal coronary pressure to aortic pressure with zero microcirculation resistance)was instantaneous wave-free ratio(IFR)without drug and fractional flow reserve(FFR)with adenosine.The IFR was 0.73,and the FFR was 0.66.Then esmolol 0.02μg/kg/min was intravenously injected.The IFR and FFR were measured again when the heart rate dropped to 60 beats/min.The IFR was 0.83,and the FFR 0.65.CONCLUSION This case report is a case of isolated MB with severe stenosis.After intraoperative drug treatment decreased the ventricular rate,an increase in the coronary function evaluation index was immediately observed to confirm the effective improvement of coronary blood flow.

Myocardial bridging phenomenon is not invariable:A case report

BACKGROUND Myocardial bridging is a common anatomical malformation,and the milking effect is a characteristic phenomenon of myocardial bridging in coronary angiography.Generally,the phenomenon is invariable.However,this article reports an inconceivably rare myocardial bridging phenomenon that breaks through our conventional views.The milking effect changed obviously in two coronary angiography examinations,which subverted the traditional deep-rooted view of the myocardial bridging phenomenon and revealed the limitations of coronary angiography in diagnosing myocardial bridging and judging the prognosis of it.CASE SUMMARY A 63-year-old man was diagnosed with ST-segment elevation myocardial infarction and received primary percutaneous coronary intervention on December 26,2019.His heart rate was 104 beats per minute,and blood pressure was 15.3/10.3 kPa.A severe milking effect was found in the left anterior descending coronary artery during his index coronary angiography on January 14,2020.The patient was given intensive medical management,including aβ1-adrenergic receptor blocker,during hospitalization and after discharge.Unexpectedly,coronary angiography showed that the previous impressive milking effect was dramatically alleviated(close to normal)at the follow-up on October 13,2020.At that moment,the patient’s heart rate was 83 beats per minute,and blood pressure was 12.7/8.0 kPa.CONCLUSION The myocardial bridging phenomenon is not invariable and,in certain circumstances,may vary.Furthermore,the autonomic nervous system may be involved in the myocardial bridging phenomenon.

Coronary artery aneurysm combined with myocardial bridge:A case report

BACKGROUND Coronary artery aneurysm combined with myocardial bridge is a very rare clinical situation.The prognosis of this clinical situation is not yet clear.CASE SUMMARY A coronary artery aneurysm and myocardial bridge in the same segment of the coronary artery were found in a 54-year-old female patient who underwent coronary angiography and intravascular ultrasound examination.Through conservative treatment,the patient was discharged from the hospital smoothly,and she was in good condition during 5 mo of follow-up.CONCLUSION Coronary artery aneurysm combined with myocardial bridge seems to have a good prognosis,but due to the rarity of this clinical situation,further research and follow-up are needed.

Quadricuspid aortic valve and right ventricular type of myocardial bridging in an asymptomatic middle-aged woman:A case report

BACKGROUND Quadricuspid aortic valve(QAV)is a very rare congenital cardiac defect with the incidence of 0.0125%-0.033%(<0.05%)predominantly causing aortic regurgitation.A certain number of patients(nearly one-half)have abnormal function and often require surgery,commonly in their fifth or sixth decade.QAV usually appears as an isolated anomaly but may also be associated with other cardiac congenital defects.Echocardiography is considered the main diagnostic method although more and more importance is given to computed tomography(CT)and magnetic resonance imaging(MRI)as complementary methods.CASE SUMMARY A 60-year-old female patient was referred for transthoracic ultrasound of the heart as part of a routine examination in the treatment of arterial hypertension.She did not have any significant symptoms.QAV was confirmed and there were no elements of valve stenosis with moderate aortic regurgitation.At first,it seemed that in the projection of the presumed left coronary cusp,there were two smaller and equally large cusps along with two larger and normally developed cusps.Cardiac CT imaging was performed to obtain an even more precise valve morphology and it showed that the location of the supernumerary cusp is between the right and left coronary cusp,with visible central malcoaptation of the cusps.Also,coronary computed angiography confirmed the right-type of myocardial bridging at the distal segment of the left anterior descending coronary artery.Significant valve dysfunction often occurs in middle-aged patients and results in surgical treatment,therefore,a 1-year transthoracic echocardiogram control examination and follow-up was recommended to our patient.CONCLUSION This case highlights the importance of diagnosing QAV since it leads to progressive valve dysfunction and can be associated with other congenital heart defects which is important to detect,emphasizing the role of cardiac CT and MRI.

Prevalence and characteristics of myocardial bridging in coronary angiogram data from consecutive 5525 patients

Background Large discrepancy of the incidence of myocardial bridging （MB） has been reported either among the postmortem studies or among the studies with coronary angiogram. This study was to investigate the prevalence of MB in large number of coronary angiograms and the angiographic characteristics of MB.Methods A total of 5525 consecutive patients who underwent first diagnostic coronary angiography from January 2003 to March 2006 in Zhongshan Hospital were enrolled in this study. MB was diagnosed when the angiographical ＂milking effect＂, defined as the systolic compression and complete or partly release of the compression in diastole, was seen in the epicardial coronary arteries. Angiography was routinely repeated after intracoronary injection of 200 pg nitroglycerin. The systolic compression and length of MB were compared before and after the administration of nitroglycerin and also before and after stent implantation in patients with significant stenosis in segment proximal to the MB.Results Among 5525 patients, MBs were found in a total of 888 patients angiographically with the prevalence of 16.1%. Atherosclerotic lesions were found more often in the segment proximal to the MB with 344/854 （40.3%） patients than in the segment distal to the MB with 47/854 （5.5%） （P 〈0.01）. The systolic compression （（43.3±13.7）% at baseline vs （54.2±14.0）% after nitroglycerine） and the average length （（20.9±7.5） mm at baseline vs （22.7±8.0） mm after nitroglycerine） of the MB segment were increased after intracoronary injection of nitroglycerin （both P 〈0.01）. Stent implantation was performed in 88 patients with significant stenosis in the segment proximal to the MB. The systolic compression and the length of the MB segment were increased after stenting compared with those before stenting （systolic compression, （49.4±14.6）% at baseline vs （57.3±12.3）% after stenting, and length of MB, （19.5±6.1） mm at baseline vs （21.8±6.3） mm after stenting, P 〈0.01）.Conclusions MB was a frequent finding in coronary angiogram with an incidence of 16.1%. Intracoronary administration of nitroglycerin and stent implantation in the segment proximal to the MB could enhance the systolic compression and the length of the MB angiographically.

Surgical outcome and clinical follow-up in patients with symptomatic myocardial bridging

Background Myocardial bridging with systolic compression of the left anterior descending coronary artery （LAD） may be associated with myocardial ischaemia. The clinical outcome in patients with surgical treatment for symptomatic myocardial bridging remains undetermined. This study assessed the middle- and long-term results of surgical treatment for symptomatic myocardial bridging. Methods From 1997 to 2006, 37 463 patients received selective coronary angiography in the Fuwai Cardiovascular Hospital, Beijing, China. Of these, 484 patients had angiographic diagnosis of myocardial bridging. Of the 484 patients, 35 underwent surgery for treatment of myocardial bridging with significant systolic arterial compression. Among the surgical treatment patients, 24 presented with other cardiac disorders, and the remaining 11 symptomatic patients with isolated myocardial bridging were included in the follow-up study. Results The angiographic prevalence of myocardial bridging was 1.3% in this study. The coronary angiographies of the 11 patients revealed myocardial bridging in the middle segment of LAD causing systolic compression 〉75% （ranging from 75% to 90%）. The mean age of patients was 48,4 years. Surgical myotomy was performed in 3 patients and coronary artery bypass grafting （CABG） in 8 patients. Eight patients were operated on with an off-pump approach and 3 with a cardiopulmonary bypass technique after median sternotomy. Conversion to on-pump CABG surgery was necessary in 1 patient because of perforation of the right ventricle. The left internal mammary artery was used in all patients with CABG. The acute clinical success rate was 100% with respect to the absence of myocardial infarction, death or other major in-hospital complications. All of the patients were followed up clinically. The median follow-up was 35.3 months （range： 6 to 120 months）. Nine patients were free from symptoms and one of them continued taking beta blockers. The remaining 2 patients with myotomy had atypical chest pain. One received coronary angiography again and no stenosis was found two years after operation; while exercise testing was performed in the other patient and revealed no evidence of myocardial ischaemia. None of the patients sustained a myocardial infarction or other major adverse cardiac events （death or vessel revascularization） during follow-up. Conclusions Myocardial bridging is a relatively common angiographic finding. Surgical myotomy or CABG should be limited to patients who are refractory to oral medication. Surgical relief of myocardial ischaemia due to systolic compression of intramyocardial coronary arteries can be accomplished with low operative risk and excellent middle- and long-term results,

Angiographic prevalence of myocardial bridging in a defined very large number of Chinese patients with chest pain

Background Muscle fibers overlying the intramyocardial segment of an epicardial coronary artery are termed myocardial bridging （MB）. Variable prevalence of MB has been described at autopsy and angiographic series with small and large sample size studies. In addition, no similar study was reported in Chinese population. The aim of this study was to investigate the angiographic prevalence of MB in consecutive 37 106 Chinese patients with chest pain from our center. Methods We conducted an observational study to evaluate the consecutive cases with MB among patients undergone selective coronary angiography, and analyzed the angiograhic prevalence and clinical features of MB in this study of very large sample size. Results Among 37 105 patients with chest pain we found 1002 cases with 1011 MBs in a retrospective manner, and the overall prevalence was 2.70%. Although more than 99% （991/1002） of patients had single bridge, 8 cases were found to have more than two MBs （seven with two, and one with three）. Altogether 54.39% of cases （545/1002） had MB without atherosclerotic lesions, and 96.24% （973/1011） of bridging located in the left anterior descending coronary artery （LAD）, mainly in the middle of LAD （792/1011,78.33%）. According to Nobel classification, of the single bridge （n=-991）, 〈50% of obstruction was predominant （471/991,47.52%）. Totally 50%-69% accounted for 34.81% （345/991）, 〉70% of obstruction was 17.65% （175/991）. Conclusions These data showed that the prevalence of angiographically detectable MB in Chinese patients with chest pain was similar to those of the previous studies, with 2.7% prevalence in this very large sample size.

Relation of myocardial bridge to myocardial infarction：a meta-analysis

Background Small case series have suggested an association of coronary myocardial bridge （MB） with myocardial infarction （MI）.However,the relationship between MB and major adverse cardiac events （MACE） remains largely unknown.The aim of this study was to assess the relationship between MB and MACE involving MI.Methods We performed a systematic search of MEDLINE,PreMEDLINE,and all EMB Reviews as well as a reference list of relevant articles according to the SPICO （Study design,Patient,Intervention,Control-intervention,and Outcome） criteria using the following keywords：myocardial bridging,myocardial bridge,intramural coronary artery,mural coronary artery,tunneled coronary artery,coronary artery overbridging,etc.Bibliographies of the retrieved publications were additionally hand searched.Studies were included for the meta-analysis if they satisfied the following criteria：（1） they evaluate the association of MB with cardiovascular endpoint event; （2） they included individuals with MB and those without MB; 3） they excluded individuals with obstructive coronary artery disease （CAD）.Studies were reviewed by a predetermined protocol including quality assessment.Dates were pooled using a random effect model.Results Seven observational studies that followed 5 486 patients eligible for the enrolled criteria were included from 7 136 initially identified articles.The prevalence of MB was 24.8％ （1 363/5 486）.During 0.5-7.0 years of follow-up of this cohort of population,crude outcome rates were 8.0％ in the MB group and 7.7％ in the non-MB group.The odds ratio of overall MACE and MI were 1.34 （95％ confidence interval （CI）：0.57-3.17,P=0.51,n=7 studies） and 2.75 （95％ CI：1.08-7.02,P ＜0.03,n=5 studies） respectively for subjects of MB compared to non-MB.Conclusion Relationship between MB and MI appears to be a real one,although the study did not reveal a connection of MB to MACE,suggesting whether the necessity of antiplatelet therapy needs to be further studied in a larger cohort of patients with MB prospectively.

Surgical treatment of myocardial bridging:report of 31 cases

Background Myocardial bridging （MB） is usually considered a benign condition but may result in myocardial ischemia, myocardial infarction （MI）, exercise-induced tachycardia, atrioventricular conduction block or even sudden cardiac death. This retrospective study summarizes our operative methods and outcomes for treatment of 31 cases of MB. Methods From January 1997 to December 2006, 31 consecutive patients （24 men and 7 women; aged 35-67 years; mean 52.3 years） with MB underwent surgical treatment. Thirteen patients had MB only and 18 patients had MB associated with other heart diseases. In preoperative cardiac function grading, 5 patients were in NYHA class Ⅰ and 18 in NYHA class Ⅱ and 8 in NYHA class Ⅲ. Among them, 15 underwent myotomy and 16 underwent coronary artery bypass grafting （CABG）. Results All patients survived and recovered uneventfully. Neither hospital or late death nor major complications occurred. Postoperative exercise testing in all patients failed to reveal any persistent ischemia. Follow-up time was 3-115 months （mean 31 months）. Follow-up angiographic studies in 21 patients （68%） demonstrated restoration of coronary blood flow and myocardial perfusion without significant residual compression of the artery. All patients were symptom-free and currently in NYHA class Ⅰ-Ⅱ. Conclusion The patients who are refractory to medication should actively undergo the surgical procedures such as myotomy and CABG. Myotomy should be advocated as the first choice because of its safety and satisfactory results.

Is myocardial bridging a bridge connecting to cardiovascular events？

Coronary arteries and their major branches usually course on the surface of the heart in the subepicardial tissue. However, a muscle fiber overlying the intramyocardial segment of an epicardial coronary artery was defined as myocardial bridging （MB）, and subsequently the artery coursing within the myocardium is called a tunneled artery. In fact, MB has previously been given a various of terms ＂intramural coronary artery＂, ＂mural coronary artery＂,

Myocardial bridging detection by non-invasive multislice spiral computed tomography： comparison with intravascular ultrasound

Background Invasive intravascular ultrasound （IVUS） is current diagnostic standard for myocardial bridging （MB）. Non-invasive multislice computerized tomography coronary angiography （MSCT） technique has provided a good anatomical view of the tunnel artery now. Methods A total of 51 consecutive patients with atypical or typical angina scheduled for IVUS were enrolled in this study and MSCT was performed 7 days before IVUS. Coronary imaging was quantified using IVUS and MSCT. Four main vessels （left main artery （LMA）, left anterior descending （LAD）, left circumflex （LCX）, right coronary artery （RCA）） were examined. Results Forty-one out of 51 （80%） patients received metaprolol （25 mg） before the MSCT scan and 25 of them were current beta-blocker users. The mean heart rate was （64_＋3） beats per minute. A total of 51 patients underwent IVUS examination （30 with MB and 21 without MB） were chosen for this study. Twenty-eight out of 30 MB cases were correctly diagnosed by MSCT and 2 patients with MB were not detected. Comparison with IVUS, the sensitivity of detection by MSCT was 93%, specificity was 100%. The lumen diameter of the tunnel artery derived from MSCT and IVUS significantly decreased from （2.9±0.3） mm to （2.4±0.4） mm （P〈0.001） and from （3.3±0.3） mm to （2.6±0.5） mm （P〈0.001）, respectively. Minimal and maximal diameters of MB derived from MSCT were significantly smaller than those from IVUS （（2.4±0.4） mm vs （2.6±0.5） mm, P〈0.05 and （2.9±0.3） mm vs （3.3±0.3） mm, P〈0.05）, respectively. Conclusions MSCT offers a reliable non-invasive method for MB in LAD and atherosclerosis diagnosis with diagnostic accuracy comparable with invasive IVUS.

Acute myocardial infarction due to myocardial bridge

Myocardial bridge （MB） is regarded as a common .anatomic variant rather than a congenital conditionanomaly, defined as the intrainyocardial course of a portion of the coronary artery. It was first mentioned by Rayman in 1737 and first described by Grainicianu in the early 1920s. The current gold standard tor diagnosing MB is coronary angiography with the typical systolic compression of the epicardial coronary vessel （milking effect）.

Acute myocardial infarction caused by myocardial bridging alone confirmed by using intravascular ultrasonography

Dear Editor: Although the underlying pathogenesis of acute myocardial infarction (AMI) caused by myocardial bridging (MB) is not fully understood, high shear stress that induces endothelial dysfunction or damage that leads to thrombus formation has been mainly consid-ered. We report a case of AMI due to MB confirmed in a series of angiographic examinations, including intra-vascular ultrasonography (IVUS). Our data may pro-vide credible evidence that supports this hypothesis.