Medical Literature

Articles by Stanford

Surgical Unroofing of Myocardial Bridges
Choi, et al. August 2022
-Details exactly how Stanford's surgeon Dr. Boyd does unroofing surgery, with great drawn illustrations

Myocardial bridges: Overview of diagnosis and management
Rogers, Tremmel, Schnittger, 2017
-This is a good paper to show to your doctor because it summarizes latest diagnosis and treatments

Surgical Unroofing of Hemodynamically Significant Left Anterior Descending Myocardial Bridges
Boyd et al, 2017
-Specifically outlines the surgery itself, unroofing

Effect of Surgical Unroofing of Myocardial Bridge on Exercise Induced QT Interval Dispersion and Anginal Symptoms in Patients with Angina in the Absence of Obstructive Coronary Artery Disease
Pargaonkar et al, 2016
-Shows that unroofing surgery “significantly improves anginal symptoms” and improves “all five dimensions of the SAQ” i.e. Seattle Angina Questionnaire

Accuracy of a novel stress echocardiography pattern for myocardial bridging in patients with angina and no obstructive coronary artery disease – A retrospective and prospective cohort study
Pargaonkar, Rogers, Schnittger, et al, 2020
-Establishes how to detect MB-related in a stress echocardiogram test: specifically, the presence of “focal septal buckling with apical sparing

Myocardial Bridge and Acute Plaque Rupture
Perl, Daniels, and Schnittger, 2016
-Important study that finds that MBs can cause plaque to form, always located just before the MB. This plaque is caused by effects of the physical squashing of the artery causing a backwash of blood, which in turn affects the inner lining of the artery. This process is recently discovered. The plaque is prone to having pieces break off, which can then get stuck in the artery and cause a heart attack, even in younger people.

Myocardial Bridging
Tremmel and Schnittger 2014
-Explains why dFFR, but *not* FFR, is an appropriate test for MB (today also iFR or RFR are used, but FFR is still "useless" for MBs)
“Traditional adenosine FFR is inadequate… and will underestimate the hemodynamic significance of most bridges… Therefore, diastolic FFR with dobutamine challenge is currently the technique of choice”

Impact of Diastolic Vessel Restriction on Quality of Life in Symptomatic Myocardial Bridging Patients Treated With Surgical Unroofing: Preoperative Assessments With Intravascular Ultrasound and Coronary Computed Tomography Angiography
Hashikata, Honda, Schnittger, Tremmel, Boyd, et al., 2021
-Breakthrough Stanford study concludes that the main factor determining symptoms *after* unroofing surgery is not % compression before surgery, but how well the artery was able to relax and reopen during diastole ie *after* compression each heartbeat. Also found 87% had compression during diastole, again debunking the common myth that MBs do not affect diastole, which often prevents patients from getting unroofing surgery.

Myocardial Bridge Muscle Index (MMI): A Marker of Disease Severity and Its Relationship with Endothelial Dysfunction and Symptomatic Outcome in Patients with Angina and a Hemodynamically Significant Myocardial Bridge
Pargaonkar, Schnittger, et al, 2018
-This is about a new method of testing to see the significance of MBs

Articles on testing for MBs

Importance of diastolic fractional flow reserve and dobutamine challenge in physiologic assessment of myocardial bridging.
Escaned J et al.
Hospital Clínico San Carlos, Madrid, Spain.
-Stanford agrees with this article, which says that the diastolic FFR or dFFR, not FFR, is the proper diagnostic indicator for MBs.

Myocardial Bridging
Tremmel and Schnittger 2014
-Explains why dFFR, not FFR, is the right test for MB
“Traditional adenosine FFR is inadequate… and will underestimate the hemodynamic significance of most bridges… Therefore, diastolic FFR with dobutamine challenge is currently the technique of choice”

Non-Stanford reports of unroofing surgery

Robotic totally endoscopic off-pump unroofing of left anterior descending coronary artery myocardial bridge: A report of two cases
Mirzai, Patel, Balkhy 2019
University of Chicago
-This article is by Dr. Balkhy at Univ. of Chicago who does robotic unroofing

Extensive unroofing of myocardial bridge: A case report and literature review
by Mok, Majdalany, and Pettersson, 2019
Cleveland Clinic, USA
-Patient had unroofing on a 10 cm mb and as a result their FFR went from .75 to .87, proving it worked

Off-pump supra-arterial myotomy for myocardial bridging
Crespo, Aramendi, et al., 2008 Spain

“We conclude that in symptomatic patients with myocardial bridging despite medical therapy, surgical myotomy can be considered an adequate therapy.”

Abu Dhabi surgeons complete Middle East’s first robotic surgery for rare heart condition
-The doctor who did the surgery Johannes Bonatti no longer works in Abu Dhabi, but he is still practicing at Univ. of Pittsburgh

Outcome of Repair of Myocardial Bridging at the Time of Septal Myectomy
Kunkala et al., Mayo Clinic, Minnesota
“Angina was improved… Unroofing should be considered in patients with angina who have significant left anterior descending artery bridging”

Robotic-assisted surgical myotomy in a 27-year-old man with myocardial bridging of the left anterior descending coronary artery
Alima, Vanden Eynden, et al. 2010, Belgium
-Surgery of MB through a left thoracoscopic approach, robotically assisted, is feasible and safe, and it might be an elegant therapeutic option in a symptomatic patient resistant to optimal medical therapy.”

Supracoronary myotomy for myocardial bridges in the setting of hypertrophic cardiomyopathy: Off-pump experience
Bakir, Karaci, et al. 2008, Turkey
“Myotomy is the gold standard in the surgical treatment of MB.”

Surgical Solutions to Anomalous Coronary Arteries and Myocardial Bridges in Adults
Cleveland Clinic, 2023

Articles on symptoms and complications of myocardial bridges

Does isolated myocardial bridge really interfere with coronary blood flow?
Daoud and Wafa 2012
-Very important study. This is one of the best studies that debunks head-on the common myth that MBs can’t cause significant symptoms because they only compress the artery during systolic. It shows that there is in fact a long, slow delay in the reopening of the artery during diastolic, so that blood flow is cut off during that delay time:

“Normally, only 15% of coronary blood flow occurs during systole and because myocardial bridging is a systolic event on angiography, its clinical significance and relevance have been questioned. [However]… angiographic and intravascular ultrasonographic studies demonstrated that vessel compression during systole is followed by the delay in the increase in luminal diameter during diastole, thus affecting the predominant phase of coronary perfusion, especially during episodes of tachycardia. These data suggest that angina, acute coronary syndromes, and arrhythmias in patients with myocardial bridging may be explained by the reduced ischemic threshold.”

“Coronary blood flow is decreased in the patients with MB compared with the patients having normal coronary.”

Presence and Relevance of Myocardial Bridge in LAD-PCI of CTO and Non-CTO Lesions
Yamamoto, K., et al, 2024
-Very important study that shows that a stent  significantly increases chances of a complete blockage of the artery aka "chronic total occlusion" or CTO. More evidence that a stent in a myocardial bridge can kill you. Never stent a myocardial bridge.

Significance of anatomical properties of myocardial bridge on atherosclerosis evolution in the left anterior descending coronary artery
Ishikawa et al. 2006
-Important study often cited by Stanford. It establishes that MBs cause atherosclerosis i.e. plaque. Stanford has later found that every one of their adult patients had some plaque buildup just before (i.e. proximal to) the MB

Haemodynamic impacts of myocardial bridge length: A congenital heart disease
Javadzadegan et al. June 2019
-“Our findings revealed a direct relationship between the length of MB and haemodynamic perturbations in the proximal segment such that the increased length of MB is associated with decreased WSS and increased residence time.”

Articles on MBs on non-LAD arteries ex. the RCA, LCX, diagonal, OM arteries

Right Coronary Artery Distribution of Myocardial Bridging
Nguyen et al. 2016   

Concludes that right coronary artery (RCA) MBs cause major symptoms and that many MBs “may go unrecognized” including RCA and LCX MBs
-Mentions reports of RCA MBs causing sudden death, severe spasms, myocardial infarction, retrosternal chest pain

Multivessel myocardial bridge involving left and right coronary arteries

José Augusto Rocha Araújo et al.
-Reports an MB in the right coronary artery.

Right coronary myocardial bridging: An extremely rare case
Caminiti et al, 2022
-"Coronary angiography showed [the RCA] narrowed completely during systole."
-"Transthoracic echocardiography showed diffuse hypokinesis with reduced ejection fraction (34%)"

Myocardial bridging of the left circumflex artery
by Deora et al.

LCX MBs may cause “significant ischemia” and require “surgical” intervention

Myocardial bridging on coronary CTA: An innocent bystander or a culprit in myocardial infarction?
Nakanishi et al
-MBs found on LAD, RCA, LCX, OM1, D2, PDA, Ramus arteries – see Table 1

Nonsymptomatic myocardial bridge causing systolic total narrowing of circumflex artery
-This study is mis-named - the patient was not nonsymptomatic, they reported "severe, squeezing chest pain" from an LCX MB that was "causing 100% systolic narrowing of LCx."


Myocardial bridge, surgery or stenting?
Li Wan et al

Non-ST Elevation Myocardial Infarction Due to Right Coronary Artery Myocardial Bridge
Saenger et al, 2021
-Reports that RCA MBs can be associated with chest pain

Articles linking MB and sudden death

Myocardial bridging: A ‘forgotten’ cause of acute coronary syndrome – a case report
Ripa et al.
-Reports major angina with no stenosis

Eight years out, Bobby Rhine’s FC Dallas legacy still burns brightly
-Pro soccer player died of a heart attack atrributed to an MB

Myocardial bridging as a cause of acute myocardial infarction: a case report 2002
Akdemir et al.
-Reports MB was a possible cause of a heart attack

Fatal outcome associated with autopsy proven myocardial bridging of the left anterior descending coronary artery.
Restetti et al
-Reports sudden deaths related to large MBs

Captain Suffers Sudden Cardiac Death During Physical Fitness
Evaluation - Alabama
-Fire captain had two MBs on LAD and LCX

Death due to myocardial bridging
by Ural et al 2015
-Turkish paper reports MB was 2 cm deep

Myocardial bridging and sudden cardiac death: Is the actual classification exhaustive?
De Giorgio et al
-Italian paper reports four deaths

Myocardial Bridging in a Young Patient with Sudden Death
Cutler et al, UTexas at Galveston
“This case adds to the growing body of anecdotal evidence that
myocardial bridging may be associated with significant cardiac events.”

Coroner rules Harry Morton’s death was due to “cardiac arrythmia”
-“A secondary cause of death is listed as ‘myocardial bridging with coronary artery atherosclerosis.’” MBs cause arrythmia.

Kristoff St. John died of heart disease
-“The coroner’s office said St. John’s significant conditions included ‘myocardial bridging of left anterior descending coronary artery.’” 

Acute myocardial infarction due to myocardial bridge

Fire Chief Suffers Sudden Cardiac Death After Physical Fitness Training – Washington
-2011 report on a fire chief who died after responding to calls. Cause of death was listed as CAD and MB.

Myocardial infarction associated with a myocardial bridge.
Feldman, et al. 1986

Can isolated myocardial bridging of the left anterior descending coronary artery be associated with sudden death during exercise?
Bestetti et al
-Tennis player who collapsed and died with no other cause found except a myocardial bridge

Articles linking myocardial bridges to other conditions

Myocardial bridging of the left anterior descending coronary artery is associated with reduced myocardial perfusion reserve: a 13N-ammonia PET study.
-Links MBs to microvascular dysfunction (MVD):
“Quantitative myocardial perfusion suggests that LAD-MB may be related to impaired perfusion reserve, an indicator of microvascular dysfunction”

Myocardial Bridge or Something Else?
Wang, et al., 2021
"An MB is very common in patients with hypertrophic cardiomyopathy (HCM)"

Articles on medications for myocardial bridges

The Myocardial Bridge: Potential Influences on the Coronary Artery Vasculature
Hiroki Teragawa, Chikage Oshita, and Tomohiro Ueda

-Says beta-blockers worsen vasospasms from MBs

Articles on bypass surgery
*Note: We now know that bypass surgery is not the first-line surgical treatment for MBs. It is only a good idea as a) an addition to unroofing, or b) as a last resort if for some reason unroofing is not possible. The reason is because a) bypasses can fail and b) after the bypass you are still left with an unroofed artery that continues to get worse endothelial dysfunction, spasms, and plaque.

Myocardial bridging over the left anterior descending: Myotomy, bypass, or both?
Ekeke et al 2015
“The surgical strategy [for MBs] should be customized. The treatment of choice is myotomy. Bypass surgery can be added when there is proximal coronary obstruction or anatomic anomalies that increase the risk of recurrence of the obstruction.”

Results of coronary artery bypass grafting in myocardial bridging of left anterior descending artery.
Bockeria, et al 2013
-Russian article suggesting bypass surgery is a fix for MBs, specifically recommending using the SVG rather than LIMA for the graft