Myocardial bridging of the coronary arteries
- Paul Sorajja, MD
Paul Sorajja, MD
- Associate Professor of Medicine
- Minneapolis Heart Institute
- Ami E Iskandrian, MD, MACC
Ami E Iskandrian, MD, MACC
- Section Editor — Noninvasive Cardiac Imaging and Stress Testing
- Distinguished Professor of Medicine and Radiology
- University of Alabama at Birmingham
The major coronary arteries, which normally are distributed over the epicardial surface of the heart, occasionally have a segmental intramyocardial course. During systole, this segment of the vessel is compressed, a condition referred to as milking or systolic "myocardial bridging" [1,2]. This phenomenon was first recognized more than 200 years ago , was first reported in depth in 1951, and was recognized angiographically in 1960.
On angiography, bridging is recognized as compression of a segment of a coronary artery during systole, resulting in narrowing that reverses during diastole. The dynamic and phasic nature of the obstruction serves to differentiate bridging from fixed coronary stenosis (image 1).
It has been thought that most instances of bridging are of little clinical significance. However, there are reports suggesting that severe bridging of the major coronary arteries can produce myocardial ischemia, coronary thrombosis, and myocardial infarction, as well as predispose the patient to atherosclerosis or sudden death [4-10].
PREVALENCE OF BRIDGING
The reported prevalence of bridging varies according to the method of evaluation. Pathologic studies have found a mean frequency of myocardial bridging of 25 percent (range 5 to 86 percent), similar to that observed in noninvasive imaging studies using coronary computed tomography [1,2,11-14]. In one autopsy study, the incidence was 50 percent . Although all major epicardial coronary arteries can be affected, involvement of the left anterior descending coronary artery (LAD) is the most common.
Angiographic studies have noted somewhat different findings. Among patients undergoing coronary angiography, the reported prevalence of myocardial bridging is 1.7 percent (range 0.5 to 16 percent), which is almost always confined to the LAD (image 1) [1,2,5,15-19]. A higher prevalence has been observed in patients with hypertrophic cardiomyopathy and in recipients of cardiac transplants [1,19]. (See 'Bridging in patients with hypertrophic cardiomyopathy' below.)
- Möhlenkamp S, Hort W, Ge J, Erbel R. Update on myocardial bridging. Circulation 2002; 106:2616.
- Alegria JR, Herrmann J, Holmes DR Jr, et al. Myocardial bridging. Eur Heart J 2005; 26:1159.
- Reyman, HC. Disertatis de vasis cordis propiis. Bibl Anat 1737; 2:366.
- Noble J, Bourassa MG, Petitclerc R, Dyrda I. Myocardial bridging and milking effect of the left anterior descending coronary artery: normal variant or obstruction? Am J Cardiol 1976; 37:993.
- Faruqui AM, Maloy WC, Felner JM, et al. Symptomatic myocardial bridging of coronary artery. Am J Cardiol 1978; 41:1305.
- Morales AR, Romanelli R, Boucek RJ. The mural left anterior descending coronary artery, strenuous exercise and sudden death. Circulation 1980; 62:230.
- Ishikawa Y, Akasaka Y, Suzuki K, et al. Anatomic properties of myocardial bridge predisposing to myocardial infarction. Circulation 2009; 120:376.
- Utuk O, Bilge A, Bayturan O, et al. Thrombosis of a coronary artery related to the myocardial bridging. Heart Lung Circ 2010; 19:481.
- Hostiuc S, Curca GC, Dermengiu D, et al. Morphological changes associated with hemodynamically significant myocardial bridges in sudden cardiac death. Thorac Cardiovasc Surg 2011; 59:393.
- Husmann L, Nkoulou R, Wolfrum M, Kaufmann PA. Myocardial bridging causing infarction and ischaemia. Eur Heart J 2011; 32:790.
- Hongo Y, Tada H, Ito K, et al. Augmentation of vessel squeezing at coronary-myocardial bridge by nitroglycerin: study by quantitative coronary angiography and intravascular ultrasound. Am Heart J 1999; 138:345.
- Iskandrian AE, Nallamothu N, Heo J. Nonatherosclerotic causes of myocardial ischemia. J Nucl Cardiol 1996; 3:428.
- La Grutta L, Runza G, Lo Re G, et al. Prevalence of myocardial bridging and correlation with coronary atherosclerosis studied with 64-slice CT coronary angiography. Radiol Med 2009; 114:1024.
- Hwang JH, Ko SM, Roh HG, et al. Myocardial bridging of the left anterior descending coronary artery: depiction rate and morphologic features by dual-source CT coronary angiography. Korean J Radiol 2010; 11:514.
- Ge J, Jeremias A, Rupp A, et al. New signs characteristic of myocardial bridging demonstrated by intracoronary ultrasound and Doppler. Eur Heart J 1999; 20:1707.
- Ge J, Erbel R, Rupprecht HJ, et al. Comparison of intravascular ultrasound and angiography in the assessment of myocardial bridging. Circulation 1994; 89:1725.
- Angelini P, Velasco JA, Flamm S. Coronary anomalies: incidence, pathophysiology, and clinical relevance. Circulation 2002; 105:2449.
- Kramer JR, Kitazume H, Proudfit WL, Sones FM Jr. Clinical significance of isolated coronary bridges: benign and frequent condition involving the left anterior descending artery. Am Heart J 1982; 103:283.
- Sorajja P, Ommen SR, Nishimura RA, et al. Myocardial bridging in adult patients with hypertrophic cardiomyopathy. J Am Coll Cardiol 2003; 42:889.
- Bourassa MG, Butnaru A, Lespérance J, Tardif JC. Symptomatic myocardial bridges: overview of ischemic mechanisms and current diagnostic and treatment strategies. J Am Coll Cardiol 2003; 41:351.
- Mouratidis B, Lomas FE, McGill D. Thallium-201 myocardial SPECT in myocardial bridging. J Nucl Med 1995; 36:1031.
- Escaned J, Cortés J, Flores A, et al. Importance of diastolic fractional flow reserve and dobutamine challenge in physiologic assessment of myocardial bridging. J Am Coll Cardiol 2003; 42:226.
- Hakeem A, Cilingiroglu M, Leesar MA. Hemodynamic and intravascular ultrasound assessment of myocardial bridging: fractional flow reserve paradox with dobutamine versus adenosine. Catheter Cardiovasc Interv 2010; 75:229.
- Ishii T, Hosoda Y, Osaka T, et al. The significance of myocardial bridge upon atherosclerosis in the left anterior descending coronary artery. J Pathol 1986; 148:279.
- Bennett JM, Blomerus P. Thallium-201 scintigraphy perfusion defect with dipyridamole in a patient with a myocardial bridge. Clin Cardiol 1988; 11:268.
- Tang K, Wang L, Shi R, et al. The role of myocardial perfusion imaging in evaluating patients with myocardial bridging. J Nucl Cardiol 2011; 18:117.
- Bestetti RB, Costa RS, Zucolotto S, Oliveira JS. Fatal outcome associated with autopsy proven myocardial bridging of the left anterior descending coronary artery. Eur Heart J 1989; 10:573.
- Chee TP, Jensen DP, Padnick MB, et al. Myocardial bridging of the left anterior descending coronary artery resulting in subendocardial infarction. Arch Intern Med 1981; 141:1703.
- Feld H, Guadanino V, Hollander G, et al. Exercise-induced ventricular tachycardia in association with a myocardial bridge. Chest 1991; 99:1295.
- den Dulk K, Brugada P, Braat S, et al. Myocardial bridging as a cause of paroxysmal atrioventricular block. J Am Coll Cardiol 1983; 1:965.
- Bestetti RB, Costa RS, Kazava DK, Oliveira JS. Can isolated myocardial bridging of the left anterior descending coronary artery be associated with sudden death during exercise? Acta Cardiol 1991; 46:27.
- Yetman AT, McCrindle BW, MacDonald C, et al. Myocardial bridging in children with hypertrophic cardiomyopathy--a risk factor for sudden death. N Engl J Med 1998; 339:1201.
- Mohiddin SA, Begley D, Shih J, Fananapazir L. Myocardial bridging does not predict sudden death in children with hypertrophic cardiomyopathy but is associated with more severe cardiac disease. J Am Coll Cardiol 2000; 36:2270.
- Tsujita K, Maehara A, Mintz GS, et al. Impact of myocardial bridge on clinical outcome after coronary stent placement. Am J Cardiol 2009; 103:1344.
- Basso C, Thiene G, Mackey-Bojack S, et al. Myocardial bridging, a frequent component of the hypertrophic cardiomyopathy phenotype, lacks systematic association with sudden cardiac death. Eur Heart J 2009; 30:1627.
- Klues HG, Schwarz ER, vom Dahl J, et al. Disturbed intracoronary hemodynamics in myocardial bridging: early normalization by intracoronary stent placement. Circulation 1997; 96:2905.
- Prendergast BD, Kerr F, Starkey IR. Normalisation of abnormal coronary fractional flow reserve associated with myocardial bridging using an intracoronary stent. Heart 2000; 83:705.
- Haager PK, Schwarz ER, vom Dahl J, et al. Long term angiographic and clinical follow up in patients with stent implantation for symptomatic myocardial bridging. Heart 2000; 84:403.
- Hering D, Horstkotte D, Schwimmbeck P, et al. [Acute myocardial infarct caused by a muscle bridge of the anterior interventricular ramus: complicated course with vascular perforation after stent implantation]. Z Kardiol 1997; 86:630.
- Zhang M, Kang WC, Moon CI, et al. Coronary artery perforation following implantation of a drug-eluting stent rescued by deployment of a covered stent in symptomatic myocardial bridging. Korean Circ J 2010; 40:148.
- Katznelson Y, Petchenko P, Knobel B, et al. Myocardial bridging: surgical technique and operative results. Mil Med 1996; 161:248.
- Hill RC, Chitwood WR Jr, Bashore TM, et al. Coronary flow and regional function before and after supraarterial myotomy for myocardial bridging. Ann Thorac Surg 1981; 31:176.
- Iversen S, Hake U, Mayer E, et al. Surgical treatment of myocardial bridging causing coronary artery obstruction. Scand J Thorac Cardiovasc Surg 1992; 26:107.
- Ochsner JL, Mills NL. Surgical management of diseased intracavitary coronary arteries. Ann Thorac Surg 1984; 38:356.
- Hiratzka LF, McPherson DD, Brandt B 3rd, et al. Intraoperative high-frequency epicardial echocardiography in coronary revascularization: locating deeply embedded coronary arteries. Ann Thorac Surg 1986; 42:S9.