1. Left Anterior Descending Artery Myocardial Bridging
A clinical approach
Chiara Fraccaro, Md PhD Giuseppe Tarantini, Md PhD
Department of Cardiac, Thoracic and Vascular Sciences, University of Padua, Padova, Italy

2. J Am Coll Cardiol. 2016 Dec 27;68(25):2887-2899

3. EPIDEMIOLOGY Necropsy series 5% to 86% Angiographic detection rate
0.5% to 12% (rest)
40% (provocative tests or i.c. nitro)
Factors accounting for heterogeinicity:
thickness and length of the MB
reciprocal orientation of the coronary artery and myocardial fibers
presence of loose connective or adipose tissue around the bridged segment
presence of an aortic outflow tract obstruction
intrinsic tone of the coronary artery wall
presence of a proximal coronary fixed obstruction
state of myocardial contractility
heart rate at the time of angiography
observer experience

4. LAD Coronary Artery Myocardial Bridging
Anatomic Properties

5. Factors that may unmask or exacerbate MB are:
PATHOPHYSIOLOGY
Factors that may unmask or exacerbate MB are:
the age of the patient
heart rate
left ventricle (LV) hypertrophy
and the presence of coronary atherosclerosis
Interaction among Tachicardia, Coronary Artery Flow, and Transmural Distribution

6. CLINICAL PRESENTATION
Asymptomatic
incidental finding
Stable
exercise-induced or silent myocardial ischemia
Unstable
coronary spasm
Thrombosis
coronary dissection
syndrome X
myocardial stunning or transient ventricular dysfunction
Takotsubo syndrome
life-threatening ventricular arrhythmias
sudden death

7. MORPHOLOGICAL ASSESSMENT
CORONARY ANGIOGRAPHY
(+ i.c. nitro)
IVUS
“half-moon phenomenon”
Shin Lin et al. J Am Heart Assoc 2013
CCT

8. INVASIVE FUNCTIONAL ASSESSMENT
The evaluation during chronotropic and inotropic stimulation is mandatory
1. Dobutamine diastolic FFR & iFR
False negative using mean pressure! Diastolic FFR o iFR better!!
overshooting of Pd over Pa

9. INVASIVE FUNCTIONAL ASSESSMENT
The evaluation during chronotropic and inotropic stimulation is mandatory
1. Dobutamine diastolic FFR & iFR

10. INVASIVE FUNCTIONAL ASSESSMENT
Doppler-tipped guidewires for measurements of intracoronary flow velocity and coronary flow reserve.
retrograde flow during systole immediately proximal to the bridged segment;
“fingertip phenomenon,” an abrupt early diastolic flow accel- eration, rapid mid-diastolic flow deceleration, and a mid-to-late diastolic plateau (“spike-and-dome” pattern).
Heinrich G. Klues et al. Circulation. 1997;96:

11. NON-INVASIVE FUNCTIONAL ASSESSMENT
Stress echocardiography
Stress cardiac magnetic resonance
Single-photon emission computed tomography and positron emission tomography
Post-processing techniques for the derivation of functional information from the anatomic assessment provided by CCT (transluminal attenuation gradient and computed tomography (CT)–derived).

12. MANAGEMENT STRATEGY