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Coronary System Tutorial
What is the Coronary System? Importance of the Coronary System Visualization of the Coronary System Biomedical Applications of the Coronary Arterial System Biomedical Applications of the Cardiac Venous System Cardiac Venous Valves

In the future, improving the quality of cardiac coronary system visualization will allow for better planning of cardiac interventional procedures and, therefore, decreased patient risk [1]. Note, that several visualization modalities are currently employed and continue to be developed so to enhance visualization of the coronary system: see following.

Angiography

Catheterization of the heart is a somewhat invasive but commonly employed procedure for visualization of the heart's coronary vessels, chambers, valves, and/or great vessels. Basic catheterization techniques involve inserting a long, flexible, radio-opaque catheter into either a peripheral vein (for venous or right heart catheterization) or peripheral artery (for coronary artery or the left heart) under fluoroscopy (continuous X-ray observation). During this invasive procedure, a radio-opaque contrast medium is commonly injected into a cardiac vessel or chamber. Thus, this type of procedure may be used to visualize the anatomical features of the coronary arteries, cardiac veins, aorta, pulmonary blood vessels, and/or ventricles. Such investigations may provide pertinent clinical information about structural abnormalities in blood vessels that restrict flow (such as those caused by atherosclerotic plaque), abnormal ventricular blood volumes, inappropriate myocardial wall thicknesses, and/or altered wall motions. However, it should be noted that multiple contrast injections can be potentially acutely deleterious to patients, especially in those with compromised cardiac outputs [2].

To date, coronary artery angiography has been the primary visualization modality used clinically. Contrast is injected into the coronary arteries to identify existing occlusions or narrowing due to atherosclerotic plaques/calcifications. This visualization approach also provides the physician with roadmaps for the delivery of percutaneous therapies (e.g., a coronary stent) or for planning a subsequent coronary artery bypass surgery (i.e., determine where best to place suture so to avoid an attempted assess to a rigid calcified arterial wall) [3].

A sample venogram from an isolated heart preparation can be seen to the right. The green sheath contains a venogram balloon catheter. The balloon is inflated to block off antegrade flow and then contrast is injected retrograde, such that the coronary venous system (branching) is visible. Such imaging techniques are typically used for mapping the target vein for the delivery of a left-sided pacing lead (e.g., for biventricular pacing therapies). For more examples of angiography, please see the Venograms section of the Atlas.

Download movie: MP4, MOV, OGG, WMV

Movie showing a venogram in an isolated heart. The movie shows a catheter cannulating the coronary sinus ostium, then switches to a fluoroscopic view of the heart, where the coronary veins become opaque as a contrast agent is injected.

Computed Tomography (CT)

Electron beam computed tomographic (CT) angiography allows minimally invasive, detailed visualization of the coronary system [4]. More specifically, multi-slice computed tomography uses a 4-dimensional functional imaging computed tomography scanner, thus to obtain structural and functional features. Obtained, high quality, virtual images show details such that transvenous lead implantation, for instance, can be better planned so to reduce both procedure times and patient risks [1].

Our lab has been obtaining computed tomography images of isolated perfusion fixed hearts with contrast injected into the coronary vasculature systems. From these scans we have generated three-dimensional models of both the cardiac veins and coronary arteries. Additionally, we have created and continue to develop a database of anatomical parameters measured from these models: e.g., which than can be used for the design of medical devices that are to be deployed within the coronary vessels.

Ultrasound

Various types of ultrasound are also used to visualize the coronary system. For instance, prior to lead implantation, tissue Doppler imaging can be utilized to identify the target implant region for a transvenous pacing lead placements [5]. Additionally, intravascular ultrasound (IVUS) can be used to identify the presence or absence of calcifications within the coronary arteries: e.g., during a procedure for the delivery of stents.

References

  1. Coatrieux JL, Hernandez AI, Mabo P, Garreau M, Haigron P. Transvenous path finding in cardiac resynchronization therapy. Functional Imaging and Modeling of Heart, Proceedings, 2005:236-45.
  2. Leon AR. Cardiac resynchronization therapy devices: Patient management and follow-up strategies. Rev Cardiovasc Med 2003;4 Suppl 2: S38-46.
  3. von Ludinghausen M. The clinical anatomy of coronary arteries. Adv Anat Embryol Cell Biol 2003;167:III-VIII, 1-111.
  4. Oginosawa Y, Abe H, Nakashima Y. Prevalence of venous anatomic variants and occlusion among patients undergoing implantation of transvenous leads. Pacing Clin Electrophysiol 2005;28:425-8.
  5. Ansalone G, Giannantoni P, Ricci R, Trambaiolo P, Fedele F, Santini M. Doppler myocardial imaging to evaluate the effectiveness of pacing sites in patients receiving biventricular pacing. J Am Coll Cardiol 2002;39:489-99.

 

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