Coronary Angiography Mark East, MD, FACC Consulting Associate of Medicine, Duke University Medical Center April 4,2009

Catheterization

Access Common Femoral Arterial Access is the most common arterial access for performing left heart catheterization. The original catheterization procedure was performed via brachial access. This site is still commonly used in patients with lower extremity peripheral access issues. Arm access also facilitates internal mammary access, especially in patients with tortuous innominant or subclavian arteries. Radial artery access is also used commonly in some practice settings. Before radial access is performed, competence of the radial artery arch should be assessed with the Allen Test. Use of pulse oximetry can facilitate interpretation of the test. Anatomic landmarks are used to identify the correct site of arterial puncture. For the femoral artery access, the femoral head provides the best visible landmark. Arterial puncture at this site remains below the inguinal ligamentIt is recommended that this site should be observed under floroscopy

Catheters Catheter selection for a routine left heart catheterization is generally straight forward. Most often, Judkins catheter types are most routinely used. For engagement of the left main coronary artery, A Judkins Left size 4 (JL4) catheter generally will generally engaged the left coronary artery in most patients with relative ease. Increasing catheter size (JL5) for tall patients or patients with dilated aorta or decreasing size (JL 3.5) in small patients is sometimes required. The right coronary artery is engaged in the LAO projection. Usually slow clockwise rotation of the JR4 in the aortic root will engage the ostium of the RCA. Specialized catheters are available to engage anomalous origins of coronary arteries and saphenous and internal mammary artery bypass grafts. Once the artery is engaged is is important to examine the pressure wave form. Normally, the waveform should mimic aortic root pressure. Dampening or ventricularization of the pressure waveform may indicate over engagement of the catheter or significant vessel stenosis. Extreme care should be taken before instillation of contrast medium without normal pressure waveforms.

Figure 2. (B) With Judkins left

Basics of Coronary anatomy The trileaflet aortic valve gives rise to 3 cusp or sinuses in the aortic root. The left coronary and right coronary cusp give rise to their respective coronary arteries while the noncoronary cusp which arises from the posterior root usually does not give rise to a coronary artery. The major epicardial vessels supplying the myocardium are the left main coronary artery that divides into the Left anterior Descending artery and Left Circumflex Artery, and the Right Coronary artery. These arteries lie on the epicardial surface and supply smaller branch vessels that eventually give rise to the microvascular network supplying the myocardium. Coronary dominance is based on the vessel that gives rise to the posterior descending artery (PDA) which travels in the posterior interventricular groove and supplies the Atrio-ventricular node (AV node). This vessel, which can be recognized by the presence of septal perforating branches, arises from the RCA in 80% of the population and the LCx in 10% of the population. Co-Dominance of the arterial circulation is found in 10% of the population where the posterior interventricular artery is formed by both the RCA and LCx. The Left main coronary artery or Left Main Trunk (LMT) originates from the left coronary cusp and bifurcates to give rise to the Left anterior descending (LAD) and Left Circumflex (LCx) coronary arteries. Occasionally, a third branch vessel, the Ramus Intermedius (RI) arises from the LMT. The LMT varies in length in many patients and in a small number of patients, the two major branch vessels arise from separate origins. The Left anterior descending coronary artery (LAD) provides blood supply to the anterior wall of the left ventricle. As it courses through the anterior intraventricular groove it provides multiple septal branches to the interventricular septum and diagonal branches to the anterior lateral wall. The LAD then courses to the ventricular apex and in some patients wraps around the apex to supply a small amount of the posterior apex. The Left Circumflex coronary artery (LCx) courses around the lateral or left atrio-ventricular groove and gives rise to multiple marginal or lateral branches. The branches are termed obtuse marginal (OM) or lateral branches depending on institutional preference. OM branches are sequentially numbered (OM1, OM2 etc…) while Lateral branches are termed based on the segment of the lateral wall they supply (High Lateral, Lateral, Posterior Lateral). As the LCx courses the AV groove it also gives rise to several atrial branches, and occasionally the sino-atrial branch (40% of the population). The Right Coronary artery (RCA) arises from the right coronary cusp. This vessel follows the right AV groove and provides branches to the right ventricle. The most proximal branches of the RCA are the conus-branch which supplies the Right ventricular outflow tract and a branch that supplies the sino-atrial (SA) node (60% of patients). The RCA then courses through the interventricular and gives rise to marginal branches and branches to the atrium. Manipulation of the coronary arteries in 3-dimensions via spacial reconstructions of the coronary arteries is helpful in interpreting coronary angiographic images.

Standard Angiographic Views For the beginner angiographer the anatomic landmarks formed by the spine, catheter and diaphragm provide information to discern which tomographic view from which the image is obtained. In the LAO view (figure 1) the catheter and spine are seen on the right side of the image, while in the RAO (figure 2) they are found on the right.

RAO 20 Caud 20

PA 0 Caud 30

LAO 50 Caud 30

LAO 50 Cran 30

PA 0 Cran 40

Right Coronary Artery

Ventriculography: With the advancement of noninvasive imaging, less emphasis is placed on the ventriculogram as part of a cardiac catheterization. However, entry into the left ventricle with hemodynamic measurement and visualization of the left ventricle using contrast ventriculography remains an important aspect of a complete angiographic study. In patients presenting acutely with myocardial infarction, assessment of myocardial and valvular function with ventriculography can provide important information to the management of the patient. In obese patients with difficult echocardiographic windows, ventriculography may provide ventricular information not obtainable from the echocardiogram.

Indications and Contraindications of the LV Gram Identification of Left Ventricular Function including wall motion abnormalities, ventricular size and mass. Identification of mitral regurgitation Identification of ventricular septal defects Contraindications: Decompensated heart Failure Extreme elevation of LVEDP Critical Aortic Stenosis Severe HOCM Left Ventricular Thrombus Contrast Allergy

Complications of the LV Gram Ventricular Arrythmias Embolization of air or thrombus Contrast related complications Decompensated heart failure Myocardial staining

Optimal Ventriculography: Unfortunately, unless biplane angiography is available, ventriculography only provides a 2-dimensional projection of the ventricle and each image will not include all of the left ventricular segments. The 2 standard views for ventriculography are the RAO (30o) which demonstrates the Anterior, Apical and Inferior ventricular walls. A LAO 60o LAO 20o Cranial view allows for better imaging of the lateral and septal ventricular walls. The latter views are particular useful in patients with lateral ischemia (especially circumflex ischemia), suspected VSD and mitral regurgitation.

RAO and LAO Ventriculography: RAO Ventricle LAO Ventricle

Left Ventriculogram Systolic View RAO

Left Ventriculogram Diastolic View RAO

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