Angiography for Percutaneous Coronary Interventions

3 Angiography for Percutaneous Coronary Interventions image



Angiography for percutaneous coronary interventions (PCIs) requires establishing the precise lesion length, morphology and degree of calcification (or thrombus), as well as the relationship to side branches and their associated ostial involvement with coronary artery disease (CAD). Before PCI, the angiographer should acquire the following additional angiographic detail:



Optimal definition of ostial and proximal coronary segment is critical to guide PCI catheter selection. Assessment of calcium from angiography is less reliable than intravascular ultrasound (IVUS) imaging but still serves a useful purpose in assessing need for rotational atherectomy and risks associated with the procedure.


Classical terminology for angiographic projections with regard to left and right anterior oblique, cranial and caudal angulation, and lateral projections remains as defined in previous discussions of diagnostic coronary angiography (see The Cardiac Catheterization Handbook, 5th edition, Chapter 4).


Visualization of vessel bifurcations, origin of side branches, the portion of the vessel proximal to a significant lesion, and previously “unimportant” lesion characteristics (length, eccentricity, calcium, and the like) will assist in device selection and identifying potential procedural risk. For total chronic vessel occlusions, the distal vessel should be visualized as clearly as possible by injecting the coronary arteries that supply collaterals and taking cineangiograms with panning long enough to visualize late collateral vessel filling and the length of the occluded segment.


Optimal radiographic imaging is also critical to determining a successful intervention, enhancing accurate interpretation of procedure results. Modification of panning technique to reduce motion artifact during imaging, optimal use of beam restrictors (collimation) to reduce scatter, and improved contrast media delivery can enhance clinical results. A working knowledge of the principles of radiographic imaging permits the interventionalist to improve imaging outcomes.


Radiation exposure is higher in PCI than diagnostic procedures. Continued awareness of the inverse square law of radiation propagation will reduce the exposure to patient, operators, and the catheter lab team. Obtaining quality images should not necessitate increasing the ordinary procedural radiation exposure to either the patient or catheterization personnel.



Common Angiographic Views for Angioplasty


The routine coronary angiographic views described below should include those that best visualize the origin and course of the major vessels and their branches in at least two different (preferably orthogonal) projections. Naturally, there is a wide variation in coronary anatomy, and appropriately modified views will need to be individualized. The nomenclature for angiographic views is described in Chapter 4 of The Cardiac Catheterization Handbook, 5th edition, but will be reviewed briefly here, emphasizing the interventionalist’s thinking.



Position for Anteroposterior Imaging


The image intensifier is directly over the patient, with the beam perpendicular to the patient lying flat on the x-ray table (Figs. 3-1, 3-2). The anteroposterior (AP) view or shallow right anterior oblique (RAO) displays the left main coronary artery in its entire perpendicular length. In this view, the branches of the left anterior descending (LAD) and left circumflex coronary arteries branches overlap. Slight RAO or left anterior oblique (LAO) angulation may be necessary to clear the density of the vertebrae and the catheter shaft in the thoracic descending aorta. In patients with acute coronary syndromes, this view will exclude left main stenosis, which can preclude or complicate PCI. The AP cranial view is excellent for visualizing the LAD with septals moving to the left (on screen) and diagonals to the right, helping wire placement.






Position for Left Anterior Oblique Imaging


In the LAO position, the image intensifier is to the left side of the patient. The LAO/cranial view also shows the left main coronary artery (slightly foreshortened), LAD, and diagonal branches. Septal and diagonal branches are separated clearly. The circumflex and marginals are foreshortened and overlapped. Deep inspiration will move the density of the diaphragm out of the field. The LAO angle should be set so that the course of the LAD is parallel to the spine and stays in the “lucent wedge” bordered by the spine and the curve of the diaphragm. Cranial angulation tilts the left main coronary artery down and permits view of the LAD/circumflex bifurcation (Fig. 3-3). Too steep an LAO/cranial angulation or shallow inspiration produces considerable overlapping with the diaphragm and liver, degrading the image.



For the RCA, the LAO/cranial view shows the origin of the artery, its entire length, and the posterior descending artery bifurcation (crux). Cranial angulation tilts the posterior descending artery down to show vessel contour and reduces foreshortening. Deep inspiration clears the diaphragm. The posterior descending artery and posterolateral branches are foreshortened.


The LAO/caudal view (“spider” view; Fig. 3-3) shows a foreshortened left main coronary artery and the bifurcation of the circumflex and LAD. Proximal and mid portions of the circumflex and the origins of obtuse marginal branches are usually seen excellently. Poor image quality may be due to overlapping of diaphragm and spine. The LAD is considerably foreshortened in this view.


A left lateral view shows the mid and distal LAD best. The LAD and circumflex are well separated. Diagonals usually overlap. The course of the (ramus) intermediate branch is well visualized. This view is best to see coronary artery bypass graft (CABG) conduit anastomosis to the LAD. For the RCA, the lateral view also shows the origin (especially in those with more anteriorly oriented orifices) and the mid RCA well. The posterior descending artery and posterolateral branches are foreshortened.



Angulations for Saphenous Bypass Grafts


Coronary artery saphenous vein grafts are visualized in at least two views (LAO and RAO). It is important to show the aortic anastomosis, the body of the graft, and the distal anastomosis. The distal runoff and continued flow or collateral channels are also critical. The graft vessel anastomosis is best seen in the view that depicts the native vessel best. A general strategy for graft angiography is to perform the standard views while assessing the vessel key views for specific coronary artery segments (Table 3-1) to determine the need for contingency views or an alteration/addition of special views. Therefore, the graft views can be summarized as follows:



Table 3-1 Recommended “Key” Angiographic Views for Specific Coronary Artery Segments



























































































































Coronary Segment Origin/Bifurcation Course/Body
Left main AP AP
  LAO cranial LAO cranial
  LAO caudal*  
Proximal LAD LAO cranial LAO cranial
  RAO caudal RAO caudal
Mid LAD LAD cranial  
  RAO cranial  
  Lateral  
Distal LAD AP  
  RAO cranial  
  Lateral  
Diagonal LAO cranial
RAO cranial
RAO cranial, caudal, or straight
Proximal circumflex RAO caudal LAO caudal
  LAO caudal  
Intermediate RAO caudal RAO caudal
  LAO caudal Lateral
Obtuse marginal RAO caudal RAO caudal
  LAO caudal  
  RAO cranial (distal marginals)  
Proximal RCA LAO  
  Lateral  
Mid RCA LAO LAO
  Lateral Lateral
  RAO RAO
Distal RCA LAO cranial LAO cranial
  Lateral Lateral
PDA LAO cranial RAO
Posterolateral LAO cranial RAO cranial
  RAO cranial RAO cranial

AP, anteroposterior; LAD, left anterior descending; LAO, left anterior oblique; PDA, posterior descending artery (from RCA); RAO, right anterior oblique; RCA, right coronary artery.


* Horizontal hearts.


From Kern MJ, ed. The cardiac catheterization handbook, 2nd ed. St Louis, MO: Mosby, 1995: 286.



Techniques for Coronary Arteriography





Angiographic TIMI Classification of Blood Flow


Thrombolysis in myocardial infarction (TIMI) flow grading has been used to assess, in a qualitative fashion, the degree of restored perfusion achieved after thrombolysis or angioplasty in patients with acute myocardial infarction. Table 3-2 provides descriptions used to assign TIMI flow grades.


Table 3-2 Thrombolysis in Myocardial Infarction (TIMI) Flow: Grade and Blush Scores






















TIMI Flow Grade Description
Grade 3 (complete reperfusion) Anterograde flow into the terminal coronary artery segment through a stenosis is as prompt as anterograde flow into a comparable segment proximal to the stenosis. Contrast material clears as rapidly from the distal segment as from an uninvolved, more proximal segment.
Grade 2 (partial reperfusion) Contrast material flows through the stenosis to opacify the terminal artery segment. However, contrast enters the terminal segment perceptibly more slowly than more proximal segments. Alternatively, contrast material clears from a segment distal to a stenosis noticeably more slowly than from a comparable segment not preceded by a significant stenosis.
Grade 1 (penetration with minimal perfusion) A small amount of contrast flows through the stenosis but fails to fully opacify the artery beyond.
Grade 0 (no perfusion) There is no contrast flow through the stenosis.
Myocardial Blush Grade


Modified from Sheehan F, Braunwald E, Canner P, et al. The effect of intravenous thrombolytic therapy on left ventricular function: a report on tissue-type plasminogen activator and streptokinase from the Thrombolysis in Myocardial Infarction (TIMI) Phase I Trial. Circulation 1987;72:817–829.




TIMI Frame Count


Contrast runoff is now performed quantitatively by using cine frame counts from the first frame of the filled catheter tip to the frame where contrast is seen filling a predetermined distal arterial end point. Myocardial blood flow has been assessed angiographically using the TIMI score for qualitative grading of coronary flow. TIMI flow grades 0 to 3 have become a standard description of coronary blood flow in clinical trials. TIMI grade 3 flows have been associated with improved clinical outcomes.


The method uses cineangiography with 6 F catheters and filming at 30 frames per second. The number of cine frames from the introduction of dye in the coronary artery to a predetermined distal landmark is counted. The TIMI frame count for each major vessel is thus standardized according to specific distal land marks. The first frame used for TIMI frame counting is that in which the dye fully opacifies the origin of the artery and in which the dye extends across the width of the artery touching both borders with antegrade motion of the dye. The last frame counted is when dye enters the first distal landmark branch. Full opacification of the distal branch segment is not required. Distal landmarks used commonly in analysis are listed here:


Stay updated, free articles. Join our Telegram channel

Jun 5, 2016 | Posted by in CARDIAC SURGERY | Comments Off on Angiography for Percutaneous Coronary Interventions

Full access? Get Clinical Tree

Get Clinical Tree app for offline access