Basics of Coronary Angiography

Dr Jain T Kallarakkal MD, DM (Cardiology)Dr Biswajit Sahoo MBBS, PGDC (Cardiology)

Coronary angiography remains the gold standard for detecting clinically significant atherosclerotic coronary artery disease

The technique was first performed by Dr. Mason Sones at the Cleveland Clinic in 1958

Coronary Angiography

To visualize coronary arteries, branches, collaterals and anomalies

Precise localization relative to major and minor side branches, thrombi and areas of calcification

To visualize vessel bifurcations, origin of side branches and specific lesion characteristics (length, eccentricity, calcium etc)

Goals

To rule out the presence of coronary stenosis, define therapeutic options, and determine prognosis.

Used as a research tool for follow-up after invasive procedures or pharmacologic therapy.

High-risk criteria include low ejection fraction and poor exercise capacity on an exercise test.

Indications

In patients with non–ST-segment elevation acute coronary syndromes with high-risk features (e.g., ongoing ischemia, heart failure)

In patients with acute ST-segment elevation myocardial infarction (STEMI)

Primary percutaneous intervention (PCI) is usually performed in the same procedure, immediately after the diagnostic procedure

Indications

Coagulopathy Decompensated congestive heart failure Uncontrolled Hypertension CVA Refractory Arrythmia GI Haemorrhage Pregnancy Inability for patient cooperation Active infection Renal Failure Contrast medium allergy

Contraindications (relative)

Major complications are uncommon (<1%) Vascular complications related to the arterial

puncture site Mortality risk is 0.1% or less. Allergic contrast reactions, worsening kidney

function, and cerebrovascular accidents are rare Ventricular fibrillation may be provoked by contrast

injection into conal branch of the right coronary artery.

Iatrogenic coronary artery dissection is a potential life-threatening complication, which usually is handled by either emergent coronary artery stenting or bypass surgery.

Complications

The left and right coronary cusp give rise to their respective coronary arteries

The major epicardial vessels are the left main coronary artery that divides into the Left anterior Descending artery and Left Circumflex Artery, and the Right Coronary artery.

Coronary Anatomy

Coronary dominance is based on the vessel that gives rise to the posterior descending artery which supplies the Atrio-ventricular node.

Recognized by the presence of septal perforating branches, arises from the RCA in 80% from and the LCx in 10% of the population.

Co-Dominance is found in 10% of the population where the posterior interventricular artery is formed by both the RCA and LCx.

Dominance

The Left main coronary artery originates from the left coronary cusp and bifurcates to give rise to the Left anterior descending and Left Circumflex arteries.

Occasionally, a third branch vessel, the Ramus Intermedius arises from the LMCA.

In a small number of patients, the two major branch vessels arise from separate origins.

Left Main Coronary Artery (LMCA)

LAD provides blood supply to the anterior wall of the left ventricle.

It provides multiple septal branches to the interventricular septum and diagonal branches to the anterior lateral wall.

The LAD in some patients wraps around the apex to supply a small amount of the posterior apex.

Left Anterior Descending Artery (LAD)

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) branches.

OM branches are sequentially numbered (OM1, OM2 etc…).

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).

Left Circumflex Artery (LCx)

RCA arises from the right coronary cusp and follows the right AV groove.

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).

RCA gives off the postero lateral and posterior descending branches at the crux cordis

Right Coronary Artery (RCA)

Normal coronaries (LCA)

Normal coronaries (RCA)

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 the catheter and spine are seen on the right side of the image, while in the RAO they are found on the right.

PA imaging places these landmarks in the center.

Cranial can usually be distinguished from caudal angulation by the presence of the diaphragm. For cranial imaging, the patient should be asked to inspire to remove the diaphragmatic shadow from the image.

Angiographic views

Generally, for circumflex and proximal epicardial visualization the caudal views are most useful.

For LAD and LAD/diagonal bifurcation visualization the cranial views are most useful.

Left Coronary System

Left Main AP, LAO cranial, LAO caudal

Proximal LAD LAO cranial, RAO caudal

Mid LAD LAO cranial, RAO cranial, Lateral

Distal LAD AP, RAO cranial, Lateral

Diagonal LAO cranial, RAO cranial

Angiographic views

Proximal circumflex RAO cranial, LAO caudal

Intermediate RAO caudal,LAO caudal

Obtuse marginal RAO caudal, LAO caudal, RAO cranial

Proximal RCA LAO, Lateral

Mid RCA LAO, Lateral, RAO

Distal RCA LAO cranial, Lateral

PDA LAO cranial

Posterolateral LAO cranial, RAO cranial

Angiographic views

Grading stenosis

The severity or degree of stenosis is measured by comparing the area of narrowing to an adjacent normal segment, and as a percentage reduction and calculated in the projection which demonstrates the most severe narrowing.

Normal distal runoff (TIMI 3)

Good distal runoff (TIMI 2)

Poor distal runoff (TIMI 1)

Absence of distal runoff (TIMI 0)

Classification of distal angiographic contrast runoff (TIMI Grade)

Grade Collateral appearance

0 No collateral circulation1 Very weak reopcification2 Reopacified segment, less dense

than the feeding vessel and filling slowly

3 Reopacified segment as dense as the feeding vessel and filling rapidly

Grading of collateral circulation

LMCA originating from right sinus of Valsalva

RCA originating from left sinus of Valsalva

RCA originating above the sinus of Valsalva or from anterior aortic wall

LAD originating from right sinus of Valsalva

LAD and LCx originating from separate ostia

Common coronary anomalies