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Coronary angiography and cardiac catheterization is a minimally invasive study.

It is a low-risk study and is currently the final anatomical study that defines the extent and severity of the disease.

It is usually performed to confirm the disease and perform a therapeutic intervention or surgery procedure.

The study is performed under local anesthesia and by means of a needle puncture, a thin plastic tube or catheter is inserted into an artery in the arm or leg and from there the catheter is slipped to the patient's heart.

The catheter is inserted into the arteries (left catheterization) or through the veins (right catheterization) and in this way the catheter is manipulated to access the different chambers of the heart, measure the pressure inside each one or inject contrast medium to study flow and assess valve function.

The most frequently performed study is coronary angiography and basically involves inserting the tip of the catheter into the coronary arteries to inject a dye and analyze the flow within them, study the anatomical distribution, and especially the presence of tamponade or clogging of the arteries by fatty deposits.

With catheterization and angiography, the Interventional Cardiologist accesses the heart to perform measurements and inject contrast medium into the coronary arteries and/or cardiac cavities.

Catheterization is a minimally invasive study that does not involve injury or blood loss and is therefore well tolerated by the patient in unstable conditions such as in cases of heart failure or acute myocardial infarction.

Even the catheterization study is the study indicated in seriously ill patients with a high risk of cardiac death in order to offer the optimal treatment to follow.

Since coronary artery obstruction is the leading cause of death in men and women worldwide, in this section we will basically refer to left catheterization and coronary angiography.



  • coronary arteries

  • coronary artery disease

  • Studies to diagnose coronary disease

2-Coronary Angiography and Catheterization

3-Coronary Angiography Imaging

  • left coronary

  • right coronary

  • Coronary stenosis or obstruction

4-functional studies

  • intracoronary ultrasound

  • pressure guide


6-Study Results: Coronary Intervention or Bypass

7-Risks and Complications



Arterias coronarias

Coronary arteries are the "irrigation" system of oxygenated blood to the heart.

They are two main branches.

They emerge from the aorta and are distributed over the surface of the heart.

Each main trunk is divided into branches that are distributed in the two ventricles (The left coronary in the left and the right supplies the right ventricle and the posteroinferior region of the left)

Usually the left coronary irrigates more territory.

The two tree-like arteries subdivide into increasingly thin branches.

As they travel across the surface of the heart, each artery branches off into the muscle to supply each segment.

The intramuscular branches are progressively thinner until they reach the capillaries, which are microscopic.


These images exemplify the segmental capillary perfusion of each artery.

The photograph on the right is an anatomical piece in which the capillary flow is observed forming a network that is distributed throughout the heart and the image is reminiscent of a "dove's nest". Each branch is independent and ends in an isolated territory.


Image by Angio-Tomography that shows the relationship of the two arteries and how there is no connection between them.

By having "independent" circulation, the territories depend on the permeability of each vessel, for this reason when a branch becomes diseased and the territory that depends on it is occluded, it can be irreversibly damaged and limit the function of the heart.

The work of "pump" of the heart depends on the same heart receiving oxygenated blood continuously and interrupted and proportional to the requirements of the muscle.

The coronary arteries are the ones that supply oxygenated blood to the heart to do its job.


Obstruction of the coronary arteries is the leading cause of death in adulthood.

The deposit of cholesterol in the arteries is called ATHEROSCLEROSIS and it occurs in practically all the arteries of the organism, but being more serious and harmful in the arteries of the brain and heart.


Coronary arteries are very susceptible to developing obstructions and blockages caused by cholesterol deposits.

Cholesterol deposits (Atherosclerosis) occur over years, slowly and progressively and do not cause any type of discomfort.

The accumulations of fat decrease the diameter of the artery and interfere with the flow of blood that the heart receives.

The decrease in blood flow interferes with the heart's ability to perform its function and causes the patient to experience pain or tightness in the center of the chest, fatigue, or shortness of breath when trying to exert himself. When the obstruction causes symptoms, the risk of heart attack increases very significantly.


Chest pain caused by blockages in the arteries of the heart is called "angina pectoris."

When the obstruction of the artery becomes >50% of the diameter is when the patient can feel discomfort.

This occurs because obstruction of >50% of the artery diameter causes decreased blood flow and interferes with heart function, increasing the risk of clot formation, heart attack, or sudden death.


When the decrease in diameter is >50%, heart function deteriorates, and pain or shortness of breath may occur on exertion.

Even when the coronary arteries are significantly blocked, if the artery is not occluded and the patient is in pain and at risk of death, the resting electrocardiogram may be normal.

Atherosclerosis of the coronary arteries is a very common disease and is conditioned by genetic factors, the degenerative phenomenon of age, and environmental and behavioral factors such as diet, exercise, stress.

Catheterization angiography shows the internal diameter of the artery and the characteristics of the atherosclerotic plaque are calculated and reconstructed.


If the artery is suddenly completely covered, the symptoms appear at rest and are signs of a heart attack or "attack" that can end in the death of the patient.


In cases where a clot forms inside the artery, it can completely occlude and cause a heart attack (see: and during the event the heart presents an arrhythmia that causes sudden death (see:


The total occlusion of a coronary artery causes a heart attack and the electrocardiogram is the test that can detect the disease.

Considering the high lethality of the disease, it is very important that the doctor be very careful when suspected and rule out the possibility of coronary disease.

In cases where the electrocardiogram is normal or the clinical picture is inconclusive, it is necessary to perform other tests to identify and confirm the disease.


Given the suspicion of coronary artery disease and due to the risk it implies for survival, doctors, based on clinical criteria, physical examination and electrocardiogram, can recommend studies and/or examinations that support or confirm the suspicion of disease.

Blood studies:


stress test

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See more stress test information at




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The tests have different abilities to detect coronary disease (narrowing or occlusion of the arteries and the degree of damage to the function of the heart).

They are chosen based on the characteristics of the patients and if the aim is to analyze the function and/or cardiac reserve. Sometimes a combination of several must be used to reach a certain diagnosis.

Coronary catheterization and angiogram:


Angiography is a test that assesses the patency of an artery and the presence of narrowing or blockage. It is the only study that shows the anatomical characteristics of the coronary arteries in real time.

The final confirmatory study is theCORONARY CATHETERISM AND ANGIOGRAPHY.

Coronary catheterization angiography confirms the presence of disease and assesses the extent and severity of atherosclerosis.

Currently, catheterization and coronary angiography is the mandatory study to confirm the disease and to choose the treatment options for angina or infarction.


Cardiac catheterization and coronary angiography is a minimally invasive procedure and is performed in a special operating room (Hemodynamics unit or laboratory: see equipped with a very sophisticated X-ray apparatus


The Hemodynamics laboratory is an isolated and sterile area to avoid contamination.

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The patient is asked to lie down on a table on which the X-ray projector rotates, and heart rate, blood pressure, oxygen saturation, and coronary blood pressure monitors are attached for monitoring during the study.

Access Route: It is the site where the catheter is inserted into the arterial system and through there it reaches the heart.

Femoral access route:


Local anesthesia injection is applied.

The puncture is made with a needle and the introducer is placed.


The only discomfort is the pain caused by injecting the local anesthetic.

Through the puncture with a needle, a guide is inserted into the artery and an introducer is slipped.

Through this, the catheter is inserted and following the path of the aorta, the catheter is advanced to the root of the heart and the study is carried out.


Through the catheter, a contrast medium is injected into the coronary artery, which is visible on X-rays and its path is "painted" (Coronary Angiography).

The injection of the contrast medium is observed in real time in each coronary artery (right and left) and the diameter, distribution, presence of disease (obstruction of the arteries) and the characteristics of the coronary flow are evaluated.


Radial access road:


In a similar way to how the femoral region is prepared, washing and antisepsis of the right or left wrist region is performed.

At this site, local anesthesia is applied and the radial artery is punctured with a needle. A flexible metal guide is inserted and the introducer is advanced into the artery. Through this, the catheters are advanced to the thorax and the study is performed in a similar way to the femoral approach.

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Radial access has the advantage of being more comfortable for the patient, does not require rest after the study, and even allows the catheterization-angiography study to be performed on an outpatient basis.

In radial access, the introducer is placed in the right or left radial artery and the catheters are inserted through this route.


Radial artery access image

CATHETERS: Catheters are very flexible plastic tubes.


The introducer advances following the metal guide wire and it is very difficult for it to injure or perforate the artery.

In experienced hands the risk of complications during arterial puncture is <1%.

The catheter or probe is advanced through the introducer. (Plastic tube 2mm in diameter and 120cm long)


The catheters have tips

Preformed to facilitate selective cannulation of coronary arteries


Except for the anesthesia puncture, which according to the pain scale is mild, the rest of the procedure is painless.

The procedure, according to the experience and preferences of the doctor, is performed by means of a puncture in the femoral artery at the level of the groin or by means of a puncture in the radial artery in the region of the wrist.

Contrast injections into the coronary arteries do not cause discomfort and are performed while the patient takes a deep breath.

The angiography of each coronary allows to see the anatomical characteristics, distribution and characteristics of the flow. In this way, the interventional cardiologist performs an anatomical analysis of the coronary arteries.



Left Coronary Angiography.


Right and left coronary images are obtained separately and recorded from different angles with multiple shots

Angiogram of the Right Coronary Artery.


Taking a different shot of each artery is necessary to ensure that its entire length is being seen.

In this way, the characteristics of the coronary arteries, their diameter and length are observed, and the occlusion or obstruction sites (STENOSIS) that limit normal blood flow are identified.

Coronary Disease: Stenosis or Coronary Obstruction.

Coronary arteries are very susceptible to depositing cholesterol on the artery wall.

These deposits interfere with blood flow and heart function.

The obstruction causes chest pain on exertion, shortness of breath, and fatigue that limits the patient's activity.

When it comes to clogging the artery causes a heart attack.


Coronary video angiography: coronary stenosis.


A significant stenosis is considered when it is greater than 50% of the diameter of the artery.

Obstruction (Stenosis) greater than 50% of the diameter of the artery decreases the normal flow and interferes with the normal function of the heart.


The image of coronary angiography must be correlated with the symptoms and clinical status of the patient. Severe stenosis of more than 60% correlates with decreased and limited coronary flow.

In the case of 50-60% coronary stenosis, it can be difficult to assess its hemodynamic repercussion and cause diagnostic errors and even cause unnecessary angioplasties.

To avoid these eventualities, additional diagnostic methods are available in the room.

4- Functional Studies


Coronary Ultrasound:


Sometimes Coronary Stenosis by conventional angiography may appear NOT significant (Obstructions less than 50% of the diameter of the artery) but when performing analysis with intracoronary ultrasound quantify significant obstructions.

This analysis is performed at the end of the study and under the clinical criteria of the Interventionist setting.

Coronary Ultrasound Catheter

The catheter is a thin tube with ultrasound crystals at the tip.

When introduced into the artery, it generates images of the wall and interior of the artery. In this way you can measure the real diameter, the characteristics of the arterial wall. Presence and characteristics of atherosclerotic plaque.

With this method you can define the wall of the artery and measure the actual diameter of the artery.

In the same way measure the area of the plaque and even the characteristics of the atherosclerosis plaque

In this way, the therapeutic decisions that best benefit the patient can be made


Coronary intravascular ultrasound criteria for stenosis and disease see:



Another attachment available is the Intracoronary Pressure Probe


Pressure guide measures pressure before and after stricture


As a final part of the coronary angiography study, the functional assessment of the contraction of the Heart can be performed.

CONTRAST VENTRICULOGRAPHY: The coronary catheters are removed and a round-tipped catheter is inserted into the ventricle.

Pressure measurements are made inside the heart

Contrast medium is injected. In this way, mobility (ventriculography) and cardiac function are assessed.


The left side of the heart (left ventricle) is the one that "pumps" blood throughout the body, therefore proper blood circulation depends on this capacity for contraction. Their function is routinely evaluated.


Right catheterization: the different cardiac cavities and the pressures are measured to detect abnormalities in the cardiac valves (catheterization).


At the end of the angiography exploration of the coronary arteries and the ventriculography study.

It is decided whether or not there is an indication to perform a coronary intervention procedure.



CORONARY INTERVENTION:   Balloon Angioplasty


Angioplasty can be performed upon completion of catheterization. See:


Video description of coronary angiography by catheterization and coronary intervention with angioplasty and coronary stent implantation. Video from Nucleus Medical Media.


In a diagnostic study of cardiac catheterization and coronary angiography in stable patients, the risk of death or DEAD COMPLICATIONS is 0.1%.

The patients with the highest risk are: Those with heart disease in advanced stages with data of decompensated heart failure and those with acute problems of heart attack.

In these patients the risk of fatal complications ranges from 0.5 to 5% and is related to the severity of the disease and less to the procedure itself. Although it must be considered that in these cases making an anatomical diagnosis and the possibility of performing therapeutic coronary intervention may be the only option to achieve improvement in the patient.


The most frequent complications are at the puncture site (ecchymosis or bruising) in <1% bleeding or bruising may require transfusions or surgical correction.

In 2% Hypotension and slow heart rate (usually transient)

In <1% Allergy generally to radiological contrast predictable if a previous reaction to the same substance has occurred. In general, they are mild reactions and easy to treat, serious reactions are very rare.

In <1% there may be impaired kidney function, mainly in diabetic patients with prior kidney damage and when high doses of contrast medium are used

In <0.1% Myocardial infarction or heart failure decompensation during ventriculography or severe arrhythmias (requiring electrical cardioversion) or cerebrovascular accidents (embolism/hemorrhage) as an indirect consequence of the study. These complications occur more frequently in people with extensive atherosclerosis, a history of previous strokes, peripheral artery disease, obesity, or previous heart damage.

In <0.01% damage to the nerves that run around the artery and neurotic pain.

Conclusion: Coronary catheterization and angiography is a diagnostic study with which the anatomy of the heart is assessed.

We can consider it as "A look at the heart"

It is a minimally invasive study that does not involve injury or blood loss and is therefore well tolerated by the patient, even in unstable conditions.

The ultimate goal of coronary angiography is to identify the site of coronary artery obstruction and that of catheterization is to measure and assess ventricular mobility and heart valve function.

The diagnostic catheterization can be ambulatory if it is performed by the arm or require 8 to 12 hours of observation in the Hospital when it is performed by the leg.

Coronary angiography is the diagnostic study that is currently considered the reference study ("Gold standard") with which the severity and extent of coronary disease is confirmed.

Based on the results of this study, the treatment that can be offered to the patient is defined and makes it possible to calculate prognoses and estimate the possibilities of treatment with coronary interventionism or bypass surgery and/or optimize pharmacological treatment.

Coronary interventions (dilating the narrowing with a balloon introduced through the catheter) can be performed at the end of the diagnostic study.

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