Heart catheterization is the insertion of a catheter into a chamber or vessel of the heart.
Obtaining access uses the Seldinger technique by puncturing the vessel with a needle, placing a wire through the needle into the lumen of the vessel, and then exchanging the needle for a larger plastic sheath.
Sheaths typically have a side port that can be used to withdraw blood or injection fluids/medications, and they also have an end hole that permits introducing the catheters, wires, coaxially into the blood vessel.
It is done both for diagnostic and interventional purposes.
cardiac catheterization example is coronary catheterization that involves catheterization of the coronary arteries for coronary artery disease and myocardial infarctions.
Catheterization is performed in special laboratories with fluoroscopy and highly maneuverable tables.
A coronary angiogram is a minimally invasive procedure to access the coronary circulation and blood filled chambers of the heart using a catheter.
A coronary angiogram is an X-ray with radiocontrast in the coronary arteries) that shows the left coronary circulation.
A coronary catheterization is a minimally invasive procedure accessing the coronary circulation and blood filled chambers of the heart using a catheter.
People with comorbidities have a higher risk of adverse events during the cardiac catheterization procedure: aortic aneurysm, aortic stenosis, extensive three-vessel coronary artery disease, diabetes, uncontrolled hypertension, obesity, chronic kidney disease, and unstable angina.
Is a visually interpreted test performed to recognize occlusion, stenosis, restenosis, thrombosis or aneurysmal enlargement of the coronary artery lumens, heart chamber size, heart muscle contraction performance, and some aspects of heart valve function.
Fluoroscopy is used to visualize the lumens of the arteries.
Measuring pressures in the heart is an important aspect of catheterization.
The catheters can transmit pressures to pressure transducers allowing the measuring pressure in any part of the heart that a catheter can be maneuvered into.
Internal heart and lung blood pressures, can be accurately measured during the test.
Blood flow measurements are estimated using the Fick principle and thermodilution, giving estimates of cardiac output.
It often requires the use of fluoroscopy to visualize the path of the catheter as it enters the heart or as it enters the coronary arteries.
The use of fluoroscopy requires radiopaque contrast, which in rare cases can lead to contrast-induced kidney injury.
There is constant exposure to low doses of ionizing radiation during procedures.
The test deals with advanced atherosclerosis – atheroma activity within the wall of the coronary arteries.
It it an appropriate test to evaluate valvular, heart muscle, or arrhythmia issues.
Coronary artery luminal narrowing reduces the flow reserve for oxygenated blood to the heart, typically producing intermittent angina.
Very advanced luminal occlusion can result on a heart attack.
Coronary catheterization does not allow the recognition of the presence or absence of coronary atherosclerosis itself, only significant luminal changes.
Indications for cardiac catheterization include the following:
Myocardial infarction: (includes ST elevation MI, Non-ST Elevation MI, Unstable Angina).
Abnormal Stress Test
New-onset unexplained heart failure
Survival of sudden cardiac death or dangerous cardiac arrhythmia
Persistent chest pain despite optimal medical therapy.
Workup of suspected Prinzmetal Angina.
The patient is usually awake during catheterization.
Usually performed with only local anaesthesia such as lidocaine and minimal general sedation.
Performing the procedure with the patient awake is safer as the patient can immediately report problems and thereby facilitate rapid correction.
Major vascular complications including death, myocardial infarction, stroke, serious ventricular arrhythmia, and occur in less than 1% of patients undergoing catheterization..
The patient is often in catheterization lab, for 20–45 minutes.
The X-ray source and imaging camera equipment surrounf the patient’s chest so images can be taken quickly from multiple angles.
A bi-plane cath lab, uses two sets of X-ray source and imaging cameras, each free to move independently, which allows two sets of images to be taken with each injection of radiocontrast agent.
During coronary catheterization blood pressures are recorded and X-ray motion picture shadow-grams of the blood inside the coronary arteries are recorded.
A catheter, typically ~2.0 mm in diameter, is guided through the large arteries of the body until the tip is just within the opening of one of the coronary arteries.
Intraarterial blood pressures are monitored through the catheter to verify that the catheter does not block blood flow.
A radiocontrast agent, selectively injected and mixed with the blood flowing within the artery.
Typically 3–8 cc of the radiocontrast agent is injected for each image to make the blood flow visible for about 3–5 seconds.
The radiocontrast agent is rapidly washed away into the coronary capillaries and then coronary veins.
The radiocontrast within the blood allows visualization of the blood flow within the arteries or heart chambers, depending on where it is injected.
When the physician records diagnostic views by activating the equipment to apply a significantly higher X-ray dose, termed cine, in order to create better quality motion picture images,
Doses of radiocontrast agents and X-ray exposure times are routinely recorded in an effort to maximize safety.
Calcification within the artery walls, located in the outer edges of atheroma within the artery walls, is sometimes recognizable on fluoroscopy as radiodense halo rings partially encircling, and separated from the blood filled lumen by the interceding radiolucent atheroma tissue and endothelial lining.
By changing the diagnostic catheter to a guiding catheter, it is possible to pass a variety of instruments through the catheter and into the artery to a lesion site.
The most commonly used are guide wires and the balloon dilation catheters.
By injecting radiocontrast agent through a tiny passage extending down the balloon catheter and into the balloon.
The balloon can be progressively expanded to make the stenosis of the artery lumen visibly enlarged.
Typical normal coronary artery pressures are in the <200 mmHg range.
The hydraulic pressures applied within the balloon may extend to as high as 19000 mmHg
Additionally, several other devices can be advanced into the artery via a guiding catheter including: laser catheters, stent catheters, IVUS catheters, Doppler catheter, pressure or temperature measurement catheter and various clot and grinding or removal devices.
Stents, which are specially manufactured expandable stainless steel mesh tubes, mounted on a balloon catheter, are the most commonly used device beyond the balloon catheter.
When the stent/balloon device is positioned within the stenosis, the balloon is inflated which, in turn, expands the stent and the artery.
The balloon is then removed and the stent remains in place, supporting the inner artery walls in the more open, dilated position.
Restenosis is the body’s response to the injury of the vessel wall from angioplasty and to the stent as a foreign body.
Using only balloon angioplasty up to 50% of patients suffered significant restenosis.
Restenosis percentage has dropped to the single to lower two digit range with the introduction of drug-eluting stents.
Sirolimus, paclitaxel, and everolimus are the three drugs used in stent coatings.
CT angiography can act as a less invasive alternative to catheter angiography.
An advantage retained by catheter angiography is the ability of the physician to perform procedure such as balloon angioplasty or insertion of a stent to improve blood flow to the artery.
It is performed for diagnostic and potentially therapeutic reasons.
The test is performed to recognize occlusion, stenosis, restenosis, thrombosis or aneurysmal enlargement of coronary arteries.
It can also determine heart chamber size, heart muscle contraction performance, and some aspects of heart valve function.
Allows measurement of intracardiac and intrapulmonic blood pressures.
Provides information about coronary artery luminal changes which have occurred as a result of end stage complications of the atherosclerotic process.
Defines the site, severity of coronary artey lesions, and can qualitative assess of coronary blood flow and identifies collateral vessels.
The patient is usually awake during coronary catheterization, ideally with only local anaesthesia such as lidocaine and minimal general sedation.
Complications include: myocardial infarction, ventricular arrhythmias, vascular complications and death.
Complication rate is less than 1%, but increases with the duration of the study which is usually 20-45 minutes.
Cardiac catheterization is the standard for the evaluation of cardiac hemodynamics.
Provides intracardiac pressure measurements, and also measurements of oxygen saturation and cardiac output.
Hemodynamic measurements usually are coupled with a left ventriculogram for the evaluation of left ventricular function and coronary angiography.
Can identify with ventriculogram potentially viable areas of the myocardium that may benefit from a revascularization procedure.
Left ventricular function can be evaluated using atrial pacing, dynamic exercise, or pharmacologic agents.
Indications for cardiac catheterization include: identification of the extent and severity of coronary artery disease, evaluation of left ventricular function, assessment of the severity of valvular or myocardial disorders such as myocardial cardiomyopathies and the determination of the presence of coronary artery disease in patients with confusing clinical presentations or chest pain of uncertain origin.
Access of the cardiac catheter is usually via the right groin, or the right radial or brachial artery.
Initially a wire catheter is placed into the femoral or radial/brachial artery and a plastic sheath is threaded over the wire and enters the artery, with removal of the wire.
The arterial sheath with a backflow prevention valve is the conduit for the procedure.
Catheters are inserted using a guidewire and moved towards the heart and once in position above the aortic valve the guidewire is then removed.
For coronoary angiograms the catheter is placed at the origins of the coronary arteries, left main stem or right coronary artery, and x-ray opaque iodine-based contrast is injected to make the coronary vessels appear on a fluoroscopy image.
The catheter in place, can be used to perform a number of procedures including angioplasty, percutaneous coronary interventions, balloon septostomy, and electrophysiological studies, measure intracardiac and intravascular blood pressures, to take tissue samples, to inject various agents for measuring blood flow in the heart, to detect and quantify the presence of an intracardiac shunt to inject contrast agents in order to study the shape of the heart vessels and chambers and how they change as the heart beats.
Catheterization of cardiac chambers and valves may be performed.
Most patients who undergo diagnostic catheterizationn for non cardiac surgery are asymptomatic and the discovery of obstructive coronary artery disease is common although no clinical trials have demonstrated benefit in outcomes, revascularization is recommended in the early half of such patients (National Cardiovascular Data Registry Cath PCI Registry).
Left heart catheterization (LHC):
measures the pressures of the left side of the heart.
can be synonymous with coronary angiography.
With a LHC a flexible wire is inserted into either the femoral artery or the radial artery and threaded toward the heart until it is in the ascending aorta.
A catheter is guided over the wire into the ascending aorta, where it can be maneuvered into the coronary arteries through the coronary ostia.
The injection of contrast allows the visualization of the flow through the coronary vessels.
If required , the uses of percutaneous coronary intervention techniques, including the use of a stent, either bare-metal or drug-eluting, to open a blocked vessel and restore appropriate blood flow.
Occlusions greater than 70% of the width of the vessel lumen are thought to require intervention.
Right heart catheter using a Swan-Ganz pulmonary artery catheter allows the physician to determine the pressures within the heart.
The heart is most often accessed via the internal jugular or femoral vein; arteries are not used.
Values are commonly obtained for the right atrium, right ventricle, pulmonary artery, and pulmonary capillary wedge mm pressures.
Right heart catheterizations also allows estimation of the cardiac output, the amount of blood that flows from the heart each minute, and the cardiac index, a hemodynamic parameter that relates the cardiac output to a patient’s body size.
Right heart catheterization is often done to evaluate pulmonary hypertension, heart failure, and cardiogenic shock.
The pulmonary artery catheter can be placed, used, and removed, or it can be placed and left in place for continuous monitoring.
Parameters obtainable from a right heart catheterization:
Right atrial pressure
Right ventricular pressure
Pulmonary artery pressure
Pulmonary capillary wedge pressure
Systemic vascular resistance
Pulmonary vascular resistance
Indications for cardiac catheterization include the following:
Acute coronary syndromes: ST elevation MI (STEMI), non-ST Elevation MI
(NSTEMI), and unstable angina
Evaluation of coronary artery disease as indicated by
Abnormal stress test
As part of the pre-op evaluation for other cardiac procedures (e.g., valve replacement) as coronary artery bypass grafting may be done at the same time
Risk stratification for high cardiac risk surgeries
Persistent chest pain despite medical therapy thought to be cardiac in origin
New-onset unexplained heart failure
Survival of sudden cardiac death or dangerous cardiac arrhythmias.
Workup of suspected coronary vasospasm
Right heart catheterization, along with pulmonary function testing and other testing should be done to confirm pulmonary hypertension prior to having vasoactive pharmacologic treatments approved and initiated.
To measure intracardiac and intravascular blood pressures
To take tissue samples for biopsy
To inject various agents for measuring blood flow in the heart
To detect and quantify the presence of an intracardiac shunt
To inject contrast agents in order to study the shape of the heart vessels and chambers and how they change as the heart beats
Pacemaker with normally located leads in the right atrium and right ventricle, respectively.
Placement of internal pacemakers and defibrillators are done through catheterization as well.
Echocardiography is a non-invasive method to evaluate the heart valves, but sometimes, the valve pressure gradients need to be measured directly because echo is equivocal for the severity of valve disease.
Catheterization by placing a catheter across the valve and measuring the pressures simultaneously on each side of the valve allows one to obtain the pressure gradient: in conjunction with a right heart catheterization, the valve area can be estimated.
Pulmonary angiography allows evaluation of the blood flow to the lungs through catheterization, by injecting contrast into the pulmonary trunk, left or right pulmonary artery, or segment of the pulmonary artery.
Cardiac shunts can be evaluated through catheterization: the oxygen saturation of blood can be sampled at various sites in and around the heart.
A left-to-right atrial septal defect will show a marked increase in oxygen saturation in the right atrium, ventricle, and pulmonary artery as compared to the mixed venous oxygen saturation from the oxygenated blood from the lungs mixing into the venous return to the heart.
By injecting contrast into the left ventricle, the outline of the ventricle can be measured in both systole and diastole to estimate the ejection fraction: it is infrequently performed.
Cardiac catheterization have permitted replacement of heart valves by means of blood vessels.
Catheterization can also be used to perform balloon septostomy, the widening of a foramen ovale, patent foramen ovale (PFO), or atrial septal defect (ASD) using a balloon catheter.
Alcohol septal ablation for
hypertrophic cardiomyopathy removes, through catheterization, and by injecting ethanol, to destroy the tissue.
By selecting an appropriate septal artery in the intended area, it essentially, causes a localized, controlled myocardial infarction of the area with ethanol.
Complications of cardiac catheterization:
Ventricular ectopy and ventricular arrhythmias
Bleeding: internal and external
Contrast induced nephropathy from contrast use
Above risks vary by many factors including: the procedure being performed, the overall health of the patient, elective vs emergent status, associated medications.