Angiography or arteriography is a medical imaging technique used to visualize lumen of blood vessels and organs of the body, with particular interest in the arteries, veins and the heart chambers. This is traditionally done by injecting a radio-opaque contrast agent into the blood vessel and imaging using X-ray based techniques such as fluoroscopy. The film of image of the blood vessels is called an angiograph, of more commonly, an angiogram.
History:- The technique was first developed in 1927 by the Portoguese physician and neurologist Egas Moniz to provide contrasted x-ray cerebral angiography, in order to diagnose several kinds of nervous diseases, such as tumors, coronary heart disease and arteriovenous malformations.
Technique:- Depending on the type of angiogram access to the blood vessels is gained most commonly through the femoral artery, to look at the left side of the heart and the arterial system or the jugular or femoral vein, to look at the right side of the heart and the venous system. Using a system of guide wires and catheters, a type of contrast agent (which shows up by absorbing the x-rays), is added to the blood to make it visible on the x-ray images.
Uses Of Coronary Angiography:- One of the common angiograms performed is to visualize the blood in the coronary arteries. A long, thin, flexible tube called a catheter is used to administer the x-ray contrast agent at the desired area to be visualized. The catheter is threaded into an artery in the forearm or leg and the tip is advanced through the arterial system into the major coronary artery. X-ray images of the transient radiocontrast distribution within the blood flowing within the coronary arteries allows visulization of the size of the artery openings.
Neuro-vascular angiography: - Another increasingly common angiographic procedure is neuro-vascular digital subtraction angiography in order to visualize the arterial and venous supply to the brain. Intervention work can also be performed
Peripheral Angiography:-Angiography is also commonly performed to identify vessel narrowing in patients with leg claudication of cramps, caused by reduced blood flow down the legs and to the feet; in patients with renal stenosis (Which commonly causes high blood pressure) and can be used in the head to find and repair stoke. These are all done routinely through the femoral artery, but can also be performed through the brachial or radial (arm) artery. Any stenosis found may be treated by the use of angioplasty.
Complication Of Coronary Angiography: - Coronary angiography is common and major complications are rare. These include Cardiac arrhythmias, kidney damage, blood clots (which can cause heart attack or stroke), hypotension and pericardial effusion. Minor complication can include bleeding or bruising at the side where the contrast is injected, blood vessel damage on the route to the heart from the catheter (rare) and allergic reaction to the contrast.
Cerebral Angiography: - Major complication in Cerebral Angiography are also rare but include stroke, an allergic reaction to the anesthetic other medication or the contrast medium, blockage or damage to one of the access veins in the leg, or thrombosis and embolism formation. Bleeding or bruising at the site where the contrast is injected are minor complications, delayed bleeding can also occur but is rare.
Patient participation: - The patient being examined or treated is usually awake during coronary catheterization, ideally with only local anaesthesia such as lidocanic and minimal general sedation, throughout the procedure. Performing the procedure with the patient awake is safer as the patient can immediately report any discomfort or problems and thereby facilitate repaid correction of any undesirable events. Medical monitors fail to give a comprehensive view of the patientâ€â„¢s immediate well-being; how the patient feels is often a most reliable indicator of procedural safety.
In the early 1960s, cardiac catheterization frequently took several hours and involved significant complications for as 2-3% of patients. With multiple incremental improvements over time, simple coronary catheterizations examinations are now commonly done more rapidly and with significantly improved outcomes. Death, myocardial infarction, stroke serious ventricular arrhythmia, and major vascular complications each occur in less than 1% of patients undergoing catheterizations. [1] However, though the imaging portion of the examination is often brief, because of setup and safety issues the patient is often in the lab for 20-45 minutes. Any of multiple technical difficulties, while nt endangering the patient (indeed added to protect the patientâ€â„¢s interests) can significantly increase the examination time.
Equipment: -Coronary catheterization is performed in a cardiac catheterization lab, usually located within a hospital. With current designs, the patient must lay relatively flat on a narrow, minimally padded, radiolucent (transparent to X-ray) table. The X-ray source and imaging camera equipment are on opposite sides of the patientâ€â„¢s chest and freely move, under motorized control, around the patientâ€â„¢s chest so images can be taken quickly from multiple angles.
Diagnostic procedures: -During coronary catheterization (often referred to as a cath by physicians), blood pressures are recorded and X-Ray motion picture shadow-grams of the blood inside the coronary arteries are recorded. In order to create the X-Ray pictures, a physician guides a small tube-like device called a catheter, typically ~2.0 mm (6-French) in diameter, through the large arteries of the body until the trip is just within the opening of one of the coronary arteries. By design, the catheter is smaller than the lumen of the artery it is placed in; internal/intra-arterial blood pressures are monitored through the catheter to verify that the catheter does not block blood flow.
The catheter is itself designed to be radiodense for visibility and it allows a clear, watery, blood compatible radiocontrast agent, commonly called an X-Ray dye, to be 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 as the radiocontrast agent is rapidly washed away into the coronary capillaries and then coronary veins.