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Pulmonary angiography (or pulmonary arteriography,conventional pulmonary angiography, selective pulmonary angiography) is a medical fluoroscopic procedure used to visualize the pulmonary arteries and much less frequently, the pulmonary veins. It is a minimally invasive procedure performed most frequently by an interventional radiologist or interventional cardiologist to visualise the arteries of the lungs.
Pulmonary angiography is useful as the confirmation test where the non-invasive imaging such as CT pulmonary angiography is inconclusive on determining the presence of pulmonary embolism. [1] The accuracy of pulmonary angiography may be higher than clinical examination, arterial blood gas results, and ventilation/perfusion scan. [2] Pulmonary angiography is also used to confirm chronic thromboembolic pulmonary hypertension (CTEPH) and provides a platform for balloon pulmonary angioplasty to treat the disease. [3]
CT pulmonary angiography has nearly entirely replaced conventional pulmonary angiography in common practice as it is less invasive, faster, safer, and provides most of the same diagnostic information with the added benefit of visualizing the lung tissue as well as other structures. Nevertheless, it is still used in cases where CT angiography is nondiagnostic.
Types of catheters that can be used are pigtail catheters and balloon occlusion catheters. Tip of the catheter is advanced through the inferior vena cava, right atrium, right ventricle, right ventricular outflow tract, pulmonary trunk, and the tip is parked in the left pulmonary artery. [4]
Conventional pulmonary angiography was first performed in 1931 by Portuguese angiography pioneers Lopo de Carvalho, Egas Moniz and colleagues. [5] Robb and Steinberg described pulmonary angiography by infusion of peripheral radiocontrast. [6] [7]
Angioplasty, also known as balloon angioplasty and percutaneous transluminal angioplasty (PTA), is a minimally invasive endovascular procedure used to widen narrowed or obstructed arteries or veins, typically to treat arterial atherosclerosis. A deflated balloon attached to a catheter is passed over a guide-wire into the narrowed vessel and then inflated to a fixed size. The balloon forces expansion of the blood vessel and the surrounding muscular wall, allowing an improved blood flow. A stent may be inserted at the time of ballooning to ensure the vessel remains open, and the balloon is then deflated and withdrawn. Angioplasty has come to include all manner of vascular interventions that are typically performed percutaneously.
Pulmonary embolism (PE) is a blockage of an artery in the lungs by a substance that has moved from elsewhere in the body through the bloodstream (embolism). Symptoms of a PE may include shortness of breath, chest pain particularly upon breathing in, and coughing up blood. Symptoms of a blood clot in the leg may also be present, such as a red, warm, swollen, and painful leg. Signs of a PE include low blood oxygen levels, rapid breathing, rapid heart rate, and sometimes a mild fever. Severe cases can lead to passing out, abnormally low blood pressure, obstructive shock, and sudden death.
Angiography or arteriography is a medical imaging technique used to visualize the inside, or lumen, of blood vessels and organs of the body, with particular interest in the arteries, veins, and the heart chambers. Modern angiography is performed by injecting a radio-opaque contrast agent into the blood vessel and imaging using X-ray based techniques such as fluoroscopy.
Interventional radiology (IR) is a medical specialty that performs various minimally-invasive procedures using medical imaging guidance, such as x-ray fluoroscopy, computed tomography, magnetic resonance imaging, or ultrasound. IR performs both diagnostic and therapeutic procedures through very small incisions or body orifices. Diagnostic IR procedures are those intended to help make a diagnosis or guide further medical treatment, and include image-guided biopsy of a tumor or injection of an imaging contrast agent into a hollow structure, such as a blood vessel or a duct. By contrast, therapeutic IR procedures provide direct treatment—they include catheter-based medicine delivery, medical device placement, and angioplasty of narrowed structures.
A pulmonary artery is an artery in the pulmonary circulation that carries deoxygenated blood from the right side of the heart to the lungs. The largest pulmonary artery is the main pulmonary artery or pulmonary trunk from the heart, and the smallest ones are the arterioles, which lead to the capillaries that surround the pulmonary alveoli.
A coronary catheterization is a minimally invasive procedure to access the coronary circulation and blood filled chambers of the heart using a catheter. It is performed for both diagnostic and interventional (treatment) purposes.
Pulmonary hypertension is a condition of increased blood pressure in the arteries of the lungs. Symptoms include shortness of breath, fainting, tiredness, chest pain, swelling of the legs, and a fast heartbeat. The condition may make it difficult to exercise. Onset is typically gradual. According to the definition at the 6th World Symposium of Pulmonary Hypertension in 2018, a patient is deemed to have pulmonary hypertension if the pulmonary mean arterial pressure is greater than 20mmHg at rest, revised down from a purely arbitrary 25mmHg, and pulmonary vascular resistance (PVR) greater than 3 Wood units.
Interventional cardiology is a branch of cardiology that deals specifically with the catheter based treatment of structural heart diseases. Andreas Gruentzig is considered the father of interventional cardiology after the development of angioplasty by interventional radiologist Charles Dotter.
Intravascular ultrasound (IVUS) or intravascular echocardiography is a medical imaging methodology using a specially designed catheter with a miniaturized ultrasound probe attached to the distal end of the catheter. The proximal end of the catheter is attached to computerized ultrasound equipment. It allows the application of ultrasound technology, such as piezoelectric transducer or CMUT, to see from inside blood vessels out through the surrounding blood column, visualizing the endothelium of blood vessels.
Cardiac catheterization is the insertion of a catheter into a chamber or vessel of the heart. This is done both for diagnostic and interventional purposes.
A catheterization laboratory, commonly referred to as a cath lab, is an examination room in a hospital or clinic with diagnostic imaging equipment used to visualize the arteries of the heart and the chambers of the heart and treat any stenosis or abnormality found.
In thoracic surgery, a pulmonary thromboendarterectomy (PTE), also referred to as pulmonary endarterectomy (PEA), is an operation that removes organized clotted blood (thrombus) from the pulmonary arteries, which supply blood to the lungs.
Computed tomography angiography is a computed tomography technique used for angiography—the visualization of arteries and veins—throughout the human body. Using contrast injected into the blood vessels, images are created to look for blockages, aneurysms, dissections, and stenosis. CTA can be used to visualize the vessels of the heart, the aorta and other large blood vessels, the lungs, the kidneys, the head and neck, and the arms and legs. CTA can also be used to localise arterial or venous bleed of the gastrointestinal system.
The history of invasive and interventional cardiology is complex, with multiple groups working independently on similar technologies. Invasive and interventional cardiology is currently closely associated with cardiologists, though the development and most of its early research and procedures were performed by diagnostic and interventional radiologists.
A CT pulmonary angiogram (CTPA) is a medical diagnostic test that employs computed tomography (CT) angiography to obtain an image of the pulmonary arteries. Its main use is to diagnose pulmonary embolism (PE). It is a preferred choice of imaging in the diagnosis of PE due to its minimally invasive nature for the patient, whose only requirement for the scan is an intravenous line.
Pulmonary artery stenosis (PAS) is a narrowing of the pulmonary artery. The pulmonary artery is a blood vessel moving blood from the right side of the heart to the lungs. This narrowing can be due to many causes, including infection during pregnancy, a congenital heart defect, a problem with blood clotting in childhood or early adulthood, or a genetic change.
Embolectomy is the emergency interventional or surgical removal of emboli which are blocking blood circulation. It usually involves removal of thrombi, and is then referred to as thromboembolectomy or thrombectomy. Embolectomy is an emergency procedure often as the last resort because permanent occlusion of a significant blood flow to an organ leads to necrosis. Other involved therapeutic options are anticoagulation and thrombolysis.
Chronic thromboembolic pulmonary hypertension (CTEPH) is a long-term disease caused by a blockage in the blood vessels that deliver blood from the heart to the lungs. These blockages cause increased resistance to flow in the pulmonary arterial tree which in turn leads to rise in pressure in these arteries. The blockages either result from organised blood clots that usually originate from the deep veins of the lower limbs of the body (thromboembolism) and lodge in the pulmonary arterial tree after passing through the right side of the heart. The blockages may also result from scar tissue that forms at the site where the clot has damaged the endothelial lining of the pulmonary arteries, causing permanent fibrous obstruction. Most patients have a combination of microvascular and macrovascular obstruction. Some patients may present with normal or near-normal pulmonary pressures at rest despite symptomatic disease. These patients are labelled as having chronic thromboembolic disease (CTED).
Balloon pulmonary angioplasty (BPA) is an emerging minimally invasive procedure to treat chronic thromboembolic pulmonary hypertension (CTEPH) in people who are not suitable for pulmonary thromboendarterectomy (PTE) or still have residual pulmonary hypertension and areas of narrowing in the pulmonary arterial tree following previous PTE.
Arterial occlusion is a condition involving partial or complete blockage of blood flow through an artery. Arteries are blood vessels that carry oxygenated blood to body tissues. An occlusion of arteries disrupts oxygen and blood supply to tissues, leading to ischemia. Depending on the extent of ischemia, symptoms of arterial occlusion range from simple soreness and pain that can be relieved with rest, to a lack of sensation or paralysis that could require amputation.