Angioscopy is the term used to describe a virtual, direct or endoscopic view of blood vessels, primarily examining the bile ducts or blood vessels.
What is angioscopy?
Angioscopy is a diagnostic procedure used to view vessels directly or indirectly. Mainly, the term is used for an endoscopic examination of blood vessels. Angioscopy is a diagnostic procedure that allows vessels to be viewed directly or indirectly. Mainly the term is used for an endoscopic examination of blood vessels. Depending on the technique, a distinction is made between conventional angioscopy, in which vessels are directly viewed visually using a special catheter, virtual angioscopy, which displays vessels in 3D, and capillary microscopy, which can be used to examine blood capillaries near the surface.
Function, effect, and goals
Conventional angioscopy involves inserting a miniature catheter that has fiberoptics or a light source. Through a vessel incision, the catheter is introduced into the particular vessel via a guide wire as well as a sheath, after which the angioscope is also advanced. This is connected to a camera that records images from the blood vessels. By flushing with a saline solution, a clear view of the inner walls of the vessels can be ensured. Conventional angioscopy can be used to assess atherosclerotic changes in vessel walls and vascular stenoses. The following vascular regions are well suited for angioscopy:
- Pelvic-leg arteries
- Pelvic-Leg Veins
- Coronary arteries
- Dialysis shunts
For a vessel to be homogeneously illuminated, extreme light intensities are needed. Used here are mainly xenon vapor lamps, because insufficient illumination can significantly affect the image quality in terms of resolution, depth of field or color. The inner catheter contains around 3000 glass fibers, via which the light is subsequently guided to the tip of the catheter. The outer sheath makes it possible to move the inner catheter back and forth so that the vessel walls and the vessel lumen can be inspected. At the tip, the catheter has a lens that widens the field of view by 45 degrees. Video documentation is important to record floating plaques or thrombi. In addition, a scene can be viewed multiple times after angioscopy. The catheter guides the angioscope directly to the lesion to be examined without injuring the vessel walls. It also provides maximum irrigation flow and optimal viewing conditions. If the inner walls of the coronary vessels are to be viewed, this is called coronary angioscopy. In this procedure, a coronary angioscope is inserted into the arterial system via the brachial artery or the femoral artery and brought into the respective coronary artery with the aid of a guide wire. The vessel is then closed for about 30 seconds using an occlusion balloon and flushed with warm Ringer’s lactate solution to allow the optic to be moved. In parallel, the image sequence is recorded on hard disk or video until sufficient meaningful image material is available. Coronary angioscopy can be used to view the inner walls of the vessels and assess any changes.This examination method is used primarily to evaluate the surface morphology of coronary lesions. For example, it is possible to differentiate between white and yellow plaque and to make a statement about the success of PTCA (percutaneous transluminal coronary angioplasty). Angioscopy can also be used to examine the bile ducts. This allows optical visualization of the bile ducts or the pancreatic duct in order to detect pathological changes in the gallbladder, liver or pancreas at an early stage and to select an appropriate treatment method. Cholangioscopy is performed, for example, to diagnose cholangitis, suspected tumors, papillary stenosis, ductal lesions or unexplained jaundice. This form of inspection was made possible by the development of mother-baby endoscopy and the introduction of the cholangioscope (baby endoscope). During a cholangioscopy, the examiner inserts a very thin endoscope with a camera into the pancreatic or bile ducts, allowing visual inspection of the mucosa.Today, cholongioscopy is used as a complementary diagnostic procedure to other methods such as MRI, CT or ultrasound. The possible applications are extremely versatile and, in addition to visual diagnosis, also allow biopsy removal and targeted therapy in the area of the bile ducts.
Risks, side effects, and hazards
Minaturization of catheters has made performing angioscopy much easier. So, in theory, angioscopy can be performed in any arterial or venous vessel. However, there are limits due to the diameter of the vessel. For example, the lower limit is a diameter of 1 mm, and the upper limit is set by illuminability and light intensity. Vessels with a diameter of 2 to 8 mm are ideal. Angioscopy becomes difficult when the vessel is very tortuous. However, if the angioscope is used correctly, vascular perforations or aneurysms do not normally occur. However, so-called flaps often occur as a result of pushing the vessel back and forth. However, there are also a number of risks that can complicate cholangioscopy or make it impossible. These include high-grade stenosis, bile duct strictures, or previous surgical intervention in the gastric region. Possible complications that may occur during cholangioscopy include:
- Minor bleeding
- Abdominal pain that lasts longer than a day
- Excessive gas accumulation in the gastrointestinal tract
- Mild pancreatitis
- Cholangitis (inflammation of the bile ducts)
- Perforation
Coronary angioscopy is considered a very safe method of investigation. Complications tend to be isolated cases that may include acute myocardial infarction or acute vascular occlusion. ECG changes or pectanginal symptoms may also occur as a result of coronary occlusions.
