Angioscopy is a minimally invasive procedure that allows physicians to directly view the interior of a blood vessel. It uses a flexible, fiber-optic catheter (angioscope) to provide real-time, high-resolution images of the vessel lining (lumen). This technique offers an “inside-out” view of the vascular system, contrasting with external imaging methods. Angioscopy is valuable for assessing the precise nature of blockages and guiding subsequent therapeutic interventions.
The Core Technique
The angioscope is a thin, flexible catheter containing a fiber-optic bundle that transmits light and relays the image back to a camera and monitor. The device is threaded into the vascular system, usually through a small puncture site in an artery (e.g., in the groin or wrist), until it reaches the site of interest.
Direct visualization within a blood vessel presents a unique challenge because the constant flow of blood obscures the camera’s lens. To overcome this, a specialized flushing system continuously or intermittently infuses a clear fluid, typically saline or a dextran solution. This fluid is delivered through the catheter or a surrounding sheath to momentarily displace the blood in the immediate viewing field.
The saline flush creates a temporary, clear window, allowing the physician to capture a sharp image of the vessel wall and any internal structures. The flow rate and pressure of the flush must be meticulously controlled to ensure a clear view without causing damage to the delicate vessel lining.
Clinical Applications
The primary value of angioscopy lies in its ability to characterize the morphology of diseased areas within the arteries, information often difficult to obtain with standard X-ray angiography. It is frequently employed in the coronary arteries to assess lesions in patients experiencing unstable angina or heart attacks. Angioscopy can precisely differentiate between various types of plaque, such as those that are yellow and lipid-rich, and those that are white and fibrous.
A major application is the real-time detection of thrombi and the identification of ruptured atherosclerotic plaques, which commonly cause acute coronary syndromes. Studies show that angioscopy is highly effective at identifying thrombi in patients with unstable angina, even when angiography results are inconclusive. The procedure can visually distinguish the color and type of a clot, such as reddish, fibrin-rich thrombi, which may respond differently to treatments than grayish-white, platelet-rich thrombi.
Angioscopy also guides and confirms the success of interventional procedures, such as angioplasty and stenting. For example, after placing a stent, the angioscope confirms that the stent is fully expanded and properly positioned against the vessel wall. In peripheral arteries, it guides the crossing of chronic total occlusions by providing visual confirmation of the guidewire’s placement within the true vessel lumen.
Procedure Details and Safety
Before undergoing angioscopy, patients are instructed to fast for several hours and must review their current medications with the medical team. This review is important for blood-thinning and antiplatelet medications, as they may need temporary adjustment to minimize bleeding risk. The procedure is performed in a catheterization laboratory under local anesthesia at the access site, often supplemented with mild sedation for patient comfort.
Once the access site is numbed, a sheath is inserted into the artery, usually in the wrist or groin, through which the angioscope catheter is advanced. The duration varies based on the complexity and purpose, but the process may last from one to several hours. Throughout the procedure, the medical team monitors the patient’s vital signs, including heart rate and blood pressure.
Following the procedure, patients move to a recovery area and typically require bed rest, particularly if the access site was in the groin, to allow the artery to seal and prevent bleeding. Potential complications are similar to those of other catheter-based procedures and include bleeding or bruising at the insertion site, infection, or damage to the vessel wall. Patients are encouraged to drink plenty of water afterward to help flush injected fluids and any contrast dye from the system.