Coronary endoscopy is also known as coronary angioscopy or coronary endoscopy. Direct observation of the inner lumen of coronary arteries with coronary endoscopy was initiated in the mid-1980s and is now used in clinical practice. As this technique can make direct observation and pathologic diagnosis of internal coronary artery lesions, it further improves the diagnostic level of coronary artery disease, thus opening up the research horizons of coronary artery disease, and provides a basis for selecting and formulating more appropriate treatment plans (PTCA, rotary excision, laser, etc.). At the same time, it can also quantitatively evaluate the effect of interventional treatment of coronary heart disease (such as PTCA, laser, etc.) (e.g., local changes before and after dilation of stenotic vessels and the prediction and prevention of restenosis, etc.).
2 Name of operationCoronary angioscopy
3 Alias of coronary angioscopyCoronary endoscopy; Coronary endoscopy
4 IndicationsCoronary angioscopy is indicated for:
1. Combined with coronary angioscopy, it is used in patients with acute coronary syndromes, that is, acute myocardial infarction and unstable angina pectoris , to provide a detailed understanding of the pathologic features of coronary artery lesions as a basis for developing a treatment plan.
2. Pathologic changes (e.g., stenosis length, severity, central or eccentric lesions, etc.) before interventional therapy (e.g., PTCA) and evaluation of post-procedural outcomes. Acute and chronic phases of myocardial infarction
5 Contraindications
1. At present, endoscopic catheters are not sufficiently thin or flexible to allow visualization of thin stenotic lesions at the end of the coronary arteries, or lesions that are in a more severe degree of tortuosity.
2. Expensive and not widely used.
6 Preparation1. Introduce the purpose, method and precautions of this operation to the patient, and obtain the patient's cooperation.
2. Coronary endoscopy is made of thin, soft fiber optics (for example, an optical fiber inner diameter of less than 3 μm, so as to make a very fine endoscopy), there are many types, only one is introduced as a representative.
(1) catheter structure
① guide catheter: the use of the usual 8F, 9F PTCA guide catheter and 5F within the guide catheter. The latter is categorized into three types: straight, varicose and balloon. It is characterized by a thin wall, a soft tip, and an embedded X-ray-impermeable localization marker, which can be delivered to the proximal end of the coronary artery and guide the endoscope to reach the vicinity of the lesion. During the operation, this guide tube can be filled with saline, Ringer's solution, etc., so that the field of view is clear; it can also be injected with contrast media and intracoronary drug delivery.
② coronary endoscopy catheter: by the center of the image-conducting fibers and the surrounding concentric arrangement of light-guiding fibers, the outer layer of polyvinyl chloride (PVC) material wrapped around the top of the fiber bundles are equipped with a miniature focusing lens; Inous et al. reported that the angioscope length of 220 cm, the outer diameter of 0.75 mm.
③ light source and camera system: coronary endoscopy Scope generally use xenon light source, the light source projected by the fiber-optic fiber to be examined stenosis, the image is transmitted by the fiber-optic fiber, to reach the frequency camera system (including cameras, light sources, color *** monitors, video printers, etc.). Video printer and monitoring system can be used for continuous recording and observation, video tape can be played back.
(2) Principle: the principle of coronary endoscopy and digestive endoscopy and bronchoscopy principle is the same. That is, the endoscope into the coronary artery system (double guiding catheter system, over the glfidewire system, monorail system). Currently, the catheter is equipped with a balloon at the tip and has the function of flexion (*** there are 2,000 to 4,000 fiber optic cables, divided into two parts: visualization and illumination) is becoming more and more sophisticated. The third generation of coronary endoscopy and additional guidewire cavity, perfusion cavity, laser fiber optic cable cavity, etc., more complete.
7 Methods 7.1 1. Methods of operationBasically the same as percutaneous transluminal coronary angioplasty (PTCA), that is:
(1) Routine seldinger method of puncture of the right femoral artery, the PTCA catheter will be inserted into the 8F smooth to the mouth of the coronary arteries, and coronary arteriography is performed.
(2) A guide wire with endoscope is inserted into the left or right coronary artery and reaches the distal part of the lesion (stenosis) (or 1 to 2 cm nearby).
(3) A 5F internal guidewire (with a soft tip) is fed along the guidewire and brought proximal to the coronary lesion. The guide wire is then withdrawn. The balloon was placed in the center of the stenosis. 10 mg of heparin saline and 200 μm of nitroglycerin were injected through the perfusion lumen, and then 5000 U of heparin were injected.
(4) While scrubbing the surface of the coronary endoscopy catheter with heparin-saline gauze to prevent coagulation, and at the same time, adjusting its focus and brightness, the coronary endoscopy was inserted through a Y connector from the internal guide tube to the proximal end of the coronary lesion; the Y connector was used for flushing and to prevent The Y-connector is used for flushing and prevents blood reflux, maintaining a clear view.
(5) The irrigation solution can be warmed Ringer's solution or 37°C saline (mixed with heparin 10 U/ml), injected from the endotracheal tube with a hand-push syringe or under pressure from a pressurizer; the volume of irrigation depends on the size of the coronary vessels and the extent of the lesion, and is generally 0.5 to 1.5 ml/s. After the balloon has been inflated (to swell the balloon and block coronary blood flow), a 10 ml syringe with a 0.6 ml/s syringe is used. After the balloon is inflated (expanding the balloon and blocking the coronary blood flow), use a 10 ml syringe to push in the fluid at a rate of 0.6 ml/s. When a large amount of flushing fluid needs to be pushed in, use an automatic flushing device or continuously push in the fluid to maintain a clear view of the coronary arteries (free of blood), and then begin to observe and videotape the situation. Note: The operation is constantly flushed and pushed into the saline solution or Ringer's solution, in order to maintain a clear field of vision. In general, every few flushes can be performed continuously for 5 to 10 seconds of observation time. At the same time, the position of the fiber catheter should be continuously moved and movements such as pushing forward and pulling back, adjusting the amount of light, etc., in order to maintain a clear field of view. The operation of the monitoring system at the same time for continuous recording.
(6) During the operation, a person should continuously monitor the electrocardiogram (or intracardiac electrocardiogram) and intracoronary pressure; if there is any abnormal change, the examination should be discontinued immediately.
(7) The operation should be continuously coordinated with coronary angiography (e.g., repeated small injections of contrast before or after PTCA at the site of the lesion in order to understand the position of the catheter and the effect of PTCA, etc.).
7.2 2. Key points of the maneuverFirst, the guide catheter is delivered to the entrance of the coronary artery, then the coronary endoscope is inserted into the guide catheter, and a 0.036-cm (0.014-in) guide wire is inserted into the endoscope (for PTCA) to reach the target site, and then the guide wire is advanced along the wire with an angiographic endoscope to the site of the atherosclerotic narrowing of the coronary artery while observing it.
7.3 3. What is seen by coronary endoscopySee Table 1 for a classification of what is seen by coronary endoscopy.
7.4 4. See Figures 1 to 12.(2) Correlation between coronary endoscopy-derived vascular cross-sectional area and actual measurements.
The correlation between coronary endoscopy-derived vessel cross-sectional area and actual measurements (Figure 13) has important clinical value.
(3) Calculation of lumen area
The calculation of lumen area is shown in Figure 14. The formula is:
Endoluminal area = (A/B) × C
where C is the cross-sectional area of the guide wire
7.5 5. Characteristics of normal coronary artery endovascular imageSystolic internal diameter is small, and diastolic internal diameter increases; the surface is smooth, flat, and grayish-white.
7.6 6. Characteristics of coronary lesions(1) Atheromatous plaques: the characteristics of the inner diameter of the coronary artery that changes with the cyclic movement of cardiac diastole and contraction no longer exists; atheromatous plaques in the lesion area, either with a convex and concave surface, or projecting into the lumen; the inner lining has a tear or undulating unevenness of the change; the color of its color is yellow, white, or a mixture of hues.
(2) Thrombus: varying in size, color, or slight movement. Generally speaking, the walled thrombus is fixed at the base, and its color varies according to its degree of old age; the floating thrombus drifts, and its color is mostly red.
(3) Plaques are divided into the following six classes:
Class I: flat, smooth, grayish-white.
Grade Ⅱ: rough surface, convex and concave in uneven shape, yellowish grayish-white.
Grade Ⅲ: in the form of a nest of rough patches.
Grade IV: plaques projecting into the cavity causing a high degree of stenosis, variable color.
Grade V: Tearing of the lining with ulceration, projecting into the lumen with a mixed hue.
Grade VI: Extremely pronounced surface roughness with small fragmentary detachments, or patchy fusion.
8 PrecautionsIssues to be addressed
1. The coronary endoscopy catheter is hopefully built to be slimmer and softer. Make it easier to pass through the stenosis of the lesion to reach the more distal part of the coronary artery (terminal part), the part with heavier bending, etc., and at the same time, reduce the complications such as tear, ***, spasm, or even perforation of the vessel lining during the operation to reach the distal end as well as to minimize the damage.
2. Coronary endoscopy can only observe part of the coronary artery lesions, its stenosis, blood flow, collateral circulation, etc. must rely on coronary angiography data, in order to get a full understanding. This not only requires a long time, more personnel, and the patient's coronary artery *** larger, so it should be improved.
3. During the operation of coronary endoscopy, in order to maintain the clarity of the field of vision, it is necessary to constantly flush with saline, which sometimes requires a larger flow rate and pressure, and is prone to cause acute coronary comorbidities, which should be improved and developed.