CEC Endovascular Techniques Chapter 1 Angiographic Techniques Section I. Arteriography Arteriography involves the injection of contrast and the acquisition of image sequences. After contrast is injected, image acquisition should begin before the contrast agent reaches the target vessel. Once the images are acquired, the patient should be asked to remain still to prevent artifacts. The amount of contrast agent injected is adjusted according to the operator’s estimate of flow and flow rate in the target vessel. In larger vessels, a catheter that delivers a sufficient dose of contrast in a short period of time should be selected. In vessels with smaller diameters, a single-hole selective catheter is sufficient. In vessels with higher resistance, the contrast injection rate can be adjusted downward and the injection time can be extended. The image acquisition rate can also be adjusted according to the blood flow rate. Zhang Jie, Department of Vascular Surgery, Beijing Luhe Hospital, Capital Medical University I. Imaging of the cephalobrachial artery Features: (1) Longer catheters and guidewires are required at a distance from the puncture point of the femoral artery; (2) Risk of stroke (caused by catheter and guidewire manipulation, microbubbles, and intracatheter thrombus). When using a contrast catheter to superselect into each branch artery of the aortic arch, the tip of the catheter should enter several centimeters or more into the branch artery to prevent catheter ejection back into the aortic arch during imaging. If there is a significant occlusive lesion in the aortic arch or in the opening of a branch vessel in the arch, the risk of stroke from catheterization is high and other imaging should be considered for the patient. Carotid angiography can be performed using a high-pressure syringe. It is important to ensure that the catheter tip is far enough away from the lesion and that the entry into the branch vessel is deep enough to avoid ejection of the catheter tip during injection, and attention should be paid to flushing the catheter with heparin saline to avoid thrombosis and repeatedly verifying to prevent the entry of small air bubbles. The bifurcation of the carotid artery can be observed in the orthogonal, oblique and lateral positions. The Townsend and lateral positions are commonly used for visualization of the intracranial arteries. In the unnamed artery, the contrast injection rate is 4-8 ml/sec for 3-4 seconds, the image acquisition is 4 frames/sec, and the projection angle is usually right anterior oblique (RAO): the contrast injection in the common carotid artery is usually 3-5 ml/sec for 2-3 seconds. The carotid bifurcation is often projected in anterior-posterior (AP) and lateral positions. Because the bifurcation site and the proximal lesion of the internal carotid artery are often located in the anterior wall of the artery, oblique and lateral views are required to better visualize the stenosis. The patient is asked to hold his breath and sink his shoulders during the imaging. 2.Subclavian arteriogram The first step of subclavian arteriogram via femoral artery puncture is the aortic arch angiogram, which is usually a good assessment of the subclavian artery. However, if the subclavian artery is severely diseased, it will be very slow to visualize compared to other branches, thus requiring an optional angiographic evaluation. After the catheter is placed in the subclavian artery, it is aspirated to check for microbubbles, flushed with heparin saline, and then connected to a high-pressure syringe. The contrast is injected at a rate of 4-6 ml/sec for 3-4 seconds and the images are acquired at 4 frames/sec. The contrast should be injected away from the disease or vertebral artery opening to prevent arterial entrapment or embolization. In most cases, a subclavian arteriogram is sufficient to assess the vertebral artery. When further clarification of the vertebral artery is needed, the vertebral artery can be hyper-selected for low-pressure contrast injection, noting that the vertebral artery is highly susceptible to spasm. In the presence of subclavian artery steal, image acquisition should be delayed until a reverse flow from the vertebral artery into the subclavian artery is demonstrated. Subclavian arteriography can also be performed with an ipsilateral brachial artery puncture approach. After catheter placement, 4-8 ml of contrast is usually sufficient to complete the subclavian arteriogram by hand. However, if the subclavian artery is severely diseased and the blood flow is small, it is extremely difficult to puncture the brachial artery, and ultrasound guidance is required. Second, aortic arch imaging Puncture the femoral artery, place a standard 4F or 5F femoral sheath, enter the guidewire until its head end is in the ascending aorta, taking care to avoid the guidewire entering the left ventricle or coronary artery causing arrhythmia, and then enter a 90-cm pigtail catheter along the guidewire with the head end placed in the ascending aorta. The image acquisition should include the aortic arch, carotid artery, and extracranial segment of the vertebral artery. The projection angle is adjusted to fully expand the aortic arch (LAO position). The guidewire is withdrawn and the pigtail catheter is connected to a high-pressure syringe. The patient is instructed to hold his or her breath and avoid swallowing movements after the start of the imaging procedure. The contrast injection rate is usually 15 mml/sec for 2 seconds and the image acquisition rate is 4 frames/sec for 6-8 seconds or until the contrast is empty. (1) The visceral and renal arteries are prone to spasm, which can cause ischemia in the organ; (2) The position of these arteries is greatly influenced by respiration and diaphragmatic movements; (3) The angle of access to the visceral and renal arteries from the femoral artery is sharp, and in some cases a proximal brachial artery puncture approach is required. 1. Abdominal trunk and superior mesenteric artery angiography The femoral artery is punctured, a guidewire is placed, and a 4F or 5F pigtail catheter is placed along the filament to the level of the diaphragm. Abdominal aortography is performed using a high-pressure syringe at a rate of 8-12 ml/sec for 3 seconds. The cobra catheter is selected to enter the visceral arterial opening at least 1-2 cm to prevent catheter ejection during diaphragmatic motion or pushing of the contrast medium. The contrast rate for the abdominal trunk and superior mesenteric artery was 4-6 ml/sec for 3 seconds, with 4 frames/sec images. The celiac trunk and mesenteric opening are best visualized in lateral projection, but their distal branches are best visualized in anterior-posterior (AP) or oblique position. If the catheter needs to remain in the visceral artery for several minutes, nitroglycerin may be given to prevent vasospasm. 2. Renal arteriogram Aortogram near the renal artery is performed first (the catheter tip is located near the opening of the renal artery), and the guidewire is delivered to the T12 level under fluoroscopy. A pigtail catheter is placed and a small amount of diluted contrast is hand-pushed to confirm that the catheter is located in the lumen. A high-pressure syringe is applied and projected in the orthogonal, right anterior oblique, and left anterior oblique positions, respectively. All three projection angles allow determination of the renal vascular anatomy and also allow estimation of the size and shape of the kidney. Usually 40 ml of contrast is injected at a rate of 15 ml/sec, while 30 ml at a rate of 12 ml/sec is sufficient for lighter patients. The catheter position can be adjusted to avoid contrast regurgitation into the superior mesenteric artery, which could interfere with the visualization of the left renal artery opening. Selective renal arteriography can provide a detailed distribution of the renal vascular anatomy. The cobra catheter is delivered to the renal hilum, the hilar region, and the tip is reshaped by partially withdrawing the guidewire, with the catheter tip sliding along the aortic wall toward the target side. In most cases, the catheter can be popped into the renal hilum. If the catheter fails to hang on to the renal artery, a hydrophilic guidewire is used to assist in feeding the catheter. The renal artery opening is slightly posterior to the lateral wall of the aorta and is usually obscured by the aortic wall. ipsilateral anterior oblique 1 0 provides a good view of the renal artery opening. The contrast rate is 3-6 ml/sec for 2-3 seconds. If the catheter needs to stay in the renal artery for several minutes, systemic heparinization is performed in advance, and nitroglycerin is given across the painful burner to prevent vasospasm. A common catheter used for aortoiliac angiography is a 4F or 5F pigtail catheter or Omni-flush catheter. The tip of the catheter is placed near the opening of the renal artery. If multiple stenting is considered, a marker catheter is used, with the first marker placed at the inferior border of the renal artery, wrapping down to the level of 12 thoracic to 1 lumbar and laterally to include both kidneys. The patient is instructed to hold his or her breath while 6-15 ml/sec of contrast is injected for 2-3 seconds, with 4 frames/sec until the contrast is empty. The anterior oblique 30-degree projection can unfold the contralateral iliac artery bifurcation and the ipsilateral femoral artery bifurcation. The imaging catheter is placed at the level of the renal artery, and the image acquisition range includes the aorta to the feet, which is known as the “stepping” technique. The other method is to perform a main iliac artery image first, then a femoral artery image, and so on, to the dorsal arteries of both feet. The key points of the “step-in” technique are: position the patient’s hips, knees and feet in a straight line under fluoroscopy, move the bed towards the head to avoid lateral movement, determine the position of the bed at the beginning and end of the image acquisition and lock it in place, then manually move the bed once from the abdominal aorta to the feet to acquire images for subtraction. The patient is instructed to remain still, the bed is returned to its original position, the contrast is injected, and the bed is controlled to track the contrast to the feet to obtain the infrarenal aorta-lower extremity artery image at a rate of 7-lO ml/sec for 8-12 seconds. Using the “step” technique, long distance images of the contrast flow range can be obtained at the same time as the contrast is injected. However, when there is an occlusive or stenotic lesion on one side of the artery, there will be a difference in the flow rate of the contrast medium in both lower extremity arteries, resulting in inadequate assessment of one lower extremity artery. In addition, due to the presence of lesions, the intra-aortic contrast may not reach the distal arteries such as the dorsalis pedis artery, and further imaging of the N and tibial arteries may be required. Femoral artery and infrapopliteal artery angiography Femoral artery angiography is performed by either a contralateral femoral artery puncture or an ipsilateral femoral artery puncture. A standard contrast catheter or sheath can be used. The contrast medium can be either hand-pushed or machine-injected. The easiest way to perform a femoral artery image is to take a segmental image of the lower extremity arteries by pushing 6-lO ml of contrast in 4-5 separate injections. In patients with occlusive lesions in the femoral artery, the tibial artery, and the dorsalis pedis artery, the following arteriograms are superselected, usually with long, straight catheters with multiple lateral holes, placed as distally as possible. Dorsalis pedis arteriogram It is usually difficult to visualize the dorsalis pedis artery with the contrast agent injected in the abdominal aorta. When detailed information about the arteries of the foot is needed, the catheter should be placed as far as possible in the N artery and 5-lO ml of contrast agent should be hand-pushed within 1-2 seconds to complete the imaging. The imaging is usually performed in a hip abduction position with the knee joint relaxed. When there is an occlusive lesion in the superficial femoral artery on the same side, the contrast is injected into the common femoral artery in an amount sufficient to reach the foot. Contrast injection can cause discomfort in the lower extremity of the ischemic side, causing limb movement and affecting the quality of the image, but this also… This also suggests the time interval between contrast injection and arrival at the ischemic limb. In patients with severe ischemia, there is usually a delay of 20 seconds after contrast is injected from the femoral artery before it reaches the foot. The sensation of contrast reaching the ischemic foot is more unpleasant for the patient, and appropriate sedation can be given before performing selective dorsalis pedis arteriography. Aortography for aortic aneurysms Aortography cannot accurately assess the true maximum aortic aneurysm diameter and the overall morphology of the aneurysm. However, it is useful to evaluate the inflow and outflow tracts. Abdominal aortic aneurysm imaging is performed with machine injection of contrast over the renal artery and not within the aneurysm lumen to avoid blowing out the thrombus in the aneurysm lumen and causing ectopic embolism. An oblique position or special angle helps to show the aneurysm neck. The contrast agent is often diluted by the time it reaches the distal part of the aneurysm, as another angiogram is often needed to assess the distal outflow@ tract. Section II venography I. Lower limb deep vein cascade imaging [Indications] To examine the patency of the deep veins of the lower limbs, the nature, extent and degree of venous obstruction and the establishment of collateral circulation, and to understand the function of the traffic branch veins and the condition of the deep venous valves. Contraindications】 1.Confirmed or highly suspected acute pulmonary artery embolism. 2.Patients with diagnosed or highly suspected acute lower limb deep vein thrombosis. 3.Patients with hypercoagulable blood. Operation method and procedure】 1.Patients lying supine on the X-ray machine platform, use 12-16 gauge vascular puncture needle to puncture the superficial dorsal foot vein of the affected limb proximally, for those who cannot easily puncture or fail to puncture can do venotomy. 2.Head high foot low position, tilt 30 degrees a 45 degrees, slow down the rate of contrast reflux. 3.Loop rubber tourniquet around the ankle to block the superficial vein. 4.Tell the patient to step on the X-ray machine pedal with the healthy limb and the affected limb in the draped position, rotate it slightly inward, and inject the contrast agent continuously and evenly. 5.Under the observation of monitor, follow the contrast agent and take ortho-imaging film from the distance of calf (ankle) joint to the pelvic area. 6.If the deep vein is patent, press the patient’s abdomen, and make the patient hold his breath and bulge his abdomen to do Valsalva exercise to observe the deep venous reflux. 7.Remove the tourniquet, let the patient lie down and slowly inject saline or heparin saline. 1.Iodine allergy test should be done before, the contrast agent is non-ionic contrast agent, currently there are Uvexan and iodixanol, renal insufficiency can use isotonic contrast agent iodixanol which has less side effects. 2. Although a few people have negative iodine allergy test, they still have different degrees of allergic reactions during the imaging, so the necessary treatment should be given at this time. 3.Geriatric patients, patients with chronic renal insufficiency, and even all patients proposed for imaging can be hydrated for 24 hours before and after imaging. Encourage the patient to drink more water after the imaging to facilitate the excretion of contrast agent. For patients with high blood viscosity, postoperative anticoagulation and decongestion therapy can be given as appropriate to avoid thrombosis. Retrograde angiography can clearly show the iliac and femoral veins, which can supplement the deficiency of the lower extremity deep vein parallelepipedal angiography, and also accurately show the location and morphology of the deep vein valves, and determine the type and degree of the incompetent deep vein valves. Contraindications】 1.Pulmonary artery embolism is diagnosed or highly suspected. 2.Patients with diagnosed or highly suspected acute lower limb deep vein thrombosis. 3.Patients with hypercoagulable blood. Operation method and procedure】 1. The patient is placed in supine position, and the skin of thigh, perineum and lower abdomen is disinfected. A small hole is made in the skin at 0.5 cm medial to the arterial pulsation of the inguinal ligament of the affected limb by local anesthesia with a sharp knife, and the common femoral vein is punctured by the Seldinger method. 2, Head high foot low position, tilt 60 degrees. 3.Patients with hypercoagulable blood. The patient is placed in the supine position, and the skin of the thigh, perineum and lower abdomen is disinfected. Local anesthesia is applied at 0.5 cm medial to the arterial pulsation of the inguinal ligament of the affected limb, and a small hole is made in the skin with a sharp knife, and the common femoral vein is punctured by the Seldinger method. 2, Head high foot low position, tilt 60 degrees. 4.Place the catheter in the external iliac vein (F), inject contrast, and observe the patency of the iliac vein and inferior vena cava. 4.Retract the catheter slowly to the level of the femoral head, inject contrast, and press the patient’s abdomen at the same time, and let him do Valsalva movement to observe the deep venous regurgitation and venous valves downward. 5.Take orthopantomogram under monitor observation. 6.Slowly inject saline or heparin saline through the catheter. 7.Remove the catheter and stop the bleeding with local compression at the puncture site. 8.Postoperative bed rest, elevate the affected limb, and get out of bed after 24h. Precautions】 The same as lower extremity deep vein paracentesis. The commonly used method for upper limb venography is to enter through the median elbow vein or peripheral dorsal hand vein, with the arm abducted 5-10 degrees, and ask the patient to hold his breath and inject 50ml of contrast agent within 5 seconds. After the injection, the patient is asked to elevate the arm 60 degrees for 3 seconds. After the injection of 10 ml of contrast agent, the patient is asked to hold his breath and the injection of contrast agent is stopped once sufficient images are obtained. IV. Inferior vena cava-iliac vein imaging Femoral vein access: 5F sheath is placed after puncture, 0.035-inch guidewire is placed in the common iliac vein, and a 5F pigtail catheter or vena cava catheter enters the common or inferior vena cava for vena cava/iliac vein imaging. Internal jugular vein access: 0.035-inch guidewire through the right atrium to the inferior vena cava or common iliac vein. Hand-push contrast rate of lO ml/sec, total volume 20 ml. V. Superior mesenteric and portal venography Superior mesenteric venography can be accomplished indirectly by superior mesenteric arteriography or directly into the superior mesenteric vein by intrahepatic puncture through the jugular vein or by percutaneous hepatic puncture. The venous phase created by the superior mesenteric artery injection provides an image of the inflow of the superior mesenteric vein region into the portal venous system. After establishing arterial access, the 4F contrast catheter is placed into the aorta, selected into the superior mesenteric artery, the catheter position is determined by hand-pushing the contrast agent, and the contrast agent is injected mechanically with a high injection rate of 5 ml/second for a total of 10 ml. The method of percutaneous hepatic puncture is an effective technique for direct access to the portal venous system. Under ultrasound guidance, the right portal vein is marked on the skin in the same plane as the overlapping right hepatic vein and the point where the portal vein is closer to the ultrasound probe, and the right portal vein is punctured aseptically with a 1 8-gauge puncture needle, allowing for imaging of the portal vein and superior mesenteric vein, as well as thrombolysis, angioplasty, and stent placement. In the 1960s, Rosch’s invention of portal venography via intrahepatic puncture of the jugular vein changed the technique of hepatic puncture and led to the development of transjugular intrahepatic portosystemic shunt (TIPS). A 10F sheath is placed into the inferior vena cava through the right internal jugular vein, an elbowed contrast catheter is selected into the hepatic vein, the tip of the sheath enters the hepatic milliportal vein, and an appropriate transjugular venipuncture needle is selected to pass from the hepatic vein through the hepatic parenchyma into the portal branch. 0.035″ stiffened guidewire is placed into the superior mesenteric vein, and the needle is replaced with a needle from the hepatic vein. The vein is replaced with a 5F porous contrast catheter and placed in the portal vein for imaging. VI. Angiography for Buga syndrome can be performed through the femoral vein or through the jugular vein. A Simmons 1 catheter or cobra catheter is applied to enter the inferior and superior hepatic vena cava from the groin and selected into the hepatic vein. A straight or angled catheter is easily placed into the hepatic outflow tract from the jugular vein. 5-10 ml of contrast is hand-pushed to reveal a specific spider-like image of the occluded hepatic silent system. In some cases, such as inferior vena cava obstruction, the best way to image is with an inferior vena cava angiogram. A pigtail catheter is placed at the level of the distal inferior vena cava at a rate of 15 ml/sec, for a total volume of 30 ml.