Fig. 28.1
Fluoroscopic unit
Images are captured using equipment that store images in a digital format where they can be displayed off line for further viewing and analysis and where reports are generated. The hemodynamic data acquired during the case are also digitally stored (Fig. 28.2). Disposable equipment come in sterile packaging. These include various supplies such as syringes, needles, wires, manifolds, sutures, clamps, bowls, gauze, drapes, towels, and catheters (Fig. 28.3). A code cart needs to always be present in the angiography suite in the event of an emergency such as a cardiac arrest or a cardiac arrhythmia that requires resuscitation of the patient.
Fig. 28.2
Example of an aortic pressure tracing during a cardiac catheterization
Fig. 28.3
Example of different coronary (a–f) and left ventricular (g) catheters. A Judkins left, B Judkins right, C Modified Amplatz Right, D Amplatz Left, E Multi-purpose, F Jacky, G Pigtail
Technique
Coronary angiography is performed via access to the femoral, radial or brachial artery. For the femoral approach, which is still the dominant route utilized in the United States, under sterile conditions, the groin is prepped and local anesthesia is applied. A needle is used to access the femoral artery through which a wire is advanced into the aorta. Fluoroscopy is used briefly to confirm the position of the wire in the aorta and the needle is exchanged over the wire for a sheath, usually 5 or 6 F, which is inserted into the femoral artery where catheter exchanges can then be made. The radial approach requires testing the patency of ulnar artery by performing an Allens’s test [2] prior to the procedure. This is done, because placement a catheter can result in thrombosis or rarely injury to the radial artery. Therefore the test is used to reduce the risk of hand ischemia ensuring adequate collateral flow from the ulnar artery. The Allen’s test is performed by having the patient clench their fist. The, physician then applies occlusive pressure to both the ulnar and radial arteries, to obstruct blood flow to the hand. The patient then opens their hand, and the patient’s fingers are observed to ensure that they have blanched. The physician then releases the occlusive pressure on the ulnar artery to determine its patency and adequate perfusion to the hand in the event of radial artery occlusion. Reversal of blanching and return of normal hand coloration or flushing the hand within 5–15 s indicates adequate perfusion of the hand by the ulnar artery allowing for use of the radial approach. Once the radial sheath is inserted a wire is advanced through the sheath to ascending aorta.
Irrespective of the route of arterial access, once the sheath is placed, a preformed catheter (Fig. 28.3) is then advanced over the wire, with fluoroscopy guidance through the sheath into the ascending aorta. A number of different catheters are used to selectively engage the left and right coronary arteries. Once selectively engaged, iodinated contrast is injected at a rate of 5–7 cc/s and cineangiography is performed in multiple angulated views with different obliquities to capture the major coronary arteries and their branches in orthogonal views for the detection of coronary stenoses. Frequently, a pigtail catheter is used to perform left ventriculography as well as aortography to assess left ventricular systolic function, the presence and severity of mitral and aortic regurgitation. If a right heart catheterization is being performed at the same time, the assessment of mitral and aortic stenosis can be performed as well. The pigtail catheter is positioned in the proximal aorta, above the coronary arteries when performing aortography and is otherwise advanced across the aortic valve into the left ventricle to perform left ventriculography or perform the hemodynamic assessment of stenotic left sided heart valves. For imaging, the pigtail catheter is connected to a power injector that is programmed to deliver contrast at a specific rate and volume into the aorta or left ventricle. The catheter has several sideholes and the distal end of the catheter is curved – both properties lend themselves to atraumatic contrast delivery while minimizing trauma to the area where it resides. After all views are obtained, the catheters are withdrawn from the body through the access sheath.
Upon completion of the cardiac catheterization the access sheath is removed. In the case of femoral access cases, frequently, vascular closure devices are used to aid in achieving hemostasis. The totality of the data suggests that these devices might reduce the incidence of bleeding, albeit at a greater financial cost as opposed to not using them. If these devices cannot be deployed, then manual compression is applied for approximately 20 min to provide hemostasis. Patients are then asked to remain supine at bed rest for a period of approximately 4 h. Radial sheaths are removed with the use of compression bands. These bands proved pneumatic compression of the radial artery and are deflated after 1–2 h. Vital signs should be done routinely as part of standard post-procedural care. Special attention should be given to the distal lower extremity pulses where the access was obtained.
Data Interpretation
There are three main coronary arteries (Fig. 28.4). The left main coronary artery takes its origin from the superior portion of the left coronary sinus and then divides into two main branches that usually supply blood to the left ventricle: the left anterior descending artery (LAD) along with its diagonal and septal branches supply the anterior, anterior septal, apical and anterolateral left ventricular (LV) walls, The left circumflex artery (LCX) along with its obtuse marginal branches supply the lateral LV wall. In 10–15 % of patients, the LCX gives rise to the posterior descending artery (PDA) which supplies blood to the inferior LV wall. The right coronary artery takes its origin from the right aortic sinus and supplies the right ventricle through its RV branches, and usually the inferior and the posterior walls of the LV through the PDA and posterior LV branches respectively.
