In order to engage a native coronary artery, a view that is orthogonal to its takeoff, i.e., LAO view, should be used (Figure 35.1). In general, with any Judkins catheter, a larger arm makes the catheter point down, whereas a shorter arm makes the catheter look up. From a femoral access-Advance the JR4 catheter to the aortic valve, then pull slightly to free the catheter, then pull and clockwise torque 90–180° in one motion (both the pull and clockwise motions must be coordinated). If the catheter is excessively torqued (>180°), one should be prepared for a slight counterclock as the catheter engages the RCA. The torque is not transmitted to the tip unless the catheter is pulled/pushed by the operator. Torquing the catheter in place does not lead to any torque transmission to the tip; then, immediately as the catheter is pulled, all the excessive torque is transmitted. The key to a successful RCA engagement is a coordinated and simultaneous pull and torque (90–180°). In addition, the catheter tip has a tendency to dive down when the torque gets transmitted, hence the importance of keeping a pulling tension on the catheter as the torque is transmitted. A second technique consists of positioning the catheter 2–3 cm above the ostium, followed by a clockwise torque; the catheter will dive into the RCA ostium. A pulling tension needs to be maintained during the torque maneuver, as the catheter may dive too low upon torque transmission. An AR catheter is handled similarly to a JR4, except that the torque transmits to the tip more easily and the catheter has less tendency to dive down upon torque transmission. It points more downward than JR4. A no-torque catheter (3DRC or Williams right catheter) is, in a way, a JR4 catheter that is already torqued (Figure 35.9). All the operator has to do is advance it to the aortic valve then pull it to engage the RCA. A slight torque may be necessary if the RCA is not immediately engaged. For experienced operators, this catheter may not offer any advantage over the JR4 catheter, including no advantage in anomalous RCA takeoff. It has a short tip like JR4 and points slightly more upward than JR4. Figure 35.1 (a) Axial cut at the level of sinuses of Valsalva. R is the right cusp, L is the left cusp, and NC is the non-coronary cusp. LAO view is orthogonal to the ostia, and therefore displays the coronary arteries in front of the operator, permitting the catheters to be torqued towards the appropriate plane. (b) Aorta opened in LAO view. NC is the most posterior cusp, and as such, it is also the lowest cusp (the aorta tilts posteriorly after its takeoff, which makes its posterior aspect lower than its anterior aspect). R is the second lowest cusp. When you see a catheter “fall down”, it is either in the R or NC cusp. R is also the most anterior cusp (toward the RV). Figure 35.2 (a) Judkins left (JL) catheter. The size of the Judkins catheter is the distance between the primary and secondary curve, in cm (JL3 → 6). The secondary curve is what sits on the contralateral aortic wall. (b) Judkins right (JR) catheter. Courtesy of Mark Freed and Robert Safian, Physician’s Press, Royal Oak, MI. Figure 35.3 In the case of an elongated or enlarged aorta (elderly, hypertensive, or tall patient), the JL4 arm may be too short and the catheter may point up and risk dissecting the left main upon contrast injection. In addition, the secondary curve may fall down and the catheter may fold on itself. Use a larger curve (JL5, JL6) to make the catheter look down and be coaxial with the ostium. Figure 35.4 The Amplatz left (AL) catheter has a “duck” shape. AL may be used to engage the left coronary artery but also a right coronary artery with superior takeoff. Courtesy of Mark Freed and Robert Safian, Physician’s Press, Royal Oak, MI. Figure 35.5 AL sits both on the back wall of the aorta and on the aortic valve (usually contralateral cusp), and thus provides support both from the opposite wall of the aorta and from the cusp. AL points up, but may point down if the AL curve is small relatively to the aorta. In addition, if the AL curve is small, the AL may not sit on the aortic valve. Unlike Judkins, a larger curve makes it point up. Reproduced with permission of Wolters Kluwer Health from Baim DS. Coronary angiography. In Grossman W, Baim DS. Grossman’s Cardiac Catheterization, Angiography, and Intervention, 7th edn. Philadelphia, PA: Lippincott Williams & Wilkins, 2006, pp. 187–221. Figure 35.6 AL engaging the RCA. AL looks up if the AL curve is proportionate to the aortic size; less frequently, AL looks down if its curve is small in relation to the aorta (e.g., AL1 in a dilated aortic root). Courtesy of Mark Freed and Robert Safian, Physician’s Press, Royal Oak, MI. Figure 35.7 The primary-to-secondary distance distinguishes Amplatz right (AR) 1, 2, and 3. The size of the secondary curve (S), per se, distinguishes AR catheter from AL catheter. AR has a smaller curve than AL. Therefore: (1) AR does not sit on the aortic cusps or the back wall of the aorta, and does not provide support from these structures; (2) as opposed to AL, AR points down. Courtesy of Mark Freed and Robert Safian, Physician’s Press, Royal Oak, MI. Figure 35.8 Engagement of RCA. The catheter must be positioned on the right cusp before pulling with a clockwise torque. If contrast puffs show the convexity of the aorta (arrow), the catheter is already too high, above the ostium. Reverse the torque, push the catheter down, and reattempt to engage. From a right radial access- The catheter is positioned on the right coronary cusp, then pulled with a clockwise torque. The catheter is much less likely to dive with torquing, compared with femoral access; in fact, the main concern is pulling the catheter out of the ascending aorta. Thus, only a slight pull and torque is required from a radial access. Figure 35.9 The 3DRC catheter is, in a way, a JR4 that is already torqued. It simplifies JR4 engagement but does not have any major advantage over JR4 for experienced operators. It may facilitate RCA engagement when the torque does not get well transmitted, e.g., steep aortic arch. In some patients, one may get the impression that the RCA origin is low, very close to the aortic valve. More specifically, in an elderly patient with an elongated, almost horizontal ascending aorta, the origin of the RCA seems to be displaced downward (Figure 35.10). In fact, the distance between the aortic valve and the coronary origin is the same as in a normal aorta; however, the level of this origin is down. That is why, in those patients, one should seek the RCA origin at a level close to the aortic valve. Once the catheter is at the outer curvature of the aorta, it is already too high, above the RCA level; it should be readvanced to the aortic valve and pulled back more slowly. Figure 35.10 (a) Origin of the RCA in a young patient. (b) Origin of the RCA in an old patient with elongated ± dilated aorta: RCA seems to be displaced downward and is at the same level as the aortic valve. Tip: the way the catheter body is shaped in the ascending aorta gives an idea about the shape of the aorta. Once the catheter reaches the outer curvature of the aorta (star), it is already too high. Also, the steepness of the aortic arch (arrow) dictates how difficult the torque transmission will be. In a steep arch, a catheter that requires less torque is preferred (AR, Williams right). The most common cause of failure to engage the RCA is an anomalous anterior and high takeoff (Figure 35.11). In this case, use an extreme LAO view, or better, an RAO view to be orthogonal to the origin of the RCA and attempt engaging in this view, initially using the JR4 catheter. JR4 may fail to engage the RCA because its tip is too short to reach. Alternatively, switch to an AL0.75 or AL1 catheter. Non-selective contrast injections help identify the level of the RCA. If the above two techniques fail or if the RCA is not seen during contrast injections over the right sinus of Valsalva, RCA may be originating further up or from the left sinus of Valsalva, in which cases a larger AL is needed. For RCA originating from the left, a larger AL (1 or 2) may be used and aimed towards the left, or a short left Judkins (JL 3 or 3.5) The RCA origin is posterior and lower than the conus origin (Figure 35.12). Thus, when the conus is engaged but not deeply so, one may continue to clockwise torque the catheter, aiming more posteriorly. If this fails, switch to a catheter that points further down, such as JR4 (if Tiger was used), or JR5 or AR1 (if JR4 was used). Figure 35.11 Axial cut at the level of the sinuses of Valsalva. Instead of LAO, RAO or 90° lateral view is orthogonal to an anterior RCA and allows easier engagement. Choose a catheter that is long enough to reach the anterior RCA. JR4, when aiming in that direction, is too centered and short rather than elongated and eccentric. AL catheter or AR2 may be necessary to reach an anterior RCA. Figure 35.12 Relationship of the conus branch and RCA. If JR4 falls into the conus branch, a catheter pointing more downward, such as JR5 or AR, will successfully engage the RCA. In patients with an elongated aorta (widely folding aorta) or a dilated aorta, such as tall or elderly hypertensive patients, the short arm of the JL4 catheter tends to fold on itself even before reaching the left coronary level (Figure 35.13–15). Even when the ostium is successfully engaged, the catheter tip points up in the left main artery, with a subsequent risk of left main dissection and inappropriate imaging (Figure 35.3). A catheter with a larger arm, i.e., larger primary-to-secondary-curve distance, should be used (e.g., JL5, JL6). Furthermore, in those cases, it is important to advance the catheter over the wire until it reaches the aortic valve before taking out the wire, to prevent the catheter from “flipping” over itself. If, on the other hand, the JL catheter is pointing down underneath the ostium, or the aorta is too narrow for the catheter, a smaller JL arm should be used. Figure 35.13 (a) Engagement of the left coronary artery in patients with normal-size aorta. (b) Engagement of the left coronary artery in patients with elongated aorta. In this case, make sure to advance the catheter all the way to the aortic valve before taking the wire out, otherwise the arm of the JL catheter may fold on itself. Reproduced with permission of Wolters Kluwer Health from Baim DS. Coronary angiography. In Grossman W, Baim DS. Grossman’s Cardiac Catheterization, Angiography, and Intervention, 7th edn. Philadelphia, PA: Lippincott Williams & Wilkins, 2006, pp. 187–221. Figure 35.14 In (i), the whole catheter falls down and tip points up→a longer JL arm is needed (e.g., from JL4 to JL5). In (ii), the catheter is in a tight space and elongated→a shorter JL arm is needed (e.g., from JL4 to JL3.5). Alternatively, in (i) or (ii), pull and readvance with a clockwise torque, which turns the catheter up. Figure 35.15 JL catheter engagement when it falls slightly below the left coronary ostium in a wide aorta. Push the catheter against the aortic valve to reshape it, and keep pushing gently until the tip catches the ostium (step 1). Next, the catheter is slightly pulled until it becomes more coaxial with the ostium (step 2). Clockwise torque may also help, as well as a deep breath which straightens the aorta. If the JL4 keeps selectively engaging the LAD in a patient with a short LM or separate ostia for the LAD and the LCx, how can the catheter be directed toward the LCx? Unlike the JR catheter, the JL catheter has a hinge point on the aorta (secondary curve) so that clockwise rotation of the JL catheter moves it posteriorly. Thus, to move the catheter from the LAD to the LCx, which is more posterior, the catheter is typically rotated clockwise. To move the catheter from the LCx to the LAD, the catheter is rotated counterclockwise. In a patient with a large aorta, when the JL4 catheter is not resting on the aorta, the opposite maneuvers may be effective. On the other hand, it is often more effective to switch catheters. Two principles allow the selection of the proper catheter: (1) the LAD points up, whereas the LCx points down; (2) a larger JL catheter arm makes the catheter point down and moves the tip from the LAD to the LCx (e.g., JL5 points down in comparison to JL4, EBU4 points down in comparison to EBU3.5). Thus, in order to move the catheter from the LAD to the LCx, one may use a larger JL catheter (JL4 → JL5); in order to move the catheter from the LCx to the LAD, one may use a smaller JL catheter (JL5 → JL4; or JL4 → JL3.5) In addition, when the LM is short, one may use a short-arm AL catheter to selectively engage the LCx (AL1.5). A short-arm AL tends to point down (opposite of short-arm JL), and thus would selectively point towards the LCx. A long-arm AL points up to the LAD. Advance a wire until it loops over the aortic valve, then advance the AL catheter all the way over the wire onto the aortic cusp: the tip of the AL must catch the cusp of interest, while the body must sit on the contralateral cusp. Next, push the catheter up with a counterclockwise rotation in order to catch the left coronary ostium, or push with a clockwise rotation in order to catch the RCA ostium (Figure 35.16). During those manipulations, the wire is kept inside the catheter body to improve catheter pushability and torqueability; the wire is pulled out when the catheter is close to the ostium. Once the AL catches the ostium, slightly withdraw the catheter for deeper and more coaxial engagement. When used to engage a SVG, the AL catheter is not advanced all the way down to the aortic valve level. The AL is advanced to the ascending aortic level above the native coronary level, then torqued while in a flat elongated shape similar to Figure 35.16 (a) until it catches the appropriate SVG ostium. Once engaged, AL is pushed to adopt its duck shape. If a well-seated AL is pulled out, the tip has a tendency to be “sucked” in deeper. Thus, in order to disengage an AL, one should push it until it prolapses out of the ostium, then clock it out (push and clock). As opposed to Judkins catheters, AL disengagement should be performed under fluoroscopy. In some cases, pushing the catheter may further advance it inside the artery; therefore, gentle maneuvering under fluoroscopy with a change in strategy may be required. More specifically, when using a small-curve AL that is not sitting on the valve, pulling the catheter may rather be needed to disengage it (Figure 35.17). Also, when an AL guide catheter is used, pushing may further advance rather than retract the catheter; this is because guide catheters are stiffer than diagnostic catheter and are less likely to flip out of the ostium with a push. Thus, when an AL guide is used, one may directly pull it under fluoroscopy, preferably over a balloon catheter. From a radial access-Severe subclavian tortuosity is likely preventing torque transmission. Perform all torquing maneuvers with the guidewire inside the catheter, to prevent kinking. Engage the left main from underneath it, by looping the catheter over the aortic valve until it catches the ostium. Guide catheters have a stiffer shaft but a larger internal diameter than diagnostic catheters. Guide catheters rely on three elements for support: (1) coaxial guide alignment with the coronary takeoff; this is the most important aspect of support and is achieved not just by advancing the catheter into the ostium but by clockwise (RCA guide) or counterclockwise torque; (2) deep engagement; (3) Support from abutting the opposite aorta and/or the aortic valve (AL guides abut both the opposite aortic wall and the aortic valve, while the extra-backup guides abut the opposite aortic wall). Guides useful for left coronary interventions (Figure 35.18) Figure 35.16 Catheterization of the left coronary artery with an Amplatz left catheter in LAO view, which spreads out the left and right coronary cusps.(a, b) The wire is sent towards the left coronary cusp, then the catheter is advanced over the wire in such a way that its tip catches the left coronary cusp, while its body aims towards the right coronary cusp. The wire is kept inside the catheter for pushability and torqueability. (c) After the tip catches the left cusp, the catheter is pushed with a slight counterclockwise torque until it catches the ostium. (d) The catheter is then pulled for more coaxial engagement. Figure 35.17 Small-arm Amplatz catheter. Pushing it may further dive it inside the left coronary artery rather than disengage it. Figure 35.18 Extra-backup guides and AL guide for the left coronary artery. XB with the long tip (XB4, as opposed to XB3.5) is useful for LCx intervention (looking down) or for a patient with a long LM. Courtesy of Cordis Corporation. Figure 35.19 Small-arm AL guide catheter (AL1) is used to engage the LCx in a patient with a short LM. A small AL arm points down towards the LCx (arrow) and provides good coaxial support for a LCx intervention in a patient with a short LM. Figure 35.20 Guide catheters for superior RCA takeoff and inferior RCA takeoff. Courtesy of Cordis Corporation. Figure 35.21 AL1 guide catheter engaging the RCA, and providing good backup support from the aortic cusp and the opposite aortic wall. In order to engage SVGs, it is important to understand their locations and takeoffs (Figure 35.22). The SVG-to-LAD or SVG-to-diagonal branch originates from the anterior surface of the aorta. The SVG-to-OM originates from the left posterior surface of the aorta. The SVG-to-RCA is best engaged in an LAO view, which is orthogonal to this SVG takeoff. SVGs to the left coronary branches are best engaged in an RAO view, which is orthogonal to the takeoff of these SVGs (Figures 35.22, 35.23) (Right SVG → LAO; Left SVG → RAO). When rings are attached to the SVGs, engage each SVG in a view orthogonal to the ring, i.e., a view where the ring is seen as a straight column. In order to engage the SVG-to-RCA, the catheter is positioned above the level of the RCA, then pulled with a counterclockwise rotation. As opposed to what may make intuitive sense, counterclockwise torquing is used to engage the SVG-to-RCA rather than clockwise torquing (this is opposite to native RCA engagement). Explanation: counterclocking a catheter 180° does not reach the same point as clocking it 180°. Imagine the catheter movement 3-dimensionally: counterclocking reaches a parallel but more posterior plane compared to clocking (Figure 35.23). SVG-RCA is often posterior compared to the native RCA; only when it is anterior, clocking may successfully engage it. Figure 35.22 Location of SVGs: LAO view is orthogonal to the takeoff of SVG-to-RCA, while RAO view is orthogonal to the takeoff of SVG-to-left coronary branches. Figure 35.23 LAO view is orthogonal to the marker of SVG-to-RCA, perfectly laying out the ostium as it comes off the aorta. The view may be angled further LAO until the marker becomes one line. In LAO, SVG-to-OM is looking at you, making it difficult to engage. RAO view is orthogonal to the marker of SVG-to-OM, while it is in line with the SVG-to-RCA. Right image–Clockwise torque of a standard catheter (e.g., JR4), tilts it anteriorly (–>toward left SVG and native RCA=1), while counterclockwise torque tilts it posteriorly (–>toward SVG-to-RCA=2); 180° torque in one direction reaches a different point than 180° in the other direction. In order to engage an SVG to a left coronary branch, advance the catheter down to the aortic valve, torque it counterclockwise, then pull up and torque clockwise around the expected level of the graft.
35
Cardiac Catheterization Techniques, Tips, and Tricks
I. View for the engagement of the native coronary arteries: RAO vs. LAO
II. Design of the Judkins and Amplatz catheters (see Figures 35.2–35.7)
III. Engagement of the RCA (see Figure 35.8)
IV. How to gauge the level of the RCA origin in relation to the aortic valve level
V. What is the most common cause of failure to engage the RCA? What is the next step?
VI. Tiger or JR4 catheter engages the conus branch. What is the next step?
VII. Left coronary artery engagement: general tips
VIII. Management of a JL catheter that is sub-selectively engaged in the LAD or LCx
IX. Specific maneuvers for the Amplatz left catheter
A. Engagement
B. Disengagement
X. If you feel that no torque is getting transmitted, what is the next step?
XI. Appropriate guide catheters for left coronary interventions
XII. Appropriate guide catheters for RCA interventions (Figure 35.20)
A. Horizontal RCA takeoff
B. Inferior RCA takeoff
C. Superior RCA takeoff
D. High anterior RCA takeoff
XIII. Selective engagement of SVGs: general tips
XIV. Specific torque maneuvers for engaging the SVGs
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