selection for the right coronary system
Shapes and sizes of commonly used guide catheters for the right coronary system are shown in Figure 5.2. The take off of the right coronary artery tends to vary more than that of the left coronary. If the take off is transverse, the most commonly used guide would probably be a Judkins Right (JR) 4. With a superiorly directed take off, a JR, Hockeystick, EBU‐R, or Amplatz R or L are more suitable. Inferiorly directed take offs can be cannulated with a multipurpose or SLS catheter. Although the JR shape does not provide much active support, the guide can often be actively engaged more deeply to augment support if required by “deep seating” it, ie advancement and clockwise rotation of the guide.
Figure 5.2 Shapes of commonly used guide catheters for the right coronary system.
Length
The standard length of a coronary guide catheter is 100 cm. Occasionally, shorter lengths (85 or 90 cm) are required to reach very distal lesions (e.g. LAD lesions via the left internal mammary artery (LIMA), distal native arteries via sequential saphenous vein grafts (SVGs), or retrograde approach to chronic total occlusions (CTO)). Longer lengths (110–115 cm) are required for unusually tall patients or severely tortuous aorto‐iliac vessels. The use of a long sheath and of longer balloon catheters (>145 cm) has partially overcome this problem but stent delivery catheters remain 135 cm.
Side holes or not?
Side holes help to maintain coronary perfusion when there is ostial obstruction by the guide catheter that results in pressure dampening. This can occur when using a larger guide caliber, in the presence of aorto‐ostial disease, non‐coaxial engagement, and in small caliber arteries encountered in smaller patients, often women. Side holes can reduce contrast opacification of the arteries with a consequent reduction in image quality and increased overall contrast dye utilization. The persistence of aortic pressure morphology can mask severe catheter‐induced pressure dampening which is of importance for measuring fractional flow reserve and may not always protect from hydraulically induced vessel dissection [2].
Variation in access site
The same guide catheters can be used for transradial access as well as transfemoral access. As a general rule, the same shape/size of the femoral artery apply using the left radial artery while for the right radial a ½ size smaller guide is often required. Dedicated transradial guide catheters include the Barbeau, Ikari, and brachial/radial curves. Such curves can be used for access to either the left or right coronary system and provide support against the contralateral aortic wall (Figure 5.3).
Figure 5.3 The Barbeau and radial/brachial curve catheters can be used via the radial route and have a “one size fits all” design for intervention to either the left or right coronary systems.
(Diagram courtesy of Cordis International.)
Vein grafts
Both right‐ and left‐sided vein grafts with a transverse origin can often be cannulated with a JR4 guide catheter; however, guide support can be suboptimal. If the vein graft points downwards (inferior or vertical such as often for right coronary artery (RCA) grafts), coaxial engagement may be difficult with a JR guide. A multipurpose or RCB guide is usually coaxially aligned when the take off is inferior and would also offer good support if required. Left‐sided vein grafts lesions can also often be attempted with a JR guide or, if more support is needed, with an Amplatz or Hockeystick guide catheter. If the ascending aorta is large or dilated, a guide with a more pronounced secondary curve is frequently required such as the left coronary bypass (LCB) or a large Amplatz left shape may be selected.
Left and right internal mammary arteries
Although the LIMA can often be reached with a JR guide, the more acute primary angle and longer tip of an internal mammary artery (IMA) guide is preferable. Short‐tip hook‐shaped IMA catheters can occasionally be required to intubate a very steep take off angle. Sometimes, because of subclavian stenosis or extreme tortuosity, the IMA can only be selectively cannulated via the left radial approach.
Gastroepiploic artery grafts
In an attempt to simulate the longevity of IMA grafts and overcome the problem of reaching the distal RCA, the gastroepiploic artery (GEA) is sometimes used as an in situ graft to the posterior or inferior surface of the heart (RCA, posterior descending artery, posterior left ventricular) [3]. The GEA can be cannulated using catheters designed for abdominal vascular intervention such as Cobra or Simmons catheters [4]. The celiac trunk is accessed from the abdominal aorta in the direction of the common hepatic artery (the other branch being the splenic artery) (Figure 5.4). The gastroduodenal artery arises in an inferior direction and gives off the pancreatico‐duodenal branch beyond which it becomes the GEA, which passes through the diaphragm to reach the inferior wall of the heart (Figure 5.4). Anastomotic stenoses are not rare and may require percutaneous treatment [5].
Figure 5.4 Vascular anatomy of a pedicle graft of the right gastroepiploic artery to right coronary artery.
Support
Complex anatomic situations including tortuosity, calcification, or diffuse atherosclerosis frequently require escalating degrees of backup support. The components of the “backup” support intrinsic to an angioplasty system includes the guide catheter, guidewire(s), and balloon(s) in the target artery. The components can be changed individually or in combination as demanded by the difficulties that are encountered. Hybrid strategies using more complex wire and/or balloon‐based techniques are sometimes required to overcome more challenging anatomies.
Guide catheter support
The role of shape selection has been discussed. Guide catheter support is either passive or active. Passive support is provided by a large diameter catheter positioned optimally in the coronary ostium whereas active support is provided by judiciously advancing a small diameter catheter to deeply intubate an epicardial artery.
Passive support
Although 6 Fr guide catheters are successfully used for most cases of angioplasty, larger catheters are required when complex lesions are encountered such as complex
