In Chapter 4 , Access, we discussed about how to obtain arterial access. In this chapter we describe the steps involved in advancing a catheter over a guidewire from the access site to the coronary ostia and engaging the coronary arteries. Neither diagnostic angiography nor PCI can be performed without engaging the coronary artery ostia. Although the steps involved in engaging the coronary arteries are simple and performed numerous times daily in the cardiac catheterization laboratory, difficulties may be encountered, potentially leading to severe complications.
5.1
Step 1. Catheter selection
5.1.1
Goal
To select a catheter that will most easily and safely engage the target coronary artery in a co-axial orientation while providing optimal support. Guide catheter selection is one of the most critical decisions to ensure procedural success, efficiency, and safety.
5.1.2
How?
Catheter selection is based on arterial access site (radial vs femoral), the target coronary vessel and the size of the aorta, as described in Section 30.2.6 . Optimal coronary engagement can be facilitated by optimal (diagnostic or guide) catheter selection.
5.2
Step 2. Advance guidewire to aortic root
5.2.1
Background
Catheter advancement is always performed over a 0.035 or 0.038 in. guidewire for both efficiency and safety (advancing catheters over a wire reduces the risk of arterial injury).
5.2.2
Goal
To advance a 0.035 or 0.038 in. guidewire to the aortic root, which will serve as rail for advancing a catheter to the coronary ostia.
5.2.3
How?
- 1.
A 0.035 or 0.038 in. J-tip guidewire is typically used for advancing the diagnostic or guide catheter.
FEMORAL access: The guidewire can be inserted to the target vessel through the access needle (or microcatheter if a micropuncture kit is used) and be used to both insert the arterial sheath and allow catheter delivery to the coronary ostia. When cases are performed by a single operator short J-tip guidewires are preferable for sheath insertion.
RADIAL access: A guidewire with a narrow J-tip is often used, such as the Baby-J wire (Terumo).
- 2.
The guidewire is advanced together with the catheter (the guidewire tip should always stay ahead of the tip of the catheter) under fluoroscopic guidance to the aortic cusps and fixed, usually by the assistant, allowing advancement of the catheter over it.
5.2.4
Challenges
5.2.4.1
Resistance or failure to advance guidewire ( Fig. 5.1 )
Step 1 . Withdraw the catheter and transduce the side arm of the access sheath. Lack of arterial waveform may mean subintimal sheath position (femoral or radial access) or severe spasm (radial access). In case of subintimal sheath position, it is best to change access site. Retrograde dissections are usually well tolerated (as the blood flow tends to seal the dissection), as long as the dissection length is short and side branches are not affected. Large femoral or iliac dissections may require endovascular repair after obtaining contralateral femoral access ( section 29.1.1 ).
Step 2 . Advance a catheter (usually JR4 or multipurpose) over the guidewire close to the resistance point, confirm the presence of arterial waveform, and then perform angiography. Angiography may reveal: (1) occlusion of the vessel, such as iliac artery or subclavian artery; (2) severe lesion; (3) severe tortuosity; (4) side branch that is selectively entered by the guidewire; or (5) aneurysm.
Step 3 . For tight lesions, tortuous vessels, or when entering a side branch or crossing an aneurysm, repeat wiring attempts can be performed using various 0.035–0.038 in. guidewires (polymer jacketed or with very soft tip) or 0.014 in. guidewires through a catheter advanced close to the segment of the vessel that is difficult to navigate through. A polymer-jacketed wire should never be inserted through a needle, as the polymer coating may be sheared off when retracting the wire. Occasionally a 0.014 in. guidewire may be needed to cross the diseased segment.
Step 4 . Changing access site may provide a solution if crossing attempts fail.
5.2.4.2
Causes of failure to advance guidewire to the aortic root
5.2.4.2.1
Subintimal guidewire position
Prevention:
- •
Do not force the guidewire, if resistance is felt with advancement through the access needle or during any stage of advancement.
Solutions:
- •
Withdraw the guidewire and attempt to advance through a different course.
- •
Change access site.
5.2.4.2.2
Occlusion between the access site and the aortic root
Prevention:
- •
Preexisting vessel occlusion cannot be prevented, but can be suspected if the pulse in the affected limb is weaker than the pulse in the contralateral limb.
- •
Forceful guidewire advancement should be avoided to prevent iatrogenic vessel dissection or perforation.
Solution:
- •
Change access site.
5.2.4.2.3
Tortuosity (iliac artery, aorta, radial, brachial, subclavian artery)
- •
Sometimes tortuosity is evident by observing the course of the guidewire or visualizing vessel calcification ( Figs. 5.2–5.5 ).
Figure 5.2
Severe iliac tortuosity (panel A) resulting in guide catheter kinking ( arrows , panel B) during attempts to engage the coronary arteries.
Figure 5.3
Example of a radial loop. (Panel A) Radial loop. (Panel B) Successful crossing with a 0.035 in. Glidewire.
Courtesy of Dr. Ioannis Paizis.
Figure 5.4
Example of a brachial loop.
Courtesy of Dr. Ioannis Paizis.
Figure 5.5
Subclavian tortuosity.
Courtesy of Dr. Ioannis Paizis.
Prevention:
- •
Tortuosity cannot be prevented, but can be suspected if prior angiograms or computed tomograms are available.
Solutions:
- •
Use different guidewires, such as the Glidewire (Terumo), Glidewire Advantage (Terumo), Bentson (Cook Medical), and Wholey (Medtronic) for femoral access and the Glidewire or “Baby-J wire” (Terumo) for radial access ( Section 30.7.8) . A 0.014 in. guidewire may be used in radial access cases to navigate through arterial loops.
- •
Advance the tip of catheter close to the tip of the guidewire to improve support.
- •
Once crossing is achieved using femoral access, consider inserting a long sheath to prevent recurrent challenges with crossing. In patients with radial access, a 300 cm long 0.035 or 0.038 in. guidewire should be used for all catheter exchanges, keeping the guidewire tip in the aortic root. Moreover, using a long (such as 45 cm) sheath that is at least 1 French larger than the catheter can significantly facilitate catheter manipulation.
5.2.4.2.4
Guidewire enters side branch
This may occur with either femoral or radial access.
Prevention:
- •
Use of J-tipped guidewires minimizes the likelihood of side branch entry.
Solutions:
- •
Perform angiography to detect the presence of side branches and determine the vessel course.
- •
J-shaped wires are less likely to enter side branches. Straight tip wires should not be used for advancing catheters. Use fluoroscopy to detect the wire position and never push a guidewire when you feel resistance .
- •
Use different guidewires, such as the Glidewire (Terumo), Glidewire Advantage (Terumo), Bentson (Cook Medical), and Wholey wire (Medtronic) for femoral access and the Glidewire or “Baby-J wire” (Terumo) for radial access ( Section 30.7.8 ).
- •
Once crossing is achieved using femoral access, consider inserting a long sheath to prevent recurrent challenges with crossing. In patients with radial access, a 300 cm 0.035 or 0.038 in. guidewire should be used for all catheter exchanges.
5.2.4.2.5
Guidewire enters aneurysm ( Fig. 5.6 )
Prevention:
- •
Aneurysms cannot be prevented—awareness of the presence of an aneurysm before cardiac catheterization may facilitate procedural planning (e.g., use radial access in patients with abdominal aortic aneurysms).
Solutions:
- •
Perform angiography to detect the size and exit point of the aneurysm.
- •
Use different guidewires, such as the Glidewire, Glidewire Advantage, Wholey, and Bentson for femoral access and the Glidewire or “Baby-J wire” (Terumo) ( Section 30.7.8) for radial access
- •
Once crossing of the aneurysm is achieved using femoral access, consider inserting a long sheath to prevent recurrent challenges with crossing. In patients with radial access, a 300 cm long 0.035 or 0.038 in. guidewire should be used for all catheter exchanges.
5.2.5
What can go wrong?
5.2.5.1
Peripheral artery dissection (see also Section 29.1.1 )
Attempts to advance a guidewire (and/or the catheter) may cause injury (dissection, perforation) of the peripheral arteries that need to be traversed to reach the coronary arteries.
Causes of dissection:
- •
Subintimal guidewire advancement.
- •
Forceful sheath or catheter advancement.
- •
Advancement of a catheter without a leading guidewire.
Prevention:
- •
NEVER use force when advancing guidewires and catheters through the peripheral vasculature.
- •
Use long sheaths in patients with severe iliac tortuosity.
- •
Perform femoral angiography with a guidewire in place to keep the sheath tip away from the arterial wall.
Diagnosis:
- •
Perform angiography in cases of challenging catheter advancement. Angiography should only be performed if there is no arterial pressure dampening.
Treatment:
- •
Most often no specific treatment is required. These are retrograde dissections that are usually sealed off by antegrade blood flow. Large dissections may require endovascular repair, usually with stenting.
- •
Switch to different access site.
5.2.5.2
Peripheral artery perforation (see also Section 29.1.2 ) ( Fig. 5.7 )
Causes:
- •
Forceful guidewire or catheter advancement into a side branch, such as the renal artery.
- •
Small caliber artery (such as small caliber radial artery).
- •
Inadvertent advancement of the sheath past the tip of the guidewire.
Prevention:
- •
Use fluoroscopy while advancing guidewires and guide catheters. Redirect the guidewire if it enters into a side branch.
- •
Avoid forceful guidewire or catheter advancement.
Diagnosis:
- •
Perform angiography when the guidewire or catheter follows an unexpected course or when resistance if felt during advancement.
Treatment:
- •
Balloon occlusion (in case of large artery perforation), such as the iliac artery or the aorta. In cases of iliac artery perforation, obtaining a second access (either femoral or radial) rapidly for balloon occlusion followed by covered stent may prevent or limit the size of a retroperitoneal hematoma.
- •
Placement of a covered stent to cover the perforation, such as the iCAST (balloon expandable, Atrium Medical) stents that require 6 or 7 French sheaths for delivery, or the Viabahn (self-expanding) or Viabahn VBX (balloon expandable) stents (W.L. Gore) that require a 7 French sheath for delivery ( Fig. 29.6 ). The smallest diameter of both the iCAST and the Viabahn stents is 5 mm.
- •
Coil (or fat or thrombus) embolization for small branch perforations, such as perforation of the inferior epigastric artery ( Section 30.18.2 ).
- •
For radial artery, advancement of a catheter over the perforated segment usually suffices to achieve hemostasis.
5.3
Step 3. Advance catheter to aortic root
5.3.1
Goal
To advance the catheter to the aortic root, next to the coronary ostia.
5.3.2
How to?
5.3.2.1
Catheter preparation
- •
Diagnostic catheters are flushed and loaded over a 0.035 or 0.038 in. guidewire before insertion through the sheath.
- •
Guide catheters are also advanced over the 0.035 or 0.038 in. guidewire. It is best to connect them to the Y-connector outside the body and flush them prior to insertion through the sheath. Using a hemostatic valve before guide insertion prevents bleeding during guide catheter insertion. Bleeding can be severe through guide catheters, especially large guide catheters (7 Fr and even more 8 Fr). Moreover, especially when using large guide catheters it is important to allow back bleeding, as aortic debris can easily be scraped into the guide catheter during advancement. If the guide is not properly cleared, injection of the debris into a coronary artery or the aorta can be catastrophic ( Section 5.4 ).
5.3.2.2
Catheter advancement
- •
The catheter is advanced under fluoroscopic guidance to the aortic root, while the 0.035 or 0.038 in. guidewire is fixed. If resistance if felt, do NOT force the guide catheter, as this may cause complications.
5.3.3
Resistance to catheter advancement
Causes:
5.3.3.1
Subintimal guidewire position
Prevention:
- •
Do not force the guide catheter, if resistance is felt during advancement through the sheath or during any other stage of advancement. In such cases, significant resistance to guidewire advancement may also have been felt earlier.
Solutions:
- •
Remove the guide and guidewire.
- •
Change access site and check flow in the affected artery via contralateral injection.
5.3.3.2
Severe stenosis
Prevention:
- •
Preexisting stenosis cannot be prevented!
Solutions:
- •
Use a different catheter with less tip angulation.
- •
Advance a long sheath (usually 45 or 55 cm long) through the stenosis, followed by catheter advancement.
- •
Dilate the stenosis. Occasionally angioplasty of iliac artery stenoses may be required in case of severe iliac lesions. Stents should generally be avoided prior to completion of the PCI, as they can be dislodged during guide catheter advancement ( Fig. 5.8 ). If iliac stents are placed (or if there are preexisting iliac stents), it is preferable to advance a long sheath through them to minimize the risk of stent deformation or dislodgement.
Figure 5.8
Peripheral stent dislodgement after guide catheter advancement through the stent ( CTO PCI Manual Online case 104 ). A peripheral self-expanding stent ( arrows , panel A) was caught at the tip of a guide catheter and dislodged into the thoracic aorta. The dislodged peripheral stent ( arrows , panel B) embolized in the abdominal aorta. The dislodged peripheral stent was snared and withdrawn into the right iliac artery and a balloon expandable stent ( arrows , panel C) was inserted ( arrows , panel C) and deployed (panel D), covering the dislodged self-expanding stent (panel E).
- •
For radial access, using a low profile sheath (such as Glidesheath Slender [Terumo] or Prelude Ideal [Merit Medical]) or a sheathless guide catheter may gently dilate the stenosis without injuring the vessel.
5.3.3.3
Tortuosity
Sometimes tortuosity is evident given the course of the guidewire or visualization of vessel calcification.
Prevention:
- •
Tortuosity cannot be prevented.
Solutions:
- •
Use different guide catheter with less distal angulation.
- •
Advance a long sheath through the area of tortuosity. Kink-resistant (such as Arrow) sheaths can facilitate catheter advancement and manipulation.
- •
Parallel sheath technique for femoral access (perform second puncture of the same femoral artery and insert a 4 French sheath, through which a stiff 0.035 in. guidewire is advanced to straighten the iliac tortuosity) .
- •
Balloon-assisted tracking (particularly for radial loops) ( Fig. 5.9 ) .
Figure 5.9
Illustration of the balloon-assisted tracking technique. A small compliant balloon (sized 1:1 with the guide catheter) is inflated halfway in and halfway out the tip of the guide catheter at low pressure (3–6 atm—the lower the pressure the more flexible the assembly will be, whereas a higher pressure increases pushability). The inflated balloon prevents the catheter from “digging” into the vessel wall (razor effect, panel A).
- •
Change access site.
5.3.3.4
Spasm
This is specific to radial access ( Fig. 5.10 ).
Causes:
- •
Small radial artery size.
- •
High origin radial artery ( Fig. 5.11 ).
Figure 5.11
Spasm in a high origin radial artery.
Courtesy of Dr. Ioannis Paizis.
- •
Radial artery tortuosity.
- •
Multiple needle passes to obtain access.
- •
Extensive catheter manipulations.
- •
Multiple catheter exchanges.
- •
Spasm is more common in women and smokers.
- •
Inadequate sedation.
Prevention:
- •
Avoid using small radial arteries: use the ulnar or femoral artery instead. This emphasizes the importance of ultrasound guidance while obtaining radial (and femoral) access.
- •
Vasodilator administration (such as verapamil 2.5 mg and/or nitroglycerin 100–200 mcg) after sheath insertion.
- •
Avoid use of large catheters, especially through small radial arteries.
- •
Adequate conscious sedation prior to obtaining access.
Solutions:
- •
Administer intra-arterial vasodilators.
- •
Subcutaneous nitroglycerin injection.
- •
More sedation.
- •
Use smaller guide catheters (such as 5 French).
- •
Use Heartrail (Terumo) guide catheters (they have a dimpled surface that decreases friction and facilitates advancement).
- •
Use a sheathless guide catheter (such as the Eaucath, Asahi) or the Railway system (Cordis) (or other dilator) with standard guide catheters.
- •
Use of hydrophilic sheaths and catheters.
- •
Use of low profile sheaths for radial access.
5.3.3.5
What to do if there is resistance advancing a catheter to the aortic root ( Fig. 5.12 )?
Step 1 . Transduce the pressure from the catheter tip. In radial access cases, severe spasm can limit catheter advancement and can be treated with vasodilator administration. For femoral cases, lack of arterial pressure waveform may suggest subintimal sheath position, and it may be best to change access site.
